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).
Ignition issues and suggested modifications for a Goshawk engine.
| Identifier | WestWitteringFiles\I\June1922\ Scan53 | |
| Date | 2nd June 1922 | |
| To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to EPC. RECEIVED X4354 X3485 ORIGINAL. GOSHAWK - IGNITION. With reference to the ignition on No.4 Goshawk, I found the distributor cover very tight to get off. I ground a square file into a scraper at the end, which was very nice to scrape this part. It should be made with a definite clearance of I should think 5/1000. On examining the facility for changing the L.T. rocker and contact maker I found it slightly difficult. This could be definitely improved as follows:- The hole in the spring might be made into a slot and the screw fastening the spring could be pointed to a long cone of 60° or slower. A break of about .010 to .012 appeared to be about right for an even make and break. This may be still less if the fibre bakelite rubbing pad is worn. This should be ascertained. (cam may need modifying.) The spring of the rocker is I understand made of steel but it's rating is too great because it is made too thick. The pressure on the points when in contact seems about right but to lift it and handle it the spring is much too rigid and very likely to be of the wrong pressure, either insufficient or excessive, both of which would be bad. Please send me a new rocker with a better spring and the improvement for facility of fitting. The contacts were found to be in good order. You will remember with this engine and ignition, I found no fault with either K.L.G. or Lodge plugs of the type supplied with the car in which the Lodge central electrode is shrouded with porcelain and not a skirt as in the earlier types. In an endeavour to get better slow running, the points of the plug were set at .030" apart - with half-break and half-make the engine still fired full throttle up to very high speed without missing. R.{Sir Henry Royce} | ||