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).
Procedure for conducting sparking plug voltage tests on Merlin engines at high altitudes.
| Identifier | ExFiles\Box 58\2\ Scan321 | |
| Date | 23th April 1936 | |
| r 6000. To Dor.{Mr Dorey}(Hucknall). c. to E.{Mr Elliott - Chief Engineer} c. to A.I.D. (Mr. Underwood) Hs{Lord Ernest Hives - Chair}/Wst.1/JH. 23.4.36. Sparking Plug Voltage Tests on Merlin Engines at High altitudes. We have now the apparatus available to enable you to carry out the above tests for us. The conditions of measurement we require are as follows :- (1) A length of Cellulose varnished H.T. cable should be passed through to the cockpit and connected to the terminal on the fixed ball of the ball gap inside the box. (2) Plug gaps should be carefully set to .015" (3) Air temperature, altitude and other engine conditions should be recorded when actually making the measurement on the ball gap. (4) The ball gap should be opened out and gradually closed up until sparks occur very intermittently the gap must not be allowed to spark frequently or at all regularly. The reading is required during the climb at every 2000 feet. We should like tests carried out on three grades of plugs, i.e., K.L.G. 868D, V14/1D, Lodge A.14/1D. in two or three different places in the engine say, A2, A6, B1 and B4. The connections to the plugs will prove a little difficult and we suggest that you use a plain wire in each case to the plug, and close to the K.L.G. screening cap about 1/2" (to avoid flash over) bare the wire and make a tee joint with the H.T. feed wire to the ball gap. Make sure the | ||