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 S. Smith & Sons discussing thermostat performance specifications and alternatives.
| Identifier | ExFiles\Box 39\4\ Scan127 | |
| Date | 9th May 1930 | |
| TELEPHONE: EAST 0149. X3499 S. SMITH & SONS (MOTOR ACCESSORIES) LTD., BIRMINGHAM WORKS. HEAD OFFICE; CRICKLEWOOD WORKS, LONDON, N.W. 2. Reply to:- 173-177, CLIFTON ROAD, ASTON, BIRMINGHAM. OUR REF. FGE/H YOURS Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}8/MJ. 9 May 1930 Messrs. Rolls-Royce Ltd., Derby. Dear Sirs, For attention of Mr. Robotham. With reference to your two letters dated 7th inst. addressed to our Main Office; we presume that the Thermostats referred to in each letter are for different purposes. We think it is possible to arrange an instrument which would commence to lift a load of 20 lbs. at a temperature of 50 to 55 degrees Centigrade. This would however require experiment. Our standard instrument commences to lift at 58° and develops a thrust of 20 lbs. at 72° Centigrade, so that if we obtain the same thrust at 3 to 5° lower temperature this will give you what you require. With regard to the matter mentioned in your other letter, the temperature you indicate (80 to 85° Cent.) indicates that your shutters require a thrust of 40 to 55 lbs. to open them. This figure is quite normal, but if you require the shutters to open at 70 to 75° there are two alternatives. One is to reduce the friction of the shutters to 17 to 28 lbs. and the other is to use the larger instrument. The practical alternative is to use the 70 m/m.{Mr Moon / Mr Moore} instead of the 60 m/m if you can accommodate the extra 10 m/m in your tank. Assuring you of our best attention, We remain, Yours faithfully, S. SMITH & SONS (MOTOR ACCESSORIES) LTD. F.{Mr Friese} J.{Mr Johnson W.M.} Helford Midland Engineer. FJH{Fred J. Hardy - Chief Dev. Engineer} CWN | ||