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).
Engine valve timing, ignition timing, power curve data, compression ratio, and clearance volume.
| Identifier | ExFiles\Box 133\4\ scan0345 | |
| Date | 11th July 1929 | |
| X 38A 1004 To EP.{G. Eric Platford - Chief Quality Engineer} from Hs{Lord Ernest Hives - Chair}/Gy. Hs{Lord Ernest Hives - Chair}/Gy1/TAJ.11.7.29. Re. S.S. X1440. X928. X490 X381. (1) Std. Valve Timing. We attach print V.527, Standard Valve Timing. (2) Std. Ignition Timing. This is 12° before T.D.C. with hand control fully advanced. (3) Power Curve We understand that the figures supplied previously for a power curve for 6 units are not likely to be obtained on Unit beds, as the exhaust systems are not alike. The silencing arrangements may make 10% difference to the power obtained at high speeds. The nearest conditions to those obtained on your unit beds gave the following figures :- R.P.M. Load* C/B.H.P. 2750 106.7 122.2 2500 119.5 124.0 2250 126.2 118.4 2000 131.8 109.8 ++ Dyno formula HP = WN / 2400 1750 135.3 98.7 1500 135.9 85.2 1250 136.5 71.1 1000 136.49 57.0 750 136.4 42.6 500 135.3 37.3 (4) Compression ratio (actual) is 4.6 (5) Clearance volume = 21.67 cu. inches. Hs{Lord Ernest Hives - Chair}/Gy. | ||