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).
Test results and failures for chassis and engine components including torque arms, dampers, and frame welding.
| Identifier | ExFiles\Box 99\2\ scan0146 | |
| Date | 28th March 1938 | |
| -3- to rebound the following test will be made - (a) Yoke deflection measured. (b) Direction of load in top triangle ascertained. (c) Lower rating springs. The attached graph shows the resistance to end load of the various rubber bearings used for these tests. We are going to test a metal sphere for the top yoke bearing and a threaded shackle for the lower main lever as an alternative in case the rubber bush development takes longer than is anticipated. (2) The engine mounting was a temporary scheme used with the universal gearbox. The correct engine mounting cannot fail at the same place. (3) The rebound buffers were quite unsatisfactory and larger rubbers such as used on the Humber will be required. We attach a print of a buffer DB.{Donald Bastow - Suspensions}695, which is made by Firestones and should be suitable for this application. The area of contact on the buffer stop bracket from the frame is too small. (4) Torque arms have been tested in the following materials - (a) Sheet steel as Packard .104" thick. (b) " " .080" thick. (c) Cast Steel. (d) Aluminium casting. We have had failures with all types except the Cast Steel which has run 82 1/2 hours satisfactorily. Although we think that the sheet metal arm in .104" could be made satisfactory we recommend that the arm should be a forging on production. The cost being 10/9d. for mild steel against 10/6d. for the sheet metal arm. The increase in weight will be 1 lb. (5) The damper bellows failed because of high pressure oil being built up behind them. This was due to a loose fitting stabilising piston. The valve unit which is about to be tested avoids the high pressure leak. (6) The main cause of the frame failures was due to welding. (a) Welding increased the frame stiffness by 13%. (b) Welding causes local high stresses due to local expansion when junction is made. (c) The heat from welding deteriorates the metal close to the weld. | ||