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Aviation History
1909
1909 - 0388.PDF
JULY 3, reported to have acheived some short nights, and finally he built a steam engine. This was in the days before the petrol engine, as it is now known, had been evolved to the degree of perfection which has now enabled him to participate in the design of one which develops 30-h.p. in 85 lbs. weight. It is also reported that Captain T. S. Baldwin, who made the U.S.A. Army dirigible " No I," assisted the two partners in the design of the motor. The Owners of the Curtiss Flyer. The present machine, which is the first that Mr. Curtiss has built since the cessation of the Aerial Experiment Association, has been constructed with a view to its being taken over by the Aeronautic Society, who will retain it for the use of members for their sport and experiment, if Mr. Curtiss performs preliminary trials with it which come up to their expectation*. Already several successful nights have been made at Hammondsport, the longest being a 3-mile journey over a figure of eight course. Since then, however, the machine has been trans- ferred to the grounds of the Aeronautic Society at Morris Park, where further trials are in progress. The price which the Aeronautic Socity have agreed to pay is $5,000. Constructional Features. The Curtiss flyer is a biplane having two decks spaced 5 feet apart by laminated shuts, which, like the main spars, are of Oregon spruce. Each deck is 28 ft. 9 in. span, and has a chord of 4 ft. 6 in. The decks are con- siderably cambered, the maximum height of the curvature being about one-ninth the chord. Baldwin rubberised silk, similar to that employed in the U.S.A. Army dirigible " No. 1," is used as surfacing, and the fabric is mounted in sections, those at the outside being fastened by a system of lacing. The fabric is stretched as tight as possible, and its rigidity is augmented by spruce ribs. The decks are single surfaced, and the ribs are enclosed in pockets sewn to the upper side of the fabric. These ribs overlap the rear spar and form a flexible trailing edge, through which a wire is run for bracing purposes. When at rest on the ground the chord of the decks is inclined at an angle of about 6° to the horizon, but this does not represent the horizontal flight position. The angles of entry and trail have not been made known. The aspect ratio, i.e., ratio of span to chord, is 6*4, which is fairly high value, and should result in corres- pondingly good lift efficiency. « At the extremities, the rear edges of the main decks have their corners cut away, similarly in the centre, where this is done in order to accommodate the propeller. It will be observed that the main decks are in no way arched on the present machine, as they were on the earlier Curtiss designs. Supplementary Surfaces. Extending fore and aft to a distance of 10 ft. 6 ins., from the edges of the main decks are two triangular outrigger frames, carrying the elevator and tail. The elevator consists of a pivoted biplane of 6 ft. span by 2 ft. chord, and having an area, therefore, of 24 sq. ft, or less than one-eleventh of the total area. This is a smaller ratio than exists in the large machines. Between the decks of the elevator, and also extending a little above the top deck, is a triangular prow, which serves the purpose of a cutwater to give sensitiveness to direction. On the other outrigger which extends rearwards, is a horizontal tail of 12 sq. ft., and a vertical rudder of 6J sq. ft. area divided into two parts so that it is symmetrical above and below the tail. In addition to these supplementary surfaces, there are two others situated between the extremities of the main decks, where they serve the same purpose as is performed by warping on the Wright machine. These balancing planes, as they may be called, have each the same dimensions (2 ft. by 6 ft.) as the decks of the elevator and tail, and it will be noticed on reference to our drawing that they extend some little distance beyond the extremities of the main planes, although the greater part of their area is between decks. This feature we consider to be of very considerable importance on the score that it is questionable practice to put supplementary planes of this description between the main decks, both because it tends to throttle the gap and thereby possibly interfere with the lift efficiency, while conversely the decks themselves may be expected to have a restricting influence on the action of the righting planes when they are tilted or dipped. The fact that a portion of the righting planes on the Curtiss flyer are quite outside the extremities of the main planes is therefore a detail which should not be overlooked. The Chassis. The machine as a whole is mounted upon a three- wheeled chassis, of which the framework is made of wood. Two of the wheels are placed immediately beneath the lower deck of the main planes, while the third is mounted on an outrigger some distance in front. All wheels are shod with 20-in. diam. pneumatic tyres. THE CURTISS BIPLANE.—General view of the machine on terra firma, showing the elevator in front of themain decks. The camber o£ the decks is particularly well shown in this view, which should be compared with the drawing. 390
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