Great Britain's 23X Class Rigid Airships: R-27 - R-30
	Researched and written by Kent O'Grady, with research assistance by Brian Turpin

©2004, 2016
He Walks with Bears Press
Saskatoon, Saskatchewan, Canada.
All Rights Reserved. No part of this article may be reproduced in any form without permission from the author.

In Memory of Private Austin William Hicks, killed at Howden Airship Station on August 16th, 1918, attempting to escape from his post during which a fire destroyed several airships.

Acknowledgements

Thanks are graciously extended to Brian Turpin who provided valuable feedback after the first release of this paper in 2004. Mr. Turpin was able to access significant primary sources during his own research that were unavailable to the author. These have improved our understanding of this almost forgotten but important component of aeronautical history. Thanks are also extended to Den and Jeanne Burchmore, Airship Heritage Trust; Marc de Piolenc, Association of Balloon and Airship Constructors; Richard and Debbie Van Treuren, Atlantis Productions; Robert MacQuarrie, Air Canada; and Terry O'Grady, my father, for assistance in the preparation of this paper.

Introduction

The 23X class of rigid airships designed and built during World War One are a subject of which little is known about, relative to other British airships. This is due to a paucity of documentation, which has been lost, destroyed, or possibly never created in the first place. Other documentation has remained buried in virtually inaccessible archives for decades. HMA R-27 through R-30 remain among the least discussed airships by aeronautical researchers of this era. The purpose of this document is to present a coalescence of as much data as possible about this class of airship. Specifications, design, strengths, weaknesses and history will be analyzed. Interesting new information will be presented and conclusions about the contribution of the 23X type of rigid airship towards Britain's war effort will then be drawn.

The State of Pre-WWI Rigid Airship Development in Great Britain (The Mayfly Experience)

HMA No. 1 (Mayfly) undergoing mooring tests at Barrow-in-Furness. This was the first time an airship was made fast to a mooring mast. She successfully withstood winds of up to 72 km/h (45 mph). Note the external keel running between the two cars.

HMA No. 1 (Mayfly) seconds before being struck by the gust, which precipitated her break up. Note the absence of the external keel between the two cars. The airship has almost entirely cleared the hangar entrance. Photo courtesy Ted Hill.

Wreckage of HMA No. 1 (Mayfly). A portion of the forward section was brought back into the hangar, with the nose relatively intact. The mid and rear sections were completely wrecked. Images such as these leave the impression the airship impacted the hangar entrance, but such was not the case. Photo courtesy Ted Hill.

Before the outbreak of hostilities, Britain followed the development of Zeppelins with consternation. Germany endeavoured to maintain secrecy regarding details of construction. By 1909 it was evident this method of transport was capable of flying from Germany, striking targets in the United Kingdom, and returning to base. Accordingly, the British embarked upon a rigid airship program of their own. They combined what little information could be gathered from intelligence sources with the engineering expertise of their own Navy; notably that acquired through submarine development.

The result of British initiative was Vickers' HMA No. 1 constructed at Cavendish Dock, Barrow-in-Furness, Cumbria. It was infamously dubbed Mayfly by the press but in reality incorporated concepts that met or exceeded German aeronautical ingenuity. These included the first duralumin framework, water ballast recovery apparatus, and simplified cruciform stabilizers (although multiple control surfaces were retained). A more aerodynamic shape was chosen over the blunt Zeppelins. Although considered progressive at the time, the "Zahm" shape would not have delivered on the promise of only 40 percent of the aerodynamic drag of contemporary Zeppelins. Nevertheless, it was arguably a step in the right direction towards streamlined rigid airships.In spite of these advances, payload calculations proved distressing. Gross lift was estimated to be 19.665 long tons (44,048 lbs/19,980 kg), with the weight being 19.589 tons (43,876 lbs/19,902 kg), not including fuel or crew.

The disposable lift of 0.076 tons (77.22 kg/170.24 lbs) was shockingly insignificant and drastic alterations were necessary if the airship was to be of any use. In spite of this poor static condition it was decided to proceed with ground handling tests. Mayfly was removed from her hangar on May 22nd, 1911 and brought to a mooring mast situated in the bay. This was the first time a rigid airship was ever made fast to a mast. She stayed there for three days riding out gales of up to 72 km/h (45 mph), proving the reliability of the mooring mast concept. Engine tests were conducted, and a considerable amount of handling experience and data was collected during these trials. However, Mayfly was incapable of static flight once fuelled and crewed, due to being overweight. In a desperate move to lighten the ship, designers eliminated the external keel and non-essential equipment after returning her to the hangar.Modifications continued until late summer. These provided the airship with a disposable lift of 3.21 tons (3,261 kg/7,190 lbs), adequate to permit flight trials and training. On September 24th HMA No. 1 was removed from the hangar tail first in preparation for flight. Just as the ship finished clearing the shed doors she was hit by a strong gust. This resulted in Mayfly rolling almost on her beam-ends (the nautical equivalent would be a ship capsizing). Shortly after righting herself, the hull framework tore apart forward of the rear car. The hull rose at the break point, tearing the envelope and briefly giving Mayfly an inverted "V" shape appearance.

The aft section rose further into the air before settling again by its forward breakpoint, whereupon the crew dove into the water to escape. The rear car submerged in the water and the tail pointed upwards until reaching a 25 degree angle. The forward section also assumed this angle with its rear also in the air. The two pieces floated a considerable distance over the water in this state. It was some feat for the personnel to secure each section using boats in the bay and return them to the hangar entrance. Unfortunately the jackstay on top of the airship remained secure tearing out several girders and causing much damage. Attempts to get the two pieces back into the hangar intact were not successful. HMA No. 1 was wrecked and became the subject of negative publicity about being a waste of taxpayer money. Fortunately there were no fatalities.

First Lord of the Admiralty Winston Churchill censored publication of the Report of the Court of Inquiry into the accident. All known copies are believed to have been destroyed so precise findings cannot be specified. It was not disputed that a gust struck the ship and that she rolled heavily as a result. Many felt this event was sufficient to cause hull breakage. Notable in this camp was H. B. Pratt, at the time a young draughtsman at Barrow not immediately attached to the HMA No. 1 team. Before the accident he calculated Mayfly would experience a critical hull failure at the first strong gust, but was ignored. Some claimed the mechanized handling gear was to blame, restraining an increasingly stressed hull to thebreak point. Still others suggested the ground crew may have mismanaged the electric winch system. A combination of these factors is also possible. Ultimately, official blame for the accident was attributed to the decision to remove the external keel to increase disposable lift which compromised hull strength. The crew and ground handling personnel were not apportioned any blame. This finding resulted in a strong conservative trend in the design of the next generation of British rigid airships.

For some time after the Mayfly accident there was little interest in rigid airships in Britain. Attempts to endorse their use were heckled in parliament and military circles. Whitehall generally concurred with Rear Admiral Sturdee who, upon viewing the wreck of HMA No. 1, exclaimed "The work of an idiot!" Although Britain continued development of non-rigid airships, she began to lag further behind France and Germany in aeronautical matters. However, commercial success with rigid airships in Germany could not be ignored given their increasing range and payload. A pivotal event occurred when the German Army ZIV (Zeppelin Company designation LZ-16) flew off course in a snowstorm in April of 1913. The crew landed to get their bearings and were embarrassed to find they had alighted at Lunéville, France. Surprised French military officials warmly greeted the Germans and took the opportunity to acquire detailed drawings and conduct an internal inspection of the airship before letting the Germans take off again. All data was in turn made available to Britain.

Rigid Airships Reinstated Amid Indecision: HMA No. 9

The British commenced a new rigid airship program, with HMA No. 9 being placed upon the drawing board. This design relied heavily upon the ZIV data acquired by the French. Vickers built a hangar on Walney Island near Barrow and commenced construction of the airship there. Churchill then suddenly ordered the contract cancelled in March of 1915. Although favourable to small non-rigid airships for naval purposes, he was an ardent adversary of the rigid airship.

The outbreak of war resulted in much indecision within political and naval circles regarding airships. Some favoured the expansion of counter-measures to deal with attacking Zeppelins only, such as aeroplanes, searchlights and anti-aircraft batteries. They saw no benefit to developing a British equivalent to the Zeppelin. Churchill argued that by the time Britain built a rigid airship of its own the war would be over. Those who advocated rigid airships never seriously entertained the notion of utilizing them to bombard German cities, even if some desired such revenge. Enlightened naval authorities saw the rigid airship as offering an effective means of extended aerial scouting over the North Sea for the Grand Fleet, especially in the hunt for U-boats. As the war progressed it became apparent the German Navy was quietly and actively using their Zeppelins for reconnaissance purposes with the High Seas Fleet. It was with the naval scouting role in mind that the British rigid airship project was resurrected for the third time in June of 1915 by A. J. Balfour, successor to Winston Churchill as First Lord of the Admiralty.

Vickers again started work upon HMA No. 9 but progress was slow. Original design and construction teams had disbanded and it took time to reassemble them. A feeling prevailed that the new airship was not a priority for the government or Navy, and work upon her would probably be cancelled again. Conservative naval authorities still complained precious funds were being wasted on aeronautics. Challenges arose in construction and delays resulted from Admiralty requests for the addition of different equipment and armament. Compounding these delays was bureaucratic red tape and the proverbial left hand not knowing what the right was doing. Airship management was partitioned between directors in charge of air services (envelope and gas cells), naval construction (whose staff were responsible for the framework but had little knowledge of aeronautics), and a director of engineering. Decisions could be made in one area without full comprehension of the impact upon others. For example, naval construction authorized components that were too heavy, yet the director of air services was not empowered to reverse the decision. Such artificial bureaucratic structures contributed substantially to undermining the performance of the first generation of British rigid airships.

When finally completed late in 1916 (over three years after work commenced) No. 9 proved to be overweight with a useful lift of only 2.1 tons (2,133 kg/4,704 lbs). This failed to meet even the revised contract of 3.1 tons (the initial call was for more than 5 tons of useful lift). By comparison, the German ZIV launched more than three years earlier had a useful lift of 8.35 tons (7,575 kg/16,700 lbs). The first flight was conducted under Captain E. Masterman on November 27th, 1916. This was a few weeks after the German "cousin" ZIV had been decommissioned as obsolete after three and a half years of service in the Army. The British Navy did not accept No. 9 and it was necessary to conduct an overhaul in order to increase the useful lift.

Elimination of the external keel was not considered. Instead, weight saving measures included replacing two of the four 180 h.p. Wolseley engines with one 240 h.p. Maybach engine. This was retrieved intact from the downed Zeppelin L-33 (Zeppelin Company designation LZ-76) along with transmission gear and propellers. Also, the three ply gas cells were replaced with newer, two ply cells. The Royal Naval Air Service (RNAS) accepted the lightened No. 9 on April 4, 1917 after this overhaul. Her new useful lift of 3.8 tons (3,861 kg/8,512 lbs) and speed of 68 km/h (42.5 mph), whilst now meeting revised contract stipulations, remained disappointing. Meanwhile, the contemporary German L-30 class Zeppelin (of which L-33 was an example) had a disposable lift of 31.89 tons (32,400 kg/71,429 lbs) and a speed of 103 km/h (64 mph). Awareness of such improved performance led to revision in the British rigid airship programme with determination to create more capable airships.

In fairness to Vickers, it should be pointed out the contract called for them to build a "rugged" airship. It was mainly intended for training, so No. 9 had to be able to withstand getting bashed about on the airfield by inexperienced handlers. As such, she was bound to be heavy. As well, she was the first rigid to fly equipped with swivelling propellers and concurrent heavy, complex machinery. What in modern parlance is termed "vectored thrust" was considered worth the weight penalty in 1916.

Britain's rigid airship crews obtained their first flying experience with No. 9. She was placed under the command of Squadron Commander W. C. Hicks and then Flight-Lieutenant George H. Scott and stationed at Howden. Several flights were conducted from here including one of 10 hours on June 20th and 12 hours 42 minutes on June 26th, 1917. Her longest single flight was also her only active naval reconnaissance which lasted 26 hours and 45 minutes commencing at 22:25 on July 20th and ending at 01:07 on the 22nd. On August 6th fog conditions prevented a landing at Howden, so No. 9 flew up to East Fortune, Scotland landing after 24 hours and 45 minutes. She remained there until August 12th before returning to Howden. On October 15th she was sent from Howden to Cranwell in order to help temporarily create hangar space for HMA No. 23 and No. 25. She conducted a number of shorter flights from Cranwell but on October 29th inclement weather necessitated a landing back at Howden (No. 23 had previously left for Pulham). Damage was incurred entering the hangar and repairs took two months, being completed in late December of 1917.

No. 9 was officially transferred to Pulham on February 20th, 1918 where various experiments were conducted along with continuing flight crew instruction under Scott's command. Mooring tests were performed utilizing a drogue over The Wash. Four flights occurred in March, the one on the 24th being of 8 hours and 55 minutes duration, which was to be her last. Structural damage was discerned upon landing, whereupon the airship was slung from the shed roof for repairs. Work was not completed until May due to delays in receipt of parts and material from Vickers. Despite being airworthy, No. 9 was not returned to flight status. She was instead devoted to mooring trials. The forward swivelling propeller arms and engines were removed from the forward car whilst the bow was reinforced. A large army tank was outfitted with a mast and in one experiment No. 9 was fastened to it, but a strong gust of wind resulted in the tank being lifted into the air. Commencing on June 5th, trials were undertaken utilizing the "three-wire" mooring system. The ship was returned to the hangar each evening but on June 8th was left moored out overnight. Winds increased to 50 km/h (30 mph) the next day but no difficulties were experienced until 12.10 pm when a transverse frame forward of the keel section failed. No. 9 was returned to the hangar where the decision was made to dismantle her. Official deletion occurred on June 28th after only 198 hours and 16 minutes of flight time. 33 additional hours were devoted to mooring trials.

The 23 Class

Authorization for the construction of additional rigid airships was granted before No. 9 was completed. The 23 Class (originally to consist of ten airships: No. 23 to 25, and R-26 to R-32 inclusive) would show improvement over No. 9 by providing an increase of between 57 and 65% in useful lift. Yet this was still insufficient to carry enough fuel for prolonged reconnaissance. These airships would thus also be relegated to experimental and training ships. R-27 through R-32 were removed from this classification once it was discerned the design could not provide the desired performance and those numbers allotted to improved designs. No. 23 to R-26 design retention was authorized because training airships were still required and work was already too advanced on these particular airships to make scrapping them viable.

No. 23 was built by Vickers at Barrow and launched on September 19th, 1917, one year behind schedule. No. 24 was contracted to Beardmore at Inchinnan, Renfrewshire and did not fly until October 27th. The order for No. 25 was placed with Armstrong-Whitworth at Selby, Yorkshire, and this airship made her first appearance on October 14th. Finally, R-26 was not contracted out to Vickers until January of 1916; she first took to the air on April 20th, 1918. This class of airship was slightly larger than No. 9 with a volume of 26,618 m3 (940,000 cu. ft.) and a length of 163 m (535 ft). The diameter remained at 16.15 m (53 ft). Four Rolls-Royce engines of 250 h.p. each provided 280 h.p. more than No. 9, resulting in an increased speed of 87.7 km/h (54.5 mph) versus 68.4 km/h (42.5 mph) for No. 9. Incremental improvement in streamlining also contributed to the higher speed; for example elevators and rudders were simplified single as opposed to multiple surfaces. Useful lift varied slightly with each airship: No. 23 - 5.98 tons (6,078 kg/13,400 lbs), No. 24 - 6.16 tons (6,260 kg/13,800 lbs), No. 25 - 5.8 tons (5,897 kg/13,000 lbs), and R-26 provided the best useful lift thus far at 6.27 tons (6,373 kg/14,050 lbs).None of these airships met with significant mishaps and collectively helped to train more airship crews. Noteworthy experiments were undertaken by No. 23 under the command of Major Ivor C. Little. These included the successful unmanned drop of a 2F.1 Sopwith Camel (N6814) aeroplane from 183 metres (600 ft) on November 3rd, 1918. (Trials conducted on October 2nd did not involve releasing the Camel, the purpose of the flight being to observe any in-flight anomalies with a parasitic aircraft). On November 6th Lieutenant R. E. Keys piloted the released Camel to a successful landing at Pulham.

Extensive mooring tests were conducted at Pulham where No. 24 successfully utilized the British high-mast system conceived by Major George Herbert Scott, which reduced the size of ground crews from hundreds of men to about one dozen. R-26 was also utilized in mooring trials. During her career she flew over the Lord Mayor's Show in London as a patriotic attraction. A few naval reconnaissance flights were undertaken including one sortie of 40 hours and 40 minutes duration under the command of Major T. Elmsley. No enemy activity was observed. R-26 provided aerial observation on November 20th, 1918, escorting surrendered German U-boats to Harwich under the command of Major W. H. Watt. SR-1 and SSE 2 also participated. In 1919 she was intentionally left out in the open during inclement weather on a less-advanced 3-wire moor to monitor her behaviour. It likely didn´t come as any surprise that she eventually incurred so much structural damage from rolling repeatedly into the ground that she had to be scrapped.

No. 25 was considered unsuccessful owing to pronounced surging of her gas cells, which rendered the airship statically unstable as the centre of gravity shifted. She was likely less popular with crewmembers. In spite of this, more flight time was accrued on her than No. 24, which acquired 192 hours 53 minutes of flight time. No. 23 recorded 321 hours 30 minutes of flight, No. 25 logged 225 hours 5 minutes, and R-26 attained 238 hours 27 minutes of total air time.

All 23 class airships were functional, but far outperformed by contemporary German airships and even by British non-rigids. If performance statistics along these lines were the sole criteria by which ordering further rigid airships was to be based, no more would have been built. But with the Battle of Jutland and the erroneous Allied perception that Zeppelins had saved the High Seas Fleet, there was a sudden surge in calls for reconnaissance airships from the Grand Fleet. Increasing British awareness of German technical progress with airships also helped badger a reluctant Britain forwards.

The 23X Class: Meaningful Useful Lift

Since the 23 class lacked the desired payload, insufficient fuel could be carried to provide extended aerial coverage for the fleet. As with HMA No. 1, the elimination of the external keel was seen as key to providing considerable weight savings. But there was no intent to physically modify any of the existing 23 class ships then nearing completion since this would result in a critical loss of strength and repetition of the break up that befell Mayfly. Rather, the R-27 through R-32 (construction upon which had yet to commence) would undergo fundamental changes in their design to safely eliminate the keel. In light of the Mayfly experience, this was still a controversial move despite engineering allowances.

The primary reason for the presence of the external keel in earlier ships was to take shear stresses and bending moments. A debate between naval contractors and air officers over keel elimination ensued. Airship crewmembers favoured retention of the external keel for safety. Chief designer Commander C.I.R. Campbell and naval contractors argued for change and their arguments prevailed. Information obtained from the wreckage of the German Army LZ-85 (Zeppelin Company number LZ-55) shot down at Salonika, and from L13 (Zeppelin Company number LZ-45) survivors, validated British designer's arguments that external keels were not a necessity. What was not immediately apparent was that the Germans were employing internal keels, but even after this was ascertained the British confidently forged ahead with their unique plan. R-27 to R-32 would be built without any keel, internal or external, resulting in the first meaningful gain in useful lift. (Note the presence of an internal crew gangway is not to be confused with a load-bearing keel which invariably incorporates a crew access gangway). These six airships were now designated part of the 23X class. Later, R-31 and R-32 would be removed from the 23X class and reclassified to provide the Short Brothers firm with the opportunity to develop wooden framed rigid airships.

It has been claimed the "X" in 23X signified experimental. Brian Turpin´s research reveals the designation was arbitrary:

The 'X' did not stand for experimental; it was just one of a series of designs being considered, many of them very advanced with such ideas as carrying the engines inside the hull surrounded by inert gas. These various designs were slowly eliminated until Commander Campbell's 'X' design was selected. This was probably the most conservative of the proposals, the Admiralty playing safe as usual; but nevertheless it was the first keel-less rigid airship to be built, designed as such from the beginning, which was itself something of an innovation.

Design proposals for the 23X class were first authorized in June, 1916 with completion anticipated by mid-1917. Design selection proved time consuming in part due to bureaucracy and as well as having to overcome the conservatism favouring not just retention of a keel, but also a heavy external keel. The Rigid Airship Committee did not actually choose Campbell's proposal until March 16th, 1917 putting the project far behind schedule.

23X Class Construction and Layout

The 23X class airships were 164.28 m (539 ft) in length with a diameter of 16.2 m (53 ft). These airships had the classic pencil shape of earlier rigid airships, with a fineness ratio of 10.14. The volume of 28,050 m3 (990,600 cu. ft.) was slightly greater than the volume of the 23 class. Useful lift was 7.5 tons (7,620 kg/16,800 lbs) for R-27 and 8.66 tons (8,800 kg/19,400 lbs) for R-29. This represented an improvement of up to 49 percent in useful lift over the 23 class.

The hull comprised 18 main transverse rings and 17 longitudinal frames, with one intermediate ring placed between each main transverse ring. The main transverse frames were spaced 9 metres (30 ft) apart. There were 18 hydrogen gas cells, each cell occupying the space between two main rings. Gas cells were fabricated from goldbeater's skin, the extremely light but highly gastight membrane extracted from cattle intestines. Each membrane measured only about 25 x 35 cm. (10 x 14 in). These membranes were cleansed by hand in a brine solution before being varnished to a cloth backing. The intestines of over 19,000 cattle were processed in order to produce one single gas cell in a 23X class airship, or over 350,000 for all 18 gas cells. Manoeuvring valves in R-27 were situated at the top of each gas cell, with automatic valves positioned at the bottom of cells; an identical arrangement to that found in the R-26. The valves of R-29, however, were situated along the side of the hull as with No. 23.

Strong girders were employed with the apex of the triangular section facing outwards in order to maintain hull strength in the absence of an external keel. Heavy weights such as fuel and ballast were also concentrated at main transverse rings to prevent longitudinal frame distortion. These weights could be suspended from radial wiring, and most accounts indicate this was the practice adopted for 23X class airships. However, construction photos of R-29 show dual "U" framed tank receptacles, positioned periodically at main transverse frames to the left and right of the gangway along its length. Their weight appears to have been borne by the transverse frame with no evidence of suspension. These tank holders were positioned with their length parallel to the walking way. The tanks had not yet been installed when these photos were taken, but the receptacles were almost certainly intended for petrol given that water ballast was typically stored in bags. All tanks and ballast bags were accessible from the main walkway. A long and wide aluminium tube ran below the petrol tanks, connecting all of them and thus permitting expeditious refuelling or jettisoning of fuel in an emergency. Additional petrol tanks were located in each car.

Inverted "U" shaped formers were placed over the crew access gangway which was built upon the lowest longitudinal girder over the centre of gravity. The gangway ran the length of most of the ship and permitted access between the cars, the tail gun point and the ladder access to the upper hull with its machine gun posts. The gas cells were shaped to permit the presence of this corridor at maximum pressure.

23X class airships were not outfitted with mooring mast spindles or bow mooring gear. They were launched and retrieved on the airship field by ground crew in the same manner as contemporary Germans handled their rigid airships, requiring hangar berthing after each flight. R-27 and R-29 are not believed to have ever utilized the three wire mooring system.

Cars

The cars were attached below the hull with crew access via ladders exposed to the slipstream, as was typical at that time. The method of car connection was changed from previous rigid designs, there being four primary angled struts joined near the lower part of the cars and thence to the hull. (In the 23 class the connecting points were on top of the car). Bumper bags were fixed to the bottom of the fore and aft gondolas, but not to the mid-ship car as it was positioned closer to the hull and would not come into contact with the ground. Handling rails for the ground crew were mounted to the fore and aft cars. Despite the absence of an external keel, the cars were not mounted as close to the hull as they could have been and a sizable airspace was retained. The logic appeared to be a desire to keep the engines and exhaust away from the outer covering and hydrogen cells within the hull but the closer positioning of the mid-ship car calls this notion into question. Car roofing materials were fire proofed. Another possibility could be that space allowed for a margin of safety for the hull framework during ground handling in gusty conditions, should car struts collapse with heavy impact. After the first trial flight, the car distance from the hull was deemed excessive and led to modifications to reduce some, but not eliminate, the distance of the forward and aft cars from the hull.

The control and navigation room in the forward car was outfitted with all standard equipment such as elevator and rudder wheels, engine telegraphs, swivel propeller telegraphs and speaking tubes. These tubes provided communication between the control room, crew access way, the forward gun post atop the hull, and the aft car. Instrumentation was illuminated. The mid-ship car accommodated two engines (except in the later version of R-29 when it was switched for a one-engine R-33 wing type car), and the rear car comprised a wireless compartment and auxiliary control station in the front and engine in the rear. Carrier pigeons were a standard part of the crew. They were probably kept in the wireless room on R-27 and R-29 in case of communication failure.

Hull Interior

The design of the newer airships denied their crew the spaciousness of the mid-ship cabin found in the keel of airships No. 23 through R-26. Although such a space could have been created within the hull of the 23X class, the nature of the internalized corridor meant a crew compartment of a similar size would impinge upon the size of the gas cell in that bay, reducing lift. The precise locations of crew rest areas in the 23X class is not known, but likely comprised little more than hammocks. The only known photo taken within the walkway of R-29 reveals the inverted U-shaped formers framing the walkway and precious little space for hammocks, which also would have been allocated at main rings for proper weight distribution. Modest space allowances existed at the main ring/catwalk intersections. One known popular retreat for the crew (weather permitting) was the upper hull, accessible via the climbing shaft to the forward machine gun post positioned at the top of the second main transverse ring. A hull-top walkway extended to the leading edge of the upper vertical stabilizer. It was a simple girder covered with duralumin sheeting, over which the outer-cover passed. However, a special fabric was employed at this point for the entire length (presumably to help prevent slipping). A lifeline made of hemp was provided to prevent crewmembers from being blown over the side. It was passed through eyelets attached to the main rings. Many crew prided themselves on being able to walk on top of the ship without resorting to the lifeline, even at higher speeds. Although a dangerous pastime, no fatalities occurred. The climbing shaft to the upper hull was comprised of aluminium rings and enclosed with kite balloon fabric.

Outer Cover

The composition of the outer cover of R-27 and R-29 is not precisely known. Many aspects of the 23X class were similar to the preceding 23 class. If this held true for the outer-covering, it would have comprised unbleached linen doped with Emaillite scheme "M" solution. This solution was at least partly composed of cellulose dope which served to keep the envelope taut, reduce air friction and reflect sunlight. The presence of aluminium dusting in this compound has not been documented, but seems probable given this process was pioneered with HMA No. 1.

A deficiency in the 23X class outer cover was the high absorption rate of rainwater. A steady shower could add a ton to the weight of the airship in less than one hour. It is not known if the 23 class experienced this deficiency. Improvements to the envelope were not undertaken for R-27 given its short lifespan. In the case of R-29 a new outer cover was provided during an overhaul, and late in her career incremental portions of the hull were given test doping, indicative of ongoing research geared towards improvement. Without further documentation, the precise composition of the 23X class outer coverings must remain tentative. Admiralty requirements dictated the envelope in the wake of the gun platform and engine cars had to be fire proofed. The cover was expected to be "as little inflammable as possible." Furthermore, the outer cover was to be "substantially impermeable to hydrogen" in front of the gun platform. This criterion was understandable but virtually impossible to deliver upon given that hydrogen, the lightest element, will ultimately penetrate even metals. However, the rapid dispersal rate of the gas in the airflow should have minimized concern. The requirement for proper ventilation between the gas cells and outer cover was specified and is known to have been accounted for, but again specifics are not available. The precise location and quantity of ventilation hoods has not been determined.

Wiring

Engineer E. H. Levitt conducted an analysis of the shear load wiring system in R-29 and found that it was inefficient. The wires were threaded loosely through the centre of a longitudinal girder and then fixed to the next joint. Thus the wire passed continuously over two panels of a different slope. Levitt opined this was not advantageous for the longitudinal members, increasing the bending stresses in them. The threaded wires tended to be loose but were adjustable to required tension by nuts. The solution to the problem would have been to attach shear load wires to the corners of each panel to avoid the different slopes. Since such remediation would require substantial time, cost and overhaul, the realistic alternatives were to re-tension the wires, redistribute weights, utilize stronger wire or employ a combination thereof. What remediation was invoked is unknown. The distribution of tension in the diagonal wires was substantial at the base due to the frame distorting transversely where loads were suspended. The diaphragm formed by transverse wires was not of adequate strength to stop frame distortion. Tests conducted on HMA No. 25 found her superior to R-29 in this regard. The Monthly Return of Items of Information for April 1918 reveals that diagonal and circumferential rewiring was complete for R-27, confirming deficiencies with wiring were detected during the construction of that airship. The possibility exists that the extent of the distortion for both airships was not quantified during operations, as many of these engineering experiments were not conducted until just prior to decommissioning the R-29 and R-27 had a too short of a life span for any detailed analysis. The frame distortion was either dealt with or found within safety parameters of the day. There is no evidence of girder failure during flight operations of the 23X class airships.

Radial wires between each gas cell ran from the main transverse rings to steel rings at the centre. The rings were encased in a two-ply fabric patch to prevent gas cell chafing. There was no axial girder. The presence of an axial wire has not been observed in any photos, diagrams or documentation.

Engines

The R-27 and R-29 were each equipped with four Rolls Royce Eagle V-12 Mark VI engines, which were forerunners of the Merlin. One was positioned in the forward car driving two swivelling propellers; two in the mid-ship car each driving their own fixed propeller; and one engine in the aft car driving two swivelling propellers. Various photos demonstrate the vector range was 180 degrees. Propeller diameter was 3.05 m (10 ft), each prop being a 4 bladed integral. Figures concerning the total horsepower vary depending upon the source. Aeronautic historians Geoffrey Chamberlain, Peter Brooks, and Patrick Abbott all state the engines generated 300 hp each, giving a total of 1,200 h.p. at full rpm's. M.J.B. Davy and Douglas Robinson indicate 250 h.p. was delivered by each engine, for a total of 1,000 h.p. It is known for certain that R-29 went through engine modifications later in her flying career. At the time the National Physical Laboratory (NPL) conducted tests with her, she was equipped with only three engines. These were of the same specifications noted above except that they produced 275 h.p. each for a total of 825 h.p. In this configuration one engine was placed in each car, and the original mid-ship car had been removed entirely and replaced with a new more streamlined R-33 wing-type car, to which was attached a single two-bladed Farringdon propeller of 4.11 m (13.5 ft) diameter.

Radiators on the forward and aft cars were square in shape and mounted on the starboard side. Circular shaped radiators were mounted on each side of the mid-ship car behind the propeller shafts. When the mid-ship car of R-29 was replaced with the newer, single engine car, only one radiator was affixed on top between the roof of the gondola and the hull of the airship. It retained a circular shape and occupied virtually the entire air space in between. All the radiators constituted considerable parasitic drag. The top speed of R-27 and R-29 is cited at 88.5 km/h (55 mph) or 91 km/h (56.5 mph) depending upon the source of information (compared with 87.7 km/h - 54.5 mph for the 23 class).

Armament

Armament arrangements were similar to that found in the 23 class. R-29 is thought to have had five Lewis guns. One was positioned in the control car and one in the rear car. Two would have been positioned on top of the hull: one at the forward gun platform, the other further aft near the upper fin leading edge. The fifth gun was placed in a very small post at the rear tip of the airship. The existence of a gun post here was initially doubted during research as no external platform or gun mount can be observed in any photos. However, an opening in the outer covering is visible here and is a bit larger than the average sized man. The existence of a firing position here is also strongly suggested in Monthly Returns of Items of Information: April 1918 where it states the "creeping way" to the rear gun post was 75% finished. This would have required some form of interior shielding to separate the position from the rear gas cell. The upper hull forward gun position is easy to note in several photos. It was probably equipped with a two-pounder gun. In the 23 class a steel ring was mounted for this, but in order to save weight it was only taken on certain flights for experiments. There is no documentation to verify if it was utilized consistently in the 23X class, but installation or removal would have been a relatively simple matter. Given the relative aggressive deployment of these airships relative to previous British rigid airships, it is probable all guns were mounted, armed and operational. R-30 was to have an interesting variation: a twelve-pounder semi-automatic cannon for use against U-boats. A special gondola for this purpose was to be situated 6 metres (20 ft) aft of the control car.

Experiments using No. 23 to carry manned aeroplanes aloft and releasing them in flight were conducted with the intent of providing British rigid airships with an additional defensive capability. 23X class airships had the lift capability to do this, but such a deployment never occurred. No documentation exists to indicate if the matter was considered for R-27 or R-29, but the weight of the aircraft would have added a considerable load to a main ring already bearing the weight of concentrated loads in the absence of a keel. In these circumstances it seems the 23X class rigid would not have been a wise choice for carrying parasitic aircraft. However, in-flight tests conducted upon R-29 demonstrated she was able to turn much more rapidly than her predecessors. Her turning radius coefficient was 9.8 versus 11.2 for R-26. This was considered to give R-29 a tactical advantage.

Details of bombing apparatus are a bit uncertain with regards to the 23X class. Given the ad hoc arrangements in the 23 class, there was likely some input offered for improvement. In the original design, the 23X Class was to have used bomb frames situated in a special room. Sighting apparatus and release gear were to be installed in the navigation room. This plan was abandoned to help increase disposable lift. Instead, bombs appear to have been attached under the walkway, possibly in the vicinity of transverse frames five and six. They were actuated by a Bowden wire release from the control car. The absence of an external keel in 23X class ships meant that any bomb carriers positioned at the bottom of the hull would be at least 7 metres (23 feet) above the hangar floor. Expeditiously moving eight 230-lb bombs into their carriers safely would thus be a challenge. A special type of tower ladder was designed, approved and ordered for this purpose. Presumably the bomb carrier attachment points were accessible to the crew from the interior catwalk, but details are not known.

R-27 Construction

HMA R-27 was built by Beardmore at Inchinnan, Scotland in 1917 and 1918. The Admiralty Authorization code was S.01667/15 and the Contract Number CP.03999/16 (which was inclusive to R-32). In October of 1917 the Monthly Items of Information reported "Work is still progressing very slowly on this ship." From this time forward a fairly complete record of construction progress exists. These reports make for rather dry reading as there is considerable repetition. What follows over the next two pages is a summation of those reports. In weighing out the relative value of the information it has been decided to include data that some may find extraneous. The objective of this paper in presenting as much data as possible about the R23X class notwithstanding, the benefit lies in revealing the multitude of areas in which construction issues arose.

By the end of the week of November 17th the hull framework was completed and all engines were installed in their cars. The outer cover was half completed, five gas cells were finished and the forecast for completion was by the end by December. The report ending December 8th stated in addition to the five gas cells completed, all others were "100% skin-lined", apparently a reference to the application of goldbeater's skin in the manufacturing process. Work on the outer cover was at a standstill, the obstacle being inadequate fabrication facilities. Provisions were made for better work areas but the projection for completion was delayed to January, 1918. At the end of the week of December 15th, the stabilizers were ready for attachment to the hull. Final coatings had been applied to 39% of the gas cells. All work on fabric was expected to be finished by January 11th and the airship completed by February, 1918.

For the week ending December 22nd, all control surfaces had been covered with fabric but still awaited attachment to their respective stabilizers which remained incomplete. All tanks were installed in the forward, midship and after cars. One set of transmission gear had been installed in the midship car and the engine for the rear car was fitted on bearers. Work on piping was nearing completion and streamlined aluminum sheeting was being riveted to the after car. Despite the closure of the Beardmore Works from December 22nd to January 3rd a report was still filed for the week ending December 29th. It added that the rudder and elevator coverings had been doped. Piping was 35% complete and water ballast valves had arrived. The second set of transmission gears was being fitted into the midship car. It was added that Beardmore's would remain closed until January 7th with no explanation provided. This may have been due to the Spanish influenza which was spreading rapidly at the time.

By January 12th all stabilizers had been attached to the hull and three-quarters covered with fabric. Piping was half finished but the installation of the second set of transmission gears into the midship car was still ongoing. For the week ending January 19th it was reported that the piping had progressed to 75% completion; likewise engine telegraphs were 75% ready. Gas cells were half assembled but the outer cover was no further past the half way mark, reflecting an absence of progress on it since November of the previous year. Little else appears to have been accomplished yet the completion date remained estimated as early February. The report for January 26th indicated the fins were fully covered but only 30% of their surface area was ready for doping. The piping was 80% finished but water ballast valves still awaited installation. The amidship car was completed and dispatched to Inchinnan. Engine telegraphs were now installed and gas cells 55% assembled.

February, the revised date of anticipated completion arrived but slow progress continued. The report of February 2nd stated the stabilizer covering was now 75% prepared for doping and the forward and midship cars were delivered to Inchinnan. It also indicated: "Engines replaced on starboard car. Propeller struts being fitted" but seemingly offers no details as to why replacement was necessary. Airship historian Brian Turpin explains: "In the weekly reports for R27, the phrase 'engines replaced' means the same as engines refitted. No doubt the engines were placed in the cars as they were completed, to make sure everything fitted correctly, and then removed for transportation." The after car was being prepared for dispatch to Inchinnan (being produced at a separate Beardmore shop). Gas cells were 66% assembled but still no progress was reported on the outer cover. The report conceded completion would be delayed until early March. The February 9th report continued to cite areas preventing timely completion such as the forward and midship cars requiring transmission gear to be refitted. The aft car was ready but had still not been transported to Inchinnan. The petrol system and associated controls were being installed and gas cells were 83% assembled, being one of the few items to reflect steady progress.

R27 in the Pulham shed along side non NS and Coastal class ships

The report for February 16th reveals little progress except that all cars were at Inchinnan and all engines had been refitted. Propeller outriggers were being attached to the midship car. Gas cells were 94% assembled and 55% complete overall. Again, Brian Turpin offers clarification as to what this means, stating:

Because many parts of the ship were made by subcontractors in separate workshops, the reports also comment on the state of the work being undertaken by these companies. So when they state that the outer cover is complete, they mean that Vickers have made up all the sections of the cover and that it is ready to be transferred to Inchinnan or Selby. Similarly with gas cells; they are made up but have not been fitted into the ship.

The report for February 23rd conceded completion could not be expected until April, but the March 2nd returns finally show real progress. Netting was complete and fixed, all cars were finished and having piping installed. The outer cover had finally advanced to 73% completion. By March 9th control surfaces were ready for attachment to stabilizers and all petrol tanks and controls were fitted. The outer cover was now 80% complete. Issues had arisen with gas cells but the problems were not detailed, simply reported as "rectified". Whether the issue was an excessive number of holes appearing or permeability in general is not clarified, but the undertaking of varnishing (presumably supplementary varnishing) was noted. The acceptance of 22% of the gas cells to this point was also reported. The only progress noted for the report on March 16th was that gas cell remediation was continuing as was varnishing and 33% of the cells had been accepted to this date.

In the week ending March 23rd, wiring fixture alteration was half complete. Gas cell rectification continued and almost half were accepted. Eight gas cells were inflated to 25%, control wires to the elevators and rudders were being fitted and outer cover installation continued. Engine and gearing trials were complete on the forward and midship cars. Another 5% of the outer cover had been completed for a total of 80%. The projection for work on R-27 to be finished was reset for May 1918. Wiring required readjustment was done by April 20th. The April 27th report noted 11 gas cells were installed and had been inflated to 25%.

By May 4th, the outer cover was 96% complete and by the 11th all gas cells were ready, all cars were ready for attachment to the hull, and the outer cover was entirely installed. On May 18th the ship finally underwent a static lift test and it was anticipated flight trials would commence by the 29th. However, a minor defect in transmission gear delayed machinery trials, which were carried out on May 24th. Lift and Trim trials were conducted on June 2nd and R-27 left her hangar for the first time on June 5th for inclination tests. She was returned to the hangar to wait for weather conducive to conducting flight trials.

The Monthly Returns reveal, insofar as construction was concerned, that data input was highly repetitive in nature. Information from earlier reports is consistently reiterated and includes items long since stated as complete. If a report was read in isolation, it could leave a false sense of progress and an impression that more had been accomplished in the preceding report period than in reality. The documentation thus becomes a dull read, especially since nothing is included to suggest what could be done to improve a slow rate of construction. It would be interesting to learn how the very precise percentages for the rate of completion were arrived at for varying items. Perhaps cross-comparisons with construction records of other rigid airships might yield clues to this and other uncertainties.

R-27 Officers and Flight Trials

Flight details for the R-27 and R-29 are documented in the Air Ministry Papers AIR/2/189 at the Public Records Office (PRO) at Kew, England; more recently renamed the National Archives. These records are organized by flight date and information deemed most relevant is also presented by date in this paper. Data gathered from other sources will be footnoted; otherwise the research source for flights may be assumed to be AIR/2/189.

Flight One. R-27's first brief trial flight was conducted on June 8th, two weeks after her sister R-29's maiden flight. Wing Captain Masterman may have put her through this trial, as he had done with the 23 class, but this is not certain. Minor teething issues were revealed and improvements were made before she was commissioned.

R-27 was placed under the command of Major Patrick Gream Nelson Ommanney on June 19th. Ommaney was a former midshipman on the battleship HMA Conqueror and son of Admiral Robert Nelson Ommanney. Born at Medway, Kent in the autumn of 1895, Ommanney enlisted in the RNAS at the age of 18. By October 1st, 1916 he was a Lieutenant and was then promoted to Flight Lieutenant on May 15, 1917. His training with airships after leaving sea duty took him to the bases at Longside and then Howden, where he stayed until at least 1919. It seems that since Ommanney was entrusted to the command of a rigid airship at the young age of 23, this would speak to his judgment, skills and ability to command. Whilst there is no doubt some truth in this, it must also be remembered that the majority of airship personnel were all quite young. Those who had experience as midshipmen in the Grand Fleet tended to gain promotion as they had training as naval officers. Of course, it does not seem likely that Ommanney having a father as an Admiral could have impinged upon his promotion to commander of R27.

Captain Frank Leonard Charmsbury Butcher was designated as second in command. Butcher was born on April 19th, 1896 and joined the RNAS on March 17, 1915. His early training was at Kingsnorth and Barrow, before he was sent as part of the Airship Expeditionary Force to the Dardanelles, from which he returned in June of 1916. He was then posted to East Fortune, then Howden and finally to Pulham. He was Second Officer of R26 under Major T. K. Elmsley before serving aboard R27.

The third officer was Lieutenant Phillips but there has been no success in tracing information about him in the absence of a first name. The complement of the two 23X class airships normally comprised Second and Third Officers along with fourteen other crewmembers, although the number of men on board could vary. No women ever flew in 23X class airships, although they were heavily involved in the construction and at times also participated in ground handling. R-27 was ready to leave for her new station at Howden by June 22nd.

Flight Two. The second flight was conducted on June 29th and was presumably delayed due to poor weather or excessive crosswinds, keeping R-27 shed-bound. The ship was airborne for six hours on what served as her delivery flight, conducted by Major Ommaney. Take-off occurred at 1040 and arrival at Howden was by 1640. The flight from Inchinnan to Howden is a distance of approximately 320 km (200 miles) in a direct line. The exact route flown is not known but an average speed of 32 km/h based upon the time aloft suggests either very strong headwinds or a circuitous route was taken. R-27 was ready for operations by July 1st but no flying was possible as sufficient hydrogen was not available at Howden until the tenth. No crew list for this flight remains.

R-27 Deployment

Flight Three. The first flight operation of R-27 was a Grand Fleet patrol and a convoy escort. The ship rose from Howden at 0340 on July 30th. On board were Major Ommaney with Captain Butcher, Lieutenant Phillips, Chief Petty Officers (CPOs) Wiseman, Thomas and Scull; Petty Officers (POs) Crudington, Holmes and Hall; Lead Machinists (LMs) Sage, Reid and Thomas; and Air Mechanics (AMs) Lawrance, Graham, Gilbert, Hicks, Poore and Hitchcock for a total crew of 18 men.

The crew searched for a U-boat reported to be operating off Flamborough, but no contacts occurred. At the conclusion of the Grand Fleet Patrol drogue trials were undertaken. Drogues could be employed for at sea mooring of an airship, drift check, or equipped with listening devices to detect U-boats. All three were undergoing trials at this time but which type of drogue was being tested on this flight was not revealed. Ommaney then joined a convoy operating from the Humber to Tyne (coded a "UT" convoy) near Flamborough and provided coverage to the Tynemouth. She then provided cover for a destroyer heading to Hornsea and spent the night cruising off the coast. R-27 kept patrolling off Filey when finally ordered to return to Howden. She landed at 0845 on July 31st concluding what proved to be her longest flight of 29 hours and 5 minutes.

Flight Four. A patrol of 8 hours and 10 minutes was conducted on August 4th. The ship departed at 1005 with a crew of 20 men on board. The crew was identical to the previous flight with the exception of Lieutenant Phillips being replaced by 3rd Officer White. CPO Thomas did not participate in this sortie but LM Setterfield was added to the complement.

The intended patrol was to be a convoy escort between the Tyne and the Humber, but fog forced revisions. Instead a patrol was undertaken 50 kilometres (30 miles) westward of Spurn. During this flight the starboard mid-ship engine ceased operating soon after departing Howden. Drogue tests continued with inconclusive results, but the nature of these tests is again not revealed. Deteriorating weather reports resulted in Howden recalling the ship. She landed at 1815 and was made ready by August 5th for her next sortie.

Flight Five. On August 7th a patrol of 16 hours and 30 minutes was performed with a launch at 0940. On this flight changes to the crew included the replacement of 3rd Officer Phillips and White by Lieutenant Coates. CPO Williams replaced CPO Thomas. LM Setterfield replaced LM Reid and LM Travers-Reid was added to the complement. Finally AM Odart replaced AM Poore for a total crew of 19. A northbound convoy from Flamborough to Scarborough was escorted as part of a patrol for the Grand Fleet. At 1345 the crew observed oil patches and Ommaney alerted the surface vessels. A trawler was ordered to guard the spot. At 1350 the submarines G6 and G12 were observed engaged in practice near Tees. Ommaney was detached from the northbound convoy to provide cover for a special southbound convoy, which was met at 1400 off the Tyne. She stayed with this convoy until recalled off Flamborough at 2310 due to increasing winds from the south-south-west, which had reached 35 knots (65 km/h or 40 mph). R-27 landed at Howden at 0210.

Flight Six. A patrol of 23 hours and 35 minutes duration was conducted on August 10th and 11th, with lift off at 1000 and a return to Howden at 0935 the following day. R-27 gave a "TU", Tyne to Humber, convoy aerial coverage. The crew on this flight comprised Major Ommaney in command with Captain Butcher (2nd Officer), Lieutenant Sprotson (3rd Officer), CPO's Thomas and Scull; PO's Crudington, Holmes and Spall; LM's Sage, Setterfield, Thomas and Gilbert; AM's Graham, Gilbert, Odart, Posse and Hitchcock. The variance confirms the 3rd Officer was typically changed, possibly to provide rotational in-flight training. There were 17 aboard this flight.

Flight Seven. A shorter patrol on August 12th was also the most active to date. R-27 left Howden at 1100 and headed out to sea to join a southbound convoy. At 12:06 a submerged submarine was observed three miles to the northeast of Flamborough Head. Ommaney altered course and two 230-lb bombs were dropped, one exploding on the estimated site of the submarine. A marker buoy was deployed but no further contact occurred. The U-boat apparently made good its escape. R-27 was recalled off Flamborough. When returning to Howden the course was altered to avoid four thunderstorms between 1310 and 1525. R-26 out of Pulham was sighted at 1320. In addition to Major Ommaney, the crew on this flight comprised Captain Butcher (2nd Officer), CPO's Thomas and Scull, Ensign Franklin US Navy, PO's Crudington, Holmes, Williams and Hall; LM's Sage, Setterfield, Thomas, Poore and Gilbert; AM's Graham, Lawrance, Odart, and Hitchcock. Winds at Howden increased to 47 km/h (29 mph) and on entering the shed a gust led to the ship impacting the doors resulting in minor damage. The affected girders were repaired the following day.

R-27 Accident

By August 13th, R-27 had accrued a total flying time of 69 hours 25 minutes. Regrettably she was still in her hangar at Howden (Number One rigid shed) on August 16th, berthed next to the non-rigid airships SSZ-38, SSZ-54 and a "composite" airship being built by an American naval airship crew in training. They were utilizing a spare envelope from SSZ-23 (but not the car of SSZ-23) and a surplus car believed to be that of the SSZ-24, non-operational at the time. The American intent was to use spares to create an operational airship as a gift to the British.

There are varying accounts as to what transpired. The most common version relates that a petrol spill occurred in the car, possibly associated with engine installation. Before a clean-up was undertaken, a wireless operator arrived and unknowingly commenced testing his wireless set. It seems more reasonable to think the operator would have had the common sense to not operate his set in the obvious presence of a fuel spill. Perhaps the clean-up did occur but had only progressed as far as fuel removal from the car floor, with more petrol having leaked into the car bilges. Sparks were generated by the operation of the wireless set which then ignited either the fumes or fuel in the bilges and caused the fire.

T. W. Jamison states fuel did spill into the bilges but also that the fire could have been started by a blowlamp (although he also notes the more commonly cited cause as sparks from wireless operation). Tom Asquith and Kenneth Deacon concur with Jamison, claiming an engineer was repairing a fuel tank of a non-rigid airship that had returned from Lowthorpe and that the blowtorch ignited the vapours. American airship historian James Shock believed gasoline was being used in the car for cleaning purposes but he is the only one to claim this. Despite these variances in describing the event, most accounts cite wireless set operation as being the ignition source. Brian Turpin's research reveals many instances when small fires started in SS Zero cars due to petrol fumes accruing in the rear of the car below the engine. These fires were usually started by the wireless spark, followed by a small explosion. This damaged the back of a number of SS Zero cars. The SSZ-17 was destroyed at Pembroke through this cause on January 22nd, 1918. (The Pembroke hangar was badly damaged but fortunately no other airships were present).

The flames at Howden spread too quickly to be contained and the composite blimp was consumed. The airships were berthed fairly tightly together enabling the spread of the flames to the other ships. Crewmembers were quick to run for their lives and one American serviceman believed to be Frank Peckham related how the successive explosions of each of the gas cells of the R-27 progressively blew him out of the hangar. With attention drawn to the presence of hydrogen as the lifting medium for these airships, it should also not be forgotten that some of these blasts were actually the result of detonating fuel tanks.

There is conflicting data as regards to the extent of the damage and what airships were destroyed in this fire. Airship historian Ces Mowthorpe states all airships burned rapidly with the exception of HMA No.6 (Parseval or P6). This was due to it being upwind of the fire and protected by the cooling in-rush of air through the open hangar doors that blew the flames away from her. Asquith and Deacon also speak of a Parseval surviving the fire. Yet flight records held at the Public Records Office at Kew indicate P6 was making a local flight at Pulham that day where it had just undergone modifications. Perhaps what Mowthorpe, Asquith and Deacon describe refers to a different airship. Careful analysis of records reveals less damage than what historians traditionally have believed. R-27, SSZ 38, SSZ-54, and the composite airship were completely destroyed. The envelope of SSZ-62 was destroyed and although the car incurred only minor damage records show it was deleted from service after August 16th. An envelope being rigged to the car of SSZ 63 also burned but the car incurred no damage and thus SSZ-63 was still operational at Howden at the time of the Armistice. Many other airships were undamaged: C*2, C*4, C*9, C4, SST 3, SST 4, SSZ 32 and SSZ 64 but not all were accommodated in the same hangar. Still, August 16th, 1918 was one of the most costly days of the war in terms of loss to British airships and equipment. One may draw a parallel, albeit on a smaller scale, between this event and the extensive loss the German Navy experienced with the destruction of several Zeppelins and hangars at Ahlhorn on January 5th, 1918. As with HMA No. 1, no report of any investigation into the cause of the fire is known to have survived.

Miraculously, there was only one fatality. An engine mechanic was burned to death as he attempted to escape from a post on the roof of the hangar. His name is not known. There were undoubtedly injuries, but the toll could easily have been worse. Perhaps names or other details were reported in local Howden papers or may still exist buried in local archives.

The corrugated roofing material of the Rigid hangar No. 1 at Howden was apparently distorted from the intense heat. Although considerable damage was incurred the structural integrity was not compromised. Airship wreckage was salvaged and the interior cleaned out. Most accounts contend repairs to the roof were not put into hand, permitting rainwater to enter in large amounts, with dire future consequences for R-31. (See the note regarding R-31 at the end of this paper).

The spectacular manner in which R-27 was lost obscures her promising performance. In two weeks this airship flew more patrol hours than her rigid predecessors combined. Major Ommaney did not shy away from attacking the enemy. Unfortunately, the contribution and tantalizing potential of this airship in hunting and confronting U-boats during her brief life was not publicized during or after the war. Anything positive was overshadowed by her untimely demise. But R-27 did set the stage for what her sister ship, R-29, would accomplish.

Summation of R-27 Activity

Total flights: 7
Total flight hours: 89 hours, 40 minutes
Total patrol flights: 5
Destroyers escorted: 1
Grand Fleet Patrols: 2
Convoys escorted: 5
Oil patches observed, reported and bombed by R-27 crew: 1
Searches for reported U-boats: 1
U-boats observed: 1
U-boats attacked: 1
U-boats destroyed: 0
Drogue trials: 2

R-28

Construction of the R-28 was contracted to Beardmore's at Inchinnan with Admiralty Authorization Nr. S.01667/15 and Contact Number CP.03999/16. Work commenced late in 1916, but the Admiralty cancelled her on November 10th. Although several components for R-28 were completed, the desire to concentrate energies on building copies of the more recently shot down L-33 prevailed. A contract for sixteen L-33 type rigids was approved and the hangar at Inchinnan was of sufficient size to help construct them. Yet almost immediately cancellation of R-28 was rescinded with work being transferred to Vickers. This Admiralty decision was a response to increasing dissatisfaction by Vickers at Barrow. The firm had placed considerable monies into airship infrastructure, but their hangar was too small for the new R-33 class airships. Vickers resented the fact that Beardmore and Armstrong-Whitworth were to receive contracts for the new airships, which they could build in the adequately sized but government subsidized hangars at Inchinnan and Selby. In sum, retention of the R-28 was partly to pacify Vickers but also to ensure their trained workforce did not become redundant and lost to conscription or otherwise dispersed. Also, the Admiralty was aware 23X class airships were quicker to produce, would make efficient training ships, and would be able to provide reconnaissance services to the fleet which the 23 class could not adequately do.

The transfer of R-28 construction from Beardmore's to Vickers was confirmed in a letter dated March 13th. Meanwhile, work on R-30 was completely cancelled and that contract was never renewed. The letter indicates approximately 15 tons of material was stored by Beardmore, with an additional 13 tons for R-30 in store by Armstrong-Whitworth's. All of it was to be transported to Barrow to help speed construction of R-28, at the discretion of Vickers. The letter appears to refer to materials like duralumin for the girders versus completed parts. At least some of this material was dispatched and assembly was started at Barrow alongside the almost finished R-26.

The Handbook on Rigid Class 23 Airships reveals specific information regarding issues encountered in the manufacture of girders for R-28, which were similar to those encountered with HMA No. 9, 23 and R-26. This was a difficulty in manufacturing straight girders, and many completed ones possessed some degree of twisting. The wearing down of jigs was discerned to be the cause of altering the pitch of the holes versus any sloppy assembly or reaming of holes as was initially believed. The variance was tiny but cumulative. Replacement jigs were ordered and took considerable time to deliver. Efforts to torque girders straight failed because the girders invariably drifted back into their unacceptable curvature. In the interim, workers at Barrow were able to overcome the problem with simple ingenuity. They used a number of bracing blanks to hold the girder being worked on perfectly straight throughout their length once tightened down.

After considerable effort was expended, a second order to cancel R-28 was received after one year of progress in construction in November of 1917. Vickers officials were less concerned this time because approval was granted for construction of the high performance R-80 designed by Barnes Wallis, which met the size restrictions of the Vickers hangar.

Some controversy surrounds how advanced R-28 construction progressed. A photograph appearing in J. A. Sinclair's Airships in Peace and War shows a complete and instrumented control car captioned as belonging to R-28. Brian Turpin has done a close analysis of this photo, noting the view out the windows of the car reveals another in-line car attached to the same airship hull. On this basis he believes this airship is not the R-28 and that the photo was mislabelled. This is because car attachment would not have occurred without completion of the hull framework and such a level of progress seems unlikely to him. Conversely, Vickers' did claim they would be able to construct one 23X class ship every eight weeks because these airships used the same tools and jigs as the 23 Class. Nevertheless, since no keel is evident in this photo he believes it is still most likely a photo taken from a car of either R-27 or R-29, the partially constructed hull on the left being one of the 33-Class ships. An engine signal indicator appears to have been preserved during the dismantling of R-28. It remained on display for many years with other airship artefacts in the Administration Block of the Royal Airship Works at Cardington and is now in the possession of Airship Heritage Trust. Was this artefact also mislabelled? Or had Vickers accomplished more work than believed? This uncertainty may not be resolved for some time in the absence of further documentation.

R-29 Construction

Work upon R-29 was undertaken by Armstrong-Whitworth at Barlow, Yorkshire, alongside No. 25. The Admiralty Authorisation number was S.01667/15 and Contract Number CP.03999/16, as with R-27.

By November 17th, 1917 the hull was nearing completion. The cars were almost finished and the gas cells were dispatched from the Vickers subsidiary, Ioco Rubber and Waterproofing Co. Ltd., located near Douglas on the Isle of Man (their works was situated in the ballrooms of the Palace and Derby Castle grounds). The outer cover underwent several alterations which were completed that month. February of 1918 was given as the estimated date for completion. By December 8th the forward car was complete and finishing touches were being applied to the other two cars. The outer cover was reported to have been installed, doped and finished by December 15th, far in advance of the same work upon R-27. However, future reports seem to contradict this claim. Given that outer envelope panels were noted as being complete and dispatched from Douglas in the January 12th report, it seems possible that not all panels had been received in December and report wording implies this even if it does not directly state this. The report for December 22nd stated estimated date of completion would be delayed from the 15th to the 28th of February.

Armstrong's Works were closed from December 22nd to the 27th, and again on January 1st, 1918, but few workers appeared between the two vacation periods. January 12th Daily Reports were still stating "Hull nearing completion" but progress was noted with the wiring and stabilizers. The January 12th report confirmed Douglas had completed all gas cells but that only three had been obtained. The fabric covering of the rudders and elevators was being doped. Six weeks after reporting that Douglas had sent the gas cells, it was still being reported that "all main gasbags have now been despatched from Douglas" which implies some kind of unexpected delay. The Report for January 19th declared the hull finished with wiring and netting to be complete within one week. Stabilizing fins were nearing completion. The cars were all constructed at Elswick. The forward car was complete and already delivered to Selby, the aft car finished and en route, but the midship car was not ready but near completion. March 15th was cited as the expected completion date.

The report for the week ending January 26th stated wiring and netting was complete and gas cell testing underway. External wiring for the rudders was ¾ complete. The aft car had arrived at Selby with the midship car now reported as complete but awaiting transport. The report states: "Test in position being carried out" but does not clarify what tests. Given this statement comes immediately after the engine delivery status; it suggests engine tests were proceeding immediately upon receipt.

Command Car of R29 under construction

Fist flight of R29

R29 discharging water ballast

A setback occurred around the start of February when wiring was damaged during gas cell tests. This was presumably due to over-pressure and repairs commenced immediately. The stabilizers were one quarter covered with fabric and "the remainder [were] being riveted up", meaning the girders within the exposed portions of the fins themselves were getting final rivets to complete the stabilizers. Rudders and elevators were now completely covered and doped. All cars were at Selby and the swivelling gear and silencers were being installed in both the forward and aft car.

In the week up to February 9th it was necessary to readjust hull wiring. Work continued on the installation of exhaust silencers and swivelling gear. All gas cells were finished. By the 16th all machinery was fitted and propeller outriggers were being installed on the midship car. The February 23rd report made it evident R-29 completion would have to be pushed back to April.

Hull wire readjustment remained incomplete as of March 2nd, but some advance was made with the stabilizing fins. These were now ¾ covered, 78% erected and half of the fabric was doped. By March 9th the fins were deemed 80% erected, but covering and doping the fin covering had not advanced. The fins were deemed 81% erected by March 23rd, but no other progress was evident and the completion date was now being pushed back to May. On March 30th it was reported that readjustments to wiring, ongoing since Feb. 7, was continuing but completion was anticipated for April 7th, with 4% progress since March 16th. The stabilizers were 85% constructed and 75% finished in terms of covering and doping. It is apparent from the April 6th report that nothing new was added and no real progress occurred, but by April 13th all wiring adjustments were finally finished.

On April 23rd the inflated airship underwent its first "lift" test in order to make ready for installation of the cars to the hull. The aft car was attached by May 4th.

Monthly Return of Items of Information: April 1918 reported all gas cells were inflated to 20%, the outer cover was installed and all identification markings were displayed by April 24th. The elevators along with the elevator and rudder control blocks were being fitted. Stabilizers were installed except for the lower fin which was complete but awaiting attachment. The control pulleys and ventilator shafts were in the process of being installed as were mooring frames. The machinery was 98% finished, petrol keel system 75% complete, and the "creeping way" to the rear gun post 75% complete. All petrol tanks were installed as were corridor nets. The frames for bomb stowage remained to be assembled and fitted.The May 18th report stated lift and trim and airborne machinery trials were going to be conducted later that same day. The first flight tests were slated for the following Tuesday, May 21st, but it turned out the lift and trim/airborne machinery trials were delayed until May 20th. An unspecified accident caused damage to the walkway, so flight trials were delayed to May 26th. R-29 left the hangar for the first time on May 25th, 1918 for inclination tests.

R-29 Trial Flight

Most sources state R-29 first flew on May 29th, 1918 but the correct date is May 26th. Close scrutiny by Brian Turpin revealed a series of photographs taken at Barlow showing R-29 being drawn out of the hangar by a civilian ground handling party. The last frame shows the airship airborne, and all of these original prints are dated May 26th. Monthly Returns of Items of Information for May, 1918, confirms this:

The ship was sufficiently complete on 25th, when she was taken out to No.8 bollard and inclined to about 25º. As good luck prevailed, the very next evening proved to be suitable for flying and at 6.15 pm the ship took the air. After a satisfactory two hours' flight she landed successfully [at 20:16-KO] and returned to the shed for numerous small alterations to be carried out.

The alterations included repositioning the attachments of all three cars to move them closer to the hull. The airship was deemed ready on June 19th and handed over to be placed in commission on June 20th under the command of Squadron Commander Godfrey Main Thomas. Thomas was born September 10th, 1895 in Jamaica. He served in the British Forces with five elder brothers during the Great War, commencing with the first Battle Squadron on the HMS Colossus as a Midshipman, being awarded the King's Medal & Dirk. His Squadron was transferred to the Royal Naval Air Service where he became a Flight Lieutenant, commanding R-29 at the age of 23. The second in Command changed over time, initially being Captain Don. Later Captain Butcher took his place, and it appears these two men accrued the most flying time in the role of second in command. However, Captain A. H. Wann and Flight Lieutenant Noel Grabowski (Atherstone) also served as second officers.

R-29 Flights and Deployment

June 20th. Flight 2. The second flight was of four hours and fifty minutes duration, from 08:20 to 13:10. This intended delivery flight from Selby to East Fortune was aborted due to increasing headwinds making a diversion to Howden preferable.

June 26th. Flight 3. An early launch at 04:45 was undertaken but poor meteorological reports again led to a message being sent to Major Thomas to abandon heading to East Fortune and return to Howden. Landing was completed at 08:15 for a flying time of three hours, thirty minutes.

June 29th. Flight 4. R-29 reached her new base at East Fortune after a nine hour flight which included an impromptu naval patrol. The airship lifted off at 03:05 and landed at 12:05. She accrued 17 hours and 20 minutes of flying time in June, for a total flying time of 19 hours, 20 minutes to date.

July 2nd - 4th. Flight 5. The first formal naval reconnaissance performed by R-29 lasted 32 hours and 20 minutes. Major Thomas ordered the ship released at 21:20 on the 2nd and she returned to East Fortune on the 4th at 05:40. This is the first flight for which a crew list remains. In addition to Major Thomas, those on board were: Capt. Don (2nd Officer), 2nd Lt. James (3rd Officer); Lt. Commander Thierry (observing passenger), CPO Jefferson, PO Thirlwall, PO Johnson, LM Holman , AM Duke (Engineers); CPO Hunt and PO Reynolds (Coxswains); LM Taylor, AM Allen, AM Moon and AM Forteath (Riggers); LM Baker and AM Lindsay (Wireless) for a total of 17 crew. This flight included the first convoy escort conducted by R-29, preceded and concluded with an extended patrol of northern waters. It was also the longest flight the R-29 ever undertook, setting an endurance record for British rigid airships up to that time. This would not be broken until after the armistice.

July 10th. Flight 6. R-29 departed East Fortune at 06:55 to conduct a patrol of 9 hours and 35 minutes, returning at 16:30. The crew for this flight was identical to the previous flight, except that Captain P. E. Maitland was on board as fourth officer (having apparently stepped down on the previous flight to make way for Lt. Cmdr. Thierry). Records state this flight was a "Middle Patrol"; which refers to mid-latitude shipping approaches and routes parallel to the East Coast southwards to the Tyne, Tees and Humber Rivers. At 11:05 an oil track was observed and two destroyers were summoned by Thomas. The destroyers deployed four depth charges but nothing further was observed.

July 15-16. Flight 7. The fourth patrol of R-29 lasted 9 hours and 40 minutes and was conducted by the same crew as on the 10th. The departure was at 2050 with landing at 0630. The effectiveness of a night patrol might be questioned but it must be remembered that at the higher latitudes of Scotland and northern England summer nights are relatively short. This overnight patrol of middle regions of the North Sea was cut short due to thick fog and heavy precipitation.

July 17. Flight 8. A patrol of 5 hours and 25 minutes commenced at 1520 with a return at 2045. The crew remained the same as on the previous two flights. R-29 escorted the Inward Force as well as the Main Force to May Island from a point 70 km (50 miles) east-south-east of that island. Having fulfilled this task, Major Thomas returned to base owing to receipt of an unfavourable weather forecast. The airship was returned to the hangar for repairs to exhaust pipes which were completed on July 22nd. The airship was ready for operations again on the 24th.

July 25. Flight 9. As normal, R-29 rose statically at 0820 and landed light at 1355. The crew was the same as on the preceding three flights except that the fourth officer Captain P. E. Maitland did not partake, for a total of 16 on board. This flight was dedicated to anti-submarine patrol with the southern approaches and the Tyne Estuary being searched. A report of a missing seaplane was received and this was also sought out but was not located. This flight constituted the sixth patrol and first search undertaken by this airship.

July 27. Flight 10. This reconnaissance lasted 20 hours and 20 minutes. Departure was at 0950 with a return at 0610 on the 28th. The crew comprised 16 on this flight, again owing to the absence of Maitland. During this night patrol of northern and southern approaches several vessels were escorted but no convoys. On return to base the ship underwent engine repairs and was ready to fly again on July 30th.

July 31-Aug. 1. Flight 11. R-29's eighth patrol of 22 hours and 30 minutes commenced with ascension at 1135 and landing at 1005 the next morning. The crew remained the same as on the previous flight but with the addition of Captain Turner for a total of 17 on board. The patrol covered the Middle approaches. A submarine was reported at 56.08N, 1.2W and R-29 altered course endeavouring to locate it, but was not successful. At 2210 the port mid-ship engine ceased operating and at 0945 the starboard engine began making a knocking noise. Thomas returned to base for engine repairs. The total flight time accrued by this airship up to midnight on July 31st was 95 hours and 20 minutes.

August 3rd. Flight 12. R-29 went aloft at 0820 and returned early at 1650 due to fog preventing useful observation. The normal flight crew of 17 were on board. On this flight Thomas escorted the destroyer HMS Umpire starting at 1030 during a patrol of the Middle Approaches. The flight lasted 8 hours and 30 minutes.

August 7th. Flight 13. The tenth patrol flight conducted lasted 11 hours and 10 minutes, commencing at 0955 and ending at 2105. It covered the Southern approaches with the usual crew.

August 9-10. Flight 14. The eleventh patrol was dedicated to the Middle approaches and lasted 7 hours and 35 minutes. Departure was at 2055 and landing at 0430 on the 10th. On this flight the regular crew was accompanied by Brigadier General E.A.D. Masterman, Lieutenant Colonel Bosanquet and Captain A.H.Wann accompanied the normal crew. Also, rigger AM Semken replaced the usual AM Moon. The total on board was 18. R-29 escorted the 4th Light Cruiser Screen and 5th Battle Cruiser Screen and Destroyers.

August 25th. On August 24th orders were received to transfer the R-29 to Pulham airship base in Norfolk. Flight 15 was intended to enable reconnaissance of Southern approaches en route. Launch was at 1155 but after one hour and 45 minutes Major Thomas elected to return to East Fortune, with little scouting accomplished. At 1230 the mid-ship exhaust pipe had fractured and by 1340 heavy rain was obscuring visibility. Questionable weather, reduced power and the increasing likelihood of being unable to provide useful reconnaissance led to this decision erring on the side of caution. The flight crew included Ensign Homer of the US Navy acting as 3rd Officer and CPO Gent replacing CPO Jefferson. R-29 had been airborne for a total of 3 hours and 30 minutes with the landing at East Fortune occurring at 1525. Repairs to the exhaust pipe were immediately undertaken and the airship was ready the following morning, but no flight was undertaken that day.

August 27th. Flight 16. Patrol 13. A flight of seven hours started at 0810 with completion at 1510. The surveillance was to cover both Northern and Southern approaches, although once again the flight was suspended due to rain obscuring visibility. Lt. James resumed duties as 3rd officer, but CPO Gent was retained on this flight. There is nothing in this flight date entry, however, that specifically states the destination remained as Pulham. Based on the orders issued on August 24th, Pulham would logically seem to be the destination, but it is more likely the transfer order was completely rescinded. There are no known photos or documentation of R-29 ever being based at Pulham or flying to it. Moreover, researcher Gordon Kinsey makes no mention of R-29 in his book Pulham Pigs (Lavenham, Suffolk: Terence Dalton, 1988), which is dedicated to Pulham and all the airships based there.

August 28th. Flight 17. Patrol 14. This flight lasted 11 hours and 45 minutes with a night time launch at 0340 and return at 1525. Major Thomas' crew was again slightly altered. CPO Jefferson returned and shared duties with CPO Gent. LM Semkin returned to assist LM Taylor, with all other crew members remaining the same. The flight was the first one dedicated to protect the Grand Fleet, and the second one in which R-29 afforded the Light Cruiser Screen aerial protection. Although the battle fleet was passed in heavy fog and not seen at 1015, it was spotted on a second sweep at 1030. R-29 was assigned to accompany the Light Cruiser Screen east of Greenwich, during which she encountered winds of 35 to 40 knots at 1,000 feet above sea level (ASL).

August 29th. Flight 18. Patrol 15. The flight duration was 12 hours and 15 minutes, with ascension at 0845 and return to base at 2100. Crew was alterations included the addition of PO Strayden for a total of 17 on board. Coverage was provided to the Middle approaches and brought the total August flight time up to 83 hours and 50 minutes.

September 3rd. Flight 19. Patrol 16. A flight of 10 hours and 15 minutes took place with ascension at 1005 and descent at 2020. The flight crew included PO Standen for a total of 17 on board. A patrol of southern approaches was made with a convoy from the Tyne to Methil ("TM" Convoy) being escorted from 1330 to 1800. This was the third convoy afforded aerial protection by R-29.

September 4th. Flight 20. Although a flight crew list is provided for this date in the Daily Reports, no flight length or details are provided.

September 5-6. Flight 21. Patrol 17. A flight lasting 20 hours and 55 minutes was performed with departure at 1005 and return at 1900 the following day. No flight crew list was provided. The Daily Report notes that this was a general patrol and escort, with the destroyers FO5, HMS Pylades & Orford being escorted between 1700 and 2030 on the 5th; the third time R-29 is known to have escorted destroyers. At 1830 Thomas dropped a calcium flare on an oil patch. FO5 followed up by dropping two depth charges but no wreckage materialized and nothing further was observed. This was the second time R-29 raised the alarm about an oil slick to vessels it was escorting, always indicative of the possibility of an enemy U-boat.

September 7th. Flight 22. Patrol 18. A flight of 8 hours and 30 minutes began at 1010 and was completed at 1840. The crew on board are referenced again: Major G.M.Thomas in command with Captain Don (2nd Officer), 2nd Lt. James (3rd Officer); CPO Jefferson, PO's Johnson, Standen and Thirlwall; LM Holt and AM Duke (Engineers); CPO Hunt, PO Reynolds, (Coxswains); LM Taylor, AM's Allen, Moon and Forteath (Riggers); LM Baker and AM Lindsay (W/T), for a total of 17 on board. This patrol of the Middle approaches was ended prematurely by orders to return to base with the expectation of poor weather.

September 15th. Flight 23. Patrol 19. A flight of 11 hours and 20 minutes was completed starting at 0600 and returning at 1720. Complement changes included Captain Butcher acting as 2nd Officer and the addition of two passengers: Lieutenant Catchpole and Ensign Homer of the US Navy. A patrol of Southern and Middle approaches was terminated when heavy rains reduced visibility. This was compounded by engine failure and rising winds, but R-29 returned safely. Repairs to the engines were completed by September 18th.

September 29th. Flight 24. Patrol 20. R-29 left East Fortune at 0835 to perform escort duties and landed 10 hours and 50 minutes later at 1925. Major Thomas was in command with Captain Butcher as 2nd Officer and Lieutenant Catchpole as 3rd Officer. Other crew included CPO Jefferson, PO's Johnson and Reynolds, AM's Parry and Duke (Engineers); CPO's Hunt, Gent (Coxswains); LM Taylor, AM's Allen and Moon (Riggers); LM Baker and AM Crouch (W/T). Passengers for this sortie included Lieutenant Grandage and Lieutenant Hall.

R-29 met up with a Scandinavian convoy ("OZ" or "HZ") which had departed Kingston-Upon-Hull. This was the fourth known convoy she was assigned to escort thus far in her career. Off the Northumberland coast, not far from Sunderland and Newbiggin Point, a crewmember of R-29 reported seeing an oil slick upon the surface of the water at about 1325 hours. Major Thomas ordered the helmsman to alter course to fly over the spot, and ordered a message sent by Aldis lamp: "Oil patch rising below me." The commander of HMS Ouse, an escorting destroyer; signalled back "Drop light over it." At this point Thomas was sufficiently convinced of the presence of an enemy submarine to order a 230-pound bomb dropped, which may have detonated very near or on target. HMS Ouse responded by deploying two depth charges. Thomas ordered a second 230-pound bomb dropped as well as a calcium flare to mark the position for the ships joining in the attack. HMS Star and two armed trawlers began deploying depth charges. One hour after the R-29 commenced the attack HMS Star reported considerable quantities of oil upon the surface and continuing to rise. Before resuming her escort of the convoy, R-29 maintained surveillance to ensure the submarine did not get away. Naval attacks continued for the next 48 hours, during which the damaged UB-115 was detected attempting to escape the attack and reach surface, but to no avail.

Commander Thomas filed the following report, which appeared in the Flight Reports:

Report of Attack On Supposed Submarine By R 29:

"On Sunday 29th September, while escorting a TM Convoy at 1325 BST, oil was sighted by R 29, rising to the surface in a position 1.22W 55.14N.
The Convoy leader HMS "Ouse" was informed by visual signal and position marked by means of a 230-lb bomb dropped with 21/2 sec delay fuse. HMS "Ouse" then dropped two depth charges.
At 1400 another 230-lb bomb was dropped and a calcium flare to mark the oil patch. Both bombs exploded in correct position ahead of the oil patch.
HMS "Ouse", "Star" and trawlers then dropped a large number of depth charges and a large quantity of oil and bubbles rose to the surface.
At about 1430, HMS "Star" reported heavy oil coming to the surface. Two hydrophone trawlers buoyed the position and remained on watch and dropped one deep depth charge.
R 29 remained in the vicinity until 1600 when she then rejoined the convoy. At the time of leaving, oil was still coming to the surface in large quantities."
Signed: Major G.M.Thomas

It was later discerned the R-29 attacked the German U-boat UB-115, which was part of the "F" flotilla stationed at Zeebrugge and under the command of German Naval Officer Thomsen. UB-115 was undertaking its maiden sortie, with 39 aboard. It was sunk in approximately 44 metres (144 ft) of water with no survivors. The extant wreckage is located at 55.14N and 01.22E (flight reports stated engagement was at 57.7N and 1.45W). It is now the occasional destination for professional divers. As with other sunken wrecks, efforts have been under way by both the British and the Germans to have it declared as an official burial site to help protect it from pilfering.

R-29 was granted partial credit for her role in destroying the UB-115. Commander Thomas was awarded the Distinguished Flying Cross and the entire crew were awarded prize funds after the Armistice for their contribution. The following article found in the files of the Airship Heritage Trust appeared in the Evening Sun in 1919, although the specific date was unfortunately not noted on the news-cutting:

AIRSHIP V. U-BOAT: COMBINED AIR AND SEA ATTACK RECALLED

PRIZE COURT AWARDS

Among the several claims for prize-money made in the Prize Court to-day for the destruction of U-boats was one in which H.M. Airship 429 (sic) was concerned with H.M. ships Ouise and Star and six armed trawlers.

As a result of a combined attack, U-115 (sic), with 37 (sic) on board, was sunk on September 29, 1918. There were no survivors.

£185 prize money was awarded.

Lieutenant W. T. A. Bird, DSO, RN of the Ouise, stated that the airship, in command of Flight-Lieutenant Godfrey M. Thomas, RAF, dropped a light over an oil patch, then a bomb, and the witness followed this up by depth charges. A vigorous bombardment by the rest followed.

SMOKE BALL

The airship later released a smoke ball and a vessel followed it and dropped other depth charges. The position was marked with a buoy, and oil covered a large area round for 36 hours after. What was supposed to be the wreck was located under the buoy.

The article was written sometime after the fact and contains errors. Although secondary sources tend to vary regarding the types and weight of bombs dropped by R-29 (Thomas´own report should have eliminated any such confusion) there is concurrence that it was the crew of the R-29 who first detected the U-boat. Extensive documentation regarding the effectiveness of airships in anti-submarine warfare in both World Wars lends credence to the claim that if R-29 had not been present, the UB-115 may well have sunk ships and left undetected. It is unfortunate (but not surprising) to find that several U-boat histories consulted fail to acknowledge the R-29 as having played a crucial role, indeed the lead role, in the destruction of UB-115. Invariably, mention is made of the Ouse and Star. Airships are often neglected in mainstream histories because of erroneous presuppositions regarding their capabilities, vulnerabilities, and success rate. Also, the concept of the airship is difficult for many to relate to in a world that now has comparatively few airships. Rather than get involved in the technical explanation of what an airship is, several war historians simply find it easier to ignore them.

If the role of the R-29 in destroying UB-115 is relatively well documented in official sources (even King George V commented upon it), other engagements are not. A number of historical accounts indicate R-29 attacked German U-boats on two other occasions. Statements made by Robin Higham, Ces Mowthorpe, Lennart Ege, Lee Payne, Lord Ventry and myself in a previous work are all very similar indicating: "the first [U-boat] escaped, the second ran on to a mine while being pursued, and the third, UB-115, was hit with a… …bomb…" None of these authors reference their source of information on this, but based on publication dates of respective works, Robin Higham was the first to mention all three incidents. Higham's The British Rigid Airship 1908-1931: A Study in Weapons Policy is a comprehensive, authoritative and well-written account but the emphasis of his research was on policy. Certainly his coverage of performance and specifics about each airship was also well done. However, since all other researchers appear to have relied upon him on this particular matter, the question must be raised, what was Higham's source of information regarding the three U-boat encounters by R-29 and was it accurate? The first U-boat having escaped is indeed possible; certainly airship crews have lost sight of submarine contacts before. Such an event would not necessarily have generated much documentation and there were oil patches sighted by both R-27 and R-29 that may have been left by U-boats. But it seems unusual that no other source of data has emerged regarding the second U-boat engagement. If R-29 pursued a submarine until it ran into a mine, was the submarine destroyed? Did the airship crew lose sight of it? With increasing doubts, I consulted Brian Turpin and the works of the late Geoffrey Chamberlain. Chamberlain attributed the destruction of the UB-115 as the sole fruit of the British rigid airship program and makes no reference to R-29's other two U-boat incidents. Brian Turpin was first to review all daily reports for R-29 in depth and found no reference to engagements with submarines other than UB-115. He did, however, find several references to sightings by R-29 of oil patches as mentioned in the flight synopsis provided in this paper. There was simply no other confirmed U-boat engagements by R-29 and thus Higham's claim has been proven inaccurate.

R-29 flew a total of 61 hours 50 minutes during September, 1918.

October 11th. Flight 25. Patrol 21. A flight of eight hours, departing at 1030 and landing at 1830, was completed. The crew comprised Major Thomas with Capt. Butcher (2nd Officer), 2nd Lt. James (Engineer Officer), 2nd Lt's Powell and Catchpole (Passengers), CPO's Hunt, LM Taylor, AM Allen (Coxswains) CPO Jefferson, PO's Johnson and Thirlwall, AM Duke (Engineers) LM Baker and AM Reekie (W/T) PO Reynolds, AM's Barton and Watson. A Tyne to Methil "TM" convoy (R-29's fifth documented convoy) was escorted, followed by a patrol of the Tyne approaches.

October 12th. Flight 26. Patrol 22. An 11 hour, 50 minute flight was completed with departure at 0700 and return at 1850. A Tyne to Methil (TM) Convoy was protected followed by an "SB" Convoy along the coast (constituting the sixth and seventh convoys documented to have been escorted by R-29). The complete flight covered an area from Peterhead to the Firth of Forth. The actual time spent with the convoys was four hours and thirty five minutes. The crew for this flight consisted of: Major Thomas, Capt. Butcher (2nd Officer) Lt. Catchpole (3rd Officer) 2nd Lt. James (Engineer Officer) 2nd Lt's Powell, Major's Johnson and Daly (Passengers) CPO's Hunt, LM Taylor, AM Allen (Coxswains) CPO Jefferson, PO's Johnson and Thirlwall, AM Duke (Engineers) PO Reynolds, LM Holt AM's Hackney and Barker (Riggers) LM Baker and AM Reekie (W/T) for a total of 20 on board.

October 13th. Flight 27. Patrol 23. Convoy 8. This flight lasted 9 hours and 50 minutes, departing at 0950 and returning at 1940. A Scandinavian convoy, "OZ61", consisting of 34 ships, was escorted between May Island and Tod Head. The C*3 (Coastal Star class non-rigid airship) assisted. R-29 carried 1146 rounds of ammunition on this flight with four guns and four 230-lb bombs. Crew: Major Thomas, Capt. Butcher (2nd Officer) Lt. Catchpole (3rd Officer) 2nd Lt's James and Powell, (Engineering Officer); Lt. Ball (Passenger) CPO's Hunt, AM Allen (Coxswains) PO's Johnson and Thirlwall, AM Duke (Engineers) PO Reynolds, LM's Holt, Richmond and Baker; AM's Penny and Constable, AC Howlett (Riggers) LM Baker (W/T) for a total of 19. Repairs to an exhaust cylinder were required. Post flight maintenance was conducted and the ship was ready for flight by October 16th.

October 17th. Flight 28. Patrol 24. R-29 was launched at 0555 and landed at 1455 for a total flight time of 9 hours. A patrol covering Bell Rock, Fife Ness and E Bell Rock in the Firth of Forth was conducted in conjunction with airship C*1, but R-29 was recalled due to weather. Crew: Major G.M. Thomas with: Capt. Butcher (2nd Officer) 2nd Lt. James (Engineer Officer) 2nd Lt's Powell and Symons CPO's Hunt,, LM Taylor, AM Allen (Coxswains) PO's Johnson and Thirlwall, AM Duke (Engineers) LM Baker (W/T) APO Reynolds, LM's Holt, Richmond AM's Forteath, Jones, Lindsay, Moon and Victory (Riggers) for a total of 20.

October 21st. Flight 29. Patrol 25. Convoy 9. Escort of a Tyne to Methil convoy was disrupted due to heavy rain obscuring vision. Nothing was sighted to that point. The flight lasted 8 hours and 55 minutes with departure at 0905 and return at 1800.
Major G.M.Thomas was in command with Capt. Butcher (2nd Officer) 2nd Lt. James (Engineer Officer) 2nd Lt's Powell and Symons CPO's Hunt, LM Taylor, AM Allen (Coxswains) CPO's Johnson and Thirlwall, AM Duke (Engineers) PO Reynolds, LM's Nash and Richmond, AM's Watson, Moon (Riggers) and LM Baker (W/T) for a total of 17.

October 23rd. Flight 30. Patrol 26. Convoy 10. R-29 departed at 0855 and returned at 1810, completing a flight of 9 hours and 15 minutes. Crew: Major G.M. Thomas with: 2nd Officer Noel Grabowsky (2nd Officer), Capt. Leetham, 2nd Lt's Haselar and Powell. CPO's Hunt, LM Taylor, AM Allen (Coxswains) CPO Johnson, PO Thirlwall, AM Duke (Engineers) PO Reynolds, LM's Holt, Richmond, AM's Forteath, Lindsay and Moon (Riggers) LM Baker (W/T) for a total of 18.
R-29 flew to a point 40 kilometres (25 miles) east of St. Abbs Head and provided aerial coverage of Alnmouth Bay. A TM Convoy was escorted. An oil patch was seen eight kilometres (five miles) northeast of Coquet Isle. Thomas ordered the summoning of surface craft and depth charges were dropped by a destroyer. The convoy of 23 ships was escorted for five hours and twenty minutes. Armament carried included four Lewis guns, four 230-lb bombs and 1216 rounds of Mark VII ammunition. This was the fourth time the crew of R-29 detected an oil slick, and the fourth time ordnance was deployed in response (either by surface vessels or R-29 or both).

October 26th. Flight 31. Patrol 27. A flight of 12 hours and 12 minutes started at 0710 and ended at 1922. This flight was ordered by the Commander in Chief at Rosyth due to the sighting of an enemy submarine at 0600 near 56.15N 1.0E. The specified mission area extended 185 kilometres (115 miles) east of Dunbar northwards to 89 kilometres (55 miles) east of Montrose. R-29 was accompanied by the North Sea class non-rigid airships NS-11 and NS-6, one flying boat and four destroyers. R-29 searched the area marked by the destroyers but nothing was observed. At 1400 poor weather prompted an order for her to return closer to base, but she continued aerial surveillance in the Firth of Forth. This was the second instance in which the crew of R-29 were called upon to search for a reported enemy submarine. Crew: Thomas in command with Lt. Catchpole (2nd Officer), Capt. Greenland and 2nd Lt. Haselar. CPO's Hunt, LM Taylor, AM Allen (Coxswains); CPO Johnson, PO Thirlwall, AM Duke (Engineers); PO Reynolds, LM's Nash and Richmond, AM's Forteath, Constable, Chinnell and Moon (Riggers) for a total of 17.

R-29 logged 69 hours 2 minutes during October.

November 3rd. Flight 32. Patrol 28. This flight provided aerial surveillance for the TM Convoy Route. It lasted 7 hours departing at 1115 and landing at East Fortune at 1815. Thomas ordered the bombing of floating wreckage at position 55.53N and 1.53W at 1230. Later, he ordered a patch of rising oil bombed at 1615, three miles east of St.Abbs Head. These actions were the sixth and seventh times precautionary ordnance was deployed due to observations by R-29 crew. Some exhaust pipes broke during flight. The crew comprised: Major Thomas with Capt. Butcher (2nd Officer) Capt's Greenland, Leetham and Grabowsky Lt's Haselar and Powell. PO Reynolds, LM Taylor, AM Allen (Coxswains) CPO Johnson, PO Thirlwall, AM Duke (Engineers) LM's Nash, Holt and Baker AM's Lindsay, Constable, Burton and Moon (Riggers) for a total of 20.

Armistice. R-29 remained ready for service at East Fortune on 11th November when hostilities ceased.

November 13th. Flight 33. Captain Butcher was in command of the first flight after the Armistice. The ground crew let the airship rise at 0935 and secured her at 1405 for a total flight time of four hours and 30 minutes. The remaining crew included Captains Greenland, Leetham and Hardee; Lt. Haselar; CPO's Hunt, Mutton, Nollie and Johnson; PO's Reynolds, Probits, and Thirlwall; LM's Holt, Baker, Richmond, Nash, Taylor and Allen; AM's Forteath, Duke, Moon, Victory and Lindsay, for a total of 23 on board. This was a special flight ordered by the General Officer Commanding (GOC) No.22 (Operations) Group, but no details of the nature of the mission were recorded. It may have been intended for the airship to participate in Victory celebrations and associated publicity. Butcher had to return to base on account of fog.

November 16th. Flight 34 commenced at 0950 and was completed at 1435 for a flight time of 4 hours 45 minutes, with Thomas back in command. Captains Greenland, Leetham and Coombes; Lt. Fox; CPO's Hunt, Calliu and Johnson; PO Reynolds; LM's Holt, Baker, Richards, Moss, Dicks, Davies, Watson, Petus, Lindsay and Allen were all on board for a total of 19. This flight was intentionally conducted over land in accordance with orders from the GOC for a special flight with NS 8 over Stirling (probably for publicity). NS 8 was able to fly over the town but R 29 had to return once again due to fog. On return she had to be laid up for repairs to the forward car and hull. Although the reports make no statement on the matter, this was likely due to either a heavy landing or a ground-handling incident.

November 22. Flight 35. A flight of two hours and fifty three minutes was completed with departure at 0947 and return at 1240. This flight was devoted to photography over the Firth of Forth. The crew comprised Major G.M.Thomas, Col. R.C.S. Hunt, Major G.H. Abell, Captains G.S. Greenland, H.A.H. Leetham, Noel (Atherstone) Grabowsky, Cowell, B.W. Hemsley and H.M.Coombes. P.S. Lt. Lownds. CPO's Hunt, Hinton and Johnson, PO Reynolds and Thirlwall. LM's Holt, Baker, Standen, Taylor, Nash and Allen. AM's Victory, Forteath and Baker, for a total of 24 people on board.

November 30. Flight 36. A flight dedicated to training airship crews was conducted with lift off at 1245 and landing at 1645 for a total of four hours. Major G.M. Thomas commanded with Capt. Noel (Atherstone) Grabowsky, Lt. Catchpole. Capt's Irwin, Sandwell, Pinkey and Dakin. Lt's Hill and Stewart. 2nd Lt. Hasler. CPO Savill. PO's Reynolds, Crudgington, Gaunt, Standers and Thirlwall. LM's Richmond, Adam, and Taylor. AM's Victory, Duke, Moon, Millgate and Olive for a total of 24 on board.

R-29 flew a mere 23 hours and 8 minutes during the month of November and there was almost no utilization until the end of December due in part to the repairs to the hull and forward car, but more importantly owing to post-war economic restraint being imposed by the government. Repairs notwithstanding, she was otherwise kept in active readiness to help impose a naval blockade of Germany in the event of a breakdown in Peace negotiations.

December 30. Flight 37 lasted two hours and 25 minutes and was conducted over the Firth of Forth "exercising", presumably in conjunction with parts of the surface fleet. Departure was at 1045 and she was secured by the ground crew at 1310. The flight crew comprised Major Thomas with Capt. A.H.Wann (1st Officer) Lt's Catchpole, Haslar, Tuck and Martin. Sgt's Reynolds, Crudgington, Gaunt, Furlonger and Fellows. Cpl. Nash. AM's Moon, Constable, Jones, Baker, Worcester and Gray for a total of 18 on board. This was the only flight conducted in December, bringing the total (known) flight time for the year up to 337 hours and 25 minutes.

1919

January 13th. Flight 38. The purpose of this flight was to test new wireless radio systems. This occupied the better part of the day, bringing the flight time to 8 hours and 22 minutes. Departure was at 0916 and return at 1838. Wann was in command on this flight but crew details were not recorded. Unfortunately the airship struck the side of the shed when being brought in causing damage to the hull structure. This took several weeks to remediate, with no further flight hours being accrued in January or February. She was ready for flight by February 25th.

March 16, 1919. Flight 39 lasted 6 hours and 25 minutes, from 0945 to 1610, in order to continue wireless "DF" trials. Captain A.H.Wann was in command with Capt. Grabowsky (1st Officer), Capt. Barron, (2nd Officer), 2nd Lt's Hasler and Wicks; Sgt's Reynolds and Crudgington; AM's Millgate, Moon and Pickett; Cpl. Taylor; Chief Mech. Pitt, Sgt's Standon and Gaunt; Cpl. Nash; AM's Duke, Victory, Wilkins and Crouch; AC1's Ward and Howlett; for a total of 21 on board.

An inadequate supply of hydrogen and an inability to generate more at East Fortune made any more flights impossible before March 25th. It is not clear if any flights actually occurred in April.

During the month of May R-29 was out of service for modification. It was discerned that the gas cells had deteriorated to the point of requiring replacement due to the extended use of hydrogen of poor purity. The midship car was also completely removed at this time and replaced with a single R-33 Class wing car with one fixed propeller. She was ready for flight by mid-June and departed East Fortune on the 15th for an extended cruise over the Firth of Forth, May Island and Berwick. She was accompanied by the R-34 over Edinburgh and during other parts of the flight, which continued until the 16th. Specifics of this publicity flight were not detailed in the reports. The flight duration was approximately six hours. At least one additional flight with R-34 in consort appears to have been made.

By August of 1919 the decision was rendered to dismantle the R-29 as an economy measure. She was not a candidate for commercial service as she did not possess the appropriate lift or layout characteristics. When the National Physical Laboratory (NPL) learned R-29 was to be deleted, they requested use of the airship in order to conduct a series of full-scale aerodynamic tests. Accordingly, the R-29 was placed at their disposal. To this end four flights were made from East Fortune, one each on September 15th and 16th, as well as on October 7th and 9th.

All NPL flights were commanded by Captain A. H. Wann. The first flight occurred on September 15th, from 1003 to 1803 (8 hours, 30 minutes); the second on September 16th from 1000 to 1845 (8 hours 45 minutes); the third on October 7th from 0950 to 1750 (8 hours) and the fourth on October 9th with lift off at 0948 but an unknown time of return. The last two flights were significant in that the covering of the upper stabilizer was reduced by one half to discern if there would be any impact upon flight stability. For the final flight the top stabilizer covering was removed entirely, but the upper rudder was left covered and operational. These tests will be covered in detail in the next section. From the time of the completion of the overhaul in June until the conclusion of the final flight on October 9th, 87 hours are believed to have been logged.

Orders were obtained to curtail the NPL flying tests and proceed with "strength tests…to be carried out during the destruction of the ship." In other words, the government was getting anxious to be rid of the expense of airships in a difficult post-war economic environment. NPL staff were exasperated because they had little success in obtaining adequate time for full scale experiments upon rigid airships in the first place. R-29 was placed in her hangar at East Fortune and her framework tested to destruction. Measurements were taken on hull members and wires, which were stressed to the breaking point in a variety of manners. This included the over-inflation of gas cells. The destruction testing commenced on October 24th and once completed the airship was broken up for scrap.

The total number of flight hours is uncertain because the duration of the flight on September 4th, 1918, and the duration of the cruise over Edinburgh and the Firth of Forth with R-34 on June 15th , 1918 is not precisely known, hence the indicator (+).

Total flight time for 1918: 337 hours 25 minutes (+)
Total flight time for 1919: 100 hours 33 minutes (+)

Total flight time: 437 hours 58 minutes (+)

R-29 Summation

Total flights: 44 (+)
Total flight hours: 438 (+)
Total patrol flights: 28, possibly 29.
Grand Fleet Patrols: at least one
Convoys escorted: 9
Oil patches/wreckage observed and reported: 7
U-boats observed: 2
U-boats attacked: 1
Drogue trials: Unknown number
Suspected U-boats: 4
Publicity Flights: 2
Flights dedicated to photography: 1
Flights dedicated to training crew: 1
Search missions: 2
Number of patrol flights in which destroyers were referenced as escorted: 8 flights and at least 14 destroyers
Total number of surface vessels escorted by R-29: Impossible to quantify precisely. References to escorting the Inward Force, Grand Fleet, Light Cruiser Screen and a multiplicity of convoys with only a select few vessels actually being named still suggests a fairly large number were escorted. For example, the number of ships in the OZ61 convoy on October 13th alone was 34 ships.

R-29 Experiments and Turning Trials

NPL staff prepared a series of in-flight experiments for R-29. Permission to conduct these was granted by the Admiralty but the tests were cut short and limited to only four flights as an economy measure. Six primary experiments were undertaken. The following is a condensed synopsis of the findings of the tests, as reported in Reports and Memoranda (R&M) 675 followed with supportive data from tests made upon scale models of R-29. It should be reiterated R-29 was equipped with three 275 h.p. Rolls Royce engines for a total of 825 h.p. at the time of the NPL test.

1. Turning trials at various speeds and rudder angles with varied modifications to the upper stabilizer.

To conduct these experiments a sundial was mounted at the top of the climbing shaft near the bow of the airship. This was considered desirable as utilization of a compass only, on a more manoeuvrable airship such as R-29, would result in a higher margin of error. Nevertheless, a master compass was also placed on a temporary mounting next to the sundial. The master compass was normally placed on top of the airship about ten feet behind the climbing shaft opening. It was discerned that using the sundial saved time in experiments rather than using the compass when angular velocity was high.

The upper stabilizer of R-29 was altered twice for this experiment. "R29" represented no change to the upper fin. "R29a" denoted approximately 28 square metres of covering removed from the forward section of the stabilizer (303 square feet). "R29b" represented all fabric removed from the upper stabilizer. No alterations were made to the metal structure of the upper fin of either "R29a" or "R29b"; nor was the rudder modified in any way.

The results of the tests were compared to similar tests conducted upon R-33. It was found R-33 would depart from a straight course by a lesser perturbation than would affect R29b. The R-33 was therefore considered less stable than R-29b (as well as R29 and R29a) due to the stabilizers of R-33 being less efficient and the hull itself being less stable. (The definition of a stable airship was cited as an airship that, for a specific rudder angle, would fly on a straight path and after a disturbance would tend to return to a straight path, even if that path was not the original one and not parallel to it).

The lateral force upon the upper rudder of R29b was 10% greater than with a stabilizer in front of it (as in R29 or R29a). It was noted the tests of R29b were conducted in atmospheric conditions far less stable than the tests upon R29, R29a, or R33. In sum, R29b was more stable than R-33.

2. Observations of course with the rudder set at small angles and amidship.

The accidental unclamping of rudders due to miscommunication corrupted test results on three low speed-turning trials of R29b. Although results were inconclusive, the opinion of Pannell and Bell was that R29b was unstable, but both R29 and R29a would probably be stable in rectilinear flight. The helmsman found R29b to be far more difficult to steer than either R29 or R29a. Indeed, he stated R29b was very inadequate in this regard, yet tests clearly showed R29b to be more stable than R-33. The conclusion was in order to attain proper stability and controllability the control surfaces must comprise a larger amount of the area taken up by the stabilizer. For rectilinear flight, course with rudders locked amid-ship indicated R29 and R29a were probably stable, whereas R29b was unstable.

3. Deceleration trials.

A "cinematographic" camera was utilized to photograph the Ogilvie airspeed indicator and a stopwatch. This permitted pressure readings and the time to be noted at leisure in the laboratory. Nevertheless, visual recordings supplemented this as assurance that data would not be lost.

Three experiments were undertaken. The first test results were spoiled due to the rubber tube to the airspeed indicator having been kinked. For the remaining two tests, atmospheric turbulence was again noted as having an impact upon results. Results were compared with R-33 and R-26. It was found R-33 had a resistance 0.77 times that of R-29. R-26 had a resistance 1.09 times that of R-29.

The mean resistance coefficient was 0.0227 compared with 0.0247 for R26 and 0.0173 for R33. The excess of 9% in resistance of R26 over R29 was owing to about 4% to external keel and 5% due to the improved form of the bow on the R-29.

4. Airspeed measurements for various engine combinations.

Government impatience to shut down airship operations for economic reasons meant curtailment of experiments. Lack of time resulted in speed measurements not being conducted in the detail Pannell and Bell would have liked. Lieutenant Hasler, chief engineer of R-29, assisted matters by supplying a full set of data he had recorded on a previous flight on September 14th. Being aware of the types of tests NPL intended to conduct, he took the initiative upon himself to collect data for comparison. This was greatly appreciated by Pannell and Bell, and his data helped to mitigate the shortage of test results.

Airspeeds for R29a and R29b were much lower than for R29. The speed of R29 was 5% higher than on R29a or R29b when rudders were amid-ship or at 5 degrees. An increase in resistance of 10% due to the removal of the fabric covering occurred. This was cited as a good example of how resistance could become very substantial as a result of a comparatively small protrusion; in this case the exposed girders of the upper fin.

5. Thrust measurements by pressure difference at the amid-ship propeller.

Pressure differences were taken at the mid-ship airscrew with an Ogilvie indicator connected to the pitot tube upstream of the airscrew on one side and on the other side to an adjustable pitot tube located in the slipstream at changing values to the radii.

A correction was necessary due to the presence of the circular radiator situated between the mid-ship car and the hull. Speed observations behind the radiator were made to help assess such corrections. The value of the speed data was negated by the lack of information about static pressure in that area.

Thrust measurements were rendered virtually useless due to interference
from the radiators. A calculation was developed to compensate, which gave a value of thrust coefficient in the same range as found in model experiments.

6. Measurement of the distribution of speed at various locations.

To determine the speed gradient below the forward gondola, the NPL flying head with Ogilvie indicator attached was hauled in at five-foot intervals. The readings of the indicator were compared with those of the R-29's anemometer. The aft side of the amid-ship radiator was also a target area, and measurements here were obtained using an anemometer head fixed to a staff and projected through a hole intentionally cut into the outer cover. A head attached to the side of the car was used for speed reference. The radiator was 4 square metres (16 square feet). It replaced the circular one, which had been in use until the NPL trials commenced.

Speed distribution was tested below the forward gondola and an increase of 17% was detected one foot below the base. Observations of speed behind the amid-ship radiator were 11% low when the forward airscrews were at rest, but 16% high when forward airscrews were running.

Experiments on a Model of Rigid Airship R-29

NPL test findings were correlated with data reported in Experiments on a Model of Rigid Airship R29, by R. Jones, D. Williams, & A. H. Bell, found in Reports & Memoranda 714, published in November 1920. Resistance measurements were taken at different speeds. It was attempted to determine forces and moments on the model in various attitudes relative to the wind. The different upper fins were used to simulate the R29, R29a, and R29b. R&M 714 only dealt with the resistance aspect. Comparisons were deferred to R&M 716, which has not been located by this researcher.

Experiments on the model included:

a. Resistance measurements at zero incidence to the wind, at speeds varying 20 - 65 feet per second.

b. Determination of longitudinal and lateral forces and yawing moments about an axis through the centre of buoyancy of the hull
-various angles of yaw
-rudders amidships inclined @ 10 and 20 degrees to the plane
symmetry of the ship
-fins and cars successively removed from the model hull as tests continued.

c. Determination of longitudinal and normal forces and pitching moments at angles of pitch between -20 and +20 degrees.

d. Measurements of the damping coefficient on the model when oscillating.

Model results proved consistent with full-scale findings.

R-30

Armstrong-Whitworth was to commence work upon R-30 early in 1917. The Admiralty scrapped plans for her in favour of the performance enhanced R-33 type designs, before construction actually commenced. One interesting proposal for R-30 included fitting her with one 12-pounder semi-automatic cannon for use against U-boats. A special gondola was to be built for this purpose 6 metres (20 ft) aft of the control car. She was also to be equipped with anti-aircraft machine guns.

A Note about R-31

Most sources discussing the Howden fire and loss of the R-27 in Rigid Hangar No. 1 also discuss the R-31. The accounts describe how damage from the fire was substantial, repairs to the roof were not undertaken, and that this led to large amounts of rainwater to penetrate.

R-31 landed at Howden on November 6th, 1918 under the command of Major E.H. Sparling because inclement weather at East Fortune prevented a safe landing there. Improved conditions did not occur until November 12th when she left for her new base. En route crew members found parts of her wooden framework under enough stress to cause concern (R-31 was built according to plans smuggled from Germany based upon Schuette-Lanz construction methods). In consequence, Lieutenant Colonel Hicks, in charge on the continuing flight, decided to return to Howden which was still the closest base. She was brought into Hangar No. 1 to await inspection. A Short Brothers work party arrived at Howden within a few days to commence repairs. Their efforts proceeded slowly and interruptions occurred when the Station was placed under quarantine due to Spanish influenza and also the Christmas holiday. Repairs resumed in January but at the beginning of February work stopped. Some sources claim that after being berthed for repairs her hull was exposed to the rainwater entering through the damaged roof which weakened the glued wooden joints to the extent that the airship became unserviceable and was broken up for scrap. But had moisture really permeated the roof and then the airship envelope making the girders unsafe? Most accounts state she was beyond economical repair and remained berthed while a Court of Inquiry was convened. R-31 was then scrapped in February and officially deleted in July 1919. Once again, no copies of the Court of Inquiry have been located, leaving the full details hidden. Was she beyond economical repair or really just another victim of fiscal cut backs? Brian Turpin has doubts and writes:

I find it hard to believe that the RNAS allowed the rain to come in through a damaged roof from the middle of August to November 1918. Howden was probably the biggest airship station with a large number of airships in service during this period. Would their Lordships of the Admiralty have tolerated such a situation for that length of time?

He points out there is a paucity of written evidence regarding this situation and wonders if the roof was actually repaired or partially repaired. He has also discerned the oft repeated statement that after the Armistice no one knew why R-31 was at Howden is not accurate. Certainly Sparling, Hicks and many Howden officials knew why she was there.

The story is told of how the wood was bought by a local firm to be cut up and sold as firewood. Unfortunately the dealer learned after buying it that it would not catch fire as it had been chemically treated to prevent burning.

Mr. Turpin raises a significant point. Secondary sources of information may be erroneous but if they are cited again and again by other researchers, the erroneous data becomes accepted as fact. Whether this is the case with the unrepaired roof of the Howden hangar remains unknown. But more detail would be of interest and perhaps more information lies buried within various archives or in diaries stored in dusty attics. R-31's twin R-32 was far more successful.

Conclusions

Rigid airship development in the United Kingdom was impeded by indecision, lack of commitment, bureaucracy, and conflicting priorities. The 23X class and R-29 in particular was the notable breakthrough, the most useful wartime rigid. She was able to deliver a blow to an enemy submarine that led to its destruction and thereby represented what could have been achieved. Although not technologically on par with German contemporaries, 23X class rigids were capable of sustained patrol which was the prime British objective in the first place. By the summer of 1918 several 23X ships could have been operational provided adequate hangar space was provided. At the minimum, assuming no additional hangars were built, two more 23X ships could have been completed. The loss of R-27 would have had less impact as the R-28 and R-30 could have been ready by the summer of 1918, assuming they had been laid down as soon as No.24 and No.25 cleared their sheds in October, 1917.

Considering the potential if more ships of this class had of been completed, the difficulties of making crucial decisions of this type in time of war are highlighted. This is particularly so for ones involving complex construction such as rigid airship projects. The Navy was lured into their cancellation decisions, unintentionally, by the airship manufactures making exaggerated claims for the speed at which they could build new ships. Armstrong Whitworth and Beardmore promised unattainably short delivery times for the 33 Class ships, with R-33 due in April, 1918, and R-34 even earlier in March. If these timetables were to be believed, why bother with the 23X Class when the much improved 33 Class would be available just as quickly? These claims were unreasonable but no one seemed to question the timing or allow for the unforeseen delays which had been a major factor in all previous rigid airship work.

Paradoxically, the Vickers claim to be able to produce one 23X class airship every two months was not unreasonable, sans bureaucratic interference and frequent policy changes. Their claim for rapid construction was also realistic because of a higher degree of standardization of parts, frames and equipment when compared with the larger, more streamlined airships that would follow. Unfortunately, British policy makers found themselves constantly seeking perfection and trying to match German aeronautical advances when data about the latest Zeppelin was acquired. Decisiveness and forward thinking could have produced practical rigid airships of the 23X class early enough to play an important reconnaissance role during the height of the German U-boat campaign during World War One. Britain could have equalled Germany in terms of building rigid airships of both quality and quantity, albeit smaller, but lacked the will. In this environment, the two 23X class rigids arrived on the scene too late to fulfill their potential.

The 23 Class suffered because Britain lacked experience in airship design and construction, and was deficient in performance terms due to errors made with HMA No.9 on which they were closely based. The 23X Class suffered in the same way, by default, but was at least a better compromise due to a significant leap of faith and belief in the engineering work by elimination of the keel. This class did offer some hope of reasonable performance, a hope which was somewhat borne out by the success of R-29. She was still rather slow and lacked the desired manoeuvrability for attacking U-boats. She also did not possess the endurance required for long patrols deep into the North Sea in company with the Grand Fleet; but was certainly a step in the right direction.

British non-rigid airships were being produced in a variety of sizes with increasing efficiency, improved range, performance, and at a fraction of the cost of either British or German rigid airships. They were increasingly capable of long flights, calling into question the viability of expensive rigid airships of any type for patrol purposes. Although plagued with development problems, the North Sea Class ultimately had the capability to stay aloft for days. NS-11 set a global endurance record of 101 hours for non-refueled flight in 1919, narrowly exceeding the record set by LZ-120. Abbott points out R-26 cost as much as 20 Sea Scout Twin (SST) non-rigids. British pressure airships flew more reconnaissance missions in a few months than all rigid airships did during the entire war. In this context, if the 23X class is to be deemed inadequate, so too were all other British rigid airships produced during and immediately after the Great War. However, within the confines of British rigid airships being produced early enough to contribute something tangible during WWI, the 23X class were the undisputed superior class, as the R-33 class came too late.

Specifications

R-27

Commander Major P. Ommaney
First flight June 8th, 1918 at Inchinnan, Scotland
Main Base of Operations Howden, Yorkshire
Length 164.29 m (539 ft)
Overall Height 22.86 m (75 ft)
Hull Diameter 16.15 m (53 ft)
Spacing of main frames 9.1 m (30 ft)
Number of main longitudinals 17
Fineness ratio 10.14
Volume 28,050 m3 (990,600 ft3)
Weight empty 25,000 kg (55,115 lbs)
Weight 21.9 tons
Typical Gross lift 30,575 kg (67,406 lbs) (1.09 kg/m3)
Typical Disposable Load 5,575 kg (12,291 lbs)
Total lift 30 tons
Useful lift 8.5 tons
Gas Cells 18
Maximum Speed 91 km/h (56.5 mph)
Normal Speed 85.29 km/h (53 mph)
Cruising Speed 72.42 km/h (45 mph)
Endurance Cruising: 23 ½ hours/1690 km (1,050 miles)
Operational Ceiling 2,103 m (6,900 ft)
Crew Variable: 16 to 21
Engines Four 250 h.p. or 300 h.p. Rolls Royce Eagle Mark VI twelve cylinder Vee
Hours flown 89 h 40 m
Termination Destroyed by fire in hangar, August 16th, 1918, Howden, Yorkshire
Cost £120,000 not including gas cells, wireless, guns, engines (supplied by the Admiralty), instruments, and electrical gear, nor profit.

R-29

Commanders Squadron Commander Godfrey M. Thomas, DFC; Flt. Lt. Butcher and Captain A.H. Wann
Length 164.45 m (539.5 ft)
Diameter 16.46 m (54 ft)
Volume 28,033 m3 (990,000 ft3)
Speed 88.51 km/h (55 mph)
Engines See R-27. Chamberlain claims L-33 Maybachs were also tried out in the 23X class, as they had been in the 23 class. He is unique in making this claim and may have been confused with references to the R-33 wing-type car that was later fitted mid-ship upon R-29.
Engines At time of NPL tests according to R&M 675:
Forward and after cars: One 275 hp Rolls Royce each driving two swivelling propellers. Amidships car, one Rolls Royce of 275 hp driving one airscrew. 825 h.p. total.
Propellers Forward and aft: 3 m (10 ft) diameter, 4 bladed, integral. Amidships: One 2 bladed Farringdon, 4.1 m (13.5 ft) diameter.
Gear ratio Forward and aft: 0.512 to 1. Amid-ship: 0.64 to 1.
Useful lift 8,800 kg (19,400 lbs or 8.66 tons)
Bomb load four 100 kg (220 lb) bombs plus smoke bombs and calcium flares
First flight June 20th, 1918, Selby, Yorkshire
Main base of operations East Fortune, Scotland
Hours/Miles flown Mowthorpe: 337 h 25 min. in 1918 and 100 h 33 in 1919 for a total of 437 h 58 min. Abbott: In 1918 she flew 335 hours covering 8,215 miles (est). After the armistice she flew another 16 hours, and then from May 1919 onwards another 87 hours. Deleted in 1919 having flown an estimated 11,334 miles for 438 hours.
Turning radius coefficient 9.8
Dismantled October 24th, 1919, East Fortune, Scotland
Cost £243,000 (est).

Known Crew of R-27

Commander Major P. Ommanney
First Officer Captain Frank Leonard Charmsbury Butcher
Third Officers Lieutenant Phillips, White, Coates, Sprotson
Chief Petty Officers Wiseman, Williams, Thomas, Scull
Petty Officers Crudington/Creedington, Holmes, Hall/Hull, Williams, Spall
Lead Machinist Gilbert, Poore, Sage, Setterfield
Air Machinists Lawrance, Graham, Gilbert, Hicks, Odart, Poore/Posse Hitchcock.
US Navy observer: Ensign Franklin

Known Crew of R-29

The following lists comprises those people known to have flown on R-29 as either crew, observers or as staff of the National Physical Laboratory. It should be remembered that the crew of R-29 was not always static.

Commanders: Major Godfrey Main Thomas (until November 30th, 1918), Flight Lieutenant A. H. Wann (November 30th, 1918 and after), Captain Butcher (in command one flight only November 13th, 1918).
Second Officers: Captain Don, Lieutenant Noel Grabowski (later used the last name Atherstone - October 23rd, 1918 and after), Flight Lieutenant Frank Leonard Charmsbury Butcher. Third Officer: Lieutenant James.

NPL Observers, last four flights:
Mr. A.H. Bell
Mr. E. F. Relf, ARCSc.
Mr. J. R. Pannell, AMIME (Note: Mr. Pannell did not simply take observations, he actively participated in the flying of the airship, taking the place of the rudder man on some occasions.

Alphabetical listing by last name (without consideration of rank) of all those known to have served as crew or who were observers or passengers on board R-29. This list is not considered exhaustive and more research is required. (Asterisk denotes those who were crew on a more regular basis):

Abell, Major G.H.
*Allen, AM, LM (Rigger, Coxswain)
*Baker, AM (Engineer)
*Baker, LM (Wireless)
Ball, Lt. (Passenger/Observer)
*Barker, AM (Rigger)
Barron, John Captain
Barton, AM
Bell, A. H. (NPL Observer)
Bosanquet, Lieutenant Colonel. (Observer/passenger)
*Burton, LM (Rigger)
Butcher, Frank Leonard Charmsbury, Flight. Lieutenant. (Commander on one flight)
Calliu, PO
Catchpole, W. Lieutenant, AFC (2nd Officer)
*Constable, AM (Rigger)
Coombes, H.M., Captain
Cowell, Captain
*Crouch, AM (Wireless)
Crudgington, Sgt.
Dakin, Captain
Daly, Major (Passenger/Observer)
Davies, LM
Dicks, LM
*Don, D. S. Captain (2nd Officer)
*Duke, S. H. Corporal, AM (Engineer in charge of aft car)
Fellows, Sgt.
Fox, H. Lieutenant.
Forlanger, Sargeant
*Forteath, AM (Rigger)
Furlonger, Sargeant.
*Gent, CPO
Grandage, Lieutenant.
Gray, AM
Gaunt, Sargeant.
Greenland, G. S. Captain
*Hackney, AM (Rigger)
Hall, Lieutenant. (Passenger)
Hardee
*Haslar (Haseler), H. N. Lieutenant (2nd Officer, Engineering Officer)
Hemsley, Captain B. W.
Hill, Lt.
Hinton, CPO
*Howlett, AC (Rigger)
*Holt, LM (Engineer)
*Holman, LM (Engineer)
*Homer, Ensign USN (3rd Officer)
Howlett, AC1
*Hunt, R. C. S. CPO (Coxswain) (Commanding Officer, East Fortune)
Irwin, Captain (Unclear if this was Carmichael Irwin - seems probable).
*James, 2nd Lieutenant. (3rd Officer)
*Jefferson, CPO
*Johnson, PO (Engineer)
Johnson, Major (Passenger/Observer)
*Jones, A. M.
King, W.
Leetham, H. A. H. Captain (3rd Officer)
Lindsay, AM
*Lindsay, LM (Wireless Operator)
Lownds, P.S. Lieutenant
Maitland, P. E. Captain (4th Officer. Not to be confused with Brig. Gen. E. M. Maitland).
Martin, Lieutenant.
Masterman, Brigadier General E.A.D. (Observer/passenger)
Millgate, AM
*Moon, AM, LM (Rigger)
Moss, LM
Mutton, PO
*Nash, Corporal. LM (Rigger)
Nollie
Olive, AM
Petrus, LM
*Penny, AM (Rigger)
Pitt, Chief Mechanic
Pannell, J. R. AMIME (NPL Observer)
*Parry, AM (Engineer)
Pickett, AM
Pinkey, Captain
Pitt, Chief Mechanic
Powell, S. P. 2nd Lieutenant. (Passenger)
Probits, CPO
Reekie, AM (Wireless Operator)
Relf, E. F. ARCSc (NPL Observer)
*Reynolds, PO (Coxswain)
Richards, LM
*Richmond, LM (Rigger)
Sandwell, Captain
Savill, CPO
*Semken, AM (Rigger)
Smith, Sergeant F. (RAF)
Standen, PO
Standon, Sargeant.
*Strayden, PO
Stewart, Lieutenant.
Symons, 2nd Lieutenant.
*Taylor, LM (Rigger, Coxswain)
Thierry, Lt. Commander (Observer/Passenger)
*Thirlwall (Thirwell), PO (Engineer)
*Thomas, Godfrey Main Major (Commander)
Tuck, Lieutenant.
Victory, AM
*Wann, A.H. Captain (Commander after final overhaul, at least 4 flights)
Ward, AC1
*Watson, AM (Rigger)
Watson, LM
Wicks, 2nd Lieutenant.
Wilkins, AM
Worcester, AM

Possible crew or observers whose presence on board not yet confirmed:
Wing Captain Masterman
Major P. Ommaney
Carmichael Irwin

Appendix: Letter of Reference Written by Captain A. H. Wann for Corporal H. Duke

The following letter was located in the archives of the Airship Heritage Trust. It coincides with the termination of the airship program as a post-war cost saving measure. Corporal Duke was looking for employment.

RAF Airship Station
East Fortune
24.10.19

This is to certify that Corporal H. Duke has served in H.M.A. Rigid 29 as engineer in charge of the after gondola.

The whole time he has been on the ship he has worked with considerable keenness and energy.

Both in the air and on the ground he brought his machinery to a very high state of efficiency.

I have no hesitation in recommending him as a clever and hardworking engineer with an excellent knowledge of aircraft engines.

A.H. Wann
Capt. HMA R29

Bibliography

Articles

O'Grady, Kent. "Airships in Anti-Submarine Warfare: Allied Airships in the Great War" in Aerostation, Journal of the Association of Balloon and Airship Constructors.Vol. 20, Nr. 2, June 1997.

Turpin, Brian. "The 23X Class Revisited" in Aerostation, Journal of the Association of Balloon and Airship Constructors. Vol. 27, Nr. 3, Fall 2004.

Books

Abbott, Patrick. Airship: Story of R34. Studley: Brewin Books, 1994.

Abbott, Patrick. Airships. Shire Album 259. Princes Risborough, Buckinghamshire: Shire Publications Ltd, 1991.

Abbott, Patrick. The British Airship at War, 1914-1918. Lavenham, Suffolk: Terence Dalton, 1989.

Asquith, Tom and Kenneth Deacon. Howden Airship Station: 1915-1930. Howden: Howden Civic Society, 2006.

Botting, Douglas. The Giant Airships. Alexandria, Virginia: Time Life Books, 1980.

Brooks, Peter W. Historic Airships. Greenwich, Connecticut: New York Graphic Society, 1973.

Brooks, Peter W. Zeppelin: Rigid Airships 1893-1940. London: Putnam, 1992.

Chamberlain, Geoffrey. Airships-Cardington. Lavenham, Suffolk: Terence Dalton Ltd., 1984.

Clarke, Basil. The History of Airships. London: Herbert Jenkins, 1961.

Collier, Basil. The Airship: A History. London: Hart-Davis, MacGibbon, 1974.

Davy, M. J. B. Aeronautics: Lighter-Than-Air Craft. London: Science Museum & HMSO, C1960.

Ege, Lennart. Balloons and Airships. New York: MacMillan Publishing Co., 1974.

Gerken, Louis C. Airships: History and Technology. San Diego, American Scientific Corporation, 1990.

Gütschow, Fred. Das Luftschiff: Geschichte, Technik, Zukunft. Stuttgart: Motorbuch Verlag, 1985.

Hartcup, Guy. The Achievement of the Airship. London: David & Charles, 1974.

Higham, Robin. The British Rigid Airship: 1908-1931. London: G. T. Foulis & Co. Ltd., 1961.

Jackson, Robert. Airships: In Peace and War. London: Cassel & Co. Ltd., 1971.

Jamison, T. W. Icarus Over the Humber: The Last Flight of the Airship R-38/ZR-2. Kingston-Upon-Hull: Lampada Press, 1988.

Johnston, E. A., OBE, FRAeS. Airship Navigator: One Man's Part In the British Airship Tragedy 1916-1930. Stroud, Gloucestershire: Skyline Publishing, 1994.

Lewitt, E. H. The Rigid Airship. London: Sir Issac Pitman & Sons Ltd, 1925.

Masefield, Peter Sir. To Ride the Storm: The Story of the Airship R.101. London: William Kimber, 1982.

Mowthorpe, Ces. Battlebags: British Airships of the First World War. Stroud, Gloucestershire: Alan Sutton Publishing, 1985.

Mowthorpe, Ces: Sky Sailors: The Story of the World's Airshipmen. Stroud, Gloucestershire: Alan Sutton, 1999.

Payne, Lee. Lighter-Than-Air. New York: Orion Books, 1991.

Robinson, Douglas H. Giants in the Sky: A History of the Rigid Airship. Seattle: University of Washington Press, 1973.

Shock, James R. British Airship Station and Hangar Locations. Maineville, Ohio: Privately published, 1998.

Sinclair, J. A. Captain. Airships in Peace and War. London: Rich & Cowan Ltd., 1934.

Sprigg, Christopher. The Airship: Its Design, History, Operation, and Future. London: Sampson Low, Marston, & Company, C1930.

Ventry, Honourable Arthur de Moleyns Lord, and Eugene Kolesnik. Airship Saga. Poole, Dorset: Blandford Books, 1982.

Ventry, Honourable Arthur de Moleyns Lord, and Eugene Kolesnik. Jane's Pocket Book of Airships. New York: Collier Books, 1976.

Whale, George. British Airships: Past, Present, and Future. London: John Lane Company, 1919.

Reports

Monthly Returns of Items of Information: May, 1918 London: Admiralty.
Jones, R. MA, D. Williams, and A. H. Bell. Reports and Memoranda No. 714. Experiments On a Model of Rigid Airship R-29. London: Aeronautical Research Committee, HMSO, 1920.

Jones, R. MA. Reports and Memoranda 716: The Application of the Results of Experiments on Model Airships to Full-Scale Turning. London: Aeronautical Research Committee, HMSO, 1921.

Pannell, J. R. AMIME, and A. H. Bell. Reports and Memoranda 675: Experiments on Rigid Airship R-29. London: Aeronautical Research Committee, HMSO, 1921.

AIR/1 and AIR/2. National Archives of Great Britain (formerly the Public Records Office). Kew, England.