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).
The comparison of sparking performance for ignition coils with cases made of various materials.
| Identifier | ExFiles\Box 39\3\ Scan222 | |
| Date | 3rd September 1923 | |
| X3573 EXPERIMENTAL REPORT. COPIES TO: R.CJ. BJ. WOR.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} EP.{G. Eric Platford - Chief Quality Engineer} PN.{Mr Northey} OY. Expl. No. X.4079. X.3513. REF. EFC1/T3.9.23. OBJECT OF TEST. Comparisone of the sparking performance of ignition coils in cases of various materials. TESTER. Mr C. A.{Mr Adams} Pignatt. CONDITIONS. SUMMARY OF TEST. This confirms the inferiority of coil cases of the Bakelite class of moulded material, as compared with cases of rubber base material. NOTE. Our report EFC2/T14.12.22 gave the result of tests made to determine the temperatures reached on the coils on Goshawk engines, and the results were from 73° to 77°C. We have now confirmed these temperatures by the use of sentinels. After preliminary trials we have had sentinels arranged for temperatures of 73° and 77°. 73° coil sentinels have melted on chassis 3GII, 4GII, 6GII, and 7GII, and 77° sentinels have not melted on any of these. Of the above, the coil is in the bracket position on 3GII, and 6GII, and in the engine position on 4GII and 7GII. As previously reported there is not more than a few degrees of temperature between these two positions. It will be seen, therefore, that 77°C may be taken as a limit of temperature reached by the coil in this country. Later, 77° coil sentinels on 3GII and 4GII have today been observed to be melted, but for confirmatory purposes further 77° sentinels are being fitted. EFC. Rept. att. | ||