Click here to return home 


Length 539ft
Diameter 53ft
Speed 57mph
Engines 4 x 300hp
Volume 990, 000cft

The 23X class was a development of the 23 class, itself often seen as merely an improvement to the No 9 design, however there were some radical changes and lessons learnt. Four of the class were originally planned, with numbers running consecutively from R.27 to R.30, but following the downing of the L-33 virtually intact, the British were able to re-think the programme and R.30 were cancelled in order to concentrate resources on the new R.33 class. R28 enjoyed a reprieve and it's construction was transferred to Vickers, but then it was cancelled to make way for Barnes Wallis' much more advanced R80 design.

R.27 its predecessors in that minor modifications to the shape of the hull gave it slightly more gas capacity, but more important was the elimination of the external keel corridor. The function of this feature was to distribute the weight of fuel tanks, ballast bags and similar items. Designers and airship officers alike grew conservative afte the loss of HMA No.1 due to hull failure, which was largely the result of the removal of it's external keel in order to generate desperately needed lift. As a result, there wa an insistence upon the retention of external keels in the 23 class for safety. In reality, with proper design, a heavy external keep was unnecessary. C.I.R. Campbell realised this and untimatley succeeded in convincing those with the ability to authorise his proposal that removal of the keep could be safely accomplished in his 23X class proposal. It's absence did result in a considerable saving of weight without causing any significant loss of strength and aslo to improved manoeuvrability. The various loads were concentrated at the bulkheads

The various loads were concentrated at the bulkheads and suspended from the radial wiring which maintained the hull in its correct polygonal shape. It is important to stress that what Campbell accomplished with R27 and R29 was not just the removal of an external keel, but the elimination of the keel altogether. Only an internal corridor, not an internal keel, was provided to allow the crew to travel between the cars. This was never attempted with any other rigid airship design.

Compare the 23 Class with the 23X Class.

Graphic copyright N Regamey

An internal corridor which allowed the crew to travel between the cars was formed by inverted U-shaped ribs positioned above the two lowest longitudinal girders, the surrounding gasbags being appropriately shaped. The corridor also gave access to the ballast bags and petrol tanks. The latter were interconnected by a long, wide aluminium tube running underneath them, an arrangement which helped with refuelling and could be used in an emergency to jettison fuel.

The four engines were again Rolls Royce Eagle V12 designs, but they were the later Series 6 models, which produced 300 hp at full revolutions. The engine arrangement was the same as that used originally for the 23 class ships, with pairs of swivelling propellers in the forward and after gondolas and twin engines driving fixed propellers in the midship car. The radical and original decision to do without a normal keel was fully vindicated when the first trials were held. Not only were the two airships able to turn more quickly than their forerunners, but the real benefit was found when the lift and trim tests were held; the disposable lift was more than 8 1/2 tons, much better than any previous British airship and allowing a more effective bomb load to be carried as well as sufficient fuel for extended cruising. One handicap common to both ships, as well as to their predecessors, was the absorbent nature of the hull's outer covering of doped linen; a few hours of rain could add around a ton of water to the weight.

R.27 was commissioned on 29th June 1918, under the command of Major P.Ommaney. She was immediatley deployed upon anti-submarine patrol duties, completing fice flights in two weeks. On August 12th she encountered a German U-boat and bombed it, but it managed to escape (this incident has invariably been confused with R29, which had another, more successful U-boat experience). FN source. Unfortunately, R27 had a very brief career.



Shown here is the R27 in Pulham shed with 3 Coastal class ships.

On 16th August she was in the hangar at Howden at the same time that some American riggers were helpfully trying to make a new airship as a give to their British hosts by attaching a spare SS Zero car to a disused envelope (This airship has often erroneously been referred to as SSZ-23). While they were completing the job some petrol was either spilt into the ca or petrol fumes were ignited (both versions of the cause have been documented) This was in turn ignited a little later by a spark when an unsuspecting operator came to test the W/T (Wireless) equipment. The flames, fed by both fuel and gas, expanded within seconds into a conflagration that totally destroyed not only the makeshift blimp and R.27, but also SSZ.38 and SSZ.54, which had been moored nearby. The envelope's of SSZ-62 and SSZ-63 burned but their cars were not damaged at all. The hangar itself survived, although with badly damaged roof. Several other airships stationed at Howden that day survived, although most were not in this shed. One airman who failed to get out in time lost his life.

R29HMA 23 X Class With the experience gained from the HMA 23 class, the further enhancements were passed on to the new HMA 23X class ships.

Related ships: HMA 1, HMA 9, HMA 23, Airship Movie Page

Copyright © 2023 Airship Heritage Trust. All Rights Reserved. Copying and/or redistributing of any files is illegal under international copyright law. Airship Hertage Trust is not responsible for the content of external sites.