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).
Preliminary results of fitting a supercharger to a Peregrine engine.
| Identifier | ExFiles\Box 3\4\ 04-page097 | |
| Date | 30th September 1932 | |
| X4553 Sg.{Arthur F. Sidgreaves - MD} From Hs.{Lord Ernest Hives - Chair} c. to Nor. c. to Sw. c. to Gr.{George Ratcliffe} c. to Ok. c. to Su. c. to By.{R.W. Bailey - Chief Engineer} Ha.1/M.30.9.32. Re. BENAPORT. The position of the Benaport engine is that we have run short preliminary tests by fitting a supercharger to existing Peregrine engines. This has enabled us to produce a power curve, but this curve can only be accepted as very approximate. The test was taken with special aero engine fuel and the blower was a temporary one. From the results we have obtained however we can anticipate a number of troubles. We shall definitely need much lower compression pistons. The detonation at low speeds would be such that the car would not be practical, even with the best anti-detonation fuels which are at present distributed. The small amount of work we have done on supercharg-ing has shown that the designs which have been satisfactory for the engine with normal carburetters have to be reconsidered when using the supercharger. We believe as regards the cylinder head joint it would be much wiser for us to accept the position that the cylinders centres should be increased rather than to struggle on and end up with an engine which is likely to give trouble in service. As regards the blower, the more experience we have had the less certain we are of the type we should go for. We started by having a preference for the Powerplus over the Rootes type. We are now nothing like so sure of this. We find that the figures taken on the Rootes type blower from the 'Alfa' car is a very poor example of this type of blower. The immediate difficulties with the Powerplus are :- | ||