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).
Engine oil properties, lubrication, and the benefits of adding fatty oil to mineral oil for aeroplane engines.
| Identifier | ExFiles\Box 77\2\ scan0014 | |
| Date | 23th April 1918 guessed | |
| is used it is liable to work up passed the piston rings into the cylinder head and cause trouble through "carbon" deposit on valves and sparking plugs. Under these conditions the viscosity of the Oil should be kept as low as practicable so as to ensure quick spread of the Oil over the cylinder walls and bearing surface, also just high enough to maintain the lubricating film under working conditions. High gravity oils for the same viscosity are more volatile than low gravity oils, they are also more liable to polymerization, under favourable conditions such as exist in motor engine cylinders. The whole question has had our most serious attention and our labours have been rewarded to the extent of receiving very large orders for Aeroplane Engine Oil(made up of Mineral Oils) from the Air Board, and our experience of petrol engine lubrication, extending over several years and with various types of engines, has conclusively proved the following points :- (1) With the addition of fatty oil to the mineral oil is a great aid to efficient lubrication. (2) It reduces the volatility of the mineral oil and gives a much better cylinder lubrication. (3) There is practically no tendency to gum and stick the piston rings. | ||