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).
Issues with piston rod length, governor springs, and controls.
| Identifier | ExFiles\Box 65\1\ scan0036 | |
| Date | 23th December 1924 | |
| R.R. 493A (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -3- Expl. No. REF. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG23.12.24. (2) Length of piston rod. The length of the rod connecting the small piston to the governor lever has a very considerable affect on the ignition curve. A variation of 1/32 of an inch in this length produces quite an appreciable result. It appears to us that it will be very difficult to give a definite length for this rod which will be satisfactory when the extremes which the limits allow in the governor cases and pistons are encountered. We have not, however, been able to try a sufficient number of governors to make sure of this, so we have taken up the question of the piston limits which will enable us to reduce the variables at this point. (3) Governor springs. The original springs given us by the D.O. for this governor provide the most satisfactory ignition advance curve. The second set of springs which we are at present using made to the same dimensions proved to be considerably weaker in use, possibly owing to the fact that they have been enamelled and may have lost some temper. The main trouble is that apparently there is not enough room to get the strength of spring we require on the governor without unduly stressing the material used. We have however taken the matter up with the D.O. who will go into it after the holidays. (4) Controls. The main point which has evidenced itself in the controls is the difficulty of initially synchronising the two ignitions due to the fact that the magneto has only contd :- | ||