AIRCRAFT SUPPLY.

Auckland Star, Volume LXXI, Issue 184, 5 August 1940, Page 6

AIRCRAFT SUPPLY.

MASS PRODUCTION. U.S.A. OUTPUT PROBLEMS. MILITARY REQUIREMENTS. (By MAKE S. WATSON.) WASHINGTON, June 20. The confident assurance of the Forde that they should be able to turn ont aeroplane engines in great quantity in a matter of months has impressed aeroplane authorities who not so long ago were inclined to scoff at suggestions of early mass production of firet-claes aeroplane motors. What may prove to be the most important consideration in the Ford programme is one significant sentence which at first caught the attention only of the expert. This was the mention that the Fords "have been studying" the Rolls-Royce motor, plus the current belief that this motor ie already in very limited hand-tooled production in the Fords' English factory. Significance lies in two circumstances. First, thie is a proved engine of high efficiency, rather than an experimental type; and second, it is a liquid-cooled engine. So late as two days ago one of the country's aviation experts was saying with real concern that, for better or worse, our present aviation development ie limited to our development of the air-cooled engine. There was no doubt that he thought thie limitation was "for worse." If, as now •seems indicated, the Ford programme calls for mass production of a tested liquid-cooled motor, this ■ materially alters our prospects. Why Air Cooling? The difference ie one which a layman can grasp readily. We have developed the air-cooled because of two dear advantages. It hae no liquid to add to weight, always important. It has no liquid container to get out of order, or to leak. So far, so good. But, as with an automobile motor using air-cooling, there must 'be a large frontal area through which the cool air hae to rush in great volume to be effective. And the larger the frontal area, the greater the air resistance against it.

This is the unhappy defect of aircooling. Resistance against a frontal area mounts approximately as the cube of increased speed—that is, if one doubles the forward speed of one's aeroplane, it is only by the exertion of eight times as much power. The problem, therefore, has been to keep down the frontal area, by skilful cowling among other methods, in which the National Advisory Committee on Aeronautics has been making very fruitful experiments. Even so, there has been a persistent effort to build up a liquid-cooled engine to meet military requirements. There is no doubt of Europe's preference for it in military use. In America, one, the Allison, has passed the experimental stage, but its production is so email that the army has felt itself practically limited to air-cooled engines for any vast expansion of the immediate future. The anxiously-awaited decision by Mr. Ford as to just what he can do may change all that. The civilian's approach to aviation is not wholly sound in war, for he coaducts an instinctive quest for efficiency and economy. Those virtues are welcomed by the military aviator, too, but they are not first in his mind. The vital thing for warfare is maximum performance— at whatever cost. Aeroplane A may be cheaper than aeroplane B, and burn less fuel and be more easily flown, but if .by greater expenditure of dollars and fuel, and skill aeroplane B can produce more speed in a pinch the military aviator must have aeroplane B.

Mass Demand Growa. Maes production is the greatest aid to economy, and this again is the hope which Mr. Ford's confidence encourages. It is very doubtful that we would want those "one thousand aeroplanes a day, all of one type," but it is certain that the army would welcome the knowledge that it can get them—or several types in lesser quantities, marked by the improvements which laboratory research and battlefield experience are steadily providing. The prime quality of mass production in peace-time commodities is cheapness. The prime quality for munitions is speed. Most of our aeroplane factories now require six thousand man-hours to produce a small aeroplane, and sixty thousand man-hours to produce a heavy bomber. Automobile factories turn out a finished car in five hundred manhours. Partly the difference is due to the much greater complexity of the aeroplane, but no small difference lies in the fact that the vast public demand for automobiles has made it worth while to step up production, and thus acquire hitherto undreamed efficiency. Sow for the first time ware threat*has created something like a mass demand for aeroplanee. Fifty thousand aeroplanes a year sounds small in comparison with several million automobiles a year but it is very much more than our factories had dreamed of before. Pilots Are Vital. Certain short cute in the making o f aeroplanes (as distinguished from their ? Z?l -* re alread y forecast. A bomber has 200,000 rivets—what would welding mean as a time saver T More, what would be saved if the aeroplane's body could be cast in plastic material stout enough for so tough a job? The former is quite likely in mas* production, and the latter far from impossible in the not distant future. The bottleneck, however, is less in aeroplanes than in engines. That is the significant thing about the Ford possibilities. And neither aeroplanes nor aeroplane engines furnish such large barriers to immediate expansion as do trained pilots.—(tf.A.X.A.)