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).
Brake system improvements by fitting needle roller bearings to the brake toggle shaft to reduce brake fade.
| Identifier | ExFiles\Box 84\2\ scan0353 | |
| Date | 10th July 1935 | |
| +rol To H.{Arthur M. Hanbury - Head Complaints} c. to Wor.{Arthur Wormald - General Works Manager} c. to Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Improved Efficiency of Brake Toggle Shaft fitted with Needle Roller Bearings. A serious defect in our brake systems is the considerable reduction of braking force which occurs when the brakes get hot. The loss is partly in the brake drums, partly in the servo. If we are able to keep either of these parts cooler, we shall improve our brakes. We have mentioned before that the mechanical efficiency of R.R. brake systems is not good, and can be improved considerably. When this is done we can use a much smaller servo output and the result will be that the "fade" will be reduced. We have recently measured the efficiency of a Bentley front brake toggle shaft fitted with two needle roller bearings in place of the usual plain bearings. The result of this test is shown on the graph herewith. We hope to be able to get a Bentley car fitted with a set all round at a not too distant date, but it is useless to do this until we are able to fit at the same time rolling toggles and tension rod linkage, of the same general type as that used on the SpectreCodename for Phantom III. We understand that the former is being detailed and the latter being designed. Please note that on a properly redesigned brake system incorporating only needle roller toggles (of these several projected improvements) that the heat generated by the servo would be only 90% of the heat generated now. HE/A.F.Martindale. | ||