R.29 differed from its predecessors
in that minor modifications to the shape of the hull had given
them slightly more gas capacity, but more important was the elimination
of the external keel corridor. The function of this feature wasw
primarily to distribute the weight of fuel tanks, ballast bags
and similar items. Designers and airship officers alike grew conservative
after the loss of HMA No. 1 due to hull failure, which was largely
the result of the removal of its external keel in order to generate
desperately needed lift. As a result, there was an insistence
upon the retention of external keels in the 23 class for safety.
In reality, with proper design, a heavy external keel was unnecessary.
C.I.R. Campbell realized this and ultimately succeeded in convincing
those with the ability to authorize his proposal that removal
of the keel could be safely accomplished in his 23X class proposal.
Its absence did effect a considerable saving of weight without
causing any significant loss of strength and also to improved
manoeuvrability. 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.
the 23 Class with the 23X Class.
The corridor 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
R.29 was the most successful British wartime rigid, being the
only one to succvessfully engage an enemy U-boat. She was commissioned
on 20th June 1918, based at East Fortune and in a brief operational
career of less than five months flew 335 hours and covered an
estimated 8,215 miles.
Once she carried out a patrol
of over 30 hours, twice more she made a flight longer than 20
She conducted at least: twenty-eight
anti-submarine patrols, nine convoy escorts, one Grand Fleet patrol,
two search missions, investigated four possible U-boat sightings,
successfully bombed and assisted in the destruction of one German
U-boat, observed, investigated and reported seven different sightings
of floating wreckage and oil patches, escorted at least fourteen
destroyers, engaged in an unknown number of drogue trials, and
made at least two photographic test flights. The total number
of ships she protected is unknown, but it must have been considerable.
For example, reference to her escorting convoy OZ61 on October
13th reveals that convoy was comprised of 34 ships alone.
It is widely but incorrectly
believed R29 engaged three German U-boats based upon an error
made by researcher Robin Higham. Her flight records are complete
and reveal no evidence that she ever pursued a U-boat until it
ran onto a mine, so it is quite unknown how this claim originated.
The belief that she attempted to bomb another U-boat, but that
it got away, is based upon a true incident that occurred with
her sister ship R27. R29 in fact only engaged one U-boat, but
this encounter was quite successful.
On Sunday 29th September,
at about half past one in the afternoon and in exceptionally calm
conditions, R.29, captained by Major G. M. Thomas, was escorting
a convoy bound for Scandinavia when a faint patch of oil was seen
discolouring the water near Newbiggin Point. A message, "Oil
patch rising below me," was signaled by Aldis lamp to HMS
Ouse, one of the escorting destroyers, which turned at once to
help. Her captain could not see the slight evidence that was apparent
to the airmen high overhead and he signalled for more information,
"Drop light over it." In reply the airship indicated
the probable whereabouts of the submarine by dropping not a flare
but a 230 lb bomb, the destroyer joining in the attack with two
depth charges as the first explosion subsided.
Then R.29 dropped a second
bomb and a calcium flare to mark the position of the oil patch,
at which point another destroyer, HMS Star, joined with Ouse and
two armed trawlers to add more depth charges to the barrage. At
half past two, HMS Star reported considerable quantities of oil
rising to the surface. destroyers then steamed off to continue
protecting the convoy.
A buoy was placed as a marker
by one of the trawlers and a deep depth charge was dropped, while
R.29 remained on watch for more than an hour. When she at last
left to rejoin the convoy at four o'clock large amounts of oil
were still bubbling to the surface. It was subsequently confirmed
from intelligence reports that UB.115 had been destroyed in the
Although British non-rigids
had several engagements with German U-boats, this was the sole
success recorded by any British wartime rigid.. If the R29 had
not been present, the UB-115 probably would have gone undetected
and it could have destroyed several ships with a concurrent loss
After the Armistice R.29
flew another 16 hours before May 1919, when her midship car was
replaced by a smaller and lighter type containing only one engine
driving a single propeller. In this modified form she flew a further
87 hours, including a flight in June over Edinburgh, Berwick,
May Island and the Firth of Forth, when she was accompanied by
She was finally deleted in
October, 1919, having covered an estimated 11,334 miles in service,
more than any other British rigid up to that time.
the experience gained from the HMA 23 class, the further enhancements
were passed on to the new HMA 23X class ships.