Italy's Huge Bombing Triplane
��A machine which is intended to do the work of heavy guns
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Photo Bernard Levy
The shock of landing is tremendous. Notice how solid are the wheels on which the machine alights, how substantial is their frame and how carefully they have been placed to distribute the shock
��THE Popular Science Monthly has already devoted space to the huge Sikorsky biplane used by Russia early in the war — a machine which had a body almost as big and comfortable as a Pullman car. German observers called it slow and cumbrous.
In spite of the disadvantages of such huge machines, all the Powers have experimented with them. Their chief merit is their load- carrying capacity. Now comes Italy with the Caproni type. According to Major R. Perfetti, head of the Italian Aeronautical Commission in the United States, the Caproni climbs 3,250 feet in thirteen minutes, 6,500 feet in twenty-seven minutes, 10,000 feet in sixty-seven minutes. It carries three men, three shell guns, 7,500 pounds of bombs and fuel for six hours. Its 900-horsepower engines drive it at a maximum speed of eighty miles an hour.
The Italians regard this huge bombing plane optimistically as the equivalent, or rather the superior of the long-range can- non. To be sure, it can drop explosives far beyond the range of the heaviest artillery; but it must not be overlooked that bombs cannot be dropped with the accuracy of shells without exposing the machine.
The Caproni is an object lesson. To lift an enormous load, great wing surface must be depended upon. A biplane is impossible, because the span would be too great. Hence, the Caproni is a triplane, and even then the span is no less than one hundred and ten feet. Carrying surface is
��thus obtained in a small compass and with deeper and stronger trussing than would be possible in a biplane. But that advantage is purchased at the expense of head re- sistance. Surface cannot be piled on sur- face without paying the price in power.
The distribution of the planes in three decks was not enough. In order that the immense structure might be solid as a whole and yet not too heavy, power must be generated by three engines, because three engines can be distributed. Each of these engines is of three hundred horse- power. The distribution of the engines over a full third of the wing span lowers by that much the leverage of the weight on the truss. Since irregularly shaped masses as they move through the air exert a con- siderable retarding effect, each engine is, of course, enclosed in a long steam line body. The middle body is the shortest; hence its three-bladed propeller is mounted in the rear. The two outer bodies have two- bladed front propellers.
These two outer bodies hold the tail between them far more rigidly than would be possible in single-fuselage construction.
Curtiss in his small fast triplane in- geniously showed that it was possible to use only three struts on account of their in- herent strength and that the head resistance increases with the number of struts.
The latest warplanes with their high land- ing speeds, are plainly expected to land only at carefully prepared grounds. That policy removes a grave objection to mere size.
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