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).
The composition and analysis of two different light alloy pistons, one for an aero engine and one for a car engine.
| Identifier | ExFiles\Box 142\4\ scan0012 | |
| Date | 20th March 1928 | |
| R.{Sir Henry Royce} c. Rg.{Mr Rowledge} c. Hs.{Lord Ernest Hives - Chair} X4112 BY3/G.20.3.28. LIGHT ALLOYS FOR PISTONS. -------------------- As a result of pressing Messrs. Hughes of London, (the firm who control the German Electron patents in this country) in regard to pistons, Mr. Goodwin paid us a further visit and brought with him two sample pistons, both in a forged alloy of magnesium but used for different purposes. The first piston was a large aero piston used on the B.M.W. Aero engine. It is approximately 6 1/2" bore on diameter, and is a well made forging closely finished inside from the dies to size. The composition of this piston is rather involved, and the approximate analysis is :- Zinc 0.20 Aluminium 0.20 Silicon .6 to 1.0 Copper .0 up to .3 Manganese .2 to .5 Mr. Goodwin said that the pistons in this particular engine had done a fair amount of work, and you will remember a photograph of the piston after 100 hours running was included in my last report. One other point in connection with the B.M.W. engine was that he confirmed that the 50 hours flying was in a seaplane. The weight of the piston without gudgeon pin or rings is 3.2 lbs. In aluminium it would weigh 5.2 lbs. The second piston was a car piston produced for the German Daimler Benz Sports Car. Its composition was :- Zinc 0 to .5 Aluminium 5.75 to 6.25 Silicon 1.5 to 2.5 Copper 0 to .3 Manganese .2 to .5 Magnesium Balance. Mr. Goodwin was of the opinion that the forged alloys would not be suitable for car work, but thought, however, that the forged alloy for aero work was worthy of consideration, as in this case conditions were not so onerous from the point of view of absence of noise. | ||