Wright Co. v. Paulhan

177 F. 261, 1910 U.S. App. LEXIS 5303
District Court, S.D. New York·Decided February 17, 1910·Published·Cited by 5 cases

Opinion

HAND, District Judge.

There is very little that I should wish to add to Judge Hazel’s opinion in the case of Wright Co. v. HerringCurtiss Co., 177 Fed. 257, were it not for the ardor of the defendant’s counsel and their insistence that a different showing has been made here. In view of the seriousness of the contest, I feel obliged to give my own reasons for this decision.

The defendant says that he does not infringe the patent because he does not use a device which automatically always presents to the wind that side of the rudder nearer the angle of lesser incidence; and that if the patent be construed as merely a combination of a vertical rudder with a-device for creating a differential in the angle of incidence of the rear marginal edges of the plane, it is not a novel discovery, but was anticipated in the art. Therefore, the first consideration must be the proper construction of the contested claims of the patent in suit.

Claim 7 is the main reliance of the complainants, and that is as follows :

“(7). In a flying-m,acbine, the combination, with an aeroplane, and means for simultaneously moving the lateral portions thereof into different angular relations to the normal plane of the body of the aeroplane and to each other, so as to present to the atmosphere different angles of incidence, of a vertical rudder, and means whereby said rudder is caused to present to the wind that side thereof nearest the side of the aeroplane having the smaller angle of incidence and offering the least resistance to the atmosphere, substantially as described.”

The specifications and diagrams upon which this claim was allowed after a pendency of three j^ears in the Patent Office, showed the tiller ropes of the vertical rudder attached to the rope which ran along the rear of the lower plane, in such wise that, when tlie marginal parts of the two planes were warped as indicated, the rudder was turned towards the margin which had the lesser angle of incidence. [263] Moreover, there was a constant proportion between the degree of deflection of the rudder and that of warping of the plane. The Blériot and arman planes, which the defendant uses, do not have the combination described, and the complainants have in fact at times abandoned it. Tt is therefore a very sound contention that if the connection between the tiller ropes and the warping device in a constant proportion, be an essential element in the combination patented, the planes which the defendant uses are in no sense infringements, and the case need not go into the question of the validity of the complainant’s patent ai all.

To an intelligent understanding of the invention and the question of how essential is the attachment of the tiller ropes to the warping rope, the method of maintaining equilibrium under the patented combination must first be set forth. Assume an aeroplane with or without dihedral sustaining surfaces, to be propelled through the air, having the combination specified, and also suppose the left wing has been accidentally depressed. That in itself will result, as all agree, in starting a revolution towards the left. This is the resultant of two motions : fiirst, the forward motion of the plane: and, second, the motion at right angles caused by the sliding of the machine laterally in its own plane and over the successive columns of air. The resultant is precisely analogous to any planetary motion. This resultant is accentuated by the movement of the center of pressure towards the depressed lateral margin, giving a greater leverage to the propeller nearer the elevated wing. Also, the vertical rudder becomes transverse in its reaction to the lateral motion of the aeroplane, and consequently the rudder is pushed up. and by its leverage further turns the direction of the plane to the left. Thus the machine will begin to revolve to the .left. Moreover, this very motion will cause the right wing to be further elevated, because of the increased'drift, or head-resistance caused by its increasing speed, and the decreased drift against the left wing, caused by its diminished speed. Thus, in turn, the initial depression creates a revolution, and that, in turn, an increased depression with its corresponding acceleration of revolution, so on co-operating till the machine will swoop downwards to the left to its entire destruction.

The first part of the patented combination for correcting the depression of the left wing is to increase the angle of incidence upon the left side, so increasing that component of the drift which is opposite to the action of gravity. However, contrary to the assumptions of earlier speculators, this alone has a precisely contrary effect to what might be expected, because although the lifting component of the drift is increased, the head-resistance is much increased, and this decreases the velocity of the left wing in greater proportion than the increase in the angle of incidence tends to raise it. That revolution, already initiated by the very tilt itself, is therefore increased by the differential in the 'angle of incidence between the two margins. The right wing, which has thus an added velocity relatively to the left wing, will, in spite of its lesser angle of incidence, rise more rapidly than the left wing. Unless the revolulion be corrected the increased [264] angle of incidence will therefore remain ineffectual to restore the balance, but will rather further disturb it, and it is therefore necessary that the rudder should be put over towards the right wing, thus counteracting the revolution. When this is done, the increased angle of incidence on the left wing becomes effectual and the left wing rises, so restoring the equilibrium of the plane. It is the combination of a differential in the angle of incidence with a rudder which operates against the side of lesser angle which produces this result.

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Wright Co. v. Paulhan, 177 F. 261, 1910 U.S. App. LEXIS 5303 (S.D.N.Y. 1910).

177 F. 261 (Wright Co. v. Paulhan) — published by Counsel Stack Legal Research, free access to 12M+ legal documents.

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