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 graph showing Brake Horsepower against Engine RPM for an aluminum engine with a turbulent head and long duration camshaft.
| Identifier | ExFiles\Box 70\1\ scan0113 | |
| Date | 7th September 1927 | |
| 10 EX. ALUM ENGINE COMP. RAT. 4.95-1 STANDARD INDUCTION AND EXHAUST LONG DURATION CAMSHAFT TURBULENT HEAD B.H.P. ENGINE R.P.M. B.H.P. C.O. OPEN ROAD WHEEL H.P. C.O. OPEN GRAPH LABELS: 17 TOOTH M.P.H 16 TOOTH M.P.H 17 TOOTH 90 M.P.H. 16 TOOTH 90 M.P.H. TABLE 1: ROAD SPEED ENGINE REV. M.P.H. | 16x52 | 17x52 80 | 2600 | 2450 70 | 2278 | 2140 60 | 1950 | 1835 50 | 1670 | 1580 40 | 1310 | 1228 30 | 978 | 920 20 | 653 | 613 TABLE 2: AVERAGE PRODUCTION FIGURE % LOSS TO ROAD WHEELS. 2750 | 33% 2500 | 28% 2250 | 22% 2000 | 22% 1500 | 20% 500 | 15% TABLE 3: AS ABOVE LOSS AT VARIOUS ROAD SPEEDS. M.P.H. | %LOSS 80 | 35% 70 | 27% 60 | 22.5% TABLE 4: DIFFERENCE IN H.P. AT ROAD WHEELS AVAILABLE. 16 & 17 TOOTH AXLE. M.P.H. | %GAIN 17x52 90 | 10.5% 80 | 4.5% 70 | 2.% STAMP: ROLLS-ROYCE LIMITED PRINT ROOM 7 SEP 1927 DERBY. | ||