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).
Letter to a supplier regarding an issue with modified aero magneto contact breaker cover clips.
| Identifier | ExFiles\Box 43\4\ Scan228 | |
| Date | 13th February 1930 | |
| X4021. EFC4/AD. 13th February, 1930. X4513W. Messrs. North & Sons, Ltd. Whippendell Rd, Watford. Dear Sirs, Type SP.{Mr Spinney}12-2 Watford aero magnetos with modified contact breaker cover clip. On the two magnetos Nos. 98033/4 to which you made, at our request, modification to the contact breaker cover clip, there has resulted a feature which has apparently been overlooked both by ourselves and yourselves namely that the cover is now free to move round (by vibration or otherwise) (in a clockwise direction looking on the contact breaker end) until the internal insulated low tension conductor goes in contact with the cam nut. This was arrived at on engine test of one of these machines. There is required some form of stop to prevent or limit rotation of the contact breaker cover in relation to the contact breaker itself. On the two machines in question we are arranging a suitable stop by the provision of a small arm on this cover. We find this possibility also obtains on the SP.{Mr Spinney}12-5 magnetos on two of which Nos. 98088/90 you replaced magnesium alloy pieces by aluminium alloy. You will no doubt take this point into account in connection with the two new SP.{Mr Spinney}12-5 machines which we have recently ordered from you. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||