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).
Windage tests at part throttle for the Paulin Bentley II (B.27.LE).
| Identifier | ExFiles\Box 160\4\ scan0042 | |
| Date | 14th March 1939 | |
| SECRET. To By. {R.W. Bailey - Chief Engineer} c. to Da {Bernard Day - Chassis Design} /Ev. {Ivan Evernden - coachwork} Rm {William Robotham - Chief Engineer} /TAS. {T. Allan Swinden} 9/JH.14.3.39. Paulin Bentley II (B.27.LE). Windage at Part Throttle. Herewith is contained an apparently watertight confirmation of the statement put forward in Rm {William Robotham - Chief Engineer} /TAS. {T. Allan Swinden} 14/JH. 1.12.38. to the effect that "the air resistance coefficient K is independent of speed, at any rate up to 80 M.P.H." so long as the correct formula for rolling resistance is used. It will be noted that since B.27.LE. has become available it has been possible to explore a speed range up to 110 m.p.h. It is suggested that previous discrepancies in the values of K which have been obtained have been due mainly to the non observance of tyre pressures, and neglecting the power loss in the dyno. drums themselves. Speed M.P.H. K C = 391K 52.4 .00120 .470 66.4 .00122 .477 88.5 .00124 .485 110 .00121 .473. Rm {William Robotham - Chief Engineer} /.T.A.Swinden. | ||