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 The British Thermostat Co. Ltd. to C.S. Steadman clarifying a discrepancy in heat dissipation calculations between two charts.
| Identifier | ExFiles\Box 149a\2\ scan0346 | |
| Date | 5th February 1936 | |
| FW 1280 Telephone: SUNBURY 456 (5 LINES). THE BRITISH THERMOSTAT CO., LTD. Makers of Scientific Instruments. TEDDINGTON WORKS. Code: BENTLEY'S. Telegrams & Cables: THERMOSTAT, SUNBURY-ON-THAMES. Windmill Road, Sunbury, Middlesex. DIRECTORS: M.PAYNE. W.A.PAYNE. J.E.SHERLOCK. L.S.SWINNERTON-DYER. 5th. February 1936. Your Ref: Hs{Lord Ernest Hives - Chair}/Std. lo/KW. Our Ref: CR.{Mr Cra???ster / Mr Chichester}1847. MP/CH. Messrs. Rolls Royce Ltd., Derby. For the attention of Mr. C.S.Steadman. My dear Mr. Steadman, I much regret the delay in dealing with your letter dated 23rd. January last. Dealing with the apparent discrepancy to which you refer. Chart No. L.592.B. gives the dissipation in horsepower for Air Inlet 60°F.{Mr Friese}, Water Mean 160°F.{Mr Friese}, while Chart No. L.592.A. gives the dissipation per square foot per °F.{Mr Friese} To transpose Chart L.592.B. to Chart L.592.A. it is necessary to ascertain the mean temperature of the air. Now - 19.8 H.P. say 835 B.T.U.per minute, take dry air with a heat absorption value of .0184 B.T.U. per cubic foot for 1°F.{Mr Friese} rise, then:- 835 / (.0184 x 1500) = 30°F.{Mr Friese} rise in air in passing through the radiator. Neglecting the log law, the arithmetical mean difference is 85°F.{Mr Friese} Substituting this for the 100 difference you had in your calculation, we have 17.7 (your figure) x 100 + 85, which gives 20.7. The slight difference is corrected [Handwritten notes:] GRY{Shadwell Grylls} Std h/w Rupson | ||