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).
Clutch jagger issues, the Paris Trials car crash, and observations on wing movement.
| Identifier | ExFiles\Box 5a\4\ 04-page096 | |
| Date | 23th August 1934 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from J.W.H. Hotel de France, Chateauroux. Indre. France. 23rd August 1934. We have made the 25 and 40/50 clutches less inclined to jagger. On 28-Ex, we found the stay rods to the frame not properly tightened up, this made an improvement. The stay rod from the pedal anchorage, we took the springs out and made it choc-a-bloc, that also helped. The cushion buffers set up two turns also helped. These modifications cured about 60% of the jaggers. The remaining 40% left 20% which can be got rid of by packing up the rubbers under the side engine feet, but this spoils the effect of the rubber mounting. The last 20% is caused by the clutch grabbing, which we cannot cure. The clutch is too fierce, as I have previously explained, and there is too little movement of the clutch. To obtain a smoother take up without going to the extreme of the rubbers in the side engine feet, we are going to try a torque lever from the gear box and cushioned by rubber in the frame channel. The ideal is a hydraulic damper fitted on the gear box, the ball end of the lever in a socket in the frame.. This method would not spoil the effect of the rubber mounting, but would steady the mass of weight oscillating, and so make a steadier take up of the clutch. We have cured all but approximately 15% of the jaggers on the 25 H.P. by the same method, i.e.- packed up the rubbers under the side engine feet; This clutch grabs and has very little movement, due to the back plate being made solid. The packing up of the rubbers, of course, cuts out the flexibility, but we are out to prove that it is not end play that is causing the jaggers. Re our tests with the Paris Trials Car. We are very sorry that these tests are definitely stopped, owing to the car having crashed coming from Belgium to Paris. Br.{T. E. Bellringer - Repair Manager} rang up to say it was a total wreck, and was being packed up and sent to Derby. Re wing movement. I do not pretend to know the fundamental reasons why the cars made by the van de Plas are so much steadier. I quote from what I have noted and seen and I think it is worth while making a study of this coachwork. I saw and tried two cars while I was down at Lillie Hall, and there was positively no movement of the wings or head lamps. Br.{T. E. Bellringer - Repair Manager} also commented on this, and his version was that the car that had no wing movement were those fitted with wings that were in one with the running board. | ||