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).
Gearbox and differential requirements for six-wheeled vehicles for the India War Department.
| Identifier | ExFiles\Box 182\M21\ img088 | |
| Date | 15th April 1930 | |
| To Wor.{Arthur Wormald - General Works Manager} from E.{Mr Elliott - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD} Hs.{Lord Ernest Hives - Chair} c. BY.{R.W. Bailey - Chief Engineer} F.{Mr Friese} Da.{Bernard Day - Chassis Design} Re - Six Wheeled Vehicles for India War Department. I have been talking to Hs.{Lord Ernest Hives - Chair} re the above, and gather that he also is of the opinion that a six wheeled vehicle fitted with our standard gear box and a back axle of about 60% of our present rato would probably not give satisfaction. The feeling is that for work on the open road, the top gear would be too low, and for ditching work the 1st. and reverse would be too high. The six wheeled vehicle is capable of being driven over almost any country under conditions where our four wheeled armoured cars would be impossible, but it requires a wider choice of gear ratios for this work. A point that Hs.{Lord Ernest Hives - Chair} raised, is that our gearbox is very highly loaded at full engine torque on the bottom ratios, and would hardly stand up to our present engine for continuous work on these gears. All this suggests that the least amount of alteration we can make is to supply the present gearbox together with a simple robust two speed box inserted in the transmissio line, the lower ratio of this latter box to be used always in the open country. For future development it is agreed by Hs.{Lord Ernest Hives - Chair} that an easy-to-change box of some description would be a great advantage where the steering occupies so much attention, and where any member of the armoured car crew is called upon to take over the driving, if and when required. The one remaining point e.g. the question of some means of locking up the differential is also agreed would be a great advantage for this work, if the operation could be performed with sufficient facility, or alternatively, the use of one of the types of automatic self locking differentials. | ||