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).
Comparing gear ratios for a proposed 3-speed gearbox against previous successful and unsuccessful cars in the Austrian Trials.
| Identifier | ExFiles\Box 137\5\ scan0047 | |
| Date | 1st September 1920 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CD. c. to BN.{W.O. Bentley / Mr Barrington} c. to Da.{Bernard Day - Chassis Design} c. to E.{Mr Elliott - Chief Engineer} c. to EY. c. to EP.{G. Eric Platford - Chief Quality Engineer} X3720 Hsl/LG9. 9. 20. X.3720 RE - 3-SPEED GEARBOX. We suggest, before we get deeply involved in the new 3-speed gearbox, we should consider the following facts:- 1. That a Rolls-Royce car fitted with a 3-speed gearbox (open touring body) driven by Mr. Radley failed to climb the hills in Austria. 2. The Austrian Trials cars which were made with 4-speed gearboxes had very little excess power on the low speed gear when climbing the hills. These cars were fitted with light bodies. Below are comparative gear ratios of these types of cars:- COMPARISON OF GEAR RATIOS OF SUCCESSFUL AND UNSUCCESSFUL CARS IN AUSTRIA BOTH FITTED WITH 895 x 135 TYRES. | Car. | Top. | 3rd. | 2nd. | 1st. | | :--- | :--- | :--- | :--- | :--- | | Mr. Radley's car which failed. | 2.96 | | 4.84 | 8.34 | | Austrian Trials Cars. | 3.25 | 4.83 | 7.22 | 11.07 | We make out that now we are fitting larger diameter wheels to our cars, the present design of 3-speed gearbox gives us practically the same gear ratios as on Mr. Radley's Car which failed in Austria, therefore, there is no reason why cars fitted with the new 3-speed gearbox should behave any better than Mr. Radley's car of 1912. Even when we use the lower gear Contd. | ||