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 regarding the performance of shutter 'calorstats' and sending a modified unit for testing.
| Identifier | ExFiles\Box 156\2\ scan0214 | |
| Date | 12th October 1939 | |
| COPY. E.6 FGE/MM. Your Ref: Rm{William Robotham - Chief Engineer}/Std.4/JH. October 12th, 1939. Messrs. Rolls Royce Ltd., DERBY. Dear Sirs, for the attention of Mr.Steadman. In reply to your letter of the 6th inst. we have again looked into the question of the shutter "calorstats" and find that, as you surmise, the drawing has been interpreted to mean that the units must lift a load of 27½ lbs. when extended .425 at a temperature of 90° centigrade. In our opinion the unloaded opening temperature does not matter very much because it is sure to fall into line with the load figure, temperature and travel given, and the tolerances stated do not permit much latitude in the boiling point of the filling spirit used. We suggest therefore that you omit reference to temperature on your drawing other than the terminal performance of 90 degrees. We acknowledge receipt of the two units which you want modified. This will be a matter of experiment as the variation is so close that it will be difficult to select fillings having the appropriate boiling points. In the meantime we are sending under separate cover one unit (Bentley .300" stroke) in which the load lifted at 95° is 23½ lbs.instead of the normal 25½/29½. This may be useful for test purposes. Yours faithfully, for S. SMITH & SONS (MOTOR ACCESSORIES) LTD. ENGINEER. | ||