|CTA-Arsenal Grand Prix|
Shortly after World War II in both French and British racing circles there were a strong urge to show the respective nations' superiority on the track as well. Most famous of these enterprises is British Racing Motors but an equally ambitious program was also started in France. Two-time Le Mans winner Raymond Sommer was the driving force behind the project. He used his notoriety to convince French minister of industry Marcel Paul to provide the necessary funding.
Although not yet made official, the general believe was that the regulations applied to the 'Voiturette' would be the formula used for the first post-War Grands Prix. Accordingly, the new French racer was built to comply with these regulations, which stipulated a maximum displacement of 1.5 litre for supercharged and 4.5 litre for naturally aspirated engines. The car was conceived at the "Centre d'étude technique de l'automobile et du cycle" (CTA) and constructed at the "Arsenal", which was more familiar with military vehicles.
Project leader was Albert Lory, who two decades earlier had designed the successful Delage Grand Prix cars. These were powered by a supercharged V8 with a 1.5 litre displacement. The V8 conceived by Lory for the new Grand Prix racer bore more than a passing resemblance to the Delage engine. Like the earlier straight eight, the new V8 was constructed with the block and heads cast in as a single piece. Another familiar sight were the large number of small studs and bolts that were used for the various covers.
Each of the two banks featured twin overhead camshafts, which were connected to the crankshaft through chains at the back of the engine. In its initial guise, the V8 was equipped with a single-stage supercharger and a twin-choke carburettor. During the development of the engine, a twin-stage 'blower' was added, which saw the power increase from 215 bhp to a claimed 275 bhp at 8,000 rpm. This power was fed to the rear wheels through an electromagnetic four-speed Cotal gearbox.
The drivetrain was mounted low in a conventional ladder frame, with the exhausts exiting through the rails. Unusual in its design, the front suspension featured a rigidly mounted axle with 'floating' drum brakes. The suspension travel was controlled by a rocked mounted at the top of the brakes, which was connect to longitudinally mounted torsion bar springs and dampers. At the rear swing axles were fitted with transversely mounted torsion bars. The hydraulic drum brakes were sourced from Lockheed.
Arsenal's experience with the construction of fighter airplanes was most obvious in the construction of the aluminium body. Closely resembling a fuselage, the panels were riveted or bolted onto several oval cross-members. A full length belly-pan was also fitted to make the car more aerodynamically efficient. Completed, the CTA-Arsenal sat relatively high on its wheels and weighed a hefty 740 kg. Dominating Grand Prix racing at the time was the Alfa Romeo 158 'Alfetta', which was considerably lower and lighter.
Testing of the first CTA-Arsenal commenced in September of 1947. Even though the chassis proved so flexible that the car could not run straight at speed, the new French hope was entered for the French Grand Prix. Sommer was dead last in the qualification practice, over half a minute slower than the pole-sitting Maserati. The race was an even bigger disaster when one of the half-shafts failed on the start-line. Ironically, Sommer would suffer the exact same fate three years later when he debuted the BRM at the British Grand Prix.
Despite the embarrassing debut, the CTA-Arsenal was shown at the Paris Auto Salon, while development continued. Two cars were readied for the 1948 French Grand Prix but once it became obvious that the CTA-Arsenal would not be competitive, they were withdrawn. It is believed that three examples off the ill-fated Grand Prix racer were built. Story has it that all three were bought by Anthony Lago and placed in a corner of the Talbot Lago factory to show his workers how it should not be done.
At least one has survived in remarkably original condition and was entered for the 2010 Monaco Historic Grand Prix. It was restored to full running just before the event and ran only briefly on a public road before a police officer intervened. Seasoned historic racer Josef Otto Rettenmaier ran the car in practice but concluded that it was not safe to compete in the actual race on the tricky road course as he did not trust the brakes.
Article by Wouter Melissen, last updated on May 10, 2012
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