the success of HMA No. 9, further ships were ordered by the
Admiralty. Along with the Vickers Company, three new contractors
were required to produce rigid ships. The Vickers Company had
already proven themselves with the design and construction of
No. 9 and were the only company with any experience of building
a large ship.
23 on take off - notice the mooring lines dangling.
the trials and design success of HMA No. 9, it was agreed that
the Zeppelin threat had to be tackled head on; the Admiralty required
more ships. There were initial problems at the Admiralty with
regards to change of staff and also general opinion regarding
rigid airships, as the successful non-rigid programme was expanding
rapidly. However in June of 1915, along with the Vickers Company,
three new contractors were selected to produce rigid ships.
three new contractors were Beardmore, Armstrong and Whitworth
and finally Shorts Brothers. All three companies were to become
famous in the world of aviation. By October 1915 the drawings
were approved and three ships were ordered. By December the pace
of design and the requirement for big ships had increased dramatically
and a further sixteen ships had been budgeted for by the Admiralty.
All of these ships were to become known as the 23 Class, which
were in effect stretched versions of the original No. 9. The designs
were seen in essence as modified versions of No.9, with an extra
bay inserted in the middle of the ship. A gun platform was added
to the top of the ship designed to take a two pound gun and two
Lewis machine guns. The platform was surrounded by 18 inch sanctions
carrying lifelines. These sanctions could be extended to double
the height in order to carry a canvas windscreen. Three other
Lewis guns were to be fitted at the extreme tail, in the control
car further aft and on the top walking way.
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.. 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).
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
bomb load was to be greater than that of HMA 9 but none was actually
specified. The ships each possessed an external keel, to the same
pattern as the No. 9. The cabin being 45 feet long contain crew
accommodation, a wireless room and a bomb room. From the keel
further aft were three gondolas which were suspended below and
accessible by open ladders. The ship gondolas also contained airtight
buoyancy bags in case the ships had to alight on water. This was
a technical requirement of all ships since HMA 1 - the Mayfly.
With this rapid expansion of the requirement for airship production,
there were a few problems in that so far, only one company had
actually built a ship and hence had all the facilities.
However to help the programme Vickers provided components to the
other three companies to assist in production. The original ships
were divided out between the various contractors and the registrations
were allocated between them. Vickers recieved H.M.A
In April 1916 the Government approved for a total fleet of 10,
23 class ships, but this was later modified in the light of further
design technology available from Germany. The later ships becoming
the R23X class and the R31 class.
HMA 23 was the first to be completed, and hence the designation
of the class of ships. There were a number of delays in the initial
constructions and the ship was completed on 26th August 1917.
On lift and trim trials, the HMA 23 was found to have a disposable
lift of only 5.7 tons due to the machinery being two tons heavier
than originally estimated. Although not unexpected, the figures
were disappointing and 2 weeks later on the 18th October the Admiralty
decided that the design must be altered. The alterations to the
ships included the removal of dynamos and bomb frames and many
other items which were deemed not necessary were removed.
measures to be undertaken were aimed at lightening the airships
by the elimination of all unnecessary weight. In addition to removal
of the dynamos, buffer wheels and bomb frames, many other small
items not considered essential were either taken out or replaced
with lighter equipment. The folding tables which had been intended
for the keel cabin were never installed and the original plan
of fitting a two-pounder gun on the top platform was also discarded.
The rear car was replaced by a smaller and lighter one containing
an engine with direct drive to a single two-bladed propeller 13
feet 6 inches in diameter. As there was now no space for the auxiliary
controls, these were transferred to the keel cabin.
Some of these modifications had already been carried out on the
first three ships, while others followed in due course. Together
they effected a marked, if not substantial, improvement to the
four of the 23 class airships were flown extensively, but although
rather more efficient than No. 9 they still did not provide the
performance which had been hoped for.
23 herself had been commissioned on 15th October 1917, and left
on that day for Pulham. She had a top speed of 52 mph and flew
a total of 8,426 miles in 321 hours and 30 minutes. Although she
carried out some patrols, usually under the command of Captain
I. C. Little, she was used mainly for training and experimental
work. Trials were undertaken in January 1918, at Pulham with a
two-pounder gun in its mounting on the top platform of HMA 23.
The gas valves were placed on either side of the hull rather than
at the top to, avoid risk of escaping gas being ignited during
shells were fired with the gun pointing downwards, but instead
of embedding themselves in the mud of the airfield as expected,
they seem to have ricochet into the surrounding countryside. The
airship took the strain well, although some flexibility was present
which would have adversely affected aiming under combat conditions.
No further action was taken in the matter because of the ever
present weight problem. Later in 1918, HMA 23 was involved in
another experiment, this time to determine whether an aeroplane
could be carried by an airship and released in mid-air either
to repel attackers or to take offensive action on its own account.
A Sopwith Camel was suspended beneath the envelope by specially
the first trial, a dummy was placed in the cockpit and the controls
were locked. As the airship flew over Pulham air station the aeroplane
was released. It glided to the ground, showing that the slipping
gear operated correctly. Another Camel was then taken up, this
time piloted by Lieutenant E. Keys. As the aeroplane left No 23
the pilot had no trouble in starting the engine. He pulled out
of the dive to fly around the airship before landing safely.
provision had been made for retrieval of the aeroplane during
flight, as the intention was that it should make its own return
to base after action. As with other unusual projects tried out
during the war, nothing further was attempted. Similar trials
were held after the war with R.33, and the method was eventually
perfected by the Americans in the early 1930s. A noteworthy departure
from routine training and testing befell No 23 on 6th December
1917, when she was sent to make an unannounced daylight flight
over London, arriving out of the mist from Pulham around midday.
At a low altitude she circled over Buckingham Palace, Whitehall
and the City, where thousands of Londoners clearly saw the lights
twinkling in her gondolas; the red, white and blue roundels on
her envelope and her designation numerals. Wartime censorship
allowed press reports of the incident ("At last. ..a British
Zeppelin"), but the airship's number could not be published,
despite its having been so publicly displayed!
in the following year No 23 flew again over London, on one occasion
accompanied by R.26, but these appear to have been the high points
in an otherwise mundane and unwarlike career. She was deleted
in September 1919.
23 recorded 321 hours 30 minutes of flight.
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. Further reading can be made in our extended
research page on the 23X Class ships