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).
Carburetter comparison for Eagle engines with different setups and compression ratios.
| Identifier | ExFiles\Box 43\1\ Scan089 | |
| Date | 26th August 1925 | |
| R.R. 499A (50m) (D.D. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -3- Expl. No. REF. Hs{Lord Ernest Hives - Chair}/TAG/LG26. 8. 25. CURVE lll. CARBURETTER COMPARISON. The engine was fitted :- (1) Eagle lX. camshafts (overlap) (2) Eagle Vlll. carburetters and induction system. (3) Eagle lX. " (4) Standard pistons 5.27 to 1. This shows that when the 4 Eagle Vlll. carburetters and induction pipes are fitted there is an increase of power at lower speeds up to 2165 r.p.m. when the curve flattens and crosses the other. The Eagle lX. carburetters and induction pipes give a good straight line with the power still rising at 2300 r.p.m. A peculiar characteristic is shown, by the dotted line which is common to both curves, but more prominent with the Eagle Vlll. carburetter. This 'kink' starts at 1900 r.p.m. and comes out at 2200. As the compression ratio is increased and the 'kink' becomes worse and the speed at which it occurs is also changed - see curves 4 and 5. This phenomenon may be due to the increased pressures coupled with the overlap shafts affecting the induction system at these particular speeds. CURVE lV. CARBURETTER COMPARISON - HIGHER COMPRESSION 6.09 to 1. The engine was fitted with :- (1) Eagle lX camshafts (overlap) (2) " Vlll carburetters and pipes. (3) " lX. (4) Higher compression pistons 6.09 to 1. As in the previous curve the 4 Eagle Vlll. carbs. are predominant at low speeds up to 2200 r.p.m. where the curve flattens out and crossing the Eagle lX. at 2280 r.p.m. - the contd :- | ||