WIKIPEDIA IS THE MOST CONCISE: “The Cisitalia Grand Prix is a single-seater car for the postwar 1.5-litre supercharged Grand Prix class, built by Italian sports car manufacturer Cisitalia and introduced in 1949. It was designed on behalf of Cisitalia by Porsche between 1946-47, and is therefore known by its Porsche project number, Type 360.”
Stuttcars is the most detailed, with the car’s Basic Technical Specs, its Story & Details, a wealth of photos from Cisitalia and Porsche, and tales of the most complex interactions among Ferdinand Porsche, his French prison, his son Ferry, race engineers Rudolf Hruschka and Robert Eberan-Eberhorst, Viennese expat Karl/Carlo Abarth, Italian auto entrepreneur Pietro “Piero” Dusio—and even for awhile there Argentina’s Juan Peron.
The Porsche Type 360 residing in the Porsche Museum. Image by Larry Stevens from Stuttcars.
The car’s innovative technology is best analyzed by Laurence Pomeroy in The Grand Prix Car Vol. 2.
Here, in Parts 1 and 2 today and tomorrow, are tidbits of the Porsche Type 360 Cisitalia GP car gleaned from these three sources.
Complications of Its Development. Wikipedia writes, “The car was commissioned by Piero Dusio in 1946. Dusio paid a large sum of money upfront, part of which was used to free Ferdinand Porsche from the French prison in which he was being held effectively in ransom. Dusio gave Porsche only 16 months to complete the car which proved too short a time to sort out the advanced design.”
Stuttcars notes, “In July 1946, Ferry Porsche was released from the prison in Dijon, France, as no war crimes could be put on him (his father Ferdinand Porsche and brother-in-law Anton Piëch remained in prison). At the same time there was one Austrian-born former racer and self-taught engineer Karl Abarth living in Italy who wanted to work with racing machines as the war was over…. In Italy, Karl Abarth had became Carlo Abarth—a name every auto enthusiast knows. [See “Fiat-Abarth Twin Cam—Snarling Brio.”] In the end of September 1946, Abarth became Porsche engineering company’s representative in Italy.”
All of the car’s design and development was complicated by the fact that Ferry was restricted to Kitzbühel, Austria. Stuttcars recounts, “As part of the deal between Cisitalia and Porsche, Carlo Abarth and Rudolf Hruschka, as well as consultant Robert Eberan-Eberhorst, started to work as employees of Cisitalia. Eberan-Eberhorst was an engineer who had worked in developing the Auto Union racing cars in the nineteen thirties.”
Ferdinand’s Approval. Stuttcars continues, “The Cisitalia Grand Prix car, internally known as Porsche 360, was designed in Gmünd, Austria in 1947. Ferdinand Porsche had been released from the prison on August 1, 1947 and he started to live in Hotel Klausner in Kitzbühel, Austria, guarded by the Allies. A couple of days later Ferry Porsche and Karl Rabe introduced the design of the type 360 and the old professor came to the conclusion that he would have done it exactly the same way.”
The Porsche Type 360. Image from Stuttcars.
Pom’s Info. In 1965 Laurence Pomeroy wrote in The Grand Prix Car Vol. 2, “From a theoretical point of view the Type 360 Porsche is certainly the most interesting post-war racing car—indeed it is one of the most ingenious design studies in the whole history of motor racing…. The notes which follow have been made possible by the kind cooperation of Dipl.-Ing. Ferry Porsche, and Prof. Dr. Ing. R.E. von Eberhorst, who have supplied full working drawings and notes on the development of this project.”
The Grand Prix Car Vol. 2, by Laurence Pomeroy, Temple Press, 1965.
A Flat-Twelve. Pom described, “The horizontally opposed twelve-cylinder engine is placed directly behind the driver’s seat and the vertically split light alloy crankcase extends outwards to form the water jackets. Individual cylinder liners in direct contact with the water are inserted and are sealed by light alloy detachable cylinder heads which are cast in one piece for each block. Each head carries two valves at an included angle of 90 degrees….”
“The valves,” Pom continued, “are opened by two camshafts for each bank through the medium of followers and a single 18 mm. plug is used set well back and with a 6 mm. passage connecting the points to the combustion chamber.”
Revealed is the great stiffness of the crank-connecting rod-piston assembly.
A Sturdy Crankshaft. The bore and stroke,” Pom recounted, “give a piston area of 45.7 sq. in. and the seven-bearing Hirth type crankshaft has a remarkably large diameter of 54 mm., which is nearly equal to the bore itself. Even the gudgeon-pin is 18 mm. diameter, or one-third of the cylinder bore…. In consequence, that section of the rod lying above the big end radii and below the gudgeon-pin fillet is little more than 1 3/4 in. long, giving an exceptionally stiff assembly.”
Twin Supercharging. Pom described, “This compact layout is greatly assisted by the manifolding arrangement in which the exhaust ports discharge directly downwards, the ingoing charge being fed to the inlet ports from two vane type blowers mounted above the crankcase.”
“On the basis of 10 h.p. per sq. in. of piston area,” Pom calculated, “this engine should have produced nearly 450 b.h.p. at 10,500 r.p.m., this being the equivalent of 370 b.m.e.p. at a piston speed of 3,350 ft./min.”
Four-wheel Drive. Pom recounted, “The knowledge that the full power of these cars could not usefully be applied owing to wheelspin led to the decision that on the Porsche Type 360 the engine should be connected to both front and rear wheels.”
Gee, no wonder Dusio was to run out of money! We’ll continue Pom’s analyses in Part 2. ds
© Dennis Simanaitis, SimanaitisSays.com, 2024