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).
Critique and specification analysis of the Smith motor for the Goshawk II engine.
| Identifier | WestWitteringFiles\G\October1921\ Scan16 | |
| Date | 17th October 1921 | |
| To R & E.{Mr Elliott - Chief Engineer} from EFC. c. to CJ & FW. c. to Hy{Tom Haldenby - Plant Engineer} & EP.{G. Eric Platford - Chief Quality Engineer} c. to Hg. & Da.{Bernard Day - Chassis Design} c. to R.R. of America Inc. ORIGINAL EFC1/T17.10.21. X.43428 - SMITH MOTOR FOR "GOSHAWK II". We have now received all the various samples of outside makes of dynamos and starter motors for the Goshawk. At the present moment the Rotax dynamo and the Lucas motor are fitted to the Goshawk engine on the test bed. The Lucas motor has been handed over for this purpose previous to bench test, the latter will be carried out later when the motor is replaced probably by the C.A.V. Generally speaking, this motor is only a mediocre job. The thickness of the carcase, and especially for the size of the motor, is exceptional, .375". We think the design of the motor is faulty inasmuch as the armature diameter, 2.50", is smaller than desirable and might be increased somewhat at the expense of the thickness of the carcase metal. The leading dimensions are :- Carcase diameter 4.50" length 4.1" thickness .375" Armature diameter 2.50" active length 1.65" ( It will be seen from this that the armature is quite small). The weight of the machine is 16 lbs. 7 ozs. The field poles are coarsely laminated and secured by two studs to the carcase. The coils and connections are not [Footer, upside down] R.R. 285A (100 T) (S.H. 798. 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 | ||