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).
Technical memorandum detailing the testing of thermometers and recording of engine temperatures for a Bentley III.
| Identifier | ExFiles\Box 97\4\ scan0118 | |
| Date | 4th November 1938 | |
| To. Rm.{William Robotham - Chief Engineer} STD ORLY 450b. CHATEAUROUX. I./.4.11.38. Mole Run/STD 8.S.V.- BENTLEY III. Thank you for your memo Rm{William Robotham - Chief Engineer}/Std.7/MH.{M. Huckerby}2.11.38. We have tested the thermometers in hot water against a glass thermometer. The Negrettis are correct to 1° but the car thermometer reads 67.5°c at an actual 63°c. The running temperature recorded by this thermometer remains remarkably steady between 81°c and 83°c rising to 85°c to 88°c with sustained maximum speed. Allowing for the error, this represents a total variation of say 76°c to 83°c, so we do not think there can be much the matter with the thermostat. Here are the temperatures taken at 20 mile intervals during part of yesterday's running for your consideration. Air. Car Thermom. Top Water Bottom Water. Under Bonnet. 11°c 82°c 76°c 72°c 32°c 10 81 77 72 34 10 82 77 73 32 9 82 77 73 33 10 82 75 72 30 10 82 75 70 32 10 81 77 72 32 10 82 77 73 31 10 82 77 73 29 § 10 § 93 § 88 § 75 § 34 10 82 73 71 30 10 82 76 72 30 10 82 75 71 30 § - This reading was taken while stopped at a level crossing. We will however, try the new thermostat unit when it arrives and see what difference it makes. Regarding your query re. undersheets, we consider these to be quite adequate. The dashboard keeps remarkably free from "road conditions". | ||