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 23.
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
The 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.
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
All 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
HMA 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 firing.
Six 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 prepared slings.
For 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.
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!
Twice 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.
No. 23 recorded 321 hours
30 minutes of flight.
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. Further reading can
be made in our extended
research page on the 23X Class ships