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).
Tests and improvements made to a starter motor unit by adjusting spring loads.
| Identifier | WestWitteringFiles\Q\2April1927-June1927\ 207 | |
| Date | 29th June 1927 guessed | |
| contd :- -4- have become very much worn, the pinion under load works back until only .250" of the teeth are in operation. We presume that in time on an owner's car the teeth of the flywheel will wear to the same degree and probably cause failure of the starter motor. During our tests we found that by increasing the spring D.51133 to 10 lbs. and reducing the spring D.51144 to 8 1/2 lbs. we obtained an all-round improvement of the starter unit. In investigating the slipping under load condition, the chief and primary cause is as stated previously - the poor surface of the cork discs. Under present conditions waxfixdirect and in the event of not being able to obtain better cork, we find that by increasing the initial load of the spring D.51376 from 31.5 lbs. to 50 lbs. we obviate the slipping. Our explanation of this is that the slipping occurs before the pinion is fully engaged, when the load applied to the clutch discs is little more than 38.5 lbs. which is insufficient for the load imposed upon the starter in this position. By increasing the strength of the spring to 50 lbs. we prevent this slipping, and the rating of the spring is not too high to prevent the nut winding up to its full movement, thereby getting the maximum load imposed upon the clutch discs when pinion is fully engaged. Hs{Lord Ernest Hives - Chair}/G.W.Hancock. | ||