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).
Vibrations and body booming issues in 40/50 and 20-HP chassis.
| Identifier | ExFiles\Box 3\1\ 01-page116 | |
| Date | 2nd October 1924 | |
| V181 Mr. Hives c/o Works Dept. EPG/H2.10.24. re. 40/50 and 20-HP. Vibrations & Body Booming. With reference to my discussion with you on the above the other day, we still continue to receive a considerable number of complete cars at the Works with this complaint, and I put it to you that some investigation work on this matter appears to be of vital importance. Although we appreciate that there are certain complete cars in which booming and the/presence of vibration is not manifest, we are quite convinced and able to demonstrate to you on certain of your Experimental cars, that there are certain features in the chassis, which, if fitted with certain booming type bodies would cause such a complete car to be condemned as being unfit to put into customers hands. Our experience in this matter as regards features on chassis which have been the means of causing objectionable complete cars may be helpful to you in order to give attention to same. These are as follows:- 40/50 Chassis. (a) General torque reaction at periods between 20 and 30 m.p.h. and "thuds". These may not be manifest when testing as a chassis, or even with test covered bodies, but when certain bodies are fixed they are objectionable and can only be alleviated by reducing the engine maximum torque, i.e. lowering compression etc. (b) Bus knocks and engine rear whipping etc. This does not necessarily cause booming, but is certainly a feature which is objectionable as regards noise when a "boomy" type of body is fitted. (c) "Periods" in the drive, axle or side shaft etc. Generally speaking there are two such periods which come on at about 20 and 30 m.p.h. These periods are always more or less manifest on the forward drive, and we feel can be affected by a certain amount of slack at the universal joint. The presence of this slack, however, causes other objectionable faults. Some amount of success has been achieved in this respect by the old type of damped spring coupling. We have also experienced periods when CONTD. | ||