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).
Power curves and performance tests for engines with higher compression pistons and different exhaust systems.
| Identifier | ExFiles\Box 179\2\ img042 | |
| Date | 10th December 1931 | |
| R.{Sir Henry Royce} From Ha/mn. c. to EG. mor. c. to E.{Mr Elliott - Chief Engineer} Ba. c. to Hy.{Tom Haldenby - Plant Engineer} x5771. x5090. POWER OUTPUT INCE VAN STEEL. We have now had power curves off three further engines fitted with the higher compression pistons and camshaft to Sch.1643/3. We find that the figure of 82 B.H.P. given in RY.49 is optimistic for this unit the mean averaging out just below 80 B.H.P. (RM.{William Robotham - Chief Engineer}54). Though the peak B.H.P. is slightly higher open exhaust with a late timing, this is worth nothing with the silencer system fitted (RM{William Robotham - Chief Engineer} 54 & 55) and therefore the earlier timing is preferred as giving a slightly better low speed B.H.P. It will be seen from RM{William Robotham - Chief Engineer}54. that though the loss with the C.O. open is negligible, with the C.O. closed about 8 B.H.P. is dissipated in the silencer. We found on the road that we obtained for the quietest exhaust system with the original small dia manifold and 1.6" inside dia down-take and front expansion box. Curve RM{William Robotham - Chief Engineer}53 shows that we are no worse off with this combination than with the large manifold and 2" straight through pipe. Curve RM{William Robotham - Chief Engineer} 57 we consider a very good average engine fitted with the approved exhaust system, compared with the existing standard fitted with the old type exhaust system. We have taken to giving timings with .020 clearance because we find that with .013 clearance the results are erratic sometimes the tappet being just on and sometimes just off the toe of the cam. Ha/mn. Att:- RM.{William Robotham - Chief Engineer} 53 54 55 57 | ||