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 from North & Sons Ltd. regarding an investigation into the fitting of magneto sleeves when heated.
| Identifier | ExFiles\Box 48\2\ Scan401 | |
| Date | 10th June 1926 | |
| Copy of letter from:- NORTH & SONS LTD., Whippendell Road, Watford. Ref.- CHK/HC.16. 10th June 1926. Messrs.Rolls-Royce Ltd., Derby. Dear Sirs, Following our letter of yesterday we beg to say that as a result of further investigation into the effect on the fitting of the sleeve when magnetos are heated up to 75°C. we find that the sleeves in the further magnetos returned become very tight at this temperature. We have also tested some new magnetos and find the same thing occurs. There appears to be little doubt that, when the sleeves are fitted as closely as we have fitted them recently in order to prevent noise, the expansion at 75°C. is sufficient to make the ring connecting the two parts of the sleeve fit too tightly in its housing, at the driving end of the magneto. There is also a small amount of distortion of this housing when heated, which accounts for the ring appearing to touch in two places only. We have made some of these sleeves sufficiently free at 75°C. and find that when this is done it is necessary to utilise the damping effect of the adjustable spring pressing on the contact breaker cover to prevent noise when the magneto is cold. We are returning to you magnetos 88679 and 83970 which have been adjusted as described and we trust that these will be found to be satisfactory when fitted to engines, both when cold and when heated by the engine. Yours faithfully, NORTH & SONS LTD. (Sgd) C.H.Kirby. Director. | ||