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).
Technical analysis and comparison of motor performance for the Goshawk engine under cold conditions.
| Identifier | WestWitteringFiles\G\October1921\ Scan36 | |
| Date | 31th October 1921 | |
| Contd. -3- EFC7/T31.10.21. With the Goshawk engine cold, requiring, according to our estimate, a motor torque of 66 lb-inches, the motor speed would, with these results, be 950, and the engine speed 113. These figures are better than those we have had in connection with the design of the R.R. motor for Goshawk II. The other quantities at this point would be :- Amperes - 150. Volts. - 9.0 B.H.P. - 1.0 Efficiency- .55 On the R.R. motor we had allowed an efficiency of 50% and our amperes were 137. The C.A.V. motor would be working almost exactly at the point of maximum power with a cold engine, which we think is the right condition, because usually the engine is warmer than this, the motor B.H.P. a little less, but the efficiency increased. For instance, if we take two-thirds of this torque, namely, 44 lb-inches, as we took in the case of the Smith machine, then under our test conditions the motor speed would be 1350, engine speed 160, amperes 112, B.H.P. .935, and efficiency .64. Characteristics of this motor, therefore, appear to be particularly well suited to the Goshawk engine, with the particular ratio which has been arranged, as we do not think the maximum rolling current, except under extremely cold conditions, would exceed 150 amperes. Even at the Contd. | ||