French national racing car with constructive overkill

Arturo Rivas
CTA-Arsenal
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Z u the best-known racing driver wisdom includes the saying that you have to go To be first, finish the race first. At the French CTA arsenal, we should reduce the demands a little and only wish that it at least crosses the starting line at some point - the 1.5-liter Grand Prix racing car from 1947 has never managed that before.

Disaster at the premiere in Lyon

Already the debut of the CTA Arsenal at the French Grand Prix on 21. September in Lyon was a complete disaster: After qualifying, Raymond Sommer found himself in 13th place on the grid, around half a minute behind pole position. When the start flag rose, the clutch collapsed and then suddenly engaged, causing a half-wave to tear off. Test drives in Montlhéry had also previously shown that the monoposto no longer drove straight at top speed (260 km /h).

The Center d'Etudes Techniques de l'Automobile et du Cycle (CTA), the French Development center for automobile and two-wheeled technology, therefore, was not deterred and built a second car for the 1948 Grand Prix in Reims, which Eugene Martin was to drive alongside Raymond Sommer. But already during training it became apparent that the cars would again be without a chance, and they were withdrawn. After that, the CTA Arsenal (the nickname 'Arsenal' comes from the armory in Châtillion near Paris where the cars were built) disappeared for many years in a corner of the Talbot factory in Suresnes.

Debacle for the French national racing car

It was a rather inglorious end to the dream of building a French national racing car that, according to the will of its builders, did should be successful like the German Silver Arrows before the war. But the problems of the state-funded CTA arsenal were easy to see even for non-specialist luminaires: the car was too heavy, the center of gravity was too high, and the technology was incredibly complex. A nightmare.

This was largely due to Albert Lory, who once designed the 1.5-liter eight-cylinder in-line engine for the Delage racing car, which won five Grand Prix in 1927 and celebrated the world championship title. But Lory had meanwhile turned to aviation technology - and perhaps because of that, one for the CTA arsenalDrive drawn, which can hardly be surpassed in terms of complicated details.

According to the racing formula valid at the time, a 1.5-liter V8 with a 90-degree bank angle and a flat 180- Grad crankshaft (as in the Alfa T33 or Ferrari 328), which is ventilated by two Roots compressors (two-stage charging) and a 52 mm Solex carburetor attached in front of it. So far, so comparatively normal.

Each cylinder bank has its own cooling circuit

It is less normal that the CTA arsenal, each cylinder bank has its own cooling circuit with water pump and radiator - and that not only the exhaust ducts, but also their valve guides are cooled. Or that the two overhead camshafts per bank are set in rotation by a gear cascade that is reminiscent of a mechanical clockwork (see photo above right). Or that a seven-piston pump is responsible for the necessary fuel pressure, the pistons of which are moved by a swash plate and which consists of 150 (!) Individual parts.

Let's continue with the four-speed gearbox of the CTA arsenal, that is attached to the rear axle (transaxle): For the lowest possible friction loss, Lory designed a difficult-to-shift gear-shift transmission and equipped it with dry sump lubrication to avoid splashing losses.

Incredible effort in the chassis

The constructive overkill did not stop at the chassis of the CTA arsenal either: Each of the four individually suspended wheels is guided vertically in dovetail guides, is sprung with torsion bars . Incredible: The hydraulic dampers installed in addition to the mechanical friction dampers are adjustable in rebound and compression and have a pressure reservoir - we're still talking about a racing car from 1947 here.

Basically, every assembly is at the CTA -Arsenal has an incredibly complex construction, repairs or maintenance work make every mechanic desperate: To change the rear brake pads, for example, the drive shafts first have to be removed and then half the wheel suspension dismantled.

Only one copy is known

So it's no wonder that for decades no one dared to approach the former French national racing car CTA-Arsenal, one copy even disappeared over time and is valid today as lost. The other, however, got to Germany via some collections in the 1990s - and there to perhaps the only person on this planet who could get the construction up and running.

'I just wanted the two most unsuccessful grand- Have prix racing cars of all time, and I've already had the OSCA 4500 G, 'says Eckhart Berg with his own dry sense of humor. The Westphalian had a few yearshad already helped one of the Delage eight-cylinders from 1927 on the jumps again - it is one of the handful of absolute specialists who mostly work in secret and treat a V12 before breakfast.

If you take a closer look at the CTA Arsenal, however, had to swallow even Berg and his long-time employee Ingo Grimm dry. 'Everything about the car is as complicated as possible, there is nothing you can do 'just for a moment'', explains Ingo Grimm. 'With the tool we are using for the CTA, there is no key that did not have to be adjusted because everything is so tight.'

Around 600 studs

To make matters worse, the two have a quality standard that cannot be adequately described with' meticulous ': When Eckhart Berg has made an engine and the camshaft case, for example, has one Row of studs, then they protrude to the exact same tenth of a millimeter. Incidentally, the CTA-Arsenal-V8 has around 600 stud bolts, 500 of which end in water or oil and have to be glued in.

With some details of the CTA-Arsenal, Berg had no other choice than deep Intervene in Lory's design: The six main bearings of the crankshaft, for example, originally had roller bearings with a diameter of 80 mm, something that nobody makes today - at least not with a fixed speed of up to 9000 rpm. The only solution: conversion to plain bearings.

Ten-plate dry clutch

The ten-plate dry clutch of the CTA arsenal was able to it didn't really work and had to give way to a two-plate clutch, and the gearbox was robbed of its senseless dry sump lubrication. In addition, there were many - very many - smaller and larger challenges that still had to be mastered, so that the small V8 was ultimately only to be put to the test after six years. when the mechanical gem, fired with a gasoline-methanol mixture, uttered its first scream - a sound that no one who has heard it up close will ever forget. The revised engine in the CTA arsenal was very healthy right from the start and immediately produced 330 hp at 6,000 revolutions. At the beginning they did not want to turn any higher - but this value alone is around 60 hp above that of 1947.

Light metal body was pressed

The chassis, brakes and body of the CTA arsenal also required a few flashes of inspiration, although little has changed in the torsion-free frame and the high center of gravity (the driver sits on the cardan shaft, which was better at the end of the 1930s) leaves. The quality of the light metal body, on the other hand, still demands respect today. It was evidently not struck, butpressed into a wooden press. Body artist Joachim Ohlinger, who took on the aluminum-magnesium shell, didn't want a fee afterwards because he had learned so much from it.

The CTA arsenal then made its first use at the historic Grand Prix in Monaco, where he did respectably in practice - but then did not take part in the race due to braking problems. Even in its third use since 1947, the car did not succeed in crossing the starting line.

In the meantime, however, several days in the workshop and several test drives have passed, and slowly the silver monoposto with the is showing French-blue frame its potential: 'From 6,000 tours the engine only really wakes up and revs up like a lightning, so that the tires spin in third gear,' says Ingo Grimm. It is estimated that the engine should now produce almost 400 hp.

Back on the racetrack

A few difficulties remain be eliminated - the gearbox is just now apart again, a limited-slip differential is missing with this performance. Still, the chances are good that the CTA arsenal will successfully cross a starting line for the first time in its life later this year. And then some competitors will be surprised what this mechanical marvel can achieve.

Fascination technology

Man can't necessarily say that the CTA arsenal made racing history. But the technology is all the more fascinating, for example the frame with the V8 engine as a supporting element. You can hear how unique the engine sounds on the video of the first test bench run .

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