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).
The effects of streamlining and gear ratios on car performance, referencing the Thomas Special car.
| Identifier | ExFiles\Box 178\1\ img012 | |
| Date | 12th October 1925 | |
| - 10 - REF. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG121025. streamlining. This was actually accomplished on The Thomas Special car this year. It is not generally realised that the outline of a car beneath the frame is of great importance with regard to wind resistance, a cushion of air tries to form between the car and the road, which can be eliminated by streamlining. Gear ratio. Owing to the high wind resistance of the bodies they carry, normal cars (touring) are not geared for max. speed but rather, lower. They are therefore rather over the peak of the power curve when all out on the road and lose perhaps 5% in H.P. This loss in H.P. can hardly be detected. The gain in acceleration, however, is appreciable. When the windage of the car is reduced considerably, 5 HP. can make an appreciable difference in speed. A sports car may therefore benefit by a high axle ratio, where a touring car would lose in acceleration, while the increase in maximum speed would not be detected. (contd). | ||