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).
Instructions concerning the use of standard 25/30 piston rings instead of high pressure rings for early Wraith engines.
| Identifier | ExFiles\Box 9\1\ 01-page08 | |
| Date | 13th January 1938 | |
| RHO. H'S. [Illegible Redacted Stamp] c. Rm.{William Robotham - Chief Engineer} 636 BY.17/G.13.1.38. WRAITH ENGINES - RE: PISTON RINGS. In order to prevent trouble arising in connection with the early Wraith engines, it will be necessary to build in engines of the first six, which are not completed, with the standard 25/30 piston and rings, and not with the high pressure rings as at present specified. Where engines have been assembled with the high pressure rings they may be left in position, but the engines should be run in carefully with castor oil, in order to obtain a good surface finish before any heavy loading is permitted to fall on the piston and rings. This is a necessary alteration, which must be applied as explained above. By BY.{R.W. Bailey - Chief Engineer} | ||