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 conducted on thermostatically controlled bonnet shutters, comparing a Ph.III car with a Lincoln.
| Identifier | ExFiles\Box 156\1\ scan0147 | |
| Date | 1st January 1936 | |
| To E. {Mr Elliott - Chief Engineer} c. to Wcr. c. to By. {R.W. Bailey - Chief Engineer} c. to Mx. {John H Maddocks - Chief Proving Officer} Thermostatically Controlled Bonnet Shutters - LeC.4698. In connection with the above scheme, we have carried out the following tests - (1) Temperatures under the bonnet of a Ph.III car were recorded (under varying running conditions) on each side of the car - at the rear end near the dashboard and at the front near the engine distributors and at approximately the positions at which a thermostat could be mounted on the bonnet. The rear position was found to differ by a negligible amount from the front position and the two sides differed by amounts varying from 5 to 8°C. The temperatures recorded were highest in town traffic or idling, reaching 60 - 63°C., while the temperatures when cruising on country roads varied from 40 - 50°C. All temperatures were measured with a standard bonnet with three hand operated shutters closed. Opening of these shutters had no appreciable effect on the temperatures. Air temperature throughout tests was 9°C. (2) A Lincoln car, fitted with thermostatically controlled bonnet shutters (this car also had thermostatic radiator shutters as Ph.III) was fitted with thermometers adjacent to each bonnet thermostat and the above tests were repeated. Temperatures recorded were again highest in town traffic or idling, reaching approx. 60°C., while the temperature when cruising on country roads varied from 45 - 55°C. The Bonnet shutters, which were fully open at approx. 45°C. and fully closed at approx. 25°C., were therefore open the whole time the car was running, and for a considerable time after it was stopped. Air temperature throughout tests was 11°C. | ||