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).
Test report comparing the performance of a Goshawk I blower fitted to a Kestrel engine.
| Identifier | ExFiles\Box 179b\2\ img071 | |
| Date | 9th November 1932 | |
| To R.{Sir Henry Royce} From Ha/Lov.{Mr Lovesey} c. to Ag. Bor. c. to Rg.{Mr Rowledge} Ty. c. to RF. Lr.{Mr Ellor} c. to Lp.{Mr Lappin} Ha/Lov.{Mr Lovesey}1/WJ.9.11.32. GOSHAWK 1 BLOWER ON KESTREL. X4658 X2965 We have carried out a complete series of tests on a Goshawk 1 blower fitted to a standard Kestrel engine and obtained figures for the performance of the engine at various altitudes and various boost pressures at ground level. Similar tests have been made on the Standard Kestrel S engine which are available for comparison with the Gos.1 type blower. It was immediately noticeable, even before measurements were taken, that the Gos.1 blower exhibited an improvement in reducing the detonation intensity of the engine at high boost pressures. Some constant speed-varying boost curves are shewn upon which are marked the detonation intensity and two points are also shewn on this print indicating the detonation intensity of the standard Kestrel S. engine taken from the Type Test results. It will be noted that at constant boost pressure the detonation intensity progressively decreases as the engine speed is increased, also that the two readings obtained on the Standard Kestrel S. shew appreciably more audible detonation for approx. the same boost pressures and speeds than with the Goshawk 1 blower. The proposed higher normal R.P.M. of Gos.1 and higher rating raises the "take off" R.P.M. to round about 2200 R.P.M. and our curves shew that the increase of speed alone lessens detonation. This together with the reduced tendency for detonation possessed by Goshawk 1 blower permits of a substantial increase in "take off" boost and power with still less detonation than the standard engine. The detonation at "take off" conditions - i.e. 1950 R.P.M. and plus 1.75 lbs/sq.in. boost - of the Std. Kestrel S. averages 15 to 20 ft. whilst Gos.1 has only 8 ft. at 3 lbs. boost and 2200 R.P.M. The take off powers being 460 H.P. and 580 H.P. respectively. These tests refer to Std. D.T.D.134 fuel. On Curve 334 F.{Mr Friese} is shewn the actual altitude power curves of Gos.1 blower and Std. Kestrel at a proposed rating of 590 HP. at 11,000 ft. altitude when taking advantage of the reduced detonating characteristic and employing a normal boost pressure of 1.25 lbs/sq.in. This results in a power of 475 B.H.P. for the endurance running under Type Test conditions which is the same power at which we run the standard Kestrel M.S. engines. | ||