To
the members of her crew, His Majesty's Airship R34 was known as
'Tiny' - inevitably. The ship was enormous: as big as a contemporary
'Dreadnought' battleship. Her overall length from bow to stern
was 643 feet, twice as long as a football field; her maximum diameter
was 79 feet and her overall height just short of 92 feet. Her
cost was around £350,000 and her total gas capacity was
1,950,000 cubic ft, giving a gross lift of about 59 tons and a
disposable lift, when the weight of the structure and permanent
fittings was discounted, of 26 tons. Like her sister ship, five
engines were fitted, each of 250h.p.
At the time,
German technical development had been kept under close observation
and R34, in particular, had departed from the engine plan of L.33
to follow instead that of the later and more advanced L.49, which
had been forced to land in France in October 1917. The former
ship had boasted six engines: one to each of the three forward
propellers, one to the rear propeller and two driving small 'wing'
propellers by shaft. On the latter vessel, the designers had done
away with this cumbersome arrangement, eliminating one engine
and the two wing propellers entirely, harnessing the power of
two rear engines to a single enlarged propeller.
Construction
began at the Beardmore Inchinnan airship factory in 1918. The
whole framework was varnished to prevent atmospheric corrosion
and heavily braced by wiring. Lengths of linen fabric were stretched
between each pair of frames, where they were attached by laces.
Narrow strips were then glued over the lacing and the covering
of the hull was painted with dope containing aluminium powder,
to reflect sunlight and so reduce superheating. In the chambers
formed by the main circumferential frames and the longitudinal
girders were the gasbags, nineteen in all and made of one thickness
of rubber-proofed cotton cloth, varnished and lined with goldbeaters'
skins. Each gasbag was contoured to fill all the available space
and was surrounded by cord mesh to prevent chafing against the
girders. Following the same design as the R33, beneath the main
body of the airship, suspended by long, wooden struts and braced
rigging wires, were four small gondolas.
As designed
in the R33, the forward gondola, appeared to be a single unit
some fifty feet long, but was actually made up of two parts separated
by a narrow gap, intended to prevent vibration from the engine
affecting the W .T. equipment. Incorporated in the forward section
were a control room and a small wireless cabin, below which, during
flight, trailed a long aerial. The control cabin was fronted with
'Triplex' safety glass and had handling rails mounted on each
side. Here were the steering and elevator wheels, the gas-valve
controls, the engine telegraph, the various navigational and WT
instruments and the toggles controlling the emergency forward
water ballast. Connecting the control-cabin with the keel was
a ladder, protected from the elements by a streamlined canvas
cover. Another cover similarly enclosed the numerous control-wire
connections that led up into the hull. In the rear section of
the forward gondola was the first of the engines, driving a single
pusher propeller 17 feet in diameter. In the middle of the lower
hull amidships were the two smaller 'wing' gondolas housing an
engine together with reversing gear -a refinement that enabled
the airship to be operated if those in the main control-cabin
failed. The rear car was ringed with a rail to assist handlers
and, as with the forward gondola, two 'bumping bags' of compressed
air were positioned underneath to help cushion landing shocks.
Each of the five engines was a Sunbeam 'Maori': a new type designed
for the Wolverhampton firm by a Frenchman, Louis Coatalen, and
intended specifically for airship use but clearly inferior to
the Rolls Royce engines used by earlier British rigids. Unfortunately,
no Rolls Royce engines could be made available as all those produced
were now reserved for aeroplane use. The Sunbeams had been accepted
reluctantly. Each engine had twelve water- cooled cylinders, which
were intended to produce full power at a theoretical 2,100 rpm,
although in practice it was rare for 1,600 r pm to be exceeded.
In the forward and wing cars, the radiators were mounted externally
and controlled by folding shutters. The after gondola of R34 contained
two engines geared to one propeller.
The engines
were each fitted with a hand starter, while the drive to the propellers
was through a sliding Hele Shaw dog-clutch and a reduction gearbox
with a ratio of 1:3.86. The clutch enabled the engine to be started
and warmed up before flight without endangering the handling-party
and made it easier to carry out repairs in the air. If the engine
should be stopped during flight, the disconnected propeller could
rotate freely in the airstream to reduce head resistance, although
if it was required to remain stationary for landing or any other
reason, a special brake was provided for this purpose. Assuming
that the airship was still moving forwards, the engine might then
be started by releasing the brake, engaging the clutch again,
and allowing the airstream to turn the engine.
In addition
to the gondolas, a considerable amount of space was available
also inside the hull and invisible to the outside observer. Running
almost the entire length of the ship was a long keel corridor,
consisting of a succession of A-shaped frames standing on the
two lowest girders, and with three auxiliary longitudinal girders
of their own to fence off the surrounding gasbags. At its widest
part, this corridor was about 10 ft across, narrowing somewhat
towards the extremities. Leading to the wing and after cars were
narrow ladders, fully exposed to the force of the elements. It
had been discovered following tests on R33 that the turning co-efficient
of the two airships was 6.4, giving a minimum turning circle some
4,100 feet in diameter. However, so strong was the effect of the
slipstream of the after propeller acting on the rudder, that with
the forward engine still and the wing propellers both running
in reverse, it was possible for R33 and R34 to pivot virtually
on the spot.
Designed slimmer
than the theoretical ideal, the aerodynamic shape of R34 was a
distinct improvement on most earlier designs - her total air resistance
being only seven per cent of a hypothetical flat disc of the same
diameter. In later airships, this was reduced even further, but
in her own day the streamlining of R34 was excellent and twice
as effective as that of her British predecessors. Even though
the R34 was designed during a time of war, the R34 was never fitted
with a full armament. In addition to bomb racks, the original
plan had been to include a ventral 'gun house' behind the rear
car, which would carry a one-pounder Pom-Pom and two Lewis machine
guns. Another Lewis gun was to be mounted on the rear platform
behind the tail, while six more were to be shared equally among
the two wing-cars, the forward gondola and the top gun platform.
A further arsenal of weapons was tp include two-pounder quick-firing
guns which were to be placed on each side of the hull and two
more were to join the Lewis guns on top. This heavy armament was
presumably intended for defence against German Zeppelins, but
in the event the gun house was never fitted and the number of
guns was considerably reduced. The original specification showed
that her bomb-load was quite considerable: twenty at 100 lb and
four at 550 lb.
The firm of
William Beardmore and Company Ltd. of Inchinnan near Glasgow began
work on R34 on 9 December 1917 and she was completed just over
a year later. Preparations to H.M.A.R34 were completed in December
1918 and her lift and trim trials were carried out successfully
on the 20th of that month. By the time R34 was ready for her test
flights, the war was over and she was too late to see active service.
On 30th December 1918, while bad weather delayed the trial flight,
the Admiralty agreed to lend their airships to the Air Ministry
for long-distance trials. R34 was specifically mentioned but because
of the persistently bad weather it was not until the following
March that she left her hangar at lnchinnan, near Glasgow, where
the Beardmore Company had their works.