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).
Specifications and effects of braided high tension cable for aero engines used with wireless systems.
| Identifier | ExFiles\Box 37\1\ scan 104 | |
| Date | 11th May 1921 | |
| R.R. 825A. (100) (H) H.{Arthur M. Hanbury - Head Complaints} Yds. 10-18-20 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 X 3/99 To En. from EFC. EFC1/T11.5.21 X.2516 - BRAIDED HIGH TENSION CABLE FOR AERO ENGINES IN CONNECTION WITH WIRELESS WORK. X 3/99 I am sorry not to have answered your En4/W21.4.21 before, but I have been away for a week and this has made me rather a rush of work since coming back, making reports of visits etc. We do not think the reduction in size of the braided high tension cable to the extent suggested should have any appreciable deleterious effect on the ignition system, and are of the opinion that if the cable will stand 2,000 volts(max) A.C. at normal frequencies for 15 minutes, this should be a sufficient test as regards insulation breakdown. It is not apparent why the braided cable should need to be better insulated than the plain. As regards the increase of electrical capacity, we do not think this would be sufficient to have any bad effect. Up to a certain point a slight capacity in parallel with the sparking plugs might even be advantageous in increasing the amplitude of the oscillatory component of the initial spark, for normal operating speeds, although of course it might have a slight effect in hindering starting if the magneto functioning in its ordinary manner, is relied upon for this purpose. We think that the cable should be as nearly of the same length as possible to ensure equivalent conditions, Contd. | ||