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).
Design specifications for a new small six-cylinder engine, referred to as the 'third line model'.
| Identifier | Morton\M1.9\ img014 | |
| Date | 16th October 1921 | |
| THIRD LINE MODEL 14 HP "SMALL CAR" To-CJ. from R.{Sir Henry Royce} Copy to WOR.{Arthur Wormald - General Works Manager} " HS.{Lord Ernest Hives - Chair} ORIGINAL. X4405 WGR/16-10-21 D/POZ/308i R3/G29/8/21. 2 RE THIRD LINE MODEL. We send you herewith a blue print of a small six-cylinder engine which is intended for the third model. This engine would be R.A.C. rating 13.9 so as to be just under the £14 tax. The stroke would be as long as it is possible to make it without cutting too much of the cylinder away (and so demanding a very long piston or connecting rod) The upper half of the crankchamber and cylinder block to be a single casting in iron, three bearings to be used for the crankshaft (see other memo) The head and the gas passages in the cylinder block will be extremely simple compared to "Goshawk II". The idea of a six cylinder engine is that it is smooth running, will permit of its high speed without irritating the occupants of the car. Its even turning moment will permit of a smaller clutch and lighter transmission. The reason for not putting all the valves in the head for this small size is owing to the proportionately larger size of the ignition plug. Also in this smaller size it is difficult to get the valves in the head unless one accepts a bad position of the ignition plug in the side of the cylinder where it is liable to produce detonations and get oiled up (as is the case in so many car engines recently designed.) Also the complicated gas passages in the head would result in very small sizes of passages, or thin and difficult casting, it being desirable from recent experience to bring out the inlet and exhaust on the same side so as to permit of running the engine with paraffin-petrol mixture. It will be noted that the shape of the crankchamber permits of a good position for the dynamo. The arrangement (Contd.) | ||