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).
Comparing the performance of different starter motors for the Goshawk engine.
| Identifier | ExFiles\Box 35\4\ scan 120 | |
| Date | 14th July 1922 | |
| Contd. EFC1/T14.7.22. This may be somewhat different when only a magneto is fitted. From this we judged that our assumed torque required to turn the Goshawk engine at 500 lb-inches was, even though it was taken for the worst condition, rather higher than we need have assumed. We at first considered that the modifica-tion to the motor windings with a view to reducing their resistance might be necessary and we had given instructions for a field winding with one less turn per pole and consid-erably less resistance to be instructed to be made up, but so far this modification does not appear necessary though we have not, of course, so far experienced starting on this chassis under winter conditions. Comparing this motor with motors of C.A.V. and Lucas makes for the Goshawk, the torque per ampere is greater than either. The speed at the working point of 66 lb-inches is rather less than that of the C.A.V. but about the same as that of the Lucas. At lower torques, Lucas and C.A.V. have higher speeds than the R.R. Attached will be found photostat copy of comparison curves, R.R. curves being representative of the average of performance with the one or two motors tested. EFC. | ||