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 air flow versus pressure difference for various Bentley cylinder head designs.
| Identifier | ExFiles\Box 86\1\ scan0049 | |
| Date | 13th December 1933 guessed | |
| BENTLEY LEC. 3673 MODEL COMPARISON OF (1) ACTUAL STD CYL. HEAD (E.B. 615) (2) WOODEN MODEL OF STD CYL. HEAD (E.B. 615) (3) WOODEN MODEL OF PROPOSED HEAD (LEC 3673) ALL CURVES AT .400" VALVE LIFT AIR FLOW - CU. FT / MIN PRESS. DIFFERENCE ACROSS VALVE - INS. Hg CURVE LABELS: (3) (2) STD MODEL (E.B. 615) (1) ACTUAL E.B. 615 HEAD - ASSUMED LINE (1A) ACTUAL E.B. 615 HEAD TESTED WITHOUT CYL. BARREL IN POSITION NOTE - CURVES (1) (2) & (3) WERE CARRIED OUT WITH CYL. BARREL IN POSITION CURVE (1A) WITHOUT CYL. BARREL. | ||