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).
Instrument boards for the Vulture model, focusing on tyre size, axle ratio, and speedometer drive.
| Identifier | ExFiles\Box 123\3\ scan0061 | |
| Date | 6th December 1933 | |
| X4704 To Ev.{Ivan Evernden - coachwork} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}3/KT.6.12.33. VULTURE INSTRUMENT BOARDS. In view of the fact that we are going to use 6.5" tyres, we propose to start the Vulture off with a 2.92 axle ratio. The makers rolling circumference figures for the tyres is based on an effective tyre radius of 14.8" but we think this is on the small side because this is the figure we get for our 6" x 18" wheels. We should therefore put the correct rolling circumference at 95". The speedometer drive ratio in the gearbox will be exactly the same as the standard 20/25 for the first Vulture, but we do not know what it will be on the independent gearbox, nor do we have any details of the latest tachometer drive, but we will look these points up and let you have them in due course. 2.92 Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} [Handwritten calculations] 2/18 x 22 = 16/2 12/35 x 16/2 x 9/22 | ||