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).
Performance comparison graph for an Engine 8 Goshawk II using standard and large diameter valves.
| Identifier | WestWitteringFiles\K\July1923\ Scan66 | |
| Date | 21th August 1923 | |
| STANDARD AND LARGE VALVES ENGINE 8 GOSHAWK II B.H.P. R.P.M. TWO CLAUDEL HOBSON HAWK CARBURRETTERS OPEN EXHAUST. BATTERY IGNITION FOR MAXIMUM POWER EXPERIMENTAL CAMSHAFT TIMING I.O. ON T.D.C. I.C. 38° PAST B.D.C. E.O. 44° BEFORE B.D.C. E.C. 3° PAST T.D.C. ENGINE WATER 80° C. BELOW 1250 R.P.M. GAS DISTRIBUTION IS SO POOR THAT IT IS NOT POSSIBLE TO OBTAIN AN ACCURATE POWER CURVE. SIMILAR TESTS WERE ALSO CARRIED OUT USING A STANDARD GOSHAWK II CARBURRETTER AND INDUCTION PIPE. UNDER THESE CONDITIONS THE LARGE VALVES GIVE NO ADVANTAGE AT ANY ENGINE SPEED, THUS NEITHER THE SIZE NOR THE SHAPE OF THE PRESENT STANDARD VALVE CAUSES ANY RESTRICTION TO THE GAS FLOW. LARGE DIAM. VALVES STANDARD DIAM. VALVES STANDARD GOSHAWK INDUCTION SYSTEM AND CARBURRETTER. OPEN EXHAUST AND STANDARD VALVES. STANDARD VALVE 1.35" LARGE DIAM. VALVE 1.625" ROLLS-ROYCE, LIMITED PRINT ROOM, 21 AUG. '23 DERBY | ||