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).
Letter discussing discrepancies in test report data and engine performance issues, including pulsations and torque reaction.
| Identifier | ExFiles\Box 5a\4\ 04-page169 | |
| Date | 10th December 1934 | |
| G.W. Hancock, Esq., Hotel de France, Chateauroux, Indre, France. Hm{Capt. W. Hallam - Head Repairs}/Rm.{William Robotham - Chief Engineer}7/KW.10.12.34. Thank you for your report of December 8th. We cannot quite understand the figure given in your daily report on 21-G-IV of the 7th December where you say that the maximum lap speed on Montlhery is 72.5 m.p.h., whereas in your report of the 6th December you say the maximum lap speed is 74.07 m.p.h. Will you please let us know which is correct. We notice that you say the pulsations of the engine can be felt in the front seat when idling. At the same time you say that the slow running is uneven. Our experience here has been that if the slow running of the car is good it does not move about on the rubber engine mounting. As an example, 20-G-IV, which has the same mounting as 21-G-IV, is quite alright until the autovac works. It is possible that your car is being affected by the petrol pumps, but we should like your opinion on this. We presume that you have some torque reaction dampers available which you can try on the car. If not you can obtain some from Paris and fit them should you find it necessary. We went over this job ourselves and came to the conclusion that on the 20/25 if sufficient load was put on the front torque reaction dampers to stop the engine moving about, it definitely spoilt the car's smoothness at intermediate and high speeds. We note the trouble that you are having with the Cadillac. Hm{Capt. W. Hallam - Head Repairs}/Rm.{William Robotham - Chief Engineer} | ||