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 discussing the use of extruded copper tubes in radiators to address engine overheating issues.
| Identifier | ExFiles\Box 38\2\ Scan162 | |
| Date | 12th September 1921 | |
| cc Mr. Nadin Mr. Belnap Mr. Bagnall X3456 Cyl - G 12921 Sept. 12, 1921 Mr. Claude Johnson, Managing Director, Rolls-Royce Ltd., London, England. Attention: Messrs. F.H.Royce & Hives. Dear Sir:- Re: Extruded Copper Tubes for Radiator In connection with Mr. Hives' letter 9/1/1920.C.6.21 to Mr. Royce on this subject, we should be glad to learn whether Mr. Hives has found any evidence of greator heat-efficiency in the radiator with copper tubes, such as a greator difference of temperature between inlet and outlet water for a given speed of flow and air speed, or a lessened tendency of the engine to boil at a given air speed. We have several cases where our cars have boiled in hot summer weather when driven hard (above 45 m.p.h.) along the level for three or four miles. This has occurred in every case with all blanking plates removed. We attribute this tendency of the cars to boil in this country partly to the high air temperatures (90° shade temperature or more) and the heating effect of the after-burning in the cylinder, due to the heavy ends of fuel which are evaporated too late to be of use and are burnt on the cylinder walls during the power stroke of the engine. If the copper tubes are satisfactory for strength there-fore, of a higher thermal conductivity than brass, and resistant to acids and alkalis in the water, it becomes desirable to adopt them in this country for the two latter reasons, quite apart from their reduced cost to us and the greater freedom from faulty tubes in building up the radiator. Finally, as an advantage of the copper tube, one would imagine that the metal is less liable than brass to crack in the case of a partial freeze-up of the radiator. We should be glad to learn whether the tubes which Mr. Hives tested on the bump test, had round or hexagon expansions. (over) | ||