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).
Design calculations and specifications for a Bonnet Thermostat.
| Identifier | ExFiles\Box 156\1\ scan0139 | |
| Date | 7th December 1935 guessed | |
| Rolls-Royce Bonnet Thermostat. 2.3/8" o {Mr Oldham} /d Bellows. Wall thickness .006". Single wall type. 19 convs. Rate 12 lbs/1/2". Mean Area = 3.36 sq.inches. Temp: 35°/45°C. VP 0 / 6 lbs.sq.inch. Load required at end of operating rod = 7 lbs. ↓ Spring + Bellows - (V.P x MA). ↑ (V.P x MA) - Bellows - (Spring + rate). ↓ 7 + 0 - 0 = 7 lbs. ↑ 20.16 - 12 - (7 + 1.16) = 7 lbs. It is questionable whether a spring giving these characteristics could be mounted in the space available. Smaller bellows will not put up the required load, and the next size larger, 2.7/8" o {Mr Oldham} /d, has much too high a rate. | ||