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).
The average power and consumption curves for F.11 & 12 production engines from August-October 1927.
| Identifier | ExFiles\Box 36\2\ scan 137 | |
| Date | 11th November 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/VH. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} Lp.{Mr Lappin} c. to EY. EP.{G. Eric Platford - Chief Quality Engineer} 'X2934 Hs{Lord Ernest Hives - Chair}/VH2/LG9.11.27. RR. F.11 & 12 PRODUCTION ENGINES. / 2965 (Aug.-Oct. 1927). Average power curves. We give herewith average power curves for the RR.F. engines so far accepted for despatch :- (a) For high comp. engines - 8/1 comp. ratio. (b) " normal " - 6/1 " " The curves are based on results corrected for barometer pressure and air temp. (760 mm. and 15°C being taken as a standard). In one or two instances when testing the high comp. engines, it has been found necessary to take the 2000 r.p.m. reading with the throttle slightly closed, owing to pre-ignition at full throttle. On these occasions, low temp., or high barometric pressure conditions have contributed to increasing the density of the charge and it may be found in subsequent full throttle power curves, that better corrected B.HP. figures can be obtained when air temps. are high or the barometer pressures low. On the border-line of pre-ignition, brake readings become unsteady, and for this reason some variations in the corrected B.HP. figures are unavoidable with 8/1 compression engines. Average consumption curves. These are given in terms of pts/HP/Hr., and represent the weakest mixture at which the B.HP. can be maintained. The curve for 8/1 comp. engines shews the best economy at high revs. This is due to the advantage gained from the increased cooling effect of the slightly richer mixture, which assist in preventing pre-ignition and consequent power loss, particularly at the lower speeds. Hs{Lord Ernest Hives - Chair}/V.Halliwell. | ||