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).
Outlining proposed modifications to the Sports Phantom engine's crankchamber.
| Identifier | ExFiles\Box 70\1\ scan0085 | |
| Date | 9th September 1927 | |
| Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} 78774 R1/M1 9.9.27. SPORTS PHANTOM ENGINE. X.8774 X.634 X.8010 Further to my memo. R4/M15.9.27., it is now possible to give more information concerning the alteration to be made to the crankchamber. We are proposing that one of your present Phantom patterns be modified in the following way :- The wall on the drivers' left side will be made straight, and tappets after the general arrgt. of the 20 HP. will be put in from the top. The oil pump will be removed from this wall to the front end of the engine and will be driven from the bottom end of the ignition tower shaft. The height of the crankchamber will be reduced from 11" to 9.5" and the carrier wheel lowered to suit. The oil pump removal takes away the weakest spot in both upper and lower half. The valve gear modification takes away the second source of weakness. The reduction to the height provides better cooling for the piston and therefore permits of the use of a small and lighter piston. These modifications together with some lightening of the connecting rods, crankpin, crank webs, and spring drive, will place the master period beyond the danger zone. We are certain that the roughness is caused either by the proximity of the master period, or the weakness of the crankchamber. We are altering both. This can be determined by running the lightened parts in the present crankchamber, and the heavy parts in the modified crankchamber. There are slight modifications to the head, and there is the new C.I. cyd. block that has to be produced in any case. This has not been decided without due consider- ation. R.{Sir Henry Royce} | ||