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).
Graph plotting power and detonation characteristics for a Bentley III engine with varying compression ratios.
| Identifier | ExFiles\Box 97\1\ scan0131 | |
| Date | 1st March 1938 | |
| BENTLEY III. COMPRESSION RATIO. POWER & DETONATION. S.28. MARCH 1938. ① STD: WRAITH CYL: HEAD (131 cc's) GASKET .010: C/R = 6.25:1. ② WRAITH HEAD (119 cc's)(.100 OFF FACE.) GASKET .050 = C/R = 6.3:1. ⓐ MIN. ADV. FOR MAX. POWER. ⓑ LINE TO AVOID DETONATION. VALVE TIMING (@ .030 CL'CE) I.O. 2° B.T. E.O. 41° B.B. I.C. 40° A.B. E.C. 3° B.T. REDLINE PETROL (No 3. SPIRIT.) PROD. BENTLEY EXH. SYSTEM. B.III. AIR BEND & SILENCER. SPEC. HPS{Horace Percy Smith - Experimental Factory Mgr}/C.P.1/VS{J. Vickers} 24-1-38 B.III No. 1 UNIT. AXIS LABELS: SPARK POSITION B.T.D.C. B.M.E.P. R.P.M. GRAPH ANNOTATIONS: C.T.S. ①a ②a ①b ②b | ||