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).
The development and testing of various damper and valve systems, detailing issues and proposed solutions.
| Identifier | ExFiles\Box 152\2\ scan0005 | |
| Date | 6th July 1937 | |
| -4- Rm{William Robotham - Chief Engineer}/Les.7/AP.6.7.37 From these tests we realized that the Armstrong damper was useless for loss of load with any valve which relied on the difference between cylinder and reservoir pressure to operate the valve. (6) In order to prevent loss of load we returned to the Armstrong double valves. A pair of lever hand control dampers were supplied with double valves Fig.III. With the damper arm static the control lever was very stiff in operation. The use of 2 valves necessitates twice the load on the control. When the damper lever was oscillating on the rig it was found impossible to move the control lever, as high pressure oil was opposing the movement of the control position. (7) The dampers were returned to the makers where rather complicated balanced valve units Fig.IV were fitted. This enabled the control lever to be moved whilst the damper levers were oscillating. The tortuous oil passages caused noticeable restriction for fast lever oscillations. These dampers were fitted to the rear of 33-EX. with the control rods connected to the present steering column damper control lever. The lever was found to be very stiff in operation. The rod control broke twice due to excessive load and the range of the dampers 60 lbs. to 110 lbs. was quite insufficient. A toggling spring as Fig.VI. was tried to reduce the load, but the control was still far too stiff. (8) It was now realized that these double spring loaded valves would make it impossible to delete the governor unit, owing to their heavy operation. For this reason a single balanced valve Rm.{William Robotham - Chief Engineer}366 was developed. This valve reduces the operation load to 1/6 of that of the Armstrong double valves, with this valve owing to the fact that the effective valve area is no longer the normal valve area for either stroke it is possible to have a large area valve with a small control load. We have now received 8 dampers as Fig.A. with valves to Rm.{William Robotham - Chief Engineer}366. One set of 4 will be fitted to G.S.IV., which we hope will shortly be running in France. One pair has been doing endurance running on the bumper and the other pair will be fitted to 33-EX. During the endurance on the bumper, the only failures have been the piston links. All these dampers have now been fitted with the strengthened type of link Fig.VII. which is quite satisfactory. With these latest dampers we find that the control becomes rather stiff when the damper lever is oscillating due to the pressure on the valve operation rod. Fig.V. shows a method which overcomes this trouble, but we are not fully satisfied with the assembly of this scheme. continued | ||