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).
Engine fuel consumption, injection advance, supercharging, and mechanical failures.
Identifier | ExFiles\Box 133\3\ scan0046 | |
Date | 28th February 1939 | |
747 Rm{William Robotham - Chief Engineer}/Id.5/MH.{M. Huckerby}28.2.39. Fuel Consumption. Loops were run and showed at 2000 R.P.M. a fuel cons. of .555 lbs/BHP/hr. for 100 lbs/sq.in. and .450 lbs/BHP/hr. at 74 lbs/sq.in. At 1500 R.P.M. the consumption was .540 lbs/BHP/hr. at 117 lbs/sq.in. and .435 lbs/BHP/hr. at 76 lbs/sq.in. Necessary Injection Advance. With constant advance and normal fuel injection the maximum pressure falls as the speed rises. The drop being about 100 lbs/sq.in. between 1000 R.P.M. and 2200 R.P.M. With a constant injection advance and very nearly constant maximum pressure of 1000 lbs/sq.in. powers of 122 lbs/sq.in. at 1000 R.P.M., 118 lbs/sq.in. at 1500 R.P.M. and 107 lbs/sq.in. at 2000 R.P.M. were obtained. The maximum pressures increased from 950 lbs/sq.in. at 47 lbs/sq.in. BMEP to 1000 lbs/sq.in. at max. power, for 2000 R.P.M. Lower speeds showing a smaller variation. Power was subject to approximately 6-8 lbs/sq.in. variation for a change in injection timing of 6°, this giving a fair idea of the variation which might be expected between cylinders. Supercharging. A Powerplus supercharger, running at half engine speed was used, and whilst reasonably good power was obtained, the fuel consumption was very poor. Not very much work was done, due to instructions from the D.S.R. Mechanical Failures. (1) Little end cracked down the rod, and was replaced by stronger rod. (2) Big End. Alternative materials have been tried as under:- (a) White metal. Three bearings run, two having failed after approximately 25 hours by crumbling on top. The third bearing has not run long enough to fail. Cont'd.{John DeLooze - Company Secretary} | ||