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).
Test report comparing the maximum regular sparking gap of various insulated coils during a heating-up process.
| Identifier | ExFiles\Box 45\4\ Scan199 | |
| Date | 4th September 1923 guessed | |
| -3- Contd. Test 2. In this test an external gap was used, making it a practical reproduction of the test as carried out on the car. The six main gaps were set at 4.0 mm. and the maximum length of external gap obtained at which regular sparking occurred at the end of each period. Time from Max.regular sparking commencement of gap (mm). heating-up process. (1) (2) (3) (4) Std. Moulden- Redmanol. PFE. Remarks. site. 0 mins. 10.5 11.5 11.0 8.5 15 " 10.5 5.5 8.0 8.5 30 " 10.5 4.0 3.0 8.5 45 " 10.5 3.5 1.0 8.5 60 " 10.0 1.5 0 8.5 75 " 9.0 0+ - 6.5 +slight missing on main gaps. 90 " 8.5 - - 6.0 105 " 8.0 - - 5.5 120 " 8.0 - - 5.0 The apparent inferiority of the paper insulated primary coil as compared with the standard stabalite, is probably due to its newness, as it has often been observed that coils improve in performance material due presumably to the drying out of the insulation. CAP. | ||