Simanaitis Says

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YESTERDAY, WE LEARNED of an optimistic post-World War II plan of returning France to the forefront of Grand Prix motor racing. Chosen to lead this effort was Albert Lory, whose Delage designs had dominated competition in an earlier era. The tale of the Arsenal CTA continues here today in Part 2, my primary source for this being Laurence Pomeroy’s The Grand Prix Car. 

Monsieur Lory’s Arsenal CTA. Pomeroy observed, “The engine was designed by Monsieur Lory and bears in many details a close relationship to his designs between 1924 and 1927. Like the 1924–5 2-litre Delages he chose to use a Vee-type engine; like the 1926-7 1 1/2-litre he settled upon eight cylinders.”

The 1947 Arsenal CTA engine cross-section shows resemblance to a pair of Lory’s 1927 DELAGE engines arranged in a Vee. This and other images from Volume Two of The Grand Prix Car.

Arsenal Design Influences. “The two iron cylinder blocks,” Pomeroy noted, “retained the usual Lory features of integral cylinder heads having two overhead valves inclined at 100 degrees, also steel plates forming the sides of the water jacket so that the castings could be throughly cleaned before the engine was assembled and run.” 

With two-stage supercharging, the Arsenal 1 1/2-liter produced around 275 hp.

“Drawn from a downdraught double-choke four-float Solex carburetter,” Pomeroy wrote, “the mixture was supplied at 30 lb. boost (3 ata.) and, with this boost pressure, well over 300 b.h.p. might well have been expected from the engine in its fully developed form.” 

Embarrassing Outings. As described in Wikipedia, “In 1947, the car was entered for the French Grand Prix, and the race, run that year at Lyon, was postponed till 21 September to enable it to compete.”

A fat lot of good that did. Raymond Sommer drove the Arsenal CTA in practice, but no more.

Raymond Sommer and the Arsenal CTA in its ill-starred debut, the 1947 French Grand Prix. This and the following images from “Reflecting on the 77th Members’ Meeting and the CTA-Arsenal,” by Doug Nye.

On race day, the Arsenal CTA’s transmission failed on the starting line; the car never left the grid. The next year, two cars were built and entered in the 1948 French Grand Prix at Rheims. They were withdrawn at the last minute.

Above and below, Josef Otto Rettenmaier’s restoration of the 1947 Arsenal CTA at Goodwood.

Pom’s Analysis—and That Locomotive Link. “Whatever merits the engine may have had were obscured by various transmission and chassis troubles…. and it should be mentioned in fairness that Monsieur Lory was not responsible for the chassis layout.”

“Open half shafts,” Pomeroy explained, “took the drive to the rear wheels, which were suspended on torsion bar springs and located by slides in a manner familiar to those who have studied locomotive design.”

Above, image from Spring Equalization for Steam Locomotives, by Douglas A. Kerr. Below, a detail of the Arsenal CTA’s front suspension shows the wheel located on sliding blocks.

“This was not a successful arrangement,” Pomeroy noted. “A variation of this strange, and, as it turned out, unhappy, concept appeared at the front end of the car….” 

It was known to work fine with locomotives, however. ds

© Dennis Simanaitis,, 2020 

2 comments on “1947 ARSENAL CTA GRAND PRIX CAR PART 2

  1. Mike B
    September 25, 2020

    Compare to Morgan’s sliding pillars? Just wondering/curious, not trying to be snarky.

    • simanaitissays
      September 29, 2020

      Not snarky at all. The two are conceptually related. They have wheel motion parallel to the slot or pillar, respectively. I suspect “stiction” would have been a similar shortcoming of either.

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