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.
Wright Brothers' Wind tunnel
They found that a slight curve or camber in the wing section would cause the moving air to travel farther over the top of the wing surface than along the under side. This made the air pressure greater under the wing, gave a suction effect above the wing, and caused it to rise, creating lift. They discovered that a wing section of the proper camber would counteract the weight of gravity. Thus, a wing must be so designed that, with a certain amount of air flowing around it, it would lift a certain weight. They also discovered that air flow against any surface attached to the wing would cause a resistance or drag. Hundreds of experiments in their wind tunnel with various types of wing shapes gave the Wrights a series of tables from which to design a wing that would create the lift for a designed weight.
The Four forces of flight
after testing more than 200 wing designs and plane surfaces in their wind tunnel, the Wright Brothers found out how to figure correctly the amount of curve, or camber, that was essential to weight-carrying wings. They discovered, too, that before man could be flown through the air, he must have his wings attached firmly to a body or platform which was firm and controllable. The Wrights in their earliest experiments had realized that to be practical their machine must be built not only to fly in a straight line, but also in order that it could be steered to the right or to the left. One day, Orville was twisting a cardboard box in his hand when Wilbur noticed it. Immediately he saw the solution to the problem of steering their airplane. The result was a design which changed the lift of either end of the wing by warping its surface. If one end of the wing was warped to give it more lift, the machine would lift on that side and fall off into a turn. Thus the problem of steering was solved by the Wrights
The Wright Brothers experimental glider
After a year of exhaustive study and experiments with models in their wind tunnel, the Wright Brothers were ready to experiment with a man-carrying glider. With the thoroughness that was typical of every move of the Wrights, the brothers asked the government to let them have information on meteorological conditions all over the country. By studying the weather charts they were able to find a locality where there was a continual flow of wind. This would be nature’s wind tunnel where they could test their glider day after day. Through their study of the charts they found that the wind conditions at Kitty Hawk, on the North Carolina coast, seemed to offer the best possibilities for their glider test. Orville and Wilbur Wright began their experiments with a small man-carrying glider at Kitty Hawk in 1900. From that time until 1903 they made hundreds of successful glider flights and kept accurate records of each flight. They recorded wind velocity, angle of flight, duration of flight, time of day, temperature, humidity, and sky conditions overhead with the typical Wright attention to detail. Each year the Wrights constructed new gliders which embodied principles they had discovered for themselves during their flights at Kitty Hawk. Each glider was larger and had longer and narrower wings than the one before. During the fall of 1902 the brothers recorded nearly a thousand flights in a glider with a wingspan of thirty-two feet. It had a front elevator and a vertical tail which helped to maintain lateral stability.
Wright Brothers first powered airplane
By 1903 the Wright Brothers were ready to build a powered man-carrying flying machine. Their experiments had shown them just how much moving air was necessary to create lift in such a machine. To create the needed thrust, an engine having eight horsepower and weighing not over 200 pounds had to be fitted into the machine. Such an engine was not available, so the Wrights built one in their shop at Dayton, Ohio. They were ready to ship their airplane to Kitty Hawk, N. C., in the fall of 1903.