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).
Outlining general conclusions from a discussion about the design of a single-cylinder engine unit and its adaptation for an Aspin cylinder head.
| Identifier | ExFiles\Box 134\1\ scan0242 | |
| Date | 23th April 1940 | |
| Rm.{William Robotham - Chief Engineer} c to Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} 1129 Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}3/GH.23.4.40. re SINGLE CYLINDER UNIT. In a discussion with Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} regarding the above unit and its adaptation to take the Aspin cylinder head and valve gear, the following general conclusions were arrived at:- (a) The original design of the engine is to be drawn up by Aspin with no other limitations except the dimensions of the lower half crankcase, the bore 3½" and the stroke 4½". Other than this the design will start from scratch. (b) The engine should be adaptable to 2-stroke or 4-stroke running and alternative valve drive gearing should be available. Ignition can of course be accommodated by the use of a double cam. (c) If the valve timing requires modification when the engine is being run as a 2-stroke, alternative valves should be designed in addition to item (b). (d) The first valve for the 4-stroke unit should give the same valve opening diagram as is at present used on the B.80 - presumably the rationalised camshaft. (e) If Aspin considers improved performance could be obtained by modifying the valve timing while still retaining the necessary qualities of slow running and tick-over, then alternative valves should be designed. (f) Cylinder heads should be designed to provide at least two plug positions. (g) Alternative drives should be provided from the crankshaft to allow the top half crankcase to be converted from overhead drive to an orthodox camshaft drive. - continued - | ||