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 performance and limitations of a Goshawk battery ignition system.
| Identifier | WestWitteringFiles\K\September1923\ Scan39 | |
| Date | 14th September 1923 | |
| R.R. 493 (40 H) (SL 12-7-23). J.H., D.{John DeLooze - Company Secretary} ORIGINAL EXPERIMENTAL REPORT. COPIES TO: A.C.(L.B.L.) WOR.{Arthur Wormald - General Works Manager} P.Y.E. D.G. E.P. BN.{W.O. Bentley / Mr Barrington} OY. Expl. No. 4357. REF: FCL/T14.9.23. OBJECT OF TEST. (1) To discover the regular external performance, as measured by length of gap in air regularly sparkable, of the Goshawk battery ignition, as limited by the safety and other H.T. gaps inside the dist. itself. (2) To determine the max. TESTER. Mr. C.A. Pignatt. CONDITIONS. possible condenser capacity, corresponding to regular sparking on gaps of such a length at normal dist. speed 700 R.P.M. and at 1200 R.P.M. (3) To determine the maximum speed of regular sparking on gaps of this length with the normal condenser capacity. CONDITIONS. For the purposes of test, a Goshawk ignition distributor head which had been conveniently fitted with three mica windows was utilised, thus it was possible to observe any sparking whatever which took place inside the distributor head. SUMMARY OF TEST. The first portion of the test is explained in my assistant's report PB.115, copy herewith, from which it will be seen that under normal conditions, which we considered to be 700 R.P.M. of the distributor (1400 r.p.m. of the engine, equivalent to approx. 28 m.p.h.) the maximum possible spark gap in air, without causing sparking inside the distributor, is 6.5 mm. The various ways in which the spark over in the distributor took place, are indicated in the table of results. It will be seen that it is quite a frequent occurrence for a portion of the path of a spark in the distributor to consist of the surface of the rotor or the distributor head moulding. It has subsequently been confirmed by carefully adjusting the third points of the spark gaps, drying the distributor, etc., that a larger gap than 6.5 mm. cannot be obtained outside without some sparking was taking place inside. This has been confirmed at normal speed and reduced voltage of supply, and also at normal voltage of supply but at a lower speed of 400 r.p.m. and at a higher speed of 1200 r.p.m. (distributor). * equivalent With the spark gaps set to this length of 6.5.mm. which is our length of gap for production testing, the maximum condenser capacity which can be connected to the contact points at normal speed (700 r.p.m. of distributor) and voltage, without causing the regular sparking to become irregular, was found to be .83 mf. At 1200 r.p.m. (dist.) the maximum condenser capacity was found to be .47 mf. Contd. * See N.B. next page. | ||