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).
Blueprint graph comparing engine performance with two different compression ratios.
| Identifier | ExFiles\Box 13\3\ 03-page371 | |
| Date | 8th December 1931 | |
| COMPARISON OF COMPRESSION RATIOS RM{William Robotham - Chief Engineer} P46 114° CAMSHAFT E 82448 OPEN EXHAUST MANIFOLD ONLY STD VALVES 1.9 INLET THROAT STD ROCKERS R.R. TWIN CHOKE CARB 1.4" DIA CHOKE COMPRESSION RATIO 5.22-1 COMPRESSION RATIO 4.65-1 B.H.P. 180 170 160 150 140 130 120 110 100 IS IN 55 EX 60.5 013 CLCE R.P.M. 500 1000 1500 2000 2500 3000 3500 B.M.E.P. LBS/SQ" 120 110 100 90 INDUCTION DEPN INS Hg 3 2 1 80 70 60 8/12/31 | ||