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).
Comparison table of engine component specifications for 20 HP, Lorraine, 40/50 HP, and Hispano models.
| Identifier | ExFiles\Box 22\1\ Scan296 | |
| Date | 1st November 1927 guessed | |
| DETAIL. | 20 HP. | Lorraine. | % diff: of Lorraine wt. | 40/50 HP. | Hispano. | % diff: of Hispano wt. Conn: rod length. | 7.95" | 9.062" | | 11.5" | 11.8" | Total connecting rod weight. | 1.551 | 1.763 | + 14% | 3.38 | 3.62 | + 7.3% Big end weight. | 1.187 | 1.250 | + 5.5% | 2.567 | 2.625 | + 2% Small end weight. | .364 | .515 | + 41% | .826 | 1.000 | + 17% Complete piston, rings, pin etc. | 1.070 | .868 | - 10% | 2.476 | 2.312 | - 6.7% Total reciprocating weight. | 1.434 | 1.38 | + 3.57% | 3.302 | 3.312 | + 3% Small end dia. | .750" | .870" | | 1.00" | 1.275" | Big end dia. | 1.50 | 1.771 | | 2.125 | 2.125 | Hs{Lord Ernest Hives - Chair}/An. | ||