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).
Spring fault causing slow armature return, and the cautious introduction and testing of new 'Y' springs.
| Identifier | WestWitteringFiles\T\2July1929-December1929\ Scan083 | |
| Date | 4th June 1929 guessed | |
| -4- slight thump in on engagement, but the chief fault of this spring is that it does not get the armature to return quickly enough when the engine starts and there is a whirr whilst the motor is spun up to a high rate of speed and left spinning for a considerable time after disengagement. If the engine is switched off after the start it stops first, and if an immediate reapplication of pressure to the push button be made after the engine has stopped, the motor may be still running. The Test Dept. have complained of this feature of the system. A number of so called Y. springs have been made to our specification and tried in experimental cars and production cars in the Test Dept. and on the whole these show up better than the Z. springs. They are of rather higher rate, but more suitable generally in the matter of maximum stress than the earlier high rate springs utilised previous to the increase of armature travel. We are however, proceeding cautiously with these because the force in all positions after first entry of the teeth is greater than in the case of the Z. spring, and we must be satisfied concerning engagement in the least favourable circumstances. Experimentally found forces in lbs. weight are as follows :- | ||