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 output improvements from tests on engines with higher compression pistons and different exhaust systems.
| Identifier | ExFiles\Box 102\5\ scan0109 | |
| Date | 10th December 1931 | |
| R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/sn.{Mr Sanderson} c. to SG.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to Hy.{Tom Haldenby - Plant Engineer} Y5090 Hs{Lord Ernest Hives - Chair}/sn.{Mr Sanderson}3/14.10.12.31. X577) POWER OUTPUT IMPROVED CURVES. We have now had power curves off three further engines fitted with the higher compression pistons and camshaft to Sch.1543/3. We find that the figure of 82 B.H.P. given in RM.{William Robotham - Chief Engineer}49 is optimistic for this unit the mean open exhaust averaging but just below 80 B.H.P. (RM.{William Robotham - Chief Engineer}54). Though the peak M.E.P. is slightly higher open exhaust with a late timing, this is worth nothing with the silencing system fitted (RM{William Robotham - Chief Engineer} 55) and therefore the earlier timing is preferred as giving a slightly better low speed M.E.P. It will be seen from RM{William Robotham - Chief Engineer}54. that though the loss with the E.O. open is negligible, with the E.C. 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 1.9" 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 .015 clearance the results are erratic sometimes the tappet being just on and sometimes just off the toe of the cam. Hs{Lord Ernest Hives - Chair}/sn.{Mr Sanderson} Att:- RM.{William Robotham - Chief Engineer} 53 54 55 57 | ||