After noting these improvements, we will look at the general outlines of such a Wright racing machine as contested for the James Gordon Bennett Cup in 1910. The two main planes are the smallest yet used on a biplane, being only 21-1/2 feet wide from tip to tip, and only 3-1/2 feet from front to rear. Thus, the aspect ratio, it will be seen is 7. They are the same general shape as the planes on the other Wright machines, and their total area is 145 square feet. The machine is steered up or down by the horizontal elevator rudder in the rear, which is oblong-shaped, 8 by 2 feet. The rudder that steers the machine from right to left is set vertically at the tail and is worked in combination with the levers that work the warping of the tips of the planes. On this little machine the twin-screw propellers, 8-1/2 feet in diameter, sweep practically the whole width of the machine. They are connected by chains to the 60-horsepower 8-cylinder Wright engine (in ordinary biplanes of this type the engine is 30 horsepower) and make 525 revolutions per minute (in ordinary machines of this type they make 450 revolutions per minute). The machine weighs a total of 760 pounds and is capable of more than 60 miles an hour. The elevation rudder is controlled by a lever set either at the right or left hand of the operator. The direction rudder is controlled by a lever that also controls the warping of the planes, as in turning it is necessary to cant the machine over to the inner side of the curve being made, in order to prevent slipping sidewise through the air. However the handle of the direction and warping lever is so arranged by a clutch system that by moving the lever simply from side to side the direction lever can be worked independently of the warping. The direction and balancing system then, we see, is worked in this manner. Say, while flying, a gust of wind causes the biplane to dip at the right end. The operator quickly moves his warping lever forward. This pulls down the tips of the right planes, and at the same time elevates the tips of the left planes. The change of the angle makes the right side lift to its normal position while it makes the left side drop. Consequently the machine is restored to an even keel and the operator lets the planes spring back to their normal shape. The large 1911 Wright biplanes, model B, are designed the same as the small racing models except that the wings have a spread of 39 feet, and a depth of 6-1/4 feet--a total area of 440 square feet. The perpendicular triangular surfaces in front like two little jib sails, are a distinguishing feature, although the latest Wright models substitute narrow vertical fins about six feet tall and six inches wide. They are placed immediately in front of the main planes. The hydro-aeroplane substitutes two aluminum floats for the wheels. CURTISS BIPLANE