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 of power losses versus RPM for the 20/25 Synchromesh 1st and 2nd motion shafts under different oil conditions.
| Identifier | ExFiles\Box 15\5\ Scan284 | |
| Date | 7th May 1932 guessed | |
| 20/25 SYNCHROMESH, POWER LOSSES DUE TO 1ST AND 2ND MOTION SHAFTS, P.II OIL AT 40°C, H.P., R.P.M., OIL TEMP RISING, COLD OIL, OIL AT 40°C, NO OIL | ||