Near the end of WW1 Britain had developed and built the Handley Page V/1500,
a heavy bomber designed to be able to bomb Berlin. Though it would never get the chance to do so,
the armistice being signed on the very day of its maiden mission, the development of the Handley
Page had spurred on others to design something even bigger. Enter Walter George Tarrant.
He had founded W.G Tarrant Ltd, it was a well-known woodworking and building contractor
based at Byfleet in Surrey. During the war they had supplied numerous structural components to
other aircraft manufacturers and had a patented method of constructing wing spars that featured
wooden lattice webs. In 1917 Tarrant wanted to move from producing aircraft components to
building a complete aircraft himself; he took out a patent for lattice-braced circular girders that
would be used in large aircraft construction and assembled a small design team. He was joined by
Marcel Lobelle - a Belgian aeronautical engineer - and W H Barling from the Royal Aircraft Factory.
Together, they drew up the design for a very large four-engine biplane bomber towards the end of
1917. Initially, it was planned for the aircraft to be powered by four of the then in-development
43.5L Siddeley Tiger V12 engines, which were expected to produce 600hp– the idea being that
they would be arranged in tandem pairs between the wings. However, it soon became evident that
the Tiger engine was plagued by delays (and in fact it would ultimately be a complete failure)
and so the decision was made to use six of the 450hp Napier Lion engines instead.
Due to this change in engine number, a third wing would be added to the aircraft,
the central wing being of the widest span and the upper and lower wings of smaller but equal span.
In this new configuration two pairs of tandem engines would be installed between the lower
and middle wing and two single engines would be mounted between the middle and the upper wing.
The four tracker and two pusher engines would all drive two-blad fixed pitch propellers. To support
the added weight, additional centre section struts ran diagonally from the upper wing and through the
central wing before connecting with the central lower fuselage – in effect creating a huge – and
hopefully very strong – warren truss. Strength would definitely be needed,
for not only was Tarrants aircraft now going to be exceedingly tall, but it was also still designed
to carry a very heavy bombload. No exact figure was given for a maximum total bombload, but the
designers had intended it to carry approximately twenty 230lb bombs, so based off that it would
have a total payload capacity of around 4600lbs. The bombs themselves would have been carried under
the central section of the lower wing, due to the truss structure connecting the wings,
this heavy load would be spread throughout the entire wing structure, rather than putting all
of it on just the lower wing and the fuselage. The fuselage itself looked very sleek and modern
for the time thanks to Tarrant’s patented design method. It was a streamlined monocoque,
constructed of lattice-webbed circular fuselage frames and covered with 2-4mm of ply. Attached
to the rear of the fuselage was a biplane tail unit. It comprised of two tailplanes,
the lower of which had a horn-balanced elevator, and the upper had a trimming surface that could
be operated by a handwheel in the cockpit. A second elevator was mounted in the tailplane gap,
but I cannot find evidence as to whether this had a balancing horn like the lower one did. It
would not surprise me, as pitch stability was of prime concern when designing the aircraft,
especially after adding the additional two engines so high above its centre of gravity.
The aircraft would be supported by two massive undercarriage structures. Each of these carried
a trio of five-foot diameter wheels that were mounted on a common axel. Each wheel assembly
was attached by struts directly beneath the engine that mounted the interplane struts, as such the
impact from landing was distributed between the three wings and their support structures.
To increase stability on landing and ground handling, the landing gear had
a very wide wheel track of over 31 feet. At one point it seems that the construction
of the aircraft was halted, though this cannot be completely verified. Some news article snippets
from 1919 and 1920 claim that construction paused after the end of the first world war, but many
other sources mention nothing of the kind, either way, it seems that construction of the aircraft
was completed around the middle of spring 1919. Due to the considerable hight of the aircraft,
it was decided to complete its final assembly in a huge balloon shed at Farnborough,
with the finished aircraft being moved in and out of the hangar sideways on a
specially built pair of railway tracks. Tarrant’s prototype bomber was complete
by May 1919, and it was given the serial designation F1765. To a public onlooker it
must have looked almost ridiculously big. The aircraft had a maximum wingspan of 131 ft 3 in,
a length of 73 ft 2 in, and a considerable height of 37ft 3 inches – for comparison that makes it
taller but shorter than the Caproni 90, which was the largest biplane ever built. The aircraft had
been completed to accommodate a crew of six, which included two pilots, however no records show of
any designed gunner emplacements, though it can be assumed that one would be in charge of bomb aiming
and at least another would be an engineer of sorts to manage the six engines. The cockpit was open,
and the rest of the crew could access the fuselage by a pair of hatches below the nose.
For reasons that were about to become painfully obvious, no performance statistics were ever
recorded, but the tabor was wind-tunnel tested by both the Royal Aircraft Establishment and the
National Physics Laboratory. It was estimated to have a maximum speed of just over 110 mph,
a surface ceiling of 13,000 ft and an endurance of approximately 12 hours.
Unfortunately, the reports of the two authorities conflicted - something not ideal when you’re
trying to find out if your new expensive prototype will fly or not – with the RAE suggesting that the
aircraft was excessively tail heavy, and the Physics laboratory suggesting otherwise.
A proposal was put forward to add 1000lbs of lead ballast in the nose to counteract this supposed
heavy tail, but Tarrant strongly disagreed with this, believing the RAE report to be incorrect.
However, the ballast was added anyway, though it is not clearly known whether Tarrant or the
two test pilots assigned to his aircraft were ever made aware of this decision.
On the 26th of May 1919 the aircraft was made ready for its maiden flight.
At the controls were Captains F G Dunn and P T Rawlings, who were accompanied by four
crewmen. After completing the lengthy process of starting the six engines,
which required the use of a large gantry and perhaps the largest Hucks starter ever built,
Dunn carried out a number of trial taxying runs before starting his take-off run.
To begin with, he opened up the four tandem engines mounted between the lower wings, and when
the aircraft was at sufficient speed to lift the tail, he opened up the two upper engines as well.
At this point witnesses saw the aircraft tip over onto its nose, its undercarriage collapsing,
and coming to rest tail-up with the front part of the nose and fuselage crushed.
Immediately follow the crash a catastrophic fire was avoided by the quick thinking of
either one of the pilots or the crew, who engaged the master cutoff switch.
Unfortunately both of the pilots would succumb to their injuries,
but the rest of the crew escaped - with the only major injury being a broken leg sustained by
one Captain T M Wilson, who was flung through the rear section of the fuselage on impact.
A subsequent investigation would conclude that the direct cause of the accident was
the sudden increase of thrust by the upper pair of engines, which caused the aircraft to pitch over.
These engines were mounted 28 feet in the air, and it was strongly suspected that the 1000lb of nose
ballast was unknown to the pilots, otherwise they would never have applied so much power –
especially as the aircraft was running a light load with minimal fuel and no simulated payload.
A second aircraft had been planned, possible as an attempt to develop the Tabor into a commercial
vehicle in the new post-war era, but it would never be built. It was deemed inherently unstable,
and the only way of rectifying it – which included removing the upper wing and engines and replacing
the four main engines with more powerful units – was too expensive to justify. And so the Tabor
would become W G Tarrants first and only foray into aircraft design. No surviving parts of the
aircraft survive today, but it certainly serves as an example that bigger is not always better.
Anyway, I hope you all enjoyed today’s video,
thank you all so much for watching, and I’ll catch you all next time.