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).
Modifying Phantom II Invar pistons to introduce flexibility for a better fit.
| Identifier | ExFiles\Box 15\3\ Scan044 | |
| Date | 23th January 1930 | |
| Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} C. Sg.{Arthur F. Sidgreaves - MD} Ry. X7040 E1/M23.1.30. PHANTOM II INVAR PISTON. X7040 X1506 We note from your reports that these pistons are likely to give as much trouble as cast iron in respect to precision of fit unless some flexibility is introduced. Compared with an all aluminium piston they should be able to operate with very little flexibility, and we suggest that a quick means of testing this would be to saw-cut the existing pads as shewn in sketch, arranging at the same time for suitable curvature, and fit, to bring the bedding right when hot. Our practice is to use flexibility on the non-pressure side only. The spring flaps would then require peaning out on the back like piston rings to introduce the necessary set. Alternatively the flaps could be drawn in with two or three countersunk screws in the split while being ground. There is no other way we can see at the moment of getting the bedding right, together with the spring on the flap. E.{Mr Elliott - Chief Engineer} SEE ORIGINAL FOR SKETCHES. | ||