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).
Issues found during testing related to water temperature, clutch performance, and a knock from the torque reaction damper.
| Identifier | ExFiles\Box 5a\3\ 03-page146 | |
| Date | 1st December 1931 | |
| Y5840 To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From G.W.H. Hotel de France, Chateauroux, FRANCE. 1/12/31. 18.G.IV. RE. WATER TEMPERATURE. We have not got over the trouble with the water temperature rise when running slow as we thought we had when we reported yesterday, and this trouble is not going to be so easily dismissed. The reason of this is, that with this type of engine we can get a much slower consistent running than is usually practicable with the present standard 25 HP. engine, and we find that at these very slow speeds, there is not sufficient circulation to keep the water cool. With a normal slow running speed the water temperature is kept at approx. 80°C, but by dropping the revs lower and retarding the ignition, in approx. 10 minutes the red lamp glows. One has only to flick the engine up momentarily and the water temperature drops to normal again. The slow running is such, that on the road we can get a steady 4 M.P.H. without any missfiring. Therefore it looks as if we shall have to fit either a slightly larger pump or else it will have to be speeded up. CLUTCH. I thoroughly tested out the clutch this morning with the G.54132 clutch springs, and find that the clutch is only just taking the drive without slipping. The slightest pressure on the foot pedal sets the engine racing away, also when starting off in top gear the clutch would hold, then slip, held, slip again, with sequence results until finally it took the drive. We are therefore too near the border line in being safe, when using these clutch springs. RE. KNOCK FROM TORQUE REACTION DAMPER, REPORTED. This was so persistent during this morning's run that we dismantled the damper at noon and located the knock. It was due to insufficient clearance for the outer plates. These had been fouling the wiring tube. This was taken up both with the D.O. and our own fitters before we came out, and they assured me that sufficient clearance had been given. We find however, as stated above, that the clearance is not sufficient. This feature has always been a close job on the 25 HP. and it is absolutely necessary that more attention will have to be given to the clearance. G.W.Hancock. G.W.H. | ||