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).
Engine mounting experiments and a proposed method for damping vibrations using the mass of the vehicle's body and frame.
| Identifier | ExFiles\Box 14\5\ Scan007 | |
| Date | 4th February 1928 | |
| FROM E.{Mr Elliott - Chief Engineer} C. to ED.{J. L. Edwards} HB.{C. E. Harcombe} RM.{William Robotham - Chief Engineer} EAC.10. ENGINE MOUNTING. [Handwritten annotations at top]: ORIGINAL X7005 X8005 X7830 X7380 In discussing recent experiments on engine mountings during visits to Derby, we arrived at the conclusion that so far as the low speed reactions were concerned it was difficult to obtain the requisite amount of damping owing to our inability to anchor the damping device with sufficient rigidity to the mass of the chassis. [Drawing of a car chassis with annotations] Body rigidly anchored here. Body flexibly mounted here. [Handwritten annotation]: ALTERNATIVELY BODY MOUNTED RIGIDLY (APPROX CENTRE OF GRAVITY ONLY) -WHERE ON X MEMBER SUPPORTED AT EACH END ON RUBBER. Cross member of frame. Whole of power torque reaction carried here through rubber mounting with additional friction dampers if necessary. These conclusions(which are embodied in experimental report HS{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}1/LG30128.) have led us to consider if it would be possible to utilise the major portion of the mass of the frame and body for damping purposes, without spoiling the insulation of the body from engine and road vibrations, torsion of chassis frame, etc. As shewn in the sketch the body carried on a subframe might be rigidly anchored to the middle of the chassis frame opposite the cross member at the front end of the "X". The subframe would then be flexibly supported elsewhere from the chassis frame as required. The engine clutch and gearbox are in one single unit and a part or the whole of the torque re-action from the power unit could be taken through rubber, with additional damping in the form of solid friction if required from the rear end of the gearbox to the cross member opposite the rigid mounting for the body. There should be no difficulty in carrying the power unit so that it remains otherwise torsionally free, yet triangulates the frame in the plan view, utilising the flexible plate scheme you devised for EAC. 10. (1) | ||