Four Small Wheels 8/2005

The 'Cars from Mars' - the first Bristol 450 Coupés by David Blumlein
Amidst the rich tapestry of participants in the Le Mans race we find a number of oddities; examples that spring to mind include the twin-boom Nardi, which was blown off the course by the passage of larger, faster cars, the Cadillac 'Le Monstre' and the little Crosley Hot Shot. In this category must surely also come the original Bristol 450 Coupés which resembled something close to a fighter plane on wheels, 'cars from Mars' they were quickly dubbed! Bizarre offers both from the 1953 24-hour race as BIZ100 and BIZ101. So how did these strange looking machines come to take part in such an illustrious race? We go back to the Second World War where the aircraft industry had inevitably expanded both in production and expertise. But, just as was the case after the first World conflict, the arrival of peace meant a drastic reduction in the demand for military aircraft. If companies were to avoid large scale unemployment and the loss of skills and facilities that would be of value in the future, diversification was essential and, not unnaturally, thought turned to car production. An obvious example after the Great War in 1918 was the aero engine manufacturer BMW which turned initially to motor-cycle production before graduating to cars via the licence-built Dixi based on the Austin Seven and thence to building their own increasingly exciting sporting cars. The Bristol Aeroplane Company was in a similar position although the emergence of passenger airliners would occupy most of their resources as did the continuing work of the aero-engine department. But military orders had been prodigious and Bristol's chief engineer, Sir Roy Fedden, had been exploring the possibility of a Bristol car with a small team of designers before peace arrived.	Their first essay was a streamlined saloon with a rear-mounted radial sleeve-valve engine (aero-engine experience here with Bristol's excellent Centaurus radial) but the machine exhibited furious oversteer when tried out on an airfield and soon had the good grace to destroy itself completely! A further project to make a small car led nowhere and it became apparent that the best way forward was to use an existing design as a basis. It so happened that H.J. Aldington, the head of Frazer Nash cars, was on the board of the Bristol Aeroplane Company and he was to furnish the firm with a starting pad. Frazer Nash had, of course, been importing exclusively the BMW cars in the late thirties as Frazer Nash-BMWs and Aldington had cultivated close links with the Eisenach company. Come the end of the war and 'H.J.' was quickly out to Germany to bring back as much as he could after the Allies had done their work. Thus did the design of the BMW 328's superb engine find its way to Filton where Bristol was setting up a Car Division. Furthermore, the aircraft team elected to take the best elements of BMW's immediate pre-war range to form the basis of the new Bristol car (which was at first to be a Frazer Nash-Bristol!) The BMW 326, with torsion bar rear suspension, was coupled with the ingenious push-rod hemispherical head 328 engine, the whole clothed rather in the style of the 327 Coupé with Autenrieth bodywork. Aldington meanwhile ensured a supply of Bristol engines for his post-war series of sports cars as part of the deal! The Bristol 400 emerged as a 4-seater 2-door saloon with a very BMW coupé look about it and amateurs started to compete in competitions, not least with the Arnolt-Bristols which were created for the American market.

Early in the Car Division's life it had been decided to produce high-performance versions of the German-based six-cylinder engine and the company began to feel that it would be better if it were to undertake a competition programme of its own - after all the Bristol engine was being used effectively by the Formula 2 Cooper-Bristols and in specialist sports car chassis where it was proving reliable thanks to the high quality of production commensurate with an aircraft company.

In fact the competitions department had been formed by Bristol as early as January 1952 and thoughts turned to such events as Le Mans. But a suitable car was not to be found in the current 403, 404 models Filton was producing. Once again an existing design came to the rescue.

This was in the form of the G-Type E.R.A. that Stirling Moss had raced in some Formula 2 events in 1952. Ex-racing driver Leslie Johnson had acquired the assets of E.R.A. when Raymond Mays and Peter Berthon had turned their attentions to creating B.R.M. and the older company was then moved to Dunstable. The G-Type was chiefly the work of Cambridge graduate David Hodkin and had a very rigid chassis with the driver alongside the propeller shaft and with the gearbox at the back giving ideal weight distribution. But it wasn't an ideally low frontal area! Johnson had intended to develop an engine using the Norton d.o.h.c cylinder head but only one unit was made and the car was raced with the increasingly ubiquitous Bristol engine. When Johnson suffered a heart attack, he acceded to medical advice and sold the G-Type and its drawings to Bristol - this would form the basis of a good sports-racer!

Bristols built three team cars with steel chassis in place of the G-Type's magnesium alloy tubular frame and covered them with bodywork created in the wind-tunnel by the Aircraft Division. It was characterised chiefly by the two large dorsal fins sprouting from the roof and extending down to the low tail. The cockpit was reminiscent of that of an enclosed fighter plane, complete with aircraft type switches and hooded dials.

The engineers improved the chassis, re-working the de Dion rear suspension and keeping the rear-mounted gearbox that fed into a final drive unit which came from a Ford commercial vehicle. The wheels were merely rims with bolting lugs which were attached to light-alloy spiders cast integral with the hubs, this aiding cooling of the large brake drums.
The car touched 124 m.p.h. on the Brabazon runway at Filton before being taken to the test track at M.I.R.A. where one lap of the "pavé" track caused the rear suspension to collapse completely! When repaired another lap saw the engine fall out owing to unsatisfactory mountings! Eventually the car behaved for three laps of this tortuous surface and was deemed able to endure 24-hours of racing.
The engine had been given a stronger crankshaft and the consultant engineer, Stuart Tresilian, ventured the opinion that the balance weights would fly off. In subsequent testing all seemed well and this was how the two team cars arrived for the Le Mans race in 1953, to be driven by Lance Macklin and Graham Whitehead (car 37) and Tommy Wisdom and Jack Fairman (car 38). Practice suggested that the cars were somewhat overgeared but they lapped some 5 seconds quicker than the other 2-litres including Porsche and Frazer-Nash entries. The need to fit extra lights, stoneguards, straps and fillers made a bit of a mess of the front end, adding to the cars' weird appearance.
In the race Tresilian was proved right. The crankshaft of #37 threw its weights after just 29 laps causing a minor fire and after 70 laps Wisdom had a similar failure, a more serious fire in the cockpit inflicting some nasty burns.
Undeterred, two cars came a month later to the Reims 12-hour race with tidied up front ends and, despite a key in the final drive failing at the start in the Whitehead car (wearing no. 22), the Fairman/Wilson car (Wisdom was still unfit after Le Mans) went on to finish 5th overall and win the 2-litre class.
Much more refined bodywork led the cars to success at Le Mans in the next two years.