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).
Secret memorandum discussing torque multiplication and rod loads for the India 4-wheel brake system.
| Identifier | WestWitteringFiles\M\2April1925-June1925\ Scan104 | |
| Date | 29th May 1925 | |
| ORIGINAL TO HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} SECRET. DA{Bernard Day - Chassis Design}1/M29.5.25. INDIA - 4 WHEEL BRAKES. x5940 Thank you for your HS{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}/LG27525. On the diagram attached to HS{Lord Ernest Hives - Chair}2/LG8724. the ordinates are definite-ly stated to be torque multiplication. On the diagram attached to HS{Lord Ernest Hives - Chair}4/LG20525. they are equally definitely stated to be rod loads. By a fortunate coincidence on the 40/50 these 2 terms are practically synonymous, but it is not so on the India in which the torque multiplication is approxi-mately 1.55 times the rod load. We think that there should be a definite system used as in other cases it is certainly likely to cause confusion. We suggest that since the torque multiplication is a figure which is indepen-dent of the lengths of levers, which may vary very consider-ably with details of the design, it would be the better unit to use. We understand that the figure of 1.250 given in HS{Lord Ernest Hives - Chair}/RM{William Robotham - Chief Engineer}/LG20525. should be output over input, and refers to the rod loads. This means that the servo is giving a torque multiplication of nearly 2., which seems extra-ord-inarily high, and is much more than we either intended or wished for. It will be desirable to try the 45° cam with larger radius as early as possible as even this may not be a suffi-cient reduction. Referring to the last part of your letter we have evidently failed to make ourselves clear. What we wished to convey to you in our previous letter was that since the same man is working the pedals, and his power is necessarily (1) | ||