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).
Investigating an engine knock in a 7-LP car by adjusting the slipper wheel.
| Identifier | ExFiles\Box 65\4\ scan0250 | |
| Date | 5th January 1928 | |
| To Wor.{Arthur Wormald - General Works Manager} from H= -GWH.{George W. Hancock - Head Chateauroux} c. to HY.{Tom Haldenby - Plant Engineer} R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} c. to MX.{John H Maddocks - Chief Proving Officer} RP. CWS. RE. KNOCK IN ENGINE OF 7-LP.{Mr Lappin} I proceeded to London as requested and tested the car. The knock was very bad at 20 m.p.h. We proceeded to Cricklewood and dismantled the slipper wheel. When taken off it required 35 lbs. to break down the initial load. Its actual slipping load was approx. 18 lbs. The cotton duck fabric was fitted and a slipping load of 12 lbs. was obtained by leaving out every alternative spring. We again tested the car after assembling but found the knock had only been reduced by 25%. The slipper was again dismantled and the initial load had increased to 15 lbs. and slipping was uneven. This is, we believe, due to localising the load. We find that a more constant load is maintained by fitting the whole of the springs. With this in view, we fitted the 20 HP. slipper wheel springs and set the slipping load at 8 lbs., the extra initial load was not more than half a pound after standing an hour. The slipper wheel was fitted up in this condition and the car again tested. The results were an improvement of 80%, so much that it needed careful listening to locate the knock that was left. There was a slight increase in crankshaft vibrations but in our opinion not sufficient to be objectionable. We took the car to Conduit St.{Capt. P. R. Strong} and CWS. FH. and Capt. Bert tried it. Their opinion was that the car was then a big improvement and passable. It was pointed out to them that our experience with cotton duck fabric was very limited and that we could not at the present time say how it would behave in time. This was clearly understood. Hm{Capt. W. Hallam - Head Repairs}/G.W.Hancock. | ||