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).
Failure of an engine starter drive and the faulty adjustment of the slipper mechanism.
| Identifier | ExFiles\Box 75\1\ scan0119 | |
| Date | 25th February 1920 | |
| HS.{Lord Ernest Hives - Chair} from EP.{G. Eric Platford - Chief Quality Engineer} c. to Bn.{W.O. Bentley / Mr Barrington} c. to BY.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Cft. X 3426 C-K.{Mr Kilner} EP{G. Eric Platford - Chief Quality Engineer}1/F25.2.20. X.3426-RE. FAILURE OF ENGINE STARTER DRIVE, AND FAULTY ADJUSTMENT OF SLIPPER. With reference to the failure of the driving shaft on Mrs. Walkers' Car 10-PP, which I demonstrated to you yesterday, I should be glad if you will take up the question of improvements and definite instructions re. adjustment of the slipper drive. We have found on test that the starter works very satisfactorily, and at the same time, the slipper drive only slips when it should do, i.e. when adjusted so that the load on the chain drive of 380 lbs. causes it to slip when the driven shaft is held in the vice. We suggest therefore that definite instructions should be given to the works that all these slipper drives should be checked for this feature, and should come within the range of 350 to 450 lbs. when tested under these conditions, and none should be allowed to pass unless they come within this range of adjustment. Will BY.{R.W. Bailey - Chief Engineer} please do this. We do not feel, however, that under this range of adjustment the slipper drives are likely to remain consistent, as we invariably give this slipper drive a short test to satisfy ourselves that it does slip before the car leaves the works, whereas an inspection of the slipper drive off 10-PP gives the appearance of not having slipped for some time. I think, therefore, that the fibre material should be replaced, and should be glad if your suggestion of using bronze plates could be tested, and if satisfactory, standardise as quickly as ever possible. In view of this breakdown, I should be glad if you will deal with this matter urgently, so that if necessary we can deal with cars retrospectively in case of this trouble. Do you think in the meantime that we might issue any instructions to our Depots as regards the examination of the adjustment of the present slipper drive? We prefer not to do this, as in testing the slipper drive for slipping, we know from experience that too much slipping of this drive cause it to develope slipping, and the starter then fails to function properly. EP.{G. Eric Platford - Chief Quality Engineer} | ||