From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Performance comparison report between a stock car and a Dubonnet streamlined car at the Autodrome of Linas-Montlhery.
| Identifier | ExFiles\Box 126\3\ scan0150 | |
| Date | 24th March 1936 guessed | |
| Automobile Club de France COMMISSION TECHNIQUE SUITE ( 2 ) DU PROCÈS VERBAL D'ESSAI N° Just before the tests, under the supervision of the technical comissioner, the cars were driven to the Renault works, and their available power at the wheel rim was measured on the special Heenan-Froude braking unit belonging to that Company. The purpose of this test was to determine whether the two cars disposed of the same power at the rim. In order to make this comparison, the maximum torque developed at the wheel rim at an engine speed of 1.000 r.p.m. was measured on both cars. The following results were recorded : For the stock car, at the speed of 31 kilometers per hour, or 19.4 miles p.h. which corresponded with an engine speed of 1.000 r.p.m. and a gear ratio of 4.11 to 1, the available power at the wheel rim measured in the run on the rollers of the braking unit amounted to 20 H.P. at 1.000 r.p.m. For the stream-lined car, at the speed of 44 kilometers per hour, or 27 1/2 miles p.h.; which corresponded with an engine speed of 1.000 r.p.m. and a gear ratio of 2.92 to 1, the available power at the wheel rim amounted to 17.9 H.P. Taking into consideration the fact that, according to the torque curves supplied to us, on engines of this type, the driving torques at 1.000 and 3.000 r.p.m. are of equal value, it may be assumed that, at 3.000 r.p.m., the stock car developed 60 H.P. at the wheel rim, whereas the stream-lined car developed only 53.7 H.P. Test Results 1°- On the speed Track of the Autodrome of Linas-Montlhery Stock car - Maximum speed recorded for one lap by the official time-keeper of the French Automobile Club : 128,843 kilometers per hour, or 80,527 miles per hour Dubonnet streamlined car + Maximum speed recorded for one lap by the official time-keeper of the French Automobile Club : 174,404 kilometers per hour, or 109,002 miles per hour Wind velocity - 12 meters per sec., or 39,4 feet per sec. 2°- Fuel consumption test, using Esso gasoline on the Speed Track Total distance covered by both cars, travelling about 200 meters, or 650 feet, apart : 104,477 kilometers or 65,297 miles at the average speed | ||