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).
Report analyzing various engine mounting systems and their associated issues like booming and jellying.
| Identifier | ExFiles\Box 182\M19\ img045 | |
| Date | 21th March 1931 | |
| - 2 - Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/KT.21.3.31.cont really very free from this complaint. Therefore experimentally we say there is no reason why booming 25 HP. cars should exist. Unfortunately the design of the rear support on 18.G.IV was such that the engine has to be taken out of the frame to remove the gearbox, for this reason and because only a few more cars were to be made, the mounting has not been standardised but will be utilised on Japan III. 40/50. This mounting has been tried on two experimental cars both of which were bad for booming. 24-EX and 25-EX. In both cases it proved to be a cure and torque reaction was adequately dealt with. Since the booms on 25-EX proved to be very resistent to any other form of cure, we deduce that the same results may be expected as on the 25 HP. The diamond mounting cannot be used with the 40/50. car as it stands because of - (1) Increase in steering shocks and decrease in selectivity. (2) Increase in jellying. From tests we have previously carried out stiffening up the front of the frame, we believe that the difficulties of making a good steering with the diamond engine mounting are very great. It will be remembered that when we made the continental P.I., the selectivity of the steering was criticised and our own opinion is that this was due to lack of torsional rigidity in the frame. We believe that our jellying difficulties have been increased by the subframe and await with interest the result of building cars in America without subframes. Other types of Engine Mounting. We have explored on the P.II. (1) Two rear feet and single point front support. (2) Two front feet and single point rear support. (3) Four diabolo soft rubber feet. (4) Rubber rear engine support. Whilst the results obtained vary with different types of body we can say. (a) Two front feet and a rear support seems the best | ||