Page:Popular Science Monthly Volume 89.djvu/541

 Popular Science Monthly

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��attained by the aeroplane that has its prcjpelier in front of a Ijoat-lxxiy. Thanks to the tractor-screw the IjipUmc has (icvcioped as much speed as the monoplane. It is even preferred, since its greater surface gi\'es more lift in emer- gencies. Unobstructed \isinn in front is often so desirable that the [)ro|)eller is sometimes placed behind the surfaces and the boat-body shortened, in spite of the increased head-resistance and decreased strength of the design with the rudders carried by poles. A beautiful solution of the problem of free \ision is obtained in large passenger-carr>ing niaciiines, with the long bodies of wiiicii rudders are integralK' combined, two tractor-screws and two separate motors l)eing nwiunted on both sides of the main botly. It is then essential to enclose the motors in separate bodies. In the big . ("icrman liattleplancs, the motor Ixjdies are Ujng and carry the rudders. I'",\en such designs waste a certain amount c)f power, because a catamaran has always less spee<l than a single boat. Hut multiple bodies and division (jf load across the span of the planes is the only method by which large aeroplanes are enabled to carry many passengers and to exhibit that strength which it has taxed all the ingenuity' of the scientific engineer to obtain even in the smaller machine.

7/05 the Bi^ Aeroplane Come

to Slayi

Mammoth aeroplanes are at i)resent a. spectacular development, especially in America. But it would be premature to include I hem in a seriously critical re\iew of the aercjplane of to-day. In the main, they ha\e not yet justified themselves, although some of the big water machines of Curtiss, are said to be in fre(|Ui'nt use. But there are no accounts of their |X'rformances under very critical air conditions, when their relative lack of strength would be a very serious matter, judging from the ex- periences of similar smaller machines. \\'hat recommended them is not economy of iierformance (because they carry relatively less per scpiare foot of surface than sm.iller water machines) but the improved facilities offered for navigation, comfort for long trips, and the advantage

��that one pilot can transport many passengers. They are also required, whenever a great radius of action is tlemanded, which can be obtained with aerofjlanes only by cutting down the passenger list and carrying more fuel instead. In a small machine, this would mean amiiulating the alighting gear.

The difficultN' of starling and alighting with a mammoth plane is serious. The impact of the heavy mass is too much for its strength, especially for the landing wheels, which have to be made very bulky and clumsy, consequently wasting ])ower in air -resistance. Transformed into a Hying boat the mammoth machine becomes more practical, because the hull partakes of all the naval advantages that follow with increased size. Strains to which they are subject from gusts must be formidable. But no technical accounts of their beha\ior in the air ha\e been jjublished.

Air-figh.ting is fully as romantic as ever were the deeds of Homer's heroes or Cooper's Indians; for this is the day of personal prowess in air-fight- ing. We need not dwell solely on the exploits of such German supermen as Immelmann and Boelke (each with a record of at least fifteen victories). Neither superiority of numbers nor of machines cuts much of a figure if it is matched against a certain mysterious personal equation, which cannot as yet be completely analyzed. It may be safe to say that rapid, masterful marks- manship plays in it no small part. It would Ije indeed a rare coincidence if this ability were likewise found combined with exceptional talents (like Pegoud's) for managing an aeroplane. If that be the case it is obvious that a fighter and flyer in one person must be more formid- able than the co-operation of a mere (Iyer and a mere fighter. We need only imagine two cavalrymen on the same horse, (assuming that they could be accommodated together as perfectly as two flyers on a machine) of whom one wields only the lance and the other manipulates the bridle. How should they communicate their respective inten- tions in fractions of a second?

But this holds good onh' in regard to small powerful racing machines which fight wasp-like at close range.

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