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).
Performance calculation comparing a 20HP model with the SS, considering engine capacity, weight, and axle ratio.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan074 | |
| Date | 16th April 1929 guessed | |
| (2) HS.{Lord Ernest Hives - Chair}, Taking the figure for litres/ton mile supplied by the 20HP. is 2820. for 33 cwts total weight. Chassis weight equals 24 cwt: Increased capacity (3.2 bore). 14% (This assumes body etc does not exceed 7.5 cwt.) Saving in weight, take as .... 5% Lower axle ratio ............ 5% _____ 24% _____ 2820 X 124% = 3500 as compared with 3670 for the SS.{S. Smith} We assume the master period will have gone up on the new crankshaft sufficiently to permit of the present top speed with a lower axle ratio, if the latter is found to be desirable. The question of compression ratio does not of course enter into the above calculation, as the contemplated increase can only be considered as bringing the MEP. into line with the SS.{S. Smith} and our competitors. E.{Mr Elliott - Chief Engineer} | ||