Opinion of the Court tion and introduced into the art a safe, efficient, and scientifically constructed mode of control, not theretofore in use or invented, and all that remains is to discuss the issue of infringement. INFRINGEMENT Three types of airplanes, known respectively as the Curtiss, De Haviland, and Loening, are alleged to infringe the patent in suit. (See finding XIX.) As set forth in detail in our findings XXI and XXII, all three of these types of airplanes in general possess a single vertical control lever or "joy stick" universally mounted at its lower end so that it is capable of moving or tilting in any direction. A transverse movement of this lever operates a hinged portion of the wings of the airplane so that the contour of the wing surfaces is distorted or altered for the specific purpose of controlling the lateral equilibrium of the plane. Manipulation of the "joy stick" or lever in a fore-and-aft direction controls a rudder or rudders pivoted on a horizontal action in such a manner as to control the longitudinal equilibrium of the airplane. In all of the Government structures the connections existent between the "joy stick" and the control surfaces of the airplanes are of such a character as to cause the airplane to tilt in the same direction as the tilt of the stick, and the response of the airplane is thus in accord with the instinctive balancing sensations of the pilot. All of the Government structures possess a separate lever (foot operated) for controlling the steering rudder. For the purpose of making the Government construction clear we reproduce on the following page one of the exhibits in the case which illustrates the Curtiss construction. The structure of the De Haviland airplane and the Loening airplane is functionally the same as the Curtiss and in construction of details substantially similar to this illustration. Referring to this illustration, a sidewise movement of the "joy stick" 61 operates through the cables hh1 which are connected to hinged portions of the ends of the upper wing 5, known in the art as ailerons. Manipulation of these ailerons causes a change in contour, or a distorting of the ends. of the wing. As we have already stated in our opinion, Opinion of the Court "The original process of wing warping has been generally if not universally superseded by ailerons, which are concededly direct mechanical equivalents for wing warping. (See Wright Co. v. Herring-Curtiss Co., 204 Fed. 597, 607, 608, later sustained by the circuit court of appeals, second circuit. See 211 Fed. 654.)" A fore and aft movement of the "joy stick " 61 operates, through lever arms e e and the cables connected thereto, to raise or lower the horizontal equilibrium control rudders 60, 60. The separate foot lever 68 controls the steering rudder 57 by means of cables. The terminology of the claims in suit is found to apply to the Government structures word for word and element by element. Defendant attempts two defenses with respect to the question of infringement. In the first defense it is suggested that the Government does not infringe due to the fact that the claims of the patent in suit use the word "stability." In this connection we quote claim 6 as an example of this use: "6. In an aeroplane, the combination of means for producing lateral stability, means for producing longitudinal stability, means for steering in a horizontal plane, a single vertical level movable in every direction for operating both said means for producing lateral stability and said means for producing longitudinal stability, and separate means for operating said steering means." [Italics ours.] Defendant alleges that "stability" is that property of an object which enables it to return to its original position if it is disturbed, and states that " in modern airplanes that is accomplished by the fixed stabilizer in the case of longitudinal stability and by the dihedral angle of the wings in the case of lateral stability. These are parts of the structure, built into the machine and producing inherent automatic stability. The stabilizer and the dihedral are not subject to the manipulation of the joy stick. The latter is not in combination with them. Thus, the modern structures do not read on the claims." In other words, the Government urges that the modern airplane is self-balancing and is not dependent upon equilibrium "joy stick" control to preserve its proper attitude. Much testimony has been presented by Opinion of the Court various of defendant's experts as to the self-flying properties of the modern airplane. This argument, however, is to a certain extent fallacious as the three types of airplanes alleged to infringe cannot by any means be considered as modern, nor is it at all certain that they possessed this socalled self-flying property stressed by the defendant. As a matter of fact, Captain Hegenberger, one of defendant's expert witnesses, was asked specifically about the Curtiss JN-4. The question and his answer are as follows: "Q. How about the JN-4? Has every plane of that type that you have flown had such inherent stability that you could fly it hands off? “A. The JN-4 longitudinally bordered on instability." In the second place, if an airplane can be designed to fly itself, why is it necessary to spend so much time instructing aeronautical pilots in the art of blind flying, as has been brought out by defendant's experts? If an airplane gets in a fog bank or a cloud and has this alleged property of flying itself by automatic inherent stability built into the plane, why does the pilot not release the controls and let the plane fly iself? In fact, why use the controls at any time? The final answer to all this argument is entirely obvious. A patentee has the right to be his own lexicographer, and any court will unhesitatingly accept a definition of a word or phrase used by the patentee if it is ascertainable from the patent. It is no defense to a charge of infringement of an apparatus or a combination described in the claim in a patent that some part of it was misnamed therein by the patentee, or that the infringer has called it by a different name. (See Advance Rumley Co. v. John Lauson Mfg. Co., 275 Fed. 249; Century Electric Co. v. Westinghouse Elec. & Mfg. Co., 191 Fed. 350, 366.) From the patent in suit it is entirely clear that by "stability" the patentee means what we have termed "equilibrium" or "equilibrium control" throughout this opinion. The three alleged infringing planes of the Government all possess the single vertical lever movable in every direction for controlling the lateral or longitudinal equilibrium Opinion of the Court of the plane connected to controlling surfaces having the same functional effects as those disclosed in the patent, and the Government cannot escape infringement on the rather remarkable theory that the Government planes fly themselves. The second defense theory advanced by defendant as to noninfringement is that the claims, if valid, should be limited to a combination comprising a single integral or unitary tail structure, and should not cover the tail structure such as is present in the Government airplane alleged to infringe, and which comprises an independent horizontal and vertical rudder. It is, of course, well settled that the courts, in order to save the patentee from the invalidation of a claim, due to prior art or a prior use, will frequently put a narrow construction on a claim so as to conform it to the exact disclosure of the specification, and thus save the claim from invalidity. This is not necessary in the case at bar. As we have already indicated in our consideration of the rather voluminous prior art cited by defendant, there is nothing in the prior art which is of an anticipatory nature. The mere fact that the plaintiff elected in the patent in suit to disclose his equilibrium control lever and the separate steering lever connected to a particular kind of a tail structure should not limit the claims to use of that of an integral vertical and horizontal rudder structure. It is the controlling means or lever which is the essence of the invention at issue, as defined by the claims, and not the tail structure of the airplane. The only difference between the elevator and rudder of the Government structures and the elevator and rudder of the ring-tail embodiment disclosed in the patent in suit is that the former has separate mountings to the fuselage, while the latter has a single mounting to the fuselage. In each case the steering rudder and elevator possess similar functions. There is some testimony in the case on behalf of the defendant as to what may be termed "cross responses." The theory of this is that the mounting of the integral tail |