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 initial results and difficulties encountered with the EAC Oil Relay Ignition Governor.
| Identifier | ExFiles\Box 65\1\ scan0060 | |
| Date | 23th January 1925 guessed | |
| HS{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer} X8685 INITIAL RESULTS EAC. OIL RELAY IGNITION GOVERNOR. The main difficulties encountered so far with this device are :- (1) The large piston carrying the cup leather kept in position by a piston ring is too good a fit. The removal of the piston ring has eliminated this feature, and the return spring now functions satisfactorily though there is a considerable amount of lag between the drop in engine r.p.m. and subsequent retardation of the spark. (2) The small inner piston actuated by the governor is a veryy good, smooth sliding fit when absolutely clean. The slightest impurity in the oil causes it to stick somewhat. In addition, when the oil is cold, the increase in viscosity causes a very definite resistance to motion. The theoretical force available on the governor shaft from the dynamic couple of the weights as at present manufactured is [strikethrough] apparently rather less than .7 lbs. at 450/500 r.p.m. In practice this is undoubtedly somewhat reduced by friction in the governor element. In addition, the leverage between the governor shaft and piston is .5. Therefore at a theoretical maximum, the force available to start the motion of the small piston at 500 r.p.m. is .35 lbs. when no controlling spring is fitted. In order to ensure that the governor weights return to their initial position of 45°, it is necessary to have a certain primary torque on the governor spring quite apart from the rating used to obtain the correct ignition curve. contd :- | ||