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).
Inspection of a Phantom fitted with De Ram shock-absorbers and a new method of building road springs using rubber strips.
| Identifier | ExFiles\Box 28\1\ Scan140 | |
| Date | 25th May 1929 | |
| P/W "Hs{Lord Ernest Hives - Chair}" PRIVATE X832 Ps8/RJ.25/5/29. I saw the Chief Engineer of Mr. De Ram yesterday. The latter is the man who is making a fair success of a what looks like a really good shock-absorber. The object of our meeting was for me to inspect a Phantom fitted with De Ram shock-absorbers, and a new method of building up road springs. Hitherto, De Ram has only fitted his shock-absorbers on condition that he reduced friction between the leaves to a minimum by polishing the surfaces and interposing brass strips. His latest idea is to interpose rubber strips and dispense with lubrication, relying on the elasticity of the rubber (Silent block principle) for displacement under working conditions. The result is that the spring leaves move over each other without surface friction, and with the shock-absorbers disconnected I alone was able to bounce the front of the car quite easily. Of course the depth of the spring is increased by approx. 1"; the thickness of the rubber strips appears to be approx. 1/8". How the car behaves on the road I cannot say, but the advantage appears to be in the fact that having reduced spring plate friction to a minimum, one is able to adjust the shock-absorber to the required damping. I did not appear to be very interested for obvious reasons, but nevertheless I was very much so, and as soon as possible shall try and get the car on the road. I believe big strides are being made in France with the Silent Block theory. Rochet-Schneider who are fitting roller bearing to the central bearing of the rear Cantilever are, I believe, about to adopt a Silent Block bush. Again, cheap and moderately priced cars are progressing rapidly in this direction. Not only spring shackles, but brake actuating shafts and other parts where the radial movement is less than 180° are being fitted with the compressed rubber bushes. I thought you would like to know this, as far as suspension is concerned it has perhaps solved a lot of problems, but how the rubber strips will stand up under extreme conditions is another thing. A test might show us. We do know here that springing is our biggest bug bear, and springing complaints a long way surpass the total of all others, and probably cost the Company more money in an endeavour to satisfy. than anything else Ps. RJ. | ||