Blueprint diagram of a piston cross-section identifying an Invar strut and areas of tightening.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan229 | |
| Date | 24th December 1929 | |
| PISTON TIGHTENS IN BORE WHERE MARKED THUS. INVAR STRUT -ROYCE, LIMITED INT. ROOM. 24 DEC 1929 COPY. ael/24/12/29 | ||
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).