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).
Potential causes for a piston failure and proposing further investigation.
| Identifier | ExFiles\Box 178\3\ img278 | |
| Date | 14th July 1932 | |
| B. } FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} } C. to CG. WOR.{Arthur Wormald - General Works Manager} DY.{F R Danby} RG.{Mr Rowledge} 19-EX. PISTON FAILURE. Referring to HS{Lord Ernest Hives - Chair}2/AD8732., we think this should undergo a thorough investigation at once. Very many years ago we had trouble with piston stops breaking, when, owing to an error, they were not kept at right angles to the piston pin. One experiment might be to place them exactly so, instead of staggered. This could be done if we pinned 2 rings only. The real reason I think may be found in the fact that at some particular high speed the inertia of the piston may cause the split portion to collapse. This could be tested by fitting unsplit pistons. The third point is that the piston may be out of balance across its centre, that is, in side elevation of the engine, the L.H. of the piston may be heavier than the R.H. half, so that there was a tendency for the piston to revolve and rub on the piston pins. Naturally you may find that none of these is the real cause, but you may find another. We understand that the piston stop failure has only occurred in the 40/50 type. If this is so it would appear to have some connection with the larger and heavier piston of the split type, because the speed and forces in the high speed aero testing one would expect to be more harmful than the car conditions even at the increased speed. R.{Sir Henry Royce} | ||