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This article was first published in 2006.
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The Bluebird, driven by
Donald Campbell, is one of the most exciting cars ever made. Not only did it set
a Land Speed Record of 403.1 mph (649 km/h) in 1964, but it did so driving all
four wheels.... This article is based on a publicity pamphlet issued in 1963, just
prior to the record attempts taking place.
In addition to excellent
technical detail, it shows clearly the pride that British companies took in being
part of the record-breaking attempt.
The Bristol
Siddeley Proteus
Donald Campbell
and his team realized from the start that the new Bluebird would have to be
powered by a turbine and the obvious unit was the Bristol Siddeley Proteus which
had already established itself as a world beater.
It was the first
large turbo-prop to be approved for use in commercial aircraft and is one of the
most powerful turbo-prop engines in international airline service. Ten airlines
make world wide use of the Proteus in Bristol Britannia aircraft which are also
used by RAF Transport Command. Well over 2 million flying hours have been
accumulated.
In 1959 a pocket power
station big enough to supply all the electrical needs of a town of 10,000 people
was commissioned in the West of England. Since then four more have been built.
The alternators are Proteus powered.
It was also in 1959 that a
new class of fast patrol boats was commissioned by the Royal Navy. They were and
still are the fastest warships in the world with a top speed of over 50 knots.
Three Proteus engines power each ship. Since then the navies of Denmark, Italy,
Germany, Sweden and USA have ordered Proteus engines for marine application.
The advantages
of the Proteus for the world's land speed record car are its high power to
weight ratio and small size. It is a high compression engine featuring the free
power turbine principle with the second two stage free turbine driving the front
and back wheels.
Proteus drives
all four road wheels and, at full throttle, delivers almost 5,000 brake
horsepower.
Chassis and
Body Structure
The Bluebird was
built by Motor Panels (Coventry) Ltd. The designers devised a structure which
combines maximum strength and rigidity with very light weight; this was achieved
through the use of a special light alloy foil formed into a ''honeycomb''
sandwich ¾ inch thick and faced on either side with high duty aluminium alloy
sheeting, the whole being bonded together by a special process using heat and
pressure.
The main beams of the frame
run the entire length of the vehicle from front to rear. High stress points were
reinforced by inserts, stiffeners and diaphragms. The beams were joined by four
cross-members forming separate compartments - the cockpit, engine gearboxes and
wheels. This structure was covered with a stressed skin of aluminium alloy to
form the body.
The whole was a completely
hand made structure measuring 30 feet long and 8 feet wide; manufacturing
tolerances were expressed in ten thousandths of an inch. High precision
components, machined brackets and special very high tensile nuts and bolts were
produced at Darlaston by another member of the Owen family of companies, Rubery
Owen & Co. Ltd, who worked closely with Motor Panels.
Bluebird was
constructed by an extension of a method employed in the aircraft industry.
Absolute accuracy was paramount; to achieve this Motor Panels evolved a
technique whereby the car was built over a heavy steel base plate mounted in
concrete.
Four jacking
points, one just inside each wheel, carried the body whilst it was being
assembled, and formed the main rig and datum. Wooden formers were made to
maintain close limits and uniformity on individual panels. These formers were
used for shaping and flanging the alloy sheets. Where panels had to be shaped to
match the outer contour of the car, wooden ''egg box'' jigs were employed.
The problem of
skinning was solved by hand-forming the outer panels to the diaphragms and
stiffeners already in position. After fitting, the individual skins were riveted
into position. Particular care was given to the smoothness of the surface to
avoid unnecessary air turbulence while the car is travelling at high speeds.
Bluebird's shape
is of advanced aerodynamic design, evolved from a long series of wind tunnel
experiments at the Imperial College of Science & Technology in London.
Transmission
The power turbine of the
Proteus Engine drives two special David Brown gearboxes through Dowty Rotol jack
shafts and barrel couplings, at a maximum input speed of 12,000 rpm.
Each gearbox
weighs only 380 lbs, and has to transmit 2,500 hp. At full engine power they
generate heat equivalent to 40 kilowatts. The two gearboxes have a fixed
reduction ratio of 3.6 to 1 and drive all four road wheels through Birfield
constant velocity couplings and floating half shafts.
This arrangement has the
great advantage of ensuring even torque to all four wheels. There is no clutch,
for the transmission is automatic through the gas stream between the primary and
power turbine stages, there being no mechanical link or connection between these
two turbines.
The Proteus is
started and the compressor run up to a predetermined speed with the car held on
the brakes. The brakes are then released and the vehicle accelerates according
to throttle opening.
The power
turbine absorbs the excess energy from the gas eflux from the primary stage.
Full power cannot be applied until the Bluebird has reached 400 mph, at any
lower speed it would result in drastic and catastrophic wheelspin.
The transmission layout is
in the simplest form and although differentials are incorporated in the system,
they are normally locked. A free-wheel arrangement operates with the front drive
shaft since, during braking, the weight of the car moves forward and has the
effect of decreasing the radium of the front wheels, thus causing them to rotate
faster than the rear wheels. This action could lead to the breaking of the half
shafts, which is prevented by the use of the free-wheel system.
Wheels and
Tyres
No tyre had ever before
been made to withstand the stresses imposed at the speeds envisaged for the
Bluebird. At 450 mph these are just 100 times greater than on the Railton
Special at 394 mph. The Dunlop Rubber Co undertook the formidable task of
solving the many problems involved. Their underground test plant, specifically
designed and constructed for this purpose, alone cost 150,000 pounds
Stirling.
After exhaustive trials,
Fort Dunlop produced a tyre with an outer coating of 1/50 inch natural rubber
covering multiple layers of rayon cord. The tyre and tube (also of natural
rubber) weighs 50lb and is inflated with nitrogen at over 100 psi. The diameter
is 52 inches.
The Dunlop Rim and Wheel Co
developed steel wheels, using ultra high quality forgings. The wheels, which
will rotate at nearly 3,500 rpm, must be very accurately balanced. The tyre and
wheel assembly weighs 245 lbs, and the Dunlop Company developed special
hydraulic equipment to facilitate rapid wheel changing during the short period
available for turn-round during a world record attempt.
Brakes
The Bluebird is equipped
with special power-operated Girling disc brakes, fitted outboard on each side of
the two gearboxes. At a full power stop the Ferodo pads or linings on these disc
brakes will run at a peak temperature of 2,200 degrees Fahrenheit, in fact
practically at white heat.
The Bluebird weighs 9,600
lb, and to stop the car from 450 mph in five miles means dissipating 76 million
foot pounds of energy in 60 seconds.
The Girling disc brakes,
with their Ferodo pads, will have to deal with 36 million foot pounds of this
total; braking power equivalent to stopping 400 fully laden saloon cars from 40
mph.
Weight is a critical factor
and Girling met the challenge by developing twin caliper discs. Each caliper,
made of magnesium alloy to save weight, consists of three pairs of brake
linings, acting on either side of each of the rotating discs. There are 24 pairs
of linings in all. The discs are keyed into the driving hubs so that they can
slide along towards the fixed linings as wear takes place. They are power
operated with compressed air.
The brakes are actuated by
a duplicated electro-pneumatic system devised by Electro-Hydraulics Ltd in
conjunction with Girlings & Norris Brothers.
The brake linings
themselves, made and developed by Ferodo, required the development of a special
friction material. The result is a pad which has withstood more severe and
continual punishment on inertia dynamometer tests than any other brake lining in
the world.
In addition to the Girling
discs, aerodynamic or air brakes are incorporated for use above 400 mph - in
this case two flaps open on either side of the rear of the car in order to
provide greatly increased air drag. They are actuated by a pneumatic hydraulic
system developed by Electro-Hydraulics Ltd.
Instruments
It is imperative
that the pilot should have continuous knowledge of both the speed of Bluebird
and the rate of acceleration while, at the same time, keeping his eyes on the
course during the record bid. For the first time in any vehicle, the readings
from speedometer and accelerometer will be projected on to the windscreen and
focused on the horizon ahead of the car so that Campbell will not have to move
his eyes or change their focus.
Smiths Motor
Accessories Ltd developed this new instrument display through the use of a
collimating lens - a lens that bends the light rays to make the object appear to
be at a distance. The new system is now being applied to high speed
aircraft.
Campbell will see two dials
- the lower, the speedometer, the upper, the accelerometer. The speed dial
revolves against a fixed pointer and it is calibrated from zero to 500 mph. The
accelerometer dial remains stationary and a pointer moves over its figures: 1,
3, 4, 5, R. When the car is travelling at 100 mph, the pointer must not exceed
the figure 1. At 200 mph it must be midway between 1 and 3; at 400 mph it must
not exceed 4 and so on.
A constant
balance must be accurately maintained between speed and acceleration since there
is a limit to tyre adhesion. The faster the vehicle is traveling, the less the
maximum permissible acceleration. The letter ‘R’ on the accelerometer represents
the highest permissible rate of deceleration or braking.
The Bluebird's
behaviour during the course of each trial run will be recorded on a special
electronic instrument carried within the vehicle. Smiths scientists developed
special transducers which send the information to the central brain. This will
record such factors as power, ground speed, acceleration, rate and degree of
roll, yaw, and the rate and degree of movement of the steering and suspension -
thus engineers will have a complete record of actual performance to match
against the computed figures and wind-tunnel data.
Control and
Hydraulic Systems
The Bluebird is 30 feet
long, 8 feet wide, with an overall height of 4 feet 9 inches. The wheelbase is
13 feet 6 inches, the track 5 feet 6 inches. The top of the aerodynamic fin when
fitted stands 7 feet 8½ inches from the ground.
The steering is
manual and in no way power-assisted. The primary movement on the steering wheel
is transmitted through a bevel gear box, duplex chain and sprockets, to a
special Burman recirculating ball system connected directly to the track rod.
The road wheels have a maximum movement of 4 degrees either way.
Suspension is
fully independent with wishbones and Girling Oleo pneumatic integral spring and
damper units permitting a vertical wheel movement of 2 inches. Units are
inflated with nitrogen and the spring rate is variable in accordance with the
pressure used.
The disc brakes
are operated by a duplicated electro-pneumatic system devised and installed by
Electro-Hydraulics Ltd, another member of the Owen family of companies. Movement
of the brake pedal progressively opens a valve admitting compressed air from
high pressure storage bottles through a network of lines and shuttle valves to
the disc brake units. In the event of failure, the pilot is immediately able to
turn to the emergency system through the operation of a selector valve in the
cockpit.
The parking
brakes form a third and completely independent system; they also are
pneumatically operated from a separate set of high pressure storage bottles and
are controlled by a lever valve from the cockpit. The parking brakes are either
full on or full off.
The air brakes
are hydraulically operated and controlled by the pilot through a system
developed by Electro-Hydraulics in association with Norris Bros; these
aerodynamic flaps are opened by two pneumatically-actuated hydraulic jacks, one
of which displaces the other to prevent any risk of a flap opening on one side
only.
The chassis incorporates an
integral jacking system to facilitate handling and rapid wheel changing during a
record attempt. An Electro-Hydraulic jack is built into each of the four wheel
bays and these are actuated by an external Dowty hydraulic power pack, which is
plugged into the control panel; the jacks may be operated independently or
together.
Fuel and
Lubricants
Donald Campbell will use BP
fuel and lubricants as he has done in all previous record attempts. Two special
fuelling vehicles were built by BP for the Bonneville Salt Flats and they will
also be used in Australia to carry the Aviation Turbine fuel which powers the
Proteus.
Bluebird's fuel
consumption is about one gallon a mile at top speed, and in order to refuel
after each run, the fuelling vehicles will be positioned at either end of the
course.
Apart from fuel,
BP is supplying seven different lubricants and greases for the engine,
gearboxes, steering, wheels, brakes and general greasing.
Some of these products had to be specially
developed to meet the severe stresses at high speeds, stresses far beyond
anything encountered with ordinary cars. The most difficult problem was
formulating a lubricant for Bluebird's two gearboxes, where the load is as much
as 4,000 pounds per inch of gear tooth width. The lubricant had to be thin
enough to provide lubrication and yet not break down under extreme stress. At
first it was thought that a castor base oil such as that used for racing cars
would be suitable, but even this was not strong enough to stand up to the
enormous pressures. After much testing a suitable oil was found, basically an
engine oil but containing special additives.
Specifications
Country of Manufacture: Great Britain
Engine: Bristol-Siddeley Proteus 705 gas
turbine aircraft engine (modified to have driveshaft at each end), Compressor 12
axial-flow stages, 1 centrifugal stage, 8 combustion chambers 2 two stage
turbines. Maximum Power, 5,000bhp at 11,000-11,800 power turbine rpm and 11,800
compressor rpm, plus 1,000lb approx. exhaust thrust at standstill diminishing
with speed
Axles: spiral bevel at front and rear
Type of drive final drive 3.6 to 1
Chassis: Aeroweb sandwich 2 skins 0.048 inch
thick light alloy spaced ¾ inch apart by resin bonded ¼ inch mesh honeycomb of
0.002 inch thick light alloy
Suspension: independent by ball-jointed transverse
wishbones
Shock Absorbers: Girling oleo-pneumatic
suspension struts with rubber rebound buffers
Steering: Gear Burman recirculating ball
quick-thread mechanism as centre section of 3-piece track rod, operated by bevel
gear and chains from steering wheel
Brakes: Girling disc brakes, inboard mounted,
with duplicated operation from compressed air reservoirs. Discs 16 3/8 inch
external diameter and 10 3/8 inch internal diameter. Air brakes to rear. In all
three separate brake systems.
Wheels: Dunlop split-rim disc wheels
Tyres: Dunlop 7.8 inch section 52 inch
external diameter
Dimensions: Wheelbase 13ft 6in., Track front
5ft 6in., Track rear 5ft 6in., Length 30ft, Weight 3.5 - 4.2 tons
Body Manufacturer: Motor Panels Ltd., material
aluminium
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