Diagram of a servo spring for damper control, showing the control lever in hard and soft positions.
| Identifier | ExFiles\Box 152\2\ scan0012 | |
| Date | 6th July 1937 guessed | |
| FIG. VI CONTROL LEVER ON TOP OF DAMPER. HARD POSITION SOFT POSITION SERVO SPRING FOR DAMPER CONTROL. | ||
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).