Calculations regarding an alteration to the Goshawk field winding for the control brush.
| Identifier | ExFiles\Box 39\2\ Scan074 | |
| Date | 15th March 1921 | |
| X.3533, ALTERATION TO GOSHAWK(Aero Engine)(Codename for 20HP Car / Aero Engine after Kestrel(Aero Engine)) FIELD WINDING FOR CONTROL BRUSH. Assumed. 9 Volts for Field Coil Volts. 3 Ohms for Field Resistance. Resistance of Mean turn = Volts per coil / A.T. per coil = 2.25 / 750 = .003 ω Length of Mean turn = 8.5" Ohms per 1000' at 15°C = 12000 x .003 / 8.5 = 4.24 C.S. of Winding Space = .65 x .75 = .487. Sq. area of 19 S.W.G. = .00250 .. Turns = 195. Length = 138' = 46 yds per coil. Res: at 20°C = 3.56 ω Current = 2.53 A A.T. 493. .. Say 195 turns of 19 S.W.G. for Field Winding i.e. same as at present for Shunt m {Mr Moon / Mr Moore} /c. Lh. {Mr Haworth} 15.3.21. | ||
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).