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).
Internal memorandum discussing the tendency for a sequence starter motor to jam and proposing design changes.
| Identifier | WestWitteringFiles\R\October1927-December1927\ Scan124 | |
| Date | 12th December 1927 | |
| FROM R.{Sir Henry Royce} C. to BJ. BY.{R.W. Bailey - Chief Engineer} SEQUENCE-STARTER. TENDENCY TO JAM. We do not know how much the teeth of the wheels of the latest starter have been rounded. E.{Mr Elliott - Chief Engineer} and I have studied this question at some length, and the following conclusions have been arrived at: E.{Mr Elliott - Chief Engineer} thinks that the Bosch specimen of a starter with similar engagement has no rounded corners at all. If this is so we ought to rig up the Bosch starter and see whether we can get this to jam, as there is no material difference between our system, and the Bosch system, of engagement. Personally I think that the engaging corners of the teeth should be left exactly as cut. Maybe they will require to be hardened and tempered, but if our system works as intended the engagement should be so gentle that all it is necessary to do is to have a high brinell gear and pinion for the life to be as long as the rest of the car. Next we say, how does the jam occur? It is not on the ends of the teeth, thus: -> [drawing of teeth] or on the face of the teeth thus: -> [drawing of teeth] but must be on the corners of the rounded teeth thus: [drawing of teeth] because the first two can be cured by altering the proportion of end pressure to torque, whereas the jam on the corner, no matter what the proportion is, the position will always be found where a jam can occur unless the spring back of the pinion prevents this happening. We are just finishing what we hope will be the final design for the motor, which is now having the armature so that it comes towards the flywheel instead of away from the flywheel. We have also made the contact maker to make by spring pressure so that it does not cause increased resistance to the end movement of the armature during engagement. It seems much simpler and better this way. If we can get a quiet engagement and quiet gears we think we shall have achieved our object, which is a very desirable one as the average starter is rather an alarming piece of apparatus on most cars, and the silent operation on such a car as our 40/50 would be a great asset, and worth the extra expense it appears to involve. We are hoping to finish (1) | ||