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).
Design improvements and testing for the sequence starter mechanism.
| Identifier | WestWitteringFiles\T\2July1928-December1928\ Scan258 | |
| Date | 11th December 1928 | |
| HS.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} EFC. } C. to BJ. BY.{R.W. Bailey - Chief Engineer} ORIGINAL SECRET. SS.{S. Smith} SEQUENCE STARTER. For a long time I have been trying to get a set of gears tested, on which the engaging corners are left sharp. The disengaging corners should be rounded as usual. Such a scheme would reduce the tendency for the motor to stick on first engage-ment when on the teazer circuit only. Secondly, one would imagine that the end pressure exerted by the motor, especially at the point of first engagement, should be as high as possible; and in the out of engagement position the spring opposing this should only be of the necessary strength to hold out the motor safely against gravity on an incline of 1 in 3. A reasonable increase in the spring pressure at complete engagement can be allowed, but different springs could be tested to prove the margin of safety, so that the spring is not too powerful to leave any risk of full engagement. I believe it has been proved that the taper armature has its limits of effectiveness in the degree of taper, but apparently a small amount of taper is an advantage. If there is any risk of failure to complete the engagement the armature in its fully engaged position can be still not opposite the poles, say 1/8" out of centre. We naturally should not make this out of centre very much, as we should like to use all the iron in the armature and fields usefully, but it would seem that we have got to do all we can to get the end pull vigorous. The amount of this end pull, and the margin compared with the strength of the spring, should be tested, reported, and recorded. Thirdly, it will be realised that we have exactly the same action in this part of our sequence starter as the Bosch system successfully used on several other cars, including the Mercedes. It surely only requires some vigorous comparisons to be made to find out why ours is not entirely satisfactory. Fourthly, it has occurred to me that there is one other point requiring attention and comparison - i.e. the strength of the spring between the armature and its pinion, known to me as the jump back spring. I should imagine this is too stiff, and suggest testing - among others - very low initial pressure, and rather high rating. My feeling is powerful end pull, gentle torque. I have written like this I believe several times before, so I must ask you to get a move on as we appear to be going backwards from what we have already done in the case of EAC. 7. R.{Sir Henry Royce} | ||