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).
Query challenging a stated direct drive ratio for the 'M' Series Bentley and requesting the overdrive efficiency loss percentage.
| Identifier | ExFiles\Box 83\3\ scan0086 | |
| Date | 11th October 1938 | |
| S/W. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} "M" Series Bentley. Cx{Major Len W. Cox - Advertising Manager}12/KW11.10.38. We are being challenged by certain of our Retailers and customers as to the accuracy of the statement contained in Rm{William Robotham - Chief Engineer}/Gry{Shadwell Grylls}6/R/938 to the effect that the direct drive is 3% lower than it was previously, i.e. 4.3 as against 4.1. Figures of 4.8 and 5% have been given us as the correct percentage. Would you please tell us how you arrive at the 3% seeing that your 4.3 and 4.1 ratios take into consideration the difference in the back axle ratio and size of tyres. We are also asked to state in one instance, for the benefit of a customer who is inclined to be rather technical, what is the percentage loss of efficiency entailed through the employment of the overdrive on 4th gear. I am not sure that we shall necessarily pass on this information to the customer, but it would be interesting to us to know the reply to his query. Cx.{Major Len W. Cox - Advertising Manager} hwb | ||