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 test results and recommendations concerning detonation at various speeds and loads.
| Identifier | ExFiles\Box 179\2\ img030 | |
| Date | 9th December 1931 guessed | |
| -2- Engine. R.P.M. Det.Pt. C/BHP. Boost. "Hg. Abs. C.R. ---------------------------------------------------------------------------------------- Std. Buzzard. 2000 'Y' 6 ft. 830 32.5 5.5/1 R.25 2000 'Y' 6 ft. 857 31.44 6/1 R.11 2000 'Y' 9 ft. 910 36.5 5.5/1 R.25 2000 'Y' 9 ft. 902 32.74 6/1 ---------------------------------------------------------------------------------------- For the next series of tests the engine was throttled to give 1000 HP at varying speeds in order to determine the speed at which detonation just became audible. This was found to be approx: 3400 RPM. Curve 102 'R' gives the detonation at various speeds with the engine developing 1000 BHP. and also at the corresponding take off power and speeds. SUMMARY From the results obtained we should recommend the two following engines. (I) An engine with a normal speed of 2400 RPM to be run on standard fuel (DTD 134). This will give an MP of 149 lbs/sq ins (Std Buzzard is 148 lbs/sq ins) which means that at normal RPM the peak loads will be less than on the standard Buzzard due to the absence of detonation (Std Buzzard det: is 'Y' 6' at 2000 RPM) There appears to be no reason why the speed should not be raised to 2400 RPM as the engine is fitted with a balanced camshaft and the low peak loads should make for very economical use of the bearings. (II) An engine with a normal speed of say 2150 RPM (165 lbs/sq ins MP) and running on an antidetonating fuel. Although the engine would have a somewhat higher MP at normal RPM. than that in case (I) it would have the advantage that there would be no detonation at the take off speed. In the case of either engine it would be necessary to adjust the blower gear ratio to give 1000 HP at which ever normal speed is decided on. Hs{Lord Ernest Hives - Chair}/H.R. Young. Att: R.101 R.102. | ||