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).
Test results table showing compression and permanent set data for a solid type piston under various weights.
| Identifier | ExFiles\Box 35\2\ scan 219 | |
| Date | 29th March 1920 guessed | |
| 1 Solid TYPE Piston X2748 4.494 dia WEIGHT IN LBS | COMPRESSION | PERMANENT SET 26 | .002 | nil 36 | .0025 | " 46 | .003 | " 56 | .0035 | " 66 | .004 | " 76 | .0045 | " 86 | .005 | " 96 | .0055 | " 106 | .006 | " 116 | .006 | " 126 | .006 | " 136 | .0065 | " 146 | .0065 | " 156 | .007 | " 166 | .007 | " 176 | .0075 | " 186 | .008 | " 196 | .0085 | " 206 | .009 | " 216 | .009 | " 226 | .0095 | " 236 | .010 | " 246 | .010 | " 256 | .010 | " 266 | .0105 | " | ||