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 comparing the characteristics of different side steering tubes.
| Identifier | ExFiles\Box 95\1\ scan0266 | |
| Date | 9th January 1936 | |
| 3rd scale SIDE STEERING TUBE CHARACTERISTICS. Y-Axis: SPRING LOAD lbs, values 0 to 400 X-Axis: MOVEMENT FROM CENTRAL POSITION, values 0 to 0.400 Data Lines: MARLES ON 25 HP, BENTLEY, STD. PH.III, STD. 25 HP DOTTED LINE SHOWS CONDITION ON 33 Ex. H.H./9/1/36 | ||