Jetrader - Winter 2017 - 49

Allahabad (India), Singapore, then Darwin
and Charleville in Australia, and ending
in Melbourne. In addition there were
16 optional fueling locations set up along
the way for the aircraft that didn't have
sufficient range capability to go non-stop
between the mandatory checkpoints. At
these checkpoints, such as Marseilles, Rome
and Athens on the route to Baghdad, the
racers would have to refuel quickly because
the time on the ground would count as flying time, whereas time at the compulsory
checkpoints could be spent sleeping, eating, servicing and refueling without any
time penalty.

The Challenge to Britain
During 1933 and into 1934, applications
to join the race came mostly from Britain,
Australia, New Zealand, Netherlands and
United States. But as the initial entries
from Britain were coming in, it was obvious that none of them would have enough
speed and range to be viable contenders.
The global depression was still affecting
British companies - including A.V. Roe,
Handley Page, Vickers and others - and
they showed no interest in developing new
aircraft that only a few people would buy.
In the January 18, 1934, issue of Flight
magazine, there was dismay that America
already had several aircraft capable of winning the race while Britain had none. Their
editors warned that "...no British machine
is in existence [that] could hope to compete against the Americans." With only
10 months remaining to race day, Geoffrey
de Havilland heard the call and was determined that there should be a serious British
effort to meet the challenge. His company
would design and build three identical
racers, to be sold for only £5,000 each,
although the whole project would probably
cost more than 10 times that amount. Thus
was born the de Havilland DH88, soon to
be named the Comet.
Within a week of the announcement by
de Havilland, an order was placed by Jim
Mollison and his wife, Amy Johnson, both
experienced fliers. They would name it
Black Magic. A second racer was ordered by
the owner of the Grosvenor House Hotel of
Park Lane, London, to be flown by C.W.A.
Scott and Campbell Black. A third one was
ordered by Bernard Rubin, an auto racing driver. Rubin hoped to be one of the
pilots, but as the starting day got closer

The de Haviland Comet Grosvenor House, showing its sleek Lines.

he was waylaid by medical problems. Owen
Cathcart-Jones and Ken Waller would do
the flying.

The Competition
An amazing variety of aircraft were
entered in the race, but the two most
impressive were American airliners: a
Douglas DC-2 and a Boeing 247D. The DC-2
was owned by KLM Royal Dutch Airlines and
flown by KLM pilots, while the lead pilot
on the 247D was the flamboyant air-racing
flyer Roscoe Turner.
KLM's Douglas DC-2 was brand new and
would be carrying three paying passengers and mail during the race. It was in
a standard airline configuration without
any auxiliary fuel tanks; consequently it
had to make pit stops at several intermediate checkpoints. For privately owned KLM,
the flight was considered more a routeproving trial than a race. Nevertheless,
KLM ground crews worked quickly at each
stopping point to get the DC-2 refueled and
back on its way.
The Boeing 247D was originally ordered
by United Airlines but completed for Roscoe
Turner. Unlike the KLM DC-2, extra fuel
tanks for the race were mounted in the
cabin. Having been built in 1933, it was
about a year older than the DC-2.

Designing the
de Havilland Comet
To put it simply, the DH88 was designed
to win a race. A cruising speed of at least

200 mph was called for, but to win the
race, it also should be able to fly nonstop between the mandatory checkpoints,
where the longest legs were the first from
Britain to Baghdad (2,530 miles) and then
Baghdad to Allahabad (2,300 miles). While
it was permissible to land for fuel at the
intermediate caches, valuable time could
be wasted there so the Comet had to be
able to lift a heavy fuel load on takeoff.
The Comet would be the first British
aircraft to incorporate three design innovations: retractable undercarriage, essential
for high-speed flight; trailing-edge splitwing flaps to provide drag and extra lift
when slowing to land; and variable-pitch
propellers for both powerful takeoff thrust
and fast cruising.
To keep it simple and light, the undercarriage would be cranked up and down
by the pilot in the front seat, so there
was no need for a hydraulic or electrical system to  do the work. Likewise,
the wing flaps were also operated by
bare-knuckle leverage.
As for the propellers, de Havilland chose
two-position units of French design. The
blades were set to fine pitch before takeoff, and after a speed of about 150 mph
was attained, they automatically snapped
into coarse pitch. The beauty of the system was that it worked by itself, so there
was no need for a propeller control system in the cockpit. The compromise was
that it could not be reset in flight to
fine pitch.
Jetrader * Winter 2017 49
Jetrader - Winter 2017

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