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).
Implementation and queries regarding a vacuum-assisted column gear change for the Senior Range.
| Identifier | ExFiles\Box 124\4\ scan0140 | |
| Date | 30th April 1940 | |
| SECRET. 1046 To Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} from Ev.{Ivan Evernden - coachwork} [Struck through] c. to Rm.{William Robotham - Chief Engineer} [Struck through] c. to Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer} Ev.{Ivan Evernden - coachwork}10/JH.30.4.40. re Column Gear Change. FJH{Fred J. Hardy - Chief Dev. Engineer} [Handwritten annotation] Senior Range. It has been decided to fit to the L.H. Silver Phantom 31.G.VII. our scheme of Vacuum assisted column gear shaft. The vacuum cylinder is shewn on PL.79 of which you will have received a print. The cylinder is 3.500 in. bore and has a stroke of 1.125 in the worst case of changing into a non-synchromesh gear. The pipeline is approx. 3 ft. long and 3/8" inside diameter from the cylinder to the induction pipe and this pipe is always at induction pipe depression. We have arranged our leverages on the assumption that on the average a change will be made at an induction pipe depression of 5.2 lbs.sq.in. of vacuum. The loads on the valve linkage are given on PL.79. We are interested to know :- (1) Will the introduction of air into the induction pipe spoil the engine idling at the moment of engaging a gear? (2) What is the best point on the induction pipe to put the vacuum pipe to the change speed cylinder. It will be seen on PL.79 that there is a clearance volume at the end of the stroke, also, the piston will halt during its stroke for the period of synchronisation, but this halt will have a very short duration if the change takes places properly. We have estimated the normal time for a gear change as 2 seconds. Ev.{Ivan Evernden - coachwork} | ||