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 and operating temperature of thermostatically controlled shutters.
| Identifier | ExFiles\Box 39\4\ Scan204 | |
| Date | 26th November 1930 | |
| HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} x3499. R3/M26.11.30. C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} C. to BY.{R.W. Bailey - Chief Engineer} EP.{G. Eric Platford - Chief Quality Engineer} CAR WORK - THERMOSTATICALLY CONTROLLED SHUTTERS. You will realise that in the earlier days when we abandoned the idea of using thermostatically controlled shutters we did so after considerable thought, seeing their limitations and disadvantages We now come back to the same conclusion that even when fitted up as best we know how they will not be without their shortcomings, and for this reason we have provided a fairly simple means of detaching the shutters from the thermostatic control for hot climates, and when running under conditions in which we fear boiling. The disadvantage of shutters is that in cold weather we would like them to keep nearer their closed position than they naturally do, and in hot weather we should like them to keep wider open than they naturally do, that is, we would like them to take some notice of the weather, and anticipate the troubles, but as they cannot be made to do so we have to make the best compromise. In fixing the temperature we naturally feared water boiling rather than the engine being too cool because owing to the fact that we have exhaust heat on the throttle, when studying the question on the last occasion, we arranged that this should be increased when thermostatically controlled shutters were fitted. The temperature of 60°C. is quite high, being 140°F.{Mr Friese}, nearly a sterilising temperature, and hardly leaves sufficient margin for emergency bursts, and at the same time we were fixing this temperature we thought it the best compromise. About the same time we got over some of the lag in the movement of the shutters by providing more frictionless bearings at the bottom of the shutters but I should not like to go any higher temperature than the amount settled, and it will be noticed that (a) we are talking about it in winter time, (b) we are not making allowance for the increased exhaust heat we have arranged to supply to the throttle. (This increased heat is being obtained by making the smaller silencer from the throttle free-r.{Sir Henry Royce}) (c) There is another point to consider i.e. the auto: control will be more nearly constant and need not therefore be quite so high to allow for accidental drops through inattention. As regards bonnet shutters we are arranging to fit three, and in the design I have suggested a pivot near the centre so that it will form 6 openings, which may look smaller than their effectiveness No knob will be required outside because we can press one part to open and another to close. | ||