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