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).
Graph showing camshaft torsional vibrations for the Wraith II engine under different conditions.
| Identifier | ExFiles\Box 136\1\ scan0302 | |
| Date | 6th October 1938 guessed | |
| CAMSHAFT TORSIONAL VIBRATIONS WRAITH II ① CAMWHEEL HAVING .015 - .020 CLEARANCE STANDARD CONDITIONS ② CAMWHEEL INERTIA INCREASED BY 125% NOW .086 LBS INS² UNITS 9 x 12 DYNAMO DRIVE RUBBER FLEXIBILITY INCREASED CAMSHAFT AMPLITUDE OF OSCILLATION (DEGREES) ENGINE R.P.M | ||