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).
Comparing carburettor and compression ratio performance curves for the Eagle IX engine.
| Identifier | ExFiles\Box 43\1\ Scan090 | |
| Date | 1st August 1925 | |
| R.R. 493a (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -4- Expl. No. REF. HS{Lord Ernest Hives - Chair}/TAG/LG26. 8. 25. Eagle lX. curve is still continuing to rise at 2300 rpm. The B.M.E.P. curves are very much better than those where the 5.27 to 1 pistons are fitted. CURVE V.{VIENNA} CARBURRETER COMPARISON 6.28 to 1. Engine was fitted with. (1) Eagle lX. camshafts (overlap) (2) " Vlll. carburetters and induction pipes. (3) " lX. " (4) Very high compression pistons 6.28 to 1 For these curves the range of speed was increased to 2400 r.p.m. As in the previous curves the Eagle Vlll. carbs. have the advantage at the lower speeds up to about 2265 r.p.m. and then flattens out crossing the other at 2265 r.p.m. Whereas with the Eagle lX. the peak of the curve appears to be much higher than 2400 r.p.m. CURVE Vl.{V. Lewis / Mr Valentine} COMPRESSION RATIO COMPARISON. These curves show the increased power obtained by increasing the compression ratios :- from 5.27 to 1 std. to (1) 6.09 to 1 and then - (2) 6.28 to 1. (3) Eagle lX. camshafts. (4) " " carburetters and induction pipes. With the 5.27 to 1 and 6.09 to 1 compression ratio the curves are practically parallel with a greater increase in power at higher speeds. With the 6.28 to 1 pistons the increase is very slight over the 6.09 to 1 at low speeds and up to 2200 r.p.m., then the lines diverge and at 2300 r.p.m. the increase in power is very large and still continues to rise at 2400 r.p.m. contd:- | ||