EATING UP PETROL

Evening Star, Issue 23498, 12 February 1940, Page 11

EATING UP PETROL

The need for conserving high-octane ipetrol for use in aircraft is placing a premium on this commodity i.i all countries involved in the war. When it is mentioned that a British Vickers-Wel-lington bomber has a total tank capacity of 750 gallons, and that any modern twin-engined bomber, with a speed of something between 250 and 300 miles per hour, uses about 100 gallons of petrol for every hour flown at top speed, it will he realised how heavy is tho call for super petrol among the warring nations, with their many' thousands of aircraft. Fighter formations on patrol duty day’ and night in Europe aro simply' eating up petrol, while an air raid, say by 20 machines, may easily consume upwards of 10,000 gallons. ft is, with a view to lessening the call on high-octane petrol that the Commonwealth Government has announced that after existing stocks of this fuel held in Australia are consumed, no further supplies of super grade petrol will be procurable by the public. Lower-octane petrol, however, will be available. In Great Britain and France similar stops have been taken to ensure adequate supplies of super petrol for military purposes.

, Some automotive experts believe that this parade of progress will not stop at high compression ratios, and that the next step to squeeze more power out of petrol may be per medium of supercharging. For years past the possibility of general application of supercharging to cars—it has already proved its worth in motor racing—has been the subject of much research. For those who do not understand what' supercharging does, it may be mentioned that it simply, means forcing more petrol-air mixture into the combustion chambers of an engine by putting greater than atmospheric pressure on the intake manifold. Tests conducted with an 8-cylinder car engine, with a 5} to 1 ratio, developed 82 h.p. at 4,000 r.p.m. using 78 octane petrol. ,By supercharging with an intake manifold pressure equal to XOin of mercury (approximately 51b per square inch above atmospheric pressure), the engine developed 160 h.p., using a very high octane petrol—viz., 90. To determine vyhiyt advantage supercharging could give the engine without requiring a fuel; higjier than 78, octape, the fuel originally Used, the compression ratio was lowered to 4.25 .to,. 1. Supercharged to lOip mercury, the engine developed 63 per cent, more power than it had with the higher compression ratio on the same fuel. _lt will thus be seen that supercharging seems to promise more of the same kind of improvement that has been effected by increasing compression ratios. When such extra power can be obtained by pressure feeding it is easier to understand why supercharging is today of interest to manufacturers of automobiles. However, the problems, including fuel economy and initial cost of the “ blower,,” are providing a wide field for research in the laboratories of motor companies, etc. The fruits of that research might some day have a far-reaching effect on the automobile industry, says the ‘ Dunlop Bulletin.