Potential issues with the Bentley 111 shock absorber control system.
| Identifier | ExFiles\Box 99\3\ scan0043 | |
| Date | 29th December 1937 | |
| LES Da {Bernard Day - Chassis Design} /Hdy. {William Hardy} 18/G.29.12.37. DY. {F R Danby} (redacted) C. Rm. {William Robotham - Chief Engineer} (redacted) 2006 BENTLEY 111. SHOCK ABSORBER CONTROL. In reply to EY.14/G.15.12.37. several points occur to me in connection with the proposal in Rm {William Robotham - Chief Engineer} /Les.8/AP. 7.12.37. as follows :- 442 ? (1). The oil in the gearbox is in a state of considerable commotion, and consequently it may be difficult to find a place from which the pump can draw where there is a sufficiently steady level. If this is not possible the pump will sometimes draw air which will result, presumably, in a fluctuating pressure. It may be necessary to place the suction point so low in the box for the above reason, that in the event of a broken pipe or leaky joint the box is emptied below the safe level. In any case the oil is likely to contain a considerable quantity of air. Make a trial with a pump driven electrically (handwritten) No doubt a trial is the only satisfactory way of determining whether the above objections are of importance. As regards viscosity effects when using gearbox oil (Castrol XL) instead of Castrol 'F' (Redwood viscosity at 22oC 2275 secs. and 1000 secs. respectively) it would appear that we should be back into the trouble complained of in the early stages of development of our present control system, of excessive lag in the response of the dampers to the control setting. We gather that Rm {William Robotham - Chief Engineer} /Les. not only does not think the provision of a governor is necessary, but also does not intend to utilise pressure rise due to viscosity effect in the control system. If this is so the question of viscosity effect with Castrol XL does not arise, excepting as mentioned above in connection with the pipe lines. We are presuming that a sufficiently large hand control valve with a low rating spring will be relatively free from viscosity effect. (3). We are not sure whether tests have been made with the governor out of action. If not, this seems to be the first thing to do. We understand that the remarks in Hd {Mr Hayward / Mr Huddy} /SB. {Mr Bull/Mr Bannister} 14/HR.17.12.37. about the governor characteristic being a debit refer only | ||
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).