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).
Tests of a car's thermostat control, specifically the design and function of the bye-pass hole in preventing radiator freezing.
| Identifier | ExFiles\Box 171\3\ img055 | |
| Date | 1st June 1920 | |
| COPY. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c.c. to CJ. En. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} By.{R.W. Bailey - Chief Engineer} Oy. Na.{Mr Nadin} Rel/LGS.6.20. X.3563.- THERMOSTAT CONTROL. We have carried out tests with a car fitted with a Thermostat, comparing different sizes of bye-pass holes in the main valve operating in the circuit between the engine and radiator. The idea of the bye-pass hole is chiefly in order to provide a vent when filling up and draining the engine of water. The hole also allows a small quantity of hot water to leak through into the radiator even though the thermostat control valve is closed. This leakage of hot water into the radiator should assist in reducing the risk of the radiator freezing up when the car is used in extremely cold climates. It should, however, be understood that when a thermostat is fitted to a car it will be necessary to take precautions to prevent the radiator freezing up when the car is used in cold climates. We should recommend that the lower half of the radiator was blanked off during the Winter months. We should like to hear from Oy. what the practice is in America to prevent radiators from freezing up when Thermostats are fitted so as to short-circuit the radiator. We have measured the temperature at the outlet of the radiator, and have found that under average conditions (Contd). | ||