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).
Road tests measuring rear wheel revolutions under different speeds and tyre pressures to analyze springing.
| Identifier | Morton\M3.7\ img002 | |
| Date | 27th June 1919 | |
| Contd. -2- EH4/LG27.6.19. to the impression we got on 49-GB with the underneath springs. The time when Mr. Royce had 7-CA in Norfolk and complained of the springing, that car was then running with rear springs which were cocked up in front and anchored beneath the axle. We feel it is a point that should be considered on the new cars. When 49-GB had the springs below the axle we ran this car on a certain piece of road, and fitted driven from the transmission, a revolution counter. We first of all drove very slowly over the road and counted the number of revolutions, we then went over it at various speeds and found that we could measure consistently that we recorded an increased number of revolutions, due undoubtedly to the back wheels leaving the ground and accelerating. Below is a table which gives these figures:- Condition M.P.H. Increase in number of rear wheel revs. Driver & one 5 nil passenger. 15 1.7 20 4.0 25 5.0 To see whether we could shew a variation we tried with different tyre pressures:- Gain in revs. on rear wheels. M.P.H. 100 lbs. 45 lbs. 5 15 3.2 .85 20 4.2 6.0 25 12.0 6.8 Contd. | ||