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).
Discussion of four methods for an over-riding hand control for dampers.
| Identifier | ExFiles\Box 179b\1\ img205 | |
| Date | 5th December 1932 | |
| HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} FROM HDY.{William Hardy} C to SG{Arthur F. Sidgreaves - MD}, WOB, E, D, BY [Struck through] OVER-RIDING HAND CONTROL TO DAMPERS. We can see at least four ways in which it would be possible to arrange the hand control of the dampers. (1) The hand control cuts the governor completely out of action, and will give any degree of damping irrespective of the car speed. (2) The hand control operates a restricting valve which is in series with the valve operated by the governor, with the result that a constant amount of damping is added to thatprovided by the governor over the whole speed range. (3) The strength of the governor is varied so that the square law curve of the governor is unaltered, but rises more or less steeply. (4) The hand control is only capable of increasing the damping. Above the speed corresponding to the damping set on the hand control the governor takes charge and increases the damping in the normal way. With method (2) the maximum reduction of maximum damping might be only one third - i.e. from 260 to 170., but this 90 lbs. gives an increasing range of variation as the speed falls. It appears to us that method (2) gives the best kind of variation. The characteristic curve of the governor is retained at all loads, which we think is an advantage, and there is no danger of running at high speed with low damping, as with (1). Method (3) gives too little range at low speeds. Method (4) is safe, but destroys the governor influence too much we think. We attach diagrams. Will you kindly let us have your opinion. We have not yet obtained R's views on this subject. [STAMP: RECEIVED HDY{William Hardy} 4 JAN 33] [SIGNATURE: Hdy{William Hardy}] | ||