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).
Comparison of efficiencies for the 40/50 HP RR and EAC.1 models, including valve timing data.
| Identifier | ExFiles\Box 72\4\ scan0063 | |
| Date | 16th November 1923 guessed | |
| PAGE 5. COMPARISON OF EFFICIENCIES OF STD. 40/50 HP. RR. & EAC.1. WITH THE 'AIR STANDARD' EFFCY: 40/50 RR. Comp. ratio = 3.99 EAC.1. " " = 4.6 'AIR STD' = 1 - 1/R^(r-1) | R.P.M. | Indicated Thermal Efficiency % | Indicated thermal efficiency / standard efficiency % X 100 | |---|---|---|---|---| | | 40/50 RR. | EAC.1. | 40/50 RR. | EAC.1. | | 500 | 21.34 | ---- | 50.25 | ---- | | 600 | ---- | 27.33 | ---- | 59.8 | | 750 | 21.24 | 27.56 | 50.0 | 60.4 | | 1000 | 23.69 | 27.31 | 55.8 | 59.8 | | 1250 | 24.00 | 30.05 | 56.5 | 66.75 | | 1500 | 24.74 | 29.49 | 58.2 | 64.6 | | 1750 | 25.50 | 29.26 | 60.0 | 64.0 | | 2000 | 25.10 | 29.52 | 59.1 | 64.7 | AIR STANDARD EFFICIENCY. | 40/50 RR. R = 3.99 | EAC.1. R = 4.6 | |---|---| | .4251 | .4569 | VALVE TIMING USED. Diagram showing valve timing: IN. OP. 2° (Inlet Open) EX. CLO. 4° (Exhaust Close) IN. CLO. (Inlet Close) at 34° EX. OP. (Exhaust Open) at 48° Timing taken with .010" tappet clearance. 110° Camshaft. | ||