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).
Speedometer calculations and testing for a 10,000-mile test on car 23-EX.
Identifier | ExFiles\Box 59\2\ Scan002 | |
Date | 17th January 1930 | |
COPY. X4308 17.1.30. EFC. from Hs{Lord Ernest Hives - Chair}/AJL. X.4308. SPEEDOMETER FOR 10,000 MILES TEST ON 23-EX. This car is to have 20" wheels fitted with Dunlop 32 x 6.75" Triple Stud tread Fort Reinforced tyres which give a figure of 622 revs/mile. The speedometer drive revs/mile corresponding to this are :- 622 x 41/11 x 2/18 x 26/8 = 836.1 revs/mile (for standard 11/41 rear axle) We are handing to you the speedometer off this car in order that you may check and correct it if necessary, and also carry out your first test to ascertain if any loss of magnetism occurs after considerable usage. HS{Lord Ernest Hives - Chair}/AJL. | ||