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).
Letter to L.P. Saunders discussing engine oil coolers, heating and ventilation systems, thermostat schemes, and radiator design.
| Identifier | ExFiles\Box 149a\3\ scan0230 | |
| Date | 17th November 1938 | |
| L.P.Sauders, Esq. -3- 17th. November 1938. Llewelyn Smith mentioned that you recommend 100% tin solder for the tube type oil coolers with which we have had so much trouble - we are rather surprised at this in view of the difficulty of getting a really good dip, and the brittle-ness of this solder. Am very interested in your remarks about heating systems - we have a system under test at present which applies warmed fresh air to the car in winter and can supply unheated air for ventilation in summer, and this appears very promising. As regards question of cooling the ventilating air in summer, we have not seriously considered this, but think that it would be difficult to justify the complication and expense in this Country with its almost complete lack of hot weather - on your side of the Atlantic, however, the scheme is probably a different proposition. Llewelyn Smith mentioned a thermostat scheme with which you were experimenting which sounds interesting - we note that it consists of a large bypass and a radiator circuit with a certain amount of restriction in it, the large bypass being closed by a thermostat unit when the cooling water exceeds some predetermined temperature. We must confess, however, that we do not understand why you do not use the system, widely used in this country, which is really the ideal one, and consists of a large bypass which is cut off when the main thermostat valve is full open, unless this is objected to on the grounds of expense. Attached is a print showing the arrangement we are using at present - this scheme, of course, materially reduces the maximum water pressure in the cylinder block under cold conditions. As you informed Llewelyn Smith, the new trend in frontal appearance (the radiator core low down placed horizontally) for once does not make the cooling problem more difficult, but rather the reverse, both on account of increased core frontal area and better air flow conditions - we are interested to hear, however, that you find it necessary to provide exits from under hood space via slots in the wall between hood and fenders. Finally, we gather that you are building an even larger car tunnel for heat dissipation tests which should be a tremendously valuable experimental asset - our chief regret is that you cannot send us the old tunnel complete, to enable us to tackle problems and make experiments which, at present, | ||