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).
Review of new adjustable shock dampers, comparing fixed loads with hand and automatic controls.
| Identifier | ExFiles\Box 105\3\ scan0324 | |
| Date | 29th March 1933 | |
| γ5520 x7120 To Sg.{Arthur F. Sidgreaves - MD} From Hs.{Lord Ernest Hives - Chair} c.c. to Wor.{Arthur Wormald - General Works Manager} c.c. to By.{R.W. Bailey - Chief Engineer} c.c. to R.{Sir Henry Royce} ADJUSTABLE SHOCK DAMPERS. We have reviewed the position of new type shock dampers adjustable and with fixed loads, the position is as follows :- Phantom ll. The new dampers are instructed to go through on production the 126th. of 'O' 2 Series. These cars will be on test about the middle of May. So far only the shock absorbers have been instructed with fixed loads, no form of either hand or automatic control has been issued. There is no doubt as regards the necessity for controllable dampers. This position is now becoming more acute. We have reports from Mx.{John H Maddocks - Chief Proving Officer} and EP.{G. Eric Platford - Chief Quality Engineer} with the latest P.2. cars, standard type, which are going through with the new carburetter, higher compression ratio, etc., can easily get up to speeds on the road where the control of the car becomes dangerous. There is no doubt that this is so - this can be safely demonstrated on Brooklands. We have, and we can demonstrate, that with controllable dampers the low rating sprung car will hold the road as good or better than a Continental car with the stiffer springs plus Hartfords. It means therefore that controllable dampers are becoming a necessity and can no longer be looked upon as refinement. The difficulty we have come up against with the automatic governor controlled damper is that the scheme depends on a relatively low oil pressure to graduate the load on the damper by holding the valve in a certain position. What we find happens on the road is when going over bad roads or a bridge the pressure in the shock absorber upsets this position of the valve and just at the time when the maximum efficiency is required of the damper the loads are considerably reduced. It is not going to be very easy to overcome this fault without introducing other problems. We do not believe we can wait for the perfection of the governor control and that we shall have to use hand control to carry on with. We have had a hand control fitted to a 25 HP. car for two years nearly. We have also run 10,000 miles on the Peregrine with hand control. We should recommend the operation of the hand control should be hydraulic rather than mechanical rods. This would mean that we should use most of the parts designed for the automatic control except at the start we should not make use of the governor. We have a car fitted up with this | ||