What the Wright Machine is Like.

Progress, Volume III, Issue 9, 1 July 1908, Page 308

What the Wright Machine is Like.

In this column, we present an illustration of a machine built on the lines of the machines now building for the Wright brothers, and for Mr. Herring, two of the contractors who have, as shown in our last issue, undertaken to supply flying machines to the United States Government. The machine illustrated was built by the Aerial Experiment Association of Canada, which has been lately formed by Dr. Alexander Bell of telephone fame, who has been prominent in aviation for many years past. It was Dr. Bell, indeed, who gave the first description of I/angley's model of the Aerodrome, a description which concluded with the emphatic statement that the model was perfect, and that it only remained for practical men to make a working machine. One can easily understand how so indefatigable a spirit as Bell should be the founder of an experimental association for the study and practice of flight. The machine constructed by this association under the direction of its enterprising founder is described in the newspapers as "along the general lines of those now being built for the U. S. government by Mr. Herring and the Wright brothers." On that acconut therefore it has a special interest, for it is on these lines that the contractors have undertaken to fly for an hour with two men aboard and to cover a a distance of thirty miles. We therefore give the full particulars as published in a late issue of the Scientific American, as follows: — "The machine consists of two superposed surfaces having a spread of 43 feet from tip to tip and a width of 6| feet from front to back at the centre, which width gradually diminishes to 4 feet at the ends proper of the planes. The front edge of the upper plane extends out 4 feet beyond the last vertical connecting posts at each end, and the silk surface tapers back from this edge to the rear edge of the plane, and has several light ribs attached to it to give it stiffness. Thus the planes are 4 x 35 feet in size, which corresponds to a supporting surface of 280 square feet, while the flexible rear edges, etc., bring this up to a total 385 square feet, which is also the weight of the machine fully equipped. Of this 185 pounds represents the weight of the machine alone, and also that of the engine and propeller, filled fuel and oil tanks, etc. Mr. F. W. Baldwin, M.E., who operated the aeroplane in its initial test, weighed 185 pounds, so that the total weight was 570 pounds, or 115 pounds for each square foot of supporting surface of a loading that was sufficiently light to make it possible for the aeroplane to rise at a speed of about 25 miles an hour and lift over 20 pounds per horse-power. In constructing this machine for the purpose of experiment, every effort was made to reduce the head resistance as much as possible, and it was with this idea in view that the planes were curved and brought nearer together at their ends (the spacing apart is 6-|- ft. at the

centre and bat 4 ft. at the ends), so that the connecting posts could be shortened. These posts are somewhat oval in cross-section, their greatest width, being from one-fourth to one-third of the distance back from the front edge. The large centre posts are 4 inches from front to back and one inch thick ; the next posts on either side are slightly smaller ; and so on to the end ones, which are 1|- inches from front to back and have a maximum thickness of -| inch. "The surfaces themselves are made of silk and contain pockets, in which are placed the curved, laminated strips extending from the front to the rear edge, and giving the surfaces their curved form. Above each pair of posts a T-shaped wood strip extends from front to back, and helps to strengthen the structure. The spacing of the vertical posts also decreases from the centre outward. The two centre posts at the front and rear edges are about 22 inches apart. The first post on

either side of these two is 6^ feet away, while the spacing between this and the next post is 5 1 feet, and from here to the outer post about 5. The planes are connected together with diagonal guys of the finest piano wire procurable. They are trussed in both a vertical and horizontal direction. "The horizontal rudder, which is 8 feet long by 2 feet wide, is located at the front end of a suitable framework, which projects out 5 feet from the forward centre posts. This framework is covered with silk in order to lessen the head resistance. The rudder is steadied at each end by rods, which run back to the planes. It is pivoted on a horizontal axis, and is operated by a vertical lever extending an equal distance above and below it and located at its centre. A wire runs runs from one end of this lever around a pulley in the body framework, and back to the other end of the lever. Attached to the pulley is a small operating lever for turning the same, and thus maneuvering the horizontal rudder. This rudder is worked by the left hand of the aviator, while the vertical

rudder is operated in a similar manner by a lever convenient to the aviator's right hand. The tail of the aeroplane consisted of but a single horizontal surface located 12 feet back of the rear edges of the planes. The dimensions of this tail were 14 feet 10 inches long by 3 feet wide, i.e., in a fore and aft direction. It was carried upon two long bamboo poles, which ran back horizontally from the lower plane, and which were well braced by other bamboo poles extending to the upper planes, and connected to the lower poles by spruce posts. This horizontal tail was also trussed on its under side to a vertical post, upon which was placed the vertical rudder. Despite this trussing, the pressure upward against the tail was so great as to cause it to buckle on one side, while the aeroplane was in the air, the result being that the machine veered sharply to the same side and landed, sliding sidewise on the ice and breaking one of the outer runners and its supporting post. The motor employed

was an 8-cylinder Curtis air cooled engine of 40 horse power. This engine was mounted on horizontal wood beams connecting the front and rear large centre posts. It carried a light bicycle wheel on its front end as a flywheel, while the 6-f eet propeller was mounted directly on the rear end of the crank-shaft. The pitch of this propeller was 4 feet, and the number of revolutions per minute that it made while the aeroplane was in flight was probably in the neighborhood of 1,200. With the aeroplane held stationary and the motor running, a thrust of 130 pounds was obtained at about 1,000. The lower plane was notched at its rear edge in the centre, to allow of the propeller revolving. "The 40-horse-power motor used had a bore and stroke of 3f and Z\ inches respectively. This engine develops its full power at about 1,800, while at the speed at which it ran during the flight (viz. 1,200 r. p. m.) it developed only about 25 horsepower. The weight of this engine complete, without accessories, is but 145 pounds, while with a separate carbureter of 14 ounces

weight upon each cylinder, and with the combined gasoline and oil tank shown as well as including the propeller, the total weight was but 200 lbs. The engine had been thoroughly tested, driving a propeller and running a motor ice-boat. "The idea of mounting the aeroplane upon runners and testing it upon the ice seems to be an excellent one, and to offer several advantages. Besides the two main runneis of substantial construction, the next to the last vertical post at the rear of the surfaces was prolonged downward, and fitted with a runner also, for the purpose of steadying the machine, and keeping it on an level keel. A runner was also fitted to the vertical rudder post, but was subsequently removed."