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).
Procedures for testing vacuum pump settings, part and full throttle flows, and the use of a Crest Volt Meter for spark gap analysis.
| Identifier | ExFiles\Box 147\5\ scan0135 | |
| Date | 8th July 1937 | |
| -6- Rm{William Robotham - Chief Engineer}/C7511/R.8.7.37. Procedure. The vacuum pump is adjusted to give a carb. depression of 18" Hg. with closed throttle (not idling), and full throttle depression equal to the maximum obtained from the particular carb and engine under test. The idling mixture is adjusted to .3 lbs air to .028 lbs fuel. (a) Part Throttle flow. Commencing at full throttle, and recording the air and fuel flow rates, the throttle is partially closed to give integral air flow rates down to .5 lbs/min, the corresponding fuel flow rates being recorded. (b) Full throttle flow. With throttle fixed in the "full open" position, the vacuum is reduced in successive stages to obtain integral air flow rates, the corresponding fuel flow rates again being recorded. Final Graphs. Air/Fuel ratio against pounds of air/min. Crest Volt Meter (Lucas). Purpose. To ascertain the voltage required to break down the spark gap (plug). The instrument consists of a variable calibrated ball gap. One ball is fixed and the other adjustable by means of a cam which carries a graduated dial to read the sparking voltage of the gap. The gap is not connected straight to the plug terminal, but is supplied from it through a rectifying valve of relatively low emission, and when the gap is adjusted until spark commences, the reading of the calibrated dial gives the maximum voltage which is occurring at the plug terminals. -------------------- | ||