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).
Investigations into power losses in tyres, focusing on standing waves at high speeds.
| Identifier | ExFiles\Box 158\2\ scan0039 | |
| Date | 9th June 1939 | |
| To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Ev.{Ivan Evernden - coachwork} Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}5/JH.9.6.39. Power Losses in Tyres - II. Further investigations into tyre losses carried out on a chassis dynamometer rig described in Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}15/JH.17.5.39. (1) Appearance and non-appearance of a standing wave in tyres travelling at high peripheral speeds. (2) Windage losses in a rotating wheel and friction losses in the rear axle. (3) The effect of tyre size on power loss. (4) Losses at full throttle in each gear. (5) The effect of rear axle loading on tyre loss. (6) The effect on curves obtained of the time allowed for warming up. ................ (1) Appearance and non-appearance of a standing wave in tyres travelling at high peripheral speeds. India tyres are so far the worst offenders in this respect. 6.50 x 16, 6.50 x 17 and 5.50 x 18 new tyres have been tested, and appear to become slightly worse in that order. With the 18" tyre it is possible to see three complete waves instead of about one and a half with the 16" tyre when travelling on the dynamometer drums at 100 m.p.h. and at rated tyre pressures. New Dunlop tyres do not wave at normal pressure up to 100 m.p.h., but the wave is just becoming apparent at that speed when the pressure is dropped to 22 lb.in.sq. Avon tyres behave as Dunlops save that the wave at low pressure is becoming apparent at about 90 m.p.h. | ||