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).
Tyre circumferences and running distances for the Goshawk Speedometer.
| Identifier | ExFiles\Box 45\3\ Scan237 | |
| Date | 6th March 1922 | |
| BY.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/TMW. X4077 Hs{Lord Ernest Hives - Chair}/TMW1/LG16.3.22. GOSHAWK SPEEDOMETER. X4077 X3602 In accordance with your request today for tyre circumferences, we give below figures for which you ask:- Dunlop Magnum tyre - 820 m/m.{Mr Moon / Mr Moore} Circumference - 8 ft. 7 1/2 ins. Distance covered by one rev. in running condition - 8' 3 1/2" Dunlop straight-sided tyre - 34 " Circumference - 8 ft. 10 ins. Distance covered by one rev. - 8ft. 5 1/4 ins. Tyre pressures - 50 lbs. Hs{Lord Ernest Hives - Chair}/TMW. | ||