The Proteus Bluebird was unique in many ways, not
least in being the first car designed for a world
land speed record attempt to use a gas turbine engine.
The unit chosen by the Bluebird’s designers
(the Norris Brothers) was a Bristol Siddeley Proteus
755, known to engineers at the time as a free turbine,
but these days referred to as a "turbo-prop".
The Proteus drove all four wheels of "Bluebird",
and at full throttle delivered 4,250 horse power.
There was no clutch and a fixed gear ratio, providing
two-pedal control. Like all turbines, the Proteus
turned over much faster than a piston engine, delivering
maximum power at 11,000 rpm.
The Bluebird was 30 feet
long, 8 feet wide, and 4 feet 9 inches high without
its removable fin (with the fin in place this stretched
to 7 ft 8” high).
It weighed a relatively modest 9,600 lb when
ready to run, and has a front track of 5 feet 6 3/4
inches and a rear track of 5 feet 6 inches.
Naturally
enough the Bluebird used aviation turbine kerosene,
and it was fortunate that BP was helping sponsor
the car, given it consumed fuel at the rate of about
one-and-a-half miles per gallon at full speed.
On Donald
Campbell's record attempt at Bonneville Salt Flats,
Utah, in 1960, the Bluebird accelerated from a standstill
to nearly 400 mph over one-and-a-half miles in 24
seconds.
Most surprising was that less than 80 per
cent of full power was then being used. This Bluebird
was then severely damaged after a huge crash later
in the same month.
The car was completely rebuilt,
thanks to the generosity of Sir Alfred Owen, with
the only noticeable changes being a different shaped
cockpit cover and the addition of a tail fin for
extra stability.
The first trials of the rebuilt
Bluebird CN7 took place at Lake Eyre in Australia
in May 1963, with the world land speed record being
set at 403.10 mph at Lake Eyre on
17th July, 1964 after months of torrential rain and
flooding.
The Proteus engine used in "Bluebird" was
of the same type used to propel the fastest warships
in the world, the Royal Navy's "Brave" class
fast patrol boats. Like all gas turbines of this type it delivered high power
for its bulk and weight, being 8 feet 01 inches long and 40 inches in diameter,
and weighing about 3000 lb.
It required no cooling system, and no clutch because
it used the equivalent of a fluid torque converter.
The output shaft was coupled permanently and directly
to bevel gears in both the front and rear axles.
The engine turbine provided no engine braking on
the over-run at low speeds, but at 400 mph approximately
500 hp was available for braking when the throttle
was closed.
There was, however, two rather more ingenious
braking systems fitted to the Bluebird. Power-air
flaps opened out from the rear of the vehicle, and
power operated Girling disc brakes were fitted to
all four wheels; remarkably for the time these discs
were able to run at a maximum temperature of 2,200
degrees F.-almost white hot.
The Bluebird's complex
cockpit instrumentation was reflected onto the windscreen
and focused onto the horizon ahead so that Campbell
could see the course and his instrument readings
simultaneously.