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).
With hand-drawn sketches discussing the design and action of a servo mechanism.
| Identifier | Morton\M20.1\ img013 | |
| Date | 1st April 1924 | |
| TO E.{Mr Elliott - Chief Engineer} BA. & ST.{Capt. P. R. Strong} FROM R.{Sir Henry Royce} ORIGINAL SECRET R2/M14. 4. 24. Copy to - C.J. HS.{Lord Ernest Hives - Chair} E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. 2 & 3. 49940 49910 SERVO. Further to my two former memos. I agree that the servo should have a stop to limit its action to about 90° forwards and say 75° backwards. I think the lifting links given by Mr. Day and mentioned by you in your report very good, but possibly it would be better:- (1) Not to superimpose the levers because of the friction created, reducing the efficiency and increasing the tendency to stick on. (2) Not to risk catching the rods if end positions incorrect or worn. My suggestions is:- [Handwritten text with strikethrough] I have set this out on a sketch board and find it quite possible. Lifting pins about .6 where it would touch the con. rod - after this it can taper. Outer one is the forward one. [Diagram annotations] 90° 75° 37 1/2° This would be the longer of the two pins. I think it would be better for each lever to have a bush so that one lever could not bind the other. plain or ball or roller bearings on here very close to forward lifting rod. [Lower diagram annotations] About .4 .5 centres. Levers interchangeable. Fit here only & on 3 pins. In the earlier design the inner pressure plate was fixed on the inner shaft. This would prevent cross winding on pins. I do not see any disadvantage of making it thus. In my last memo. I shewed plan of balance lever to provide for con. rods being in 2 planes about 1/4" apart. (1) | ||