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).
Modifications and experiments for a sequence starter mechanism, focusing on spiral angles and spring drives.
| Identifier | WestWitteringFiles\P\July1926-September1926\ Scan086 | |
| Date | 1st September 1926 | |
| TO DFG. FROM R.{Sir Henry Royce} C. to - BJ.WOR.{Arthur Wormald - General Works Manager} HS.{Lord Ernest Hives - Chair}BY. re. SEQUENCE STARTER. ORIGINAL R1/M1.9.26. X7650 As far as I can see the chief thing which is wrong about this is the spiral angle. Mr. Stent is sending you instructions for two shafts for the present arrangement, which will also require two new pinions and a box for carrying the rubber of the spring drive. The idea is to make the spiral angle very much less, namely, 20° instead of 58°. This is trusting more to the out of gear spring pushing the pinion out of gear directly the engine fires. We intend however to keep a small spiral angle so as to assist in the engagement, and also to assist in the releasing of the piston. You will see that this great reduction in angle will very much reduce the tendency to thump on engagement, but to enable you to choose the best angle for the purpose we have asked you to make a second shaft and pinion with only 5° of helical angle, and we anticipate that this second pinion will not be drawn in the full depth by the teaser torque, and we intend to use with this second shaft the original arrangement of making the main switch circuit as soon as the solenoid gets to the end of its stroke. It is probable that this pinion will only run with a small engagement, but we think this will not matter for the object of the experiment. It will prove whether this sequence starter is silent under this condition, and we can alter the solenoid for a sufficient stroke to enable it to make the whole engagement if it is thought to be a better scheme. You will see therefore that we consider this sequence starter will, with modifications, perform all its functions as intended and give a reliable and silent start with keys which are parallel, though we consider the slight amount of spiral in a favourable direction an advantage. You will notice in Mr. Stent's sketches a modification to the spring drive. This is a very simple scheme suitable for early experimental purposes, but may be quite satisfactory for production if we can find some rubber having good elastic qualities that will not mind lubricating oil. The scheme depends on the spring drive for the perfection, silence, and reliability, of its action, and it will be noticed that the present spring drive would no longer work with such a small angle of keys. Regarding the teaser circuit for this arrangement apparently it should be left as originally arranged. We should first try the 17 gauge, and if this is satisfactory, try the original 18 gauge, or try your change of voltage scheme on this part of the circuit to find the margin of safety. (1) | ||