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).
4-cylinder Mercedes supercharger.
| Identifier | ExFiles\Box 22\5\ Scan130 | |
| Date | 18th November 1924 | |
| R.R. 493A (20H) (D.A. 652 20-3-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF Hs{Lord Ernest Hives - Chair}/Rml/L618.11.24. 4-CYL. MERCEDES SUPERCHARGER. This is a four cyl. engine 80 X 130 - total displace- ment 2,614 c.c's. It is fitted with overhead valves operated by a single overhead valve camshaft and rockers. The performance of the engine without the supercharger is not particularly meritorious, the maximum B.M.E.P. obtained being just over 100 lbs/sq.in. With the supercharger the B.M.P. is raised to 126 lbs/sq.in. It was impossible to reach the peak of the power curve with the supercharger in action owing to the inlet valve stems being weak and the springs necessarily very strong to eliminate bounce. Two inlet valves actually broke at speeds of about 3000 r.p.m. Investigations were confined, as far as possible, to the supercharger. The performance of the engine with the supercharger in action is very erratic. The blower draws air through a large exhaust heated muff and blows it through the carb. which is air-tight. In order to feed petrol into the float chamber when supercharging, the fuel is supplied at 3 lbs/sq.in pressure, which is further supplemented by an impellor which comes into action with the blower. The blower is driven off the front end of the crankshaft by straight cut bevel gears at 3 1/3 engine speed. contd :- | ||