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 comparing power, B.M.E.P, and specific consumption for Penthouse, Hemispherical, and Semi-Hemispherical cylinder heads on a 500cc Rudge Unit.
| Identifier | ExFiles\Box 133\1\ scan0017 | |
| Date | 23th March 1936 | |
| FIG. IV 500 CC RUDGE UNIT COMPARISON OF CYLINDER HEADS POWER BORE 3.346" STROKE 3.464" C.R. = 7.3 VALVE TIMING (TAPPET CLCE .020) O 4° E E.O. 50° E C 50° L E.C. 7° L PENTHOUSE HEMISPHERICAL SEMI-HEMISPHERICAL B.M.E.P. (LBS/IN²) 160 150 140 130 120 PISTON SPEED (FT/MIN) 1736 2000 2500 3000 3500 R.P.M. 3000 3500 4000 4500 5000 5500 6000 B.H.P. 32 30 28 26 24 22 20 18 16 14 12 SPEC. CONS. (PT/BHP/HR) .700 .600 .500 .400 ALE / 23 3 36 | ||