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 calculations and analysis of lap speeds and windage drag for car models B-23-AE and B-35-AE.
| Identifier | ExFiles\Box 160\2\ scan0204 | |
| Date | 22th August 1934 | |
| Appendix. (3) If we had 118.5 H.P. at 4300 R.P.M. on B-23-AE instead of 92.5 at 4150 R.P.M. there would be available 26 H.P. more for windage because - V ∝ ³√P. Lap Speed = 95 x { (106.35) / (80.35) }^(1/3) = 95 x 1.1 = 104.5 M.P.H. B-35-AE (Hall's Car). Tests 2 & 4. As originally tested by Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} on Brooklands with 92.5 H.P. at 4150 R.P.M., the lap speed was 90 M.P.H. This corresponds to Test 2. The windage drag was 344 lbs. at 90 M.P.H. If we had had 118.5 H.P. the lap speed would have been 90 x { (107.3) / (82.5) }^(1/3) = 98.0 M.P.H. Windage drag = 344 x 98² / 90² = 406 lbs. In the final test trim (test 4) the drag is reduced to (406 / 425) x 406 = 389 lbs. Because V₂³ = (V₁² P₂ x 375) / R₁ V₂ = { (98² x 107.3 x 375) / 389 }^(1/3) = 99.7 M.P.H. This car (Test 4) actually lapped at 99.5 M.P.H. EV.{Ivan Evernden - coachwork} | ||