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).
The development and whirling tests of Phantom III clutch friction facings.
| Identifier | ExFiles\Box 129\3\ scan0309 | |
| Date | 22th June 1936 | |
| Hs{Lord Ernest Hives - Chair}/Smth.6/KW.22.6.36. Phantom III Clutch. During the development of the Ph.III clutch we have found rubber bonded friction facings to be the only ones to give us a reasonable smoth take up. The first we tried was "Hycoe", manufactured in America. Apart from the fact that this material was unobtainable in England, its very high density made it unsuitable for high speed running. We then turned to Ferodo "No.6" material, which is of a similar construction, but lighter, and found this to have similar satisfactory characteristics from the point of view of take up. When Phantom III went on to production we had no alternative but to recommend this facing. It has been moderately satisfactory from the point of view of take up, but it was found that the fabric was liable to strech under centrifugal loading when hot. We have recently thickened the facings and made other modifications to prevent this trouble. Following is an account of some whirling tests we have been doing to test various types of plates from this standpoint. In most of the tests we heated the plates up to about 175°C. before whirling. The following were the results - (1) Standard Borg & Beck plate, lined with American Hycoe, .125" thick; all inside rivets passing through both facings. Both facings burst at 5250 r.p.m., cold. (A facing of this material failed in a car when disengaging the clutch at high engine revs.). (2) Borg & Beck plate lined with .125" thick "No.6" facings in the old manner. When cold these burst after about ½ min. at 5400 r.p.m. When hot at 4500 r.p.m. one facing burst, and the other stretched off the rivets. (3) Borg & Beck plate of new type with .165" facings and common rivets in the inner row. Rivet holes in facings drilled (not moulded as on production). O.K. at 6400 r.p.m. cold; slight stretch at 4800 r.p.m. hot, and more at 5400 r.p.m. hot. Marked improvement on original type. | ||