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).
Frame distortion tests, specifically measuring torsional stiffness and front-end jellying.
| Identifier | ExFiles\Box 28\5\ Scan059 | |
| Date | 29th May 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to Hy.{Tom Haldenby - Plant Engineer} J45 Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey}1/KT. 29.5.31. X.8380. X.7380. X.457. X.7005. X.8005. FRAME DISTORTION TESTS P.II. R.A.C.VII. AND P.I. We have carried out a series of tests to measure the effect of various types of engine mounting on torsional frame stiffness with a view to gaining some information on front end jellying. The method of testing adopted was to clamp a piece of girder iron to the front end of the frame, 3" behind the front spring shackle, the weight of the front was carried by the girder iron on a knife edge placed midway between the dumbirons. Load was applied by hanging weights on to one end of the girder iron; the frame deflection consequent upon applying the load was measured 5" to the rear of the front spring shackle. The rear springing was made solid by removing the rubber buffer blocks inserting wooden blocks and clamping the rear axle up solid to the frame, in addition wheels with no tyres fitted were used on the rear during the tests. In all the results shewn it will be noticed that two values of deflection are obtained for load applied, the lower value is given when the load is applied, and the higher when the loads are taken off, thus the difference between the two readings appears to be a measure of internal damping in the frame. Figs. 1. and 11. give the results obtained on 20-EX. it is noticeable that the degree of damping increases with the frame deflection. The extra crossmember on the front was a large tubular member 4" in dia. which was previously used for road front end jellying tests. Additional stiffness at the extreme front end does not make very much difference, this confirms tests carried out on the road. Two additional tests were carried out on this car but were not recorded as they made no difference, they were (1) steering disconnected entirely from the dashboard, (2) scuttle entirely isolated from the dashboard. The next tests were carried out on 25-TX (Fig. III) and shew the effect of full diamond engine mounting; the results shew very little difference between full diamond mounting and rear feet out; when full diamond mounting is used the extra front cross member employed to carry the front end of the engine, takes the place of the stiffness given by the engine when solid front feet are employed. | ||