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).
Conclusions and summary on the effectiveness of thermostatically controlled bonnet and radiator shutters.
| Identifier | ExFiles\Box 156\1\ scan0148 | |
| Date | 1st January 1936 | |
| -2- Conclusions. (a) As long as the radiator shutters are controlling the water temperature of the car, the bonnet shutters will not exercise any control over the under bonnet temperature. This is obvious since the radiator shutters will always adjust themselves to give the requisite amount of cooling air for given set of running conditions. This is borne out in practice as indicated above. (b) Thermostatically controlled bonnet shutters of the Lincoln type, if used in conjunction with radiator shutters, and adjusted to be fully open under full throttle maximum cooling conditions (as they must be) will also run full open under traffic and idling conditions, and will be partly open under light cruising conditions. Hence, thermostatically controlled bonnet shutters amount to the same as hand operated ones, except that they ensure that the owner does not forgett to open them. Summary. We do not think it worth while to continue further with this scheme with the present system of radiator shutters. Should we revert to the radiator grille scheme at any time, the scheme might then be of use. If automatic control of the bonnet shutters is considered necessary, the operation might be managed by means of a thermostat in the water system or by oil pressure operation. Hs {Lord Ernest Hives - Chair} /Std. | ||