The criticism is a shrewd and searching one. But it is based on the airplane and the motor of to-day without allowance for the development and improvement which are proceeding apace. It contemplates a craft which has but one motor, but the more modern machines have sufficient lifting power to carry two motors, and can be navigated successfully with one of these out of service. Experiments furthermore are being made with a device after the type of the helicopter which with the steady lightening of the aircraft motor, may be installed on airplanes with a special motor for its operation. This device, it is believed, will enable the airplane so equipped to stop dead in its course with both propellers out of action, to hover over a given spot or to rise or to descend gently in a perpendicular line without the necessity of soaring. It is obvious that if this device prove successful the chief force of the objections to aėrial navigation outlined above will be nullified.
The menace of infrequent landing places will quickly remedy itself on busy lines of aėrial traffic. The average railroad doing business in a densely populated section has stations once every eight or ten miles which with their sidings, buildings, water tanks, etc., cost far more than the field half a mile long with a few hangars that the fliers will need as a place of refuge. Indeed, although for its size and apparent simplicity of construction an airplane is phenomenally costly, in the grand total of cost an aėrial line would cost a tithe of the ordinary railway. It has neither right of way, road bed, rails, nor telegraph system to maintain, and if the average flyer seems to cost amazingly it still foots up less than one fifth the cost of a modern locomotive though its period of service is much shorter.
Just at the present time aircraft costs are high, based on artificial conditions in the market. Their construction is a new industry; its processes not yet standardized; its materials still experimental in many ways and not yet systematically produced. A light sporting monoplane which superficially seems to have about $250 worth of materials in it--exclusive of the engine--will cost about $3000. A fighting biplane will touch $10,000. Yet the latter seems to the lay observer to contain no costly materials to justify so great a charge. The wings are a light wooden framework, usually of spruce, across which a fine grade of linen cloth is stretched. The materials are simple enough, but every bit of wood, every screw, every strand of wire is selected with the utmost care, and the workmanship of their assemblage is as painstaking as the setting of the most precious stones.
[Illustration: © International Film Service.
A German "Gotha"--their Favorite Type.]
"REMEMBER THE LEAST NEGLIGENCE MAY COST A LIFE!" is a sign frequently seen hanging over the work benches in an airplane factory.
When stretched over the framework, the cloth of the wings is treated to a dressing down of a preparation of collodion, which in the jargon of the shop is called "dope." This substance has a peculiar effect upon the cloth, causing it to shrink, and thus making it more taut and rigid than it could be by the most careful stretching. Though the layman would not suspect it, this wash alone costs about $150 a machine. The seaplanes too--or hydroaėroplanes as purists call them--present a curious illustration of unexpected and, it would seem, unexplainable expense. Where the flyer over land has two bicycle wheels on which to land, the flyer over the sea has two flat-bottomed boats or pontoons. These cost from $1000 to $1200 and look as though they should cost not over $100. But the necessity of combining maximum strength with minimum weight sends the price soaring as the machine itself soars. Moreover there is not yet the demand for either air-or seaplanes that would result in the division of labour, standardization of parts, and other manufacturing economies which reduce the cost of products.
To the high cost of aircraft their comparative fragility is added as a reason for their unfitness for commercial uses. The engines cost from $2000 to $5000 each, are very delicate and usually must be taken out of the plane and overhauled after about 100 hours of active service. The strain on them is prodigious for it is estimated that the number of revolutions of an airplane's engine during an hour's flight is equal to the number of revolutions of an automobile's wheels during active service of a whole month.
