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).
Analysing issues with the EAC throttle governor's heavy hand control.
| Identifier | ExFiles\Box 66a\3\ scan0041 | |
| Date | 9th February 1925 | |
| To BY.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} 48140 Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}1/LG9.2.25. EAC. THROTTLE GOVERNOR. A source of complaint on this governor since its inception, has been that in order to obtain reasonable high road speeds, a heavy load is thrown on the hand control. The initial source of this trouble was that the EAC. governor had twice the power of the 40/50 HP. and was given the same mechanical advantage with regard to the controlling spring as on the 40/50 HP. This can be overcome by increasing the leverage between the controlling spring and the governor which, of course, reduces the sensitiveness of the arrangement. We found however, that even under these conditions we cannot get a 40° throttle opening at high speeds from the new cam with a reasonable load upon the hand control. We have ascertained that the reason for this is the position of the throttle closing spring. The resistance to closing a butterfly throttle is experienced at small throttle openings when the unbalanced suction is high. We find that we require a couple of 2+ in.lbs. to ensure that this butterfly throttle closes. With the type of spring fitted, owing to the effective length available being small, the pull from this spring when the throttle is fully open gives a torque of 6 lbs.in. In addition, the cam which is opening the throttle is at this point working at a very small radius about the throttle spindle. The result is that a heavy pull is contd :- | ||