Science: Gas and Supergas

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For 25¢ a gallon the U.S. oil industry can now produce quantities of aviation gasoline so powerful that present airplane engines in production cannot make full use of it. Fuel technology has outstripped mechanical progress, inverting the aviation picture of 16 years ago.

In those days engine designers were frustrated for want of high-test gasoline. Mail planes roared along on 60 octane pap. As late as 1929 designers and flyers never dreamed of using 100 octane gasoline, the presumably unattainable "perfect" fuel.

Not until 1931 was the first 100 octane gasoline made—and then only in laboratory flaskfuls at a cost of $10 a gallon.

Today 100 octane gasoline costs only 15¢ a gallon f.o.b. refinery. It powers all first-line U.S. and British warplanes, gives them 20% more power per gallon than Germany's usual 90 octane. But even this supergas—70% more powerful than 1931's best 87 octane fuel—is a back number with fuel technologists, who have recently concocted "no octane" gasoline—50% more powerful than 100 octane. Of this liquid dynamite the U.S. could produce overnight several hundred thousand gallons a day.

Its use would give planes smaller fuel loads, lighter engine weights per horse power, less head resistance, lower cooling loads, greater speed. But this is one case in which the war is not stimulating aviation progress but hampering it, and "no octane" gas will not be harnessed now for two big reasons: 1) To build stronger engines capable of using "no octane" gasoline would require retooling, and thereby much lost production which the U.S. cannot afford while Hitler is on the rampage.

2) Every two gallons of "no octane" gasoline contain the vital ingredients of three gallons of 100 octane. And right now the U.S. and Britain are having a hard time wringing enough 100 octane gas out of their refineries.

Into the Octane Stratosphere. This month U.S. oil companies, greased by a promise of some $150,000,000 from the RFC, are moving fast to triple their 1,818,000-gallon-a-day capacity for 100 octane gas. As late as last May 0PM's Petroleum Consultant, Dr. Robert Erastus Wilson, thought the oil industry "with its genius for overbuilding" could produce "twice the present domestic and foreign demand," though at a meeting of the Society of Automotive Engineers he advised "a 25% expansion in 100 octane capacity" to be on the safe side. But that was before Britain began bombing Germany, before the U.S. began helping Russia, before the new U.S. bomber program sent high octane demand estimates soaring.

Development from World War I's 55 octane gas to World War II's 100 octane plus came slowly. Octane rating is the index of antiknock qualities.* Before 1922 the only way to raise this rating was to increase the percentage of isooctane (and similar compounds). Isooctane is a hydrocarbon, C8H18, which is one of the hundreds of compounds which make up the chemical mixture called gasoline. But isooctane alone makes a poor fuel because it is not volatile enough, does not readily carburet into explodible vapor.

Next came tetraethyl lead, introduced in 1922, which acts like a high content of isooctane. Added to the best leadless gasoline, it raises the octane rating to around 90.