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).
Calculation of vehicle speed increases based on changes to BHP, frontal area, and weight.
| Identifier | ExFiles\Box 97\1\ scan0279 | |
| Date | 22th December 1938 | |
| H50. also 1380. To Rm.{William Robotham - Chief Engineer} COPY FOR FILES. Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}22/JH.22.12.38. Given a max. lap speed of 88 m.p.h. with 128 clutch B.H.P. it is estimated that 160 clutch B.H.P. would give an increase of 7½% i.e. to 94¾ m.p.h. Assuming, Frontal area of car 24 sq.ft. Total weight with two 1.84 tons. passengers. Tyre pressures. 35 lbs/in². ................... As a point of interest this is equivalent to reducing the frontal area (K being assumed unchanged) by 24% i.e. to 18¼ sq.ft. ................... Reduction of 1 sq.ft. would give a speed gain of 1 m.p.h, which same result would require a reduction in weight by 21% i.e. to 1.45 tons. ................... Rm{William Robotham - Chief Engineer}/T.A.Swinden. | ||