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).
Calculations on the aerodynamic drag of a streamlined saloon car, comparing forward and reverse motion and the effect of increased power on speed.
| Identifier | ExFiles\Box 160\2\ scan0166 | |
| Date | 30th January 1933 guessed | |
| (3) STREAMLINED SALOON IN REVERSE. Drag forward of standard saloon (no front wings) = 311 lbs. at 86 M.P.H. ∴ Drag at 95 M.P.H. = (311 x 95²) / 86² = 380 lbs. Drag in reverse at 86 M.P.H. = 257 lbs. ∴ drag at 95 M.P.H. = (257 x 95²) / 86² = 326 lbs. Reduction in drag by reversing = 54 lbs. = 14.2% Streamline forward drag at 95 M.P.H. = 321 lbs. ∴ drag at 95 M.P.H. in reverse. = 275 lbs. V₂ = (95² x 81 x 375) / 275 = 100 M.P.H. Increase in speed with increase in power. F₂ = (V₂³ F₁) / V₁³ or V₂ = (F₂/F₁)^(1/3) V₁ If one adds 18 H.P., the H.P. available at road wheels for windage is 99 H.P. Lap speed, standard saloon = 86 x (99/81)^(1/3) = 92 M.P.H. Lap speed, streamlined car = 95 x (99/81)^(1/3) = 101.5 M.P.H. ------------------- | ||