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).
Inconsistencies in timing procedures for aero engines and requesting a standardized, written scheme.
| Identifier | ExFiles\Box 33\4\ Scan082 | |
| Date | 21th June 1927 | |
| X1770 Rg.{Mr Rowledge} Hs.{Lord Ernest Hives - Chair} BY4/H.{Arthur M. Hanbury - Head Complaints} 21.6.27. AERO ENGINES - TIMING. Apparently none of our aero engines are timed by the instructions marked, in the case of the Eagle and Falcon 3, on the annulus gear, and even the tappet clearance appears to vary at times in the hands of different people. This being the case, it is most important that we should have accurate and definite instructions as to the timing of Condor 4. and Condor 3.A. in order to put this matter beyond dispute. In the case of Condor.3.A. engines, a disc is provided with a sighting hole to enable the tester to see the disc in question and fix the settings, but in the case of Condor 4. no disc is available, and the only provision which has been made so far is a special fitting to go in a sparking plug hole with a rod which can be measured by feelers to find when the piston is on its maximum centre. In view of the foregoing positions, we would like to have definite information which will be worked to on all engines so that same can be handed to the AID. and the anomalies which have existed on other engines cut out. The anomalies I refer to are that apparently on Eagle engines none of the marked-on positions are worked to, either for the ignition or the valves. Apparently testers set these so much early and so much late of the authorised position indicated on the engine. This practice is entirely wrong, as anyone dismantling the engine will naturally re-set it to the engraved markings shown on the annulus gears. One other point which causes no end of confusion is the exact clearance at which valves are to be set, and also the cold clearance to be produced after the valves have been set, as obviously variations in either of these will throw the timing hopelessly out between one engine and another. What I would like to have is a thoroughly considered scheme for the timing for:- a/- Condor 4. b/- Condor 3.A. c/- Falcon 10, 11, & 12. Valves & Magneto covering all the above points, in writing, so that there will be no question as to the procedure. In turn, I will Con. | ||