Road tests investigating propeller shaft coupling fouling issues.
| Identifier | ExFiles\Box 11\5\ 05-page079 | |
| Date | 23th April 1934 guessed | |
| X7941 -2- RE. PROPELLER SHAFT COUPLINGS FOULING. We have made more extensive tests on the road to convince ourselves of the trouble. There is no doubt that the root of the trouble is the soft riding position. There is no doubt that the axle winds up when the brakes are applied. We have verified this by the brake foot pedal. This goes hard down on the boards and would go some more. It is difficult to describe exactly the movement of the axle when the brakes are applied. The first thing one notices is the chassis frame lifts right up, and from what I could observe, the propeller shaft came within 1.00" of the top of the slot in the rear cross-member. At the same time the nose of the axle turns downwards. With the damper control in the maximum position, and same braking applied; the foot pedal is approx. .500" off the floorboard. The chassis frame does not lift so high, and we cannot see any turning of the axle. When observing your tests, keep in mind that our rear cross-member has been moved back, thus giving more clearance for the propeller shaft. CLUTCH MANIPULATION. Two distinct movements of the axle take place when the clutch is let in sharply at 20 M.P.H. The axle first lifts up with a turning action, then goes down with a reverse turning action. When using the minimum damping this movement is so great as to cause the axle to just touch the buffers. Then it appears to go the reverse way the same amount. With the maximum load on the dampers the movement is not more than 2.00" either road, and the axle does not revolve or turn. It will be impossible to reproduce these features on the dynamometer as there is not sufficient grip of the road wheels on the revolving wheels. I have looked up a drawing of the relative positions of the dampers on the frame, and observe no alterations have been made. The moving back of the cross member may be allowing more movement of the propeller shaft. An investigation to see whether there are marks on the production propeller shaft where it goes through the cross member would enlighten the possibility of this. We have on previous tests had the shaft fouling, but have put it down to insufficient clearance. We have sent you a sketch showing where the coupling has fouled. Indents in the metal have been made. S.H.Hancock. C.W.H. | ||
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).