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).
Knocking sound from the front of a car, traced to the reaction dampers and requesting an increase to the friction area.
| Identifier | ExFiles\Box 182\M19\ img217 | |
| Date | 1st August 1931 | |
| P II JEX(?) ORIGINAL To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}4/A1L1.8.31. 17941. We have the following note from GWH.{George W. Hancock - Head Chateauroux} in France :- "We noticed after fitting the new plates that a very pronounced knock developed in the front of the car after a few miles had been run (it sounded like a bad front shock damper), but we traced it to the reaction dampers. At first we thought it was due to insufficient clearance for the centre bolt, but after giving more clearance and curing the knock for a short period, it came back as bad as ever. We could produce it by rocking the car, and by driving the car under load. We found every time we let the clutch in, we obtained the knock, more pronounced if let in quickly, the reason being the rocking over of the engine. The knock was caused by the high unit of pressure on the small area of the friction plates causing them to momentarily stick and move in jerks. The friction plates were very dry, a condition which must be expected in their position. To overcome the knock we saturated them in oil, and for the present it has disappeared." We discovered the same thing on the scuttle damper i.e unit load too high, knocks. The reason the load has to be high on the 40/50 is to reduce jellying, on the 25 HP. the loads required are only 4 - 8 lbs instead of 40 since jellying does not cause trouble, therefore we hope the existing dampers on this car will do the job. We should like you to increase the friction area on the 40/50 in any way you think fit, and we will send the parts out to the car. This is urgent as it will soon be returning. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||