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).
Different designs for Phantom engine pistons, with a requirement from Mr. Royce.
| Identifier | ExFiles\Box 66\1\ scan0095 | |
| Date | 19th May 1926 | |
| To BY.{R.W. Bailey - Chief Engineer} FROM E.{Mr Elliott - Chief Engineer} C. to BJ. Hs.{Lord Ernest Hives - Chair} Y8040 E3/M19.5.26. PHANTOM PISTONS -X.8040. We send you herewith drawings LeCs .2237. 2243. and 2245., shewing respectively 2 bolt pedestal piston, single bolt pedestal piston and ordinary diagonal web piston. All of these are suitable either for the lighter Phantom engine with 4½ to 1 compression, or for the aluminium block and head of the lighter Phantom engine adapted to the existing crankcase and long con. rods either by adding ½" to the bottom of the cylinder block or by using ½" liner. These pistons can also be tested on the standard Phantom engine as now produced, when they would give a compression ratio of about 4.3 to 1. Mr.Royce requires that the casting shall be so made and machined as to eliminate the irregular and stiffened form of the section at the top of the flaps which exists on our present pistons. You will notice that with this end in view the horizontal slot has been made wider and cuts into the piston at the point where the thickness changes from the portion behind the rings to the spring skirt. The object of making these 3 pistons is to find out which is the best of the 3 from the point of view of light weight combined with absence of production knocks. We are inclined to favour the single bolt design - LeC 2243. E.{Mr Elliott - Chief Engineer} | ||