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 for a 10 EX aluminium engine with a turbulent head and long duration camshaft.
| Identifier | ExFiles\Box 69\4\ scan0190 | |
| Date | 7th September 1927 | |
| 10 EX. ALUM ENGINE COMP. RAT. 4.95-1 STANDARD INDUCTION AND EXHAUST LONG DURATION CAMSHAFT TURBULENT HEAD Graph Data: Vertical Axis (Y): B.H.P. Horizontal Axis (X): ENGINE R.P.M. Curve 1: B.H.P. C.O. OPEN Curve 2: ROAD WHEEL H.P. C.O. OPEN Top M.P.H. Scale: 17 TOOTH M.P.H, 16 TOOTH M.P.H. Bottom M.P.H. Scale: 16 TOOTH M.P.H. Right Vertical Labels: 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 RPM | % Loss 2750 | 38% 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 | ||