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).
Fuel calibration and investigation into improved ratings for the Goshawk engine.
| Identifier | ExFiles\Box 27a\4\ Scan210 | |
| Date | 14th September 1933 | |
| -2- He/Ymc.S/WJ.14.9.33. Cont'd.{John DeLooze - Company Secretary} (1) D.T.D.224. Experience with production Goshawk engines shewed that this fuel was of too low an octane value for the existing Goshawk ratings and so the standard F.S. Kestrel rating was taken as the basis of comparison to determine what could be expected from the use of the new fuel. Finally a consumption loop was taken to determine roughly the calorific value of the fuel. (2) D.T.D.230. (a) Calibration of the fuel. A different method was used to compare this fuel with D.T.D.134 as the increase in octane value of the former over the latter is of such magnitude as to render the old Kestrel rating useless as an absolute basis. The course taken therefore was to consider the F.S. Kestrel rating evaporatively cooled on D.T.D.134 and the F.S. Goshawk rating evaporatively cooled on D.T.D.230 and determine the amount by which the latter was superior to the former. As in the case of D.T.D.224 a consumption loop was taken for the purpose of determining the calorific value of the fuel. (b) Investigation of an Improved Rating for the Goshawk. Tests had previously been carried out on Kestrel No.27 fitted with a Goshawk supercharger having 10.06/1 gears and a rating of - 700 BHP/2600 RPM/+ 4½ lbs/sq.in. at 11,500 ft. obtained running water cooled. Since Kestrel V No.25 was fitted with 8.8/1 supercharger gears, the method of investigating the possibility of this rating on D.T.D.230 was to run at 9/10ths. the power obtained at + 4½ lbs/Sq.in. boost on this engine, and not 9/10ths. Sea level power. Additional tests were taken to obtain a rating for the engine as it stood (i.e. with the 8.8/1 supercharger gears) since the tests with the 10.06/1 gears had shown that the supercharger efficiency was excessively impaired with the increased rotor speed. The method employed to increase the rating to the figure obtained with the 10.06/1 gears was to increase the engine speed to 2900 R.P.M. An alteration to the conditions of test was made in that the rating was obtained | ||