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 considerations and test results for the 25/30 HP and Wraith engines.
| Identifier | ExFiles\Box 161a\4\ scan0141 | |
| Date | 30th March 1936 | |
| (5) carburetter. This is in abeyance at the moment on account of precedence of more urgent work. The four port induction pipes and cylinder heads are now on test and have been erected initially with the automatically controlled exhaust jacket heating. This method of heating can be replaced on the same scheme by water heating as and when required. Engine Mounting. Design department will give consideration to an alternative engine mounting for raising the axis of movement at the front end. This however is not regarded as an urgent item. 25/30 HP. ENGINE. As a result of the investigation carried out on the single cylinder universal unit fitted with Bentley cylinder head as mentioned in E.1/HP.30.3.36, it is understood that an improved timing was indicated, but that the results could not be obtained on the main engine. It is desirable that a report should be issued on the work done. In connection with the design investigation into the possibility of improving the valve port and passage areas on this engine, it has been found impracticable to do much in this direction without making the present cylinder head more difficult for production. A modification for improving the exhaust valve guide cooling has been instructed and is on test. WRAITH ENGINE. As the first Wraith chassis engine will be the 25/30 HP. unit any suggestions that are practicable for improving this engine should be considered, and one of these is to reduce the number of studs per cylinder by leaving out the centre studs, at the same time proportionately increasing the size of the others. This allows of an increase in the diameter of the inlet valves and a modification of the timing which should improve slow running and increase the peak horse-power. In connection with this the Experimental department could make a test preferably on a Bentley engine, leaving out the centre studs, with a view to seeing if the cylinder head joint is satisfactory under these conditions. [Handwritten in left margin]: Report on 4 port Head. | ||