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).
Technical drawing of a Hispano Servo mechanism with dimensions and ratios.
| Identifier | WestWitteringFiles\K\December1923\ Scan48 | |
| Date | 4th December 1923 guessed | |
| HISPANO SERVO. RATIO ENG SPEED (DIRECT) TO SERVO SPEED = 29 TO 1. INSIDE DIA. DRUM 7.5" 120° 7.75" FERODO. 2" WIDE. 33° 3.075 33° 27° 7.48 DIA. 'OFF' POSN SECTN ACROSS A.A. 2.100. .275. 1.30. 1.64. .180 50 13.4 P.P. (initials) | ||