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 failure in a Goshawk 11 engine, attributing the cause to coil overheating.
| Identifier | ExFiles\Box 45\4\ Scan056 | |
| Date | 6th November 1922 | |
| R.R. (SD676 19-7-17) M.P.18:865 UW 4079 EFC. BY1-P6.11.22. X 6079 IGNITION FAILURE - GOSHAWK 11. As reported verbally I experienced one of the failures previously reported upon by EP{G. Eric Platford - Chief Quality Engineer}, and as the result of the conditions and peculiar results I am inclined to consider the reasons of failure and remedy for same are as follows;- (1) Failure. I consider this failure due to the coil over-heating and that the failure was gradual, although the effect was apparently sudden. It appears to me the resistance in secondary winding rises seriously, due to fairly large increase of temperature and this effect is more pronounced under medium or slow running conditions, but so long as the engine speed is kept up, or the throttle is not full open, if the engine speed is lower the resistance to sparking in the mixture is not too great for spark to cross the points, but if you stop the engine and then try to start, or if the engine speed drops and you open the throttle so as to fill the cylinder with full charge the increase of resistance is sufficient under these conditions to prevent spark passing altogether. In the first place my original failure was after about 40 miles of medium and low speed driving, enforced by twisting and narrow roads, with heavy body. By cutting out the ballast I found I could run normally and drove like this to my destination about 3 miles further. Before returning the coil had cooled right down, due to 3/4 hour wait, but with ballast still out the coil again heated up and stopped me after only 10 miles running. We got going by allowing coil to cool and then put ballast again into circuit, but all the rest of my drive, some further 30 miles, I found I could only keep going by keeping engine running at high speed and using my second gear whenever I was compelled to slow down the car speed. In all I had some 6 or 8 involuntary stops and my conclusions were they were directly due to increased resistance of secondary caused by the coil over-heating, I think the Goshawk shews the trouble more than the 40/50, due to the fact of ballast being all in close connection with the coil and keeping it hotter in consequence. I am of the opinion that I produced the effects on 11.Goshawk.7. in the first place by keeping jacket water too high 90° - 95°C, by use or misuse of louvres, and it seems to me I escaped similar trouble when I recently ran the Goshawk with touring body, because;- contd. | ||