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).
Request for comparative data on Stabilite and Mouldensite coils to establish a standard figure of merit.
| Identifier | WestWitteringFiles\J\November1922\ Scan19 | |
| Date | 11th August 1920 | |
| R.R. 285A (100 T) (S.H. 159. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 (3) MR. Elliott is preparing a drawing of the experimental coil which I hope you will be able to put through quickly. I should be glad if you could send me one of the Stabilite coils for the Goshawk which is here, and also if you could let me know at an early date if you can detect any superiority of the Stabilite coils over the Mouldensite ones you are proposing for standardisation in the near future. Can you get a figure of mint for every coil, and particularly for every style of coil such as, with a standard spark gap say of 10m/m in air, at a standard temperature of 90° centigrade, and with a standard voltage of say 8 volts; regular sparking can be obtained from 100 to 1500 distributor revs, with a ballast resistance of ? ohms, the ballast resistance being varied to find the figure of mint of the coil; the only other convenient method would be the sparking distance with the standard ballast resistance, or with a given leakage in the H.T. circuit, equal to a leaky plug or other leaky insulating surface or materials. R.{Sir Henry Royce} | ||