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).
Technical report on crankshaft periods, damper friction and clutch problems.
| Identifier | ExFiles\Box 74\2\ scan0316 | |
| Date | 9th September 1921 | |
| Contd. -2- This will avoid us holding up the chassis for quietening the axle. The 14½ angle gears are also in hand. There is nothing in the noise which we consider cannot be overcome without any serious alteration. There were two very distinct crankshaft periods on the car. One was at 30 to 35 M.P.H., the other was at 47 to 50 M.P.H. We have since reproduced these same periods on the Test Bed by decreasing the friction on the damper. If we increase the friction on the damper these periods disappear. This is being done. (XL2HH We have had trouble with the clutches on both engines. In one case the clutch would not disengage. We found that this was due to the light steel plate buckling. In the second case, we had the clutch jaggering when engaging. We found that this was due to the light steel plate running out-of-truth and to the fabrics not being perfect in thickness. We have experienced considerable trouble in keeping these light steel discs true when machining them. So far most of those that have been produced have had to be stretched after machining. Mr.Herbert Frood of the Ferodo Company, when he was at the works in conn-ection with fabric for these clutches, considered that we should have considerable difficulty in keeping the light thin disc true. He said he felt sure we should have to make it stiffer. BY.{R.W. Bailey - Chief Engineer} and myself discussed with Mr. Frood that several makers using the single plate disc clutch actually take the drive through the fabric disc. contd:- | ||