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).
Carburetter throat sizes and air valve specifications for the Goshawk 11.
| Identifier | ExFiles\Box 5\4\ 04-page041 | |
| Date | 13th April 1932 | |
| To O.J. for R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} c. to C.J. c. to Wor.{Arthur Wormald - General Works Manager} c. to Hs.{Lord Ernest Hives - Chair} c. to BY.{R.W. Bailey - Chief Engineer} Handwritten: X4228 E2/113.4.32. RE. GOSHAWK 11. CARBURETTER. X.4228. x12768 The high speed throat on the 40/50 carburetter is 50% larger in diameter than the low speed throat. the 40/50 sizes are :- (diagram showing two throat sizes: .9 and .6) Reducing these in proportion to 85 to 55 HP. and correcting for jet tube diameters which are slightly different from each other on the Goshawk, then the Goshawk throats should be:- (diagram showing two throat sizes: .723 and .453) The diameters given to Derby for these throats were .750 and .500 which sizes are based on the Goshawk giving 60 HP. Although we got nearly 70 HP. on Goshawk 1. with aero type carburetter this is reduced to 55 HP. with expanding type carb. for both Goshawk 1 and 11. With regard to the air valve the 40/50 (1.25 dia. by .7 total stroke) to the Goshawk (originally 1.05 dia. by .6 total stroke) was in the proportion of 85 to 60 HP. but the stroke of the Goshawk valve was afterwards increased to the same figure as the 40/50. The shape of the air ports and high speed throat ports was not specified from WW. but I can find nothing contd:- | ||