The Pfitzner machine has proved very speedy, and has made some remarkably sharp turns on an even keel. OTHER MONOPLANES. Several machines of the monoplane type have been produced, having some feature distinct from existing forms. While all of these have flown successfully, few of them have made any effort to be classed among the contestants for honors at the various meets. One of these, the Fairchild monoplane, shows resemblances to the R-E-P, the Antoinette, and the Bleriot machines, but differs from them all in having two propellers instead of one; and these revolve in the same direction, instead of in contrary directions, as do those of all other aeroplanes so equipped. The inventor claims that there is little perceptible gyroscopic effect with a single propeller, and even less with two. The propeller shafts are on the level of the plane, but the motor is set about 5 feet below, connections being made by a chain drive. [Illustration: The Beach type of the Antoinette, an American modification of the French machine, at the Boston Exhibition, 1910.] The Burlingame monoplane has several peculiarities. Its main plane is divided into two wings, each 10 feet in spread and 5 feet in depth, and set 18 inches apart at the body. They are perfectly rigid. The tail is in two sections, each 4 feet by 5 feet, and set with a gap of 6 feet between the sections, in which the rudder is placed. Thus the spread of the tail from tip to tip is 16 feet, as compared with the 21½ foot spread of the main plane. The sections of the tail are operated independently, and are made to serve as ailerons to control the lateral balance, and also as the elevator. The Cromley monoplane, another American machine, is modelled after the Santos-Dumont _Demoiselle_. It has a main plane divided into two wings, each 9 feet by 6 feet 6 inches, with a gap of 2 feet between at the body; the total area being 117 square feet. At the rear of the outer ends are hinged ailerons, like those of the Farman biplane, to control the lateral balance. The tail is 12 feet in the rear, and is of the “box” type, with two horizontal surfaces and two vertical surfaces. This is mounted with a universal joint, so that it can be moved in any desired direction. The complete structure, without the motor, weighs but 60 pounds. The Chauviere monoplane is distinct in having a rigid spar for the front of the plane, but no ribs. The surface is allowed to spread out as a sail and take form from the wind passing beneath. The rear edges may be pulled down at will to control the lateral balance. It is driven by twin screws set far back on the body, nearly to the tail. [Illustration: The Morok monoplane at the Boston Exhibition. It has the body of the Bleriot, the wings of the Santos-Dumont, and the sliding wing tips of the Pfitzner.]