Testing the girder-built body of an aircraft
Put together scientifically and from sections of wood specially tested, a remarkable strength may be obtained by such a method of building. The figure shows how a girder aircraft body, supported by trestles only at its ends, may support from its centre, without yielding, a tray containing a number of heavy weights
The Control of a Biplane
The driver of a modern-type aeroplane, sitting snugly within its hull, has a wheel and instrument-board before him, as sketched. As he flies across country he has many things to think of. Holding the control-wheel in both hands, his feet resting upon the rudder-bar, his eyes rove constantly among the instruments [Pg 163]on the dashboard before him. He glances at the compass often, for it is by this that he steers; and when the air is clear, and the earth below plainly seen, he will every now and then glance over the side of the hull, so as to be on the look-out for a landmark that may tell him he is on his course. A. Pilot’s seat B. Hand-wheel (pushed forward or backward operates elevator; twisted sideways works ailerons) C. Foot-bar actuating rudder D. Compass E. Dial showing number of revolutions per minute that engine is making F. Gauge showing pressure in petrol tank G. Speed indicator H. Dial showing altitude I. Clock J. Switch for cutting off ignition.
Racing Deperdussin Monoplane (top view)
Racing Deperdussin Monoplane (front view)
showing the “stream-line” effect which is gained by tapering the body, also the simplification of the landing chassis, and the use of a minimum of wires. photo id=7984]
Racing Deperdussin Monoplane (side view)
In the development of speed, some remarkable craft are built. Each year there is an international air race for the possession of the Gordon-Bennett trophy, and to win this designers build special craft. In tiny monoplanes, engines of high power are installed; and the sustaining wings are so reduced, to give a maximum speed, that the machines appear more like projectiles than flying craft. A purely racing-type monoplane is seen in figure.. It represents a Deperdussin, which, with an engine of 160 horse-power, reached a speed of 130 miles an hour. How small this machine was, in relation to its engine-power, will be realised from the fact that the sustaining surface of its wings amounted to only 104 square feet—far less lifting area, in fact, than Lilienthal used in his gliders. Wires and struts are reduced to a minimum; the body is tapered and smoothed. Such a machine, although it carries speed to an extreme, and is in reality a “freak,” teaches useful lessons. But though it provides data for the construction of high-speed scouts, a monoplane of this type would be useless for cross-country flying; and for the reason that it cannot be manœuvred, prior to an ascent, upon anything save the smoothest of ground. Its wings being so small, to ensure a maximum of speed, the machine will not rise until it has run forward a long distance across the ground; and during this run it attains a speed of nearly 90 miles an hour. At such a pace, unless the ground below its wheels was level, it would leap, swerve, and probably overturn. When alighting from a flight, also, again owing to the smallness of its wings, the craft has to plane down so fast that its pilot could not land safely unless he had below him a surface that was absolutely smooth. A. Propeller B. Shield to lessen wind resistance C. Sloping shield which encloses engine (also to minimise wind-pressure). Air passes between the shields B and C to cool the motor. D. Pilot’s seat E. Padded projection against which, when at high speed, the pilot rests his head F. Sustaining-plane Very slightly cambered G. Rudder H. Elevating-plane I. Landing wheels.
Construction of a Monoplane wing
Banked turn on a biplane