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).
Information regarding the use of Ethylene Glycol in pressure cooling systems for aero engines.
| Identifier | ExFiles\Box 149a\3\ scan0232 | |
| Date | 16th November 1938 | |
| Rm{William Robotham - Chief Engineer}/Std.1/MH.{M. Huckerby}16.11.38. INFORMATION RE ETHYLENE GLYCOL AND PRESSURE COOLING SYSTEMS AS USED ON R.R. AERO ENGINES. (A) ETHYLENE GLYCOL. (1) Average operating temperature - 95°C. (2) Maximum operating temperature - 120°C, but tests have been run at 150°C. (3) Increase in metal temperature with Glycol as compared with water - approx. 40°C - this has severely increased the trouble of cylinder heads cracking between valves, experienced by the Aero people. (4) No doping of castings to remedy porosity is permissible with Glycol. (5) Glycol helps to prevent corrosion but attacks high temperature solder. (6) Pure Ethylene Glycol has a freezing point of -14°C = 25° of frost, which is not so low as the maximum frost protection we specify at present. (7) It is necessary to maintain coolant above a given % of ethylene glycol (for aero work minimum is 95% to cover operation at altitudes of 30,000 feet, while for car work minimum would probably be about 80%) and this necessitates sealing of cooling system since ethylene glycol is hygroscopic. In the event of overheating it becomes necessary to check % of ethylene glycol in coolant. (8) Radiators for Ethylene Glycol use copper tubes and 50/50 solder. | ||