Full opinion text
BRENNAN, Chief Judge. This is the usual patent infringement action requesting the usual relief. The problems involved therein are rendered difficult because of the complex nature of the inventions claimed and the machines involved. Plaintiff’s devices principally contemplate an all-electrieally operated blind flight airplane trainer as distinguished from pneumatically or hydraulically operated machines. The lengthy record is made up of evidence involving aeronautics, electrical engineering, aerodynamics and mathematics, the understanding of which taxes the capacity of one untrained therein. Jurisdiction is based upon the provisions of the statute and is undisputed. The Pleadings. The action was commenced by the filing of a complaint on December 16, 1955. It charged the threatened infringement by the defendant of three patents in that the defendant was engaged in the present manufacture of an infringing device to be completed and delivered to a purchaser in the future. An amended complaint was filed on June 20, 1957. This pleading asserted infringement and threatened infringement of ten specific patents by the same and other proposed machines. An answer was served January 16, 1958 which denied the material allegations of the complaint and raised the issues of invalidity, non-infringement and license. Through the cooperation of counsel, certain pretrial orders were entered which restricted the trial to the issues involved in four separate patents and in some twenty-two claims thereof. The action was brought to trial in December of 1958 and was completed in March 1959. Over 5,500 pages of testimony were offered and over 500 exhibits received. Lengthy briefs have been filed by the parties; oral argument has been made and the issues are before the court for decision. The Patents. Set out below are the patents referred to by number and the numbered claims of each which are involved in this litigation. They appear in the order in which they were filed and in which they were litigated. Patent No. 2,494,508, filed June 18, 1941, issued January 10, 1950. (This patent will be referred to as 508). The claims involved are numbered 11, 13, 19, 29, 32, 33, 35, 38 and 45. Patent No. 2,366,603, filed December 20, 1941, issued January 2, 1945. (This patent will be referred to as 603). The claims originally involved are numbers 3, 25, 40, 52, 60, 62, and 101. Claims 6Q and 62 were conceded to be invalid during the trial and are therefore removed from the case. The non-infringement of claim 101 was also conceded. Patent No. 2,475,314, filed November 25, 1943, issued July 5, 1949. (This patent will be referred to as 314). The claims involved are numbers 14, 42 and 46. Patent No. 2,560,528, filed March 27, 1945, issued July 10, 1951. (This patent will be referred to as 528). The claims involved are numbers 24, 25 and 28. It may be said generally that as involved here, the above patents and the claims in litigation here apply to and involve devices intended to be used in aircraft flight training. Patent 508 is claimed to be a basic patent comprising a stationary machine in which are located controls simulating those found in an actual airplane. The movement of the controls by the trainee create electrical impulses which are transmitted and refined through electrical circuits and mechanisms to instruments similar to those in an actual plane. Said circuits and mechanisms are so interconnected, arranged and calibrated as to reflect upon the indicators the effect of the control movements made by the operator. In addition, there is a charting device which automatically traces the path over or along which the plane would proceed in accordance with the movement of the controls. This patent also contains apparatus simulating radio range signals which are operable to enable the trainee to determine his position as an aid to navigation. Patent 603 generally is an improvement over 508 in its flight control mechanism and contains further refinements in aid of navigation through simulated radio signals. Patents 314 and 528 have to do primarily with additional improvements or refinements of airplane navigation aids by the use of simulated radio signals. Throughout the testimony, the machines involved are generally referred to by the plaintiff as “simulators” while the defendant seems to more often use the designation of the machines as “trainers”. The terms appear to have been used interchangeably and the devices are intended to afford ground training and experience to aircraft operating personnel whereby they may become familiar with the action of an actual airplane in its different attitudes in response to the operation of the controls. In general, they are land bound prototypes of actual airplanes responsive to the techniques of airplane operation and navigation. The Parties. Plaintiff, Curtiss-Wright Corporation, is generally known as a manufacturer of airplane parts and related machines or equipment. It holds an exclusive license from plaintiff, Dehmel, to make use of the patents involved in its manufacturing activities except for certain rights retained by Bell Telephone Laboratories under the first three patents mentioned above. Under the license, first above mentioned, Curtiss-Wright has the right at its election to sue an infringer of the patents covered by the license and to join Dehmel as a party plaintiff in such a suit. The use of the designation “plaintiff” in this decision will be deemed to include both plaintiffs unless otherwise indicated. Plaintiff, Richard C. Dehmel, is the record owner of the patents involved in this litigation and the inventor of the devices described therein. He is at present the Director of Engineering of the Electronic Division of Curtiss-Wright at Carlstadt N. J. His collegiate education included a Bachelor of Science degree from the University of California which included some study of mechanical and electrical engineering. He was employed by the Bell Telephone Laboratories from his graduation in 1927 until 1943, receiving a Master’s Degree in Metallurgy from Columbia University and the degree of Ph.D. in Chemistry in 1936. * His employment by Bell embraced the development and design of telephone apparatus and electrical circuitry. He was stationed at Los Angeles in 1937 or 1938 until the middle of 1941 where he was primarily engaged in the supervision of all area electrical circuit operation and development as applied to the telephone system. In July 1941, Dehmel was transferred to New York and assigned by his employer to work upon a “gun director” which had been designed by Bell and intended to assist in the aiming accuracy of anti-aircraft guns. He was sent by his employer to England in 1941 to deliver, test and demonstrate such a gun director. He returned to Bell Laboratories in the latter half of 1942 and continued to work in the general area of gun fire control systems until he joined Cur-tiss-Wright in 1943. Dehmel early developed an interest in airplanes. He obtained a pilot’s license and while stationed in California, he conceived the idea of an electrically operated flight trainer and started to develop his idea about January 1941. A model was built in Dehmel’s home or workshop and was assembled upon a trial and error system. On June 18, 1941, Dehmel filed his application for the 508 patent here involved. A short time thereafter, he was transferred by Bell from Los Angeles to New York and the model, above mentioned, was brought to his residence at Summit N. J. It is apparent that the model was thereafter modified or changed as the result of experimentation and on December 20, 1941, Dehmel filed his application for patent 603. The remaining two patents in suit, to wit: 314 and 528, were applied for on November 25, 1943 and March 27, 1945 respectively. Both of these dates are after Dehmel’s employment with Curtiss-Wright and it may be fairly inferred that same were the result of further experimentation and research. Defendant, Link Aviation Inc., is the successor to the business established in the 1920’s by Edwin A. Link who was a pioneer in the airplane trainer industry. The business has been practically continuous since at least 1936. Link is the conceded manufacturer of the alleged infringing structure which is referred to as the E 600. This trainer or simulator was manufactured at Binghamton N. Y. and both the manufacture and sale were completed by the time of the filing of the amended complaint. The Controversy and Machines Involved. The extremely technical nature of the proof offered, taken together with the technical language of the patents themselves adds to the layman’s difficulty in appraising the specific points in controversy. Generally speaking, it is the plaintiff’s contention that Dehmel was the first to conceive, disclose and reduce to practice an airplane trainer in which all operations and computations, starting from the control movements by the student through to the dial movements of the flight instruments, are affected and controlled entirely by electrical signals and electrically operated means. The claims in suit fall into two distinct categories. All of the claims of Patent 508, except claim 19, and all of the claims of Patent 603, except claim 25, are concerned with the attitudes of an airplane in flight. While the two claims, mentioned above, and all of the claims of 314 and 528 are concerned with the position of the plane as disclosed by simulated electrical signals finding their source from radio stations. In other words, both problems of flight control and navigation are claimed to be solved in plaintiff’s patents. Since plaintiff asserts infringement of both the flight training and navigation aid claims, the litigation naturally divides itself into two parts. The controversy as it involves the flight training claims will be first considered. The control of an airplane in flight is directed by the operation of an aileron, rudder, elevator, throttle and stabilizer. The operation of one or more of such controls by the pilot is reflected in the movement of the plane which is disclosed to such a pilot by the readings upon the affected instruments which are located upon a panel within his vision. The Dehmel device contains controls and instruments which simulate those found in the actual plane. The movement of the controls sets off electrical impulses which are transmitted through intricate electric circuits and are altered through the action of potentiometers, rheostats, tachometers and electrically operated motors so as to produce upon the simulated instruments indications of the effect of such operations upon the flight of an actual plane. Inasmuch as the action of a control may have an effect upon more than one movement of the plane, the electrical mechanism is so interconnected as to ultimately compute the total effect upon a plane of any such movement and to disclose same upon the instrument dials. It is readily understood that the action of such mechanism involves the use of the techniques used in “computer machines”. It seems to be conceded that Dehmel made no patentable invention in the mechanical or electrical elements, above referred to. Potentiometers, motors, rheostats etc. were old in the electrical art and the use of electrical computers was known long before Dehmel. The concept of an entirely stationary trainer wherein the trainee must rely entirely upon instrument reading and-discard entirely any reaction which he might otherwise obtain together with the use of electrical means in computing and conveying the effects of control movements is urged as such a radical departure from the training afforded in prior in-strumentalities as to justify findings of patentability and infringement. The contention must be weighed against the patent disclosures and must be rejected if Dehmel’s disclosure appears in the prior art or if it is only the advancement of the prior art to be expected by the skill of those engaged therein. 35 U.S. C.A. § 103. As indicated above, the claim of infringement is limited to the Link E 600, the history and structure of which will be briefly described. The E 600 is an outgrowth of the trainer development program adopted by Link after the close of World War II. Electrical components and techniques had so far advanced during the war that it seemed advisable to adopt same in the Link manufacturing operation. Although Link manufactured and delivered electronic computer type airplane trainers to the Government after the close of the war, the E 600 was the first electronic simulator built and sold to a non-government customer. It was a prototype of the actual plane known as the Convair 240 and was delivered to an organization known as Flight Safety Inc. in May 1956 and put to actual use at LaGuardia Field, New York City. The E 600 was mathematically designed and built. A knowledge of certain characteristics of the Convair 240 was the actual starting point of the construction of the E 600. Aeronautical engineers then transposed such characteristics into aerodynamic equations of quantity or force and electrical engineers devised the electrical circuits, mechanisms and components which would compute the effect of such forces, or solve the equations. The whole process involves the skill and experience of those especially engaged in the manufacture of computer mechanisms. This is essential if accurate results are to be obtained. Although the E 600 is designed and built upon a mathematical background or approach which is entirely a different approach than that of Dehmel, the plaintiff contends that the mechanism involved in obtaining the ultimate result uses the same components as disclosed in Deh-mel or their equivalents and therefore infringes. The Development of Trainers or Simulators. It would seem advisable to refer briefly to the development of the art involved in this litigation in order to provide an understanding or background for the consideration thereof. The manufacture of airplane trainers or training apparatus has developed into a major industry. This is shown by the fact that in 1957 the sales of such apparatus by Curtiss-Wright amounted to upwards of 18 million dollars. The complexity and refinements of present day trainers are evidenced by the increasing cost thereof but business economics dictate that such trainers are of practical necessity wherever men are taught to operate modern aircraft. Link appears to have been the principal manufacturer of trainers prior to and perhaps through World War II. The early models of the Link device were built empirically. They were designed and built on a trial and error basis and as the result of experimentation. A principal feature of the Link devices was the movement of the chassis which was intended to simulate the movements of an actual airplane in flight and thereby transmit the sensations so created to the trainee. Such movements were responsive to the operation of the controls and the mechanism involved reflected the results principally through hydraulic or pneumatic mechanism. The Dehmel devices, as disclosed in the patents, were also empirically derived. The response to the movements of the controls was shown however by variable electrical means in distinction to the hydraulic or pneumatic means used by Link. Another distinction or difference is that the chassis of the Dehmel device is stationary and the trainee must depend upon the reading of the instruments alone to ascertain the effect of the movement of the controls. In Link, the trainee depends upon visual changes and sensations produced by the motion of the chassis in simulating the different attitudes of an actual plane. The modern approach in the manufacture of trainers may be termed mathematical or analytical. This approach seems to be contemporaneous with the development of mathematical computing machines which received an impetus in the early 1940’s. As understood, this approach is outlined in the prior background description of the E 600. The modern trainer then becomes the prototype of the particular plane which it simulates. It may be readily concluded that the mathematical approach, described above, affords a more accurate and effective training instrument since each type of plane has its own characteristics and will differ from another in its attitudes under the varying conditions to be encountered. Prior to the advent of World War II, Curtiss-Wright did not build airplane trainers. Upon the advent of World War II, Link was frozen by a Government regulation and limited to the manufacture of trainers of the type previously made. In 1940, Bell built the gun director, using computer and electrical techniques in solving the equations for aiming antiaircraft guns. About 1943, Bell manufactured electrically operated flight trainers under Government auspices. After the War, Link undertook a development program to adapt its business to the new techniques and its first electronic computer type of trainer was ordered by the Government on September 20, 1946 and delivered in 1949. Curtiss-Wright never manufactured a trainer built empirically or in accordance with the Dehmel patents. Its first sale was made in 1946. Invention. An approach to the decision must necessarily rest upon an understanding and finding as to the bases upon which pat-entability rests. This question, ordinarily not too difficult, has become troublesome by reason of the lack of consistency in the evidence relating thereto, the language of the patents themselves and the various contentions advanced. A critical and detailed examination of the record, the documents and the briefs is therefore required. Patentability implies invention which in turn requires novelty and utility. The approach to the conclusion of the existence of invention must be made with a comprehension of the problem to be solved, the state of the prior art, the extent of the advance therein, the result obtained and the usefulness thereof. Broadly speaking, the problem was to simulate the attitudes of the plane in flight through grounded apparatus responsive to the action of simulated controls, such responsiveness being reflected upon simulated visible airplane instruments or dials. The result sought was to acquaint operating personnel with the actual behavior of a plane in flight and to familiarize them with the interrelated effects of the movement of one or more controls upon a plurality of responses. While economy in cost of the apparatus and the operation thereof were a consideration in the solving of the problem, accuracy and true simulation were overriding considerations. The record is devoid of any considerable evidence of previous attempts to build an all electrically operated trainer with the exception of the Aerostructor, hereinafter referred to. The concept of such a machine was disclosed in the German Patent No. 568731 by Roeder as early as July 6, 1929. It can be fairly said that the fruition of the idea awaited the advent of the more intricate planes and the availability of electrical mechanisms capable of performing the computing functions required to show accurate results. The threat and actuality of World War II provided both the necessary impetus and materials required. The usefulness of the Dehmel machine is open to serious question. Plaintiff contends that, even though no trainer has been built based upon his disclosure, his basic idea “opened the door to the modern mathematical analysis and design of electronic simulators”. The argument is carried farther by the contention that the trainers made by Bell Laboratories during the war, the technique of which was later made available to the defendant, were actually disclosed by Dehmel and adopted by Bell. This contention lacks factual support. How much, if any, knowledge Dehmel drew from Bell’s “gun director” and how much, if any, knowledge Bell drew from the Dehmel patent disclosures are not directly litigated in this action and is pure speculation on the record as it stands. These patents are “means” or “apparatus” patents as distinguished from “method” or “process”' patents. The file wrapper of 508 directs a change in title of the application by eliminating the word “method” therefrom since no such claims appear in the case. The use of electricity as the motive power or use of electrical connections and operating means in place of mechanical connections or means would not involve invention is also indicated in the file wrapper of 508 in rejecting certain claims. The statement follows — “ * * Simply replacing mechanical connections and operating means with electrical connections and operating means as in Koster or Crane for actuating the indicators in accordance with control movement would not involve invention.” It would seem to follow that the use of electricity and electrical components has been overemphasized in the evidence, thereby losing track of the essential that their use to be patentable must produce a new or different result from that obtained by pneumatic or hydraulic power and mechanical connections and components. Plaintiff Dehmel himself, in his testimony, indicates that multiple integrations and interrelationships between the electrical circuits are important items showing novelty or invention. Integration and double integration were known to the prior art. In fact, they appear in the Link C2 trainer but, more important, integration is not claimed as an essential step in the flight claims involved here. Interconnected electrical circuits were also old in the art and it is the court’s understanding that same are a necessary part of any electrical computing device and has so been recognized long before Dehmel who claims no invention in the particular circuits disclosed in the specifications. Dehmel’s use of a stationary cockpit and simulated instruments is frequently referred to in the evidence and briefs. The fixed cockpit however is not an element of the claims involved which appear to be broad enough to apply to both a stationary and movable chassis. It is not understood that the item of simulated instruments is seriously urged as an essential item and no particular stress is placed thereon by plaintiff. At this point it would seem advisable to briefly refer to the legal precedents which appear to hold in effect that the contentions as to integration, interconnected electrical circuits, stationary cockpit and simulated instruments, as disclosed, may not in themselves be considered as supporting invention. The claims define the limits of the patent. Graver Tank & Mfg. Co. v. Linde Air Products Co., 336 U.S. 271, 277, 69 S.Ct. 535, 93 L.Ed. 672. Stated in another way as in Application of Berliner, 195 F.2d 918, 920, 39 CCPA 928 — “The particular feature or fact upon which an applicant predicates patentability must not only be disclosed in the specification but also brought out in the claims”. Cited with approval in Application of Wright, 256 F.2d 583, 45 CCPA 1005. Here, as in In re Rundell, 48 F.2d 958, at page 959, 18 CCPA 1290, there is nothing in the claims which call for particular electrical devices or particular operative connections by which the motors are controlled and the results disclosed upon the dial. Thus no invention may be claimed in the particular elements not disclosed in the claims. Although running counter to some of the contentions advanced in plaintiff’s brief, he cites the 1952 amendment to 35 U.S.C.A. § 112, which applies only to combination claims, and the cases of Stearns v. Tinker & Rasor, 9 Cir., 252 F.2d 589 and Bryan v. Sid W. Richardson, Inc., 5 Cir., 254 F.2d 191 are cited, all of which indicate that he relies upon the result of a combination, rather than the novelty of a particular element. An examination of the file wrappers in 508 and 603 does not clarify the court’s understanding of just where invention rests. Claim 11 of Patent 508 is one of the broadest of the flight claims. It appears as Claim 87 as submitted to the Patent Office as a part of an amendment in 1945. Together with other claims, it was rejected as not properly defining the invention and as indefinite, ambiguous and inaccurate. We next find that the words “for ground training” were inserted in lines 1 and 2 and the claim was thereafter allowed. This court does not pretend to understand the procedures of the Patent Office- but to say the least, it is difficult to comprehend how the addition of the three words, above referred to, which disclosed the purpose of the invention, can help in any way in defining the invention itself. In fact, the three apparently essential amending words do not appear at all in the flight claims of 603. The reading upon the instruments reflects the direction and speed of electrically controlled motors and again referring to the file wrapper, it is plain that the use of an indicator to show the speed of a motor is not patentable invention. It may be noted that in the brief submitted, it is at least intimated by the plaintiff that even conceding that Dehm-•el’s concept of a wholly electrically operated trainer device was not new and that the components making up same and their interrelated action as a computing apparatus were long understood; that invention may be found in the selection by Dehmel of the “hardware” used in his ■device. Reliance upon B. G. Corp. v. Walter Kidde & Co., 2 Cir., 79 F.2d 20 is misplaced. In that decision, Paulson -used specific metals in the elements of the structure of his device. Here the components of the Dehmel structure are described generally, not specifically, and the -claims are replete with such terms as “variable electrical devices” and “electro-responsive means”, thereby giving a -choice of components to the practitioner. It is beyond argument that Dehmel did not invent the physical components which he claims are the operable means of his device; neither did he invent the computer techniques which determine the result obtained. If invention is to be found, it exists in the arrangement and •operation of the mechanism found between the controls and the instruments-. Approaching the question in a negative manner and by eliminating those features which were previously well-known and those not claimed, we arrive inevitably at the conclusion that the flight •claims of the patents involved claim a combination of old mechanical and electrical elements so arranged and operated as to produce an improved result. If the claims are to be sustained, it must be, because “ * * * of the fact of combination rather than the novelty of any particular element”. Faulkner v. Gibbs, 338 U.S. 267, at page 268, 70 S.Ct. 25, 94 L.Ed. 62. The test of patentability of a combination of old elements is so clearly laid down in the oft quoted case of Great Atlantic & Pacific Tea Co. v. Supermarket Equipment Corp., 340 U.S. 147, 71 S.Ct. 127, 95 L.Ed. 162, that repetition or discussion is unnecessary. To a great extent, it depends upon whether or not the result achieved is an improvement over prior mechanism. Improvement is a relative term and is determined largely by public acceptance or, in its absence, by expert appraisal. Evidence of public acceptance is lacking here and plaintiff’s operating expert seems at best to go no farther than to say that the Dehmel device “ * * * was as good and was maybe slightly better than the Link Trainer”. Whether or not Dehmel’s disclosure gave impetus to the advancements in the electronic type of trainer or whether they followed from the availability of materials and the know-how of mathematicians and engineers is a disputed question. The factual background hereinbefore stated brings us to an evaluation thereof and an application of the principles of law insofar as they pertain -to the questions required to be decided in this litigation. The general rules of law relative to patent litigation are not in dispute here. The rules relative to presumption of validity, burden of proof and the case law construction of the patent statutes are not disputed and require no particular discussion. Whether Dehmel’s arrangement of electrical and mechanical components, found between the controls and instruments, are such an advancement in the art' as to constitute invention is an essential question. Even if same may be considered as an advancement in the art, it must be of such a nature as to be beyond the ordinary skill of those engaged therein. Assuming that invention exists, it is not patentable if it was known or used by others in this country before the invention thereof by Dehmel. 35 U.S.C.A. § 102(a). The range of accomplishment to be expected of those skilled in the art and the question of prior use, last above referred to, are principally to be determined by the evidence offered in connection with a device known as the Aerostructor and same will be determined after a discussion thereof. Aerostructor. The Aerostructor was a device intended to provide ground training for those interested in aircraft operation. The device consisted of a stationary chassis in which the trainee was seated and in a position to operate the simulated airplane controls. When so operated, the movement thereof actuated electrical impulses through various electrical means which were transmitted to be finally represented by the action of a motor which rotated an artificial photographic horizon so as to convey to the student, to whom the horizon was visible, an impression of the movements of a plane. The device was the concept of one Travis and came to fruition through his own efforts and those of his two associates. Economy in the cost of manufacture and operation, together with a knowledge of electricity, prompted its use over pneumatic or hydraulic means to motivate the photographed horizon in accordance with the movements of the controls. The first model was constructed in 1939 and the early part of 1940 when it was displayed in the Museum of Science and Industry in New York City. Later models were developed and it is apparent that the construction time of same overlapped. In any event, one of said models was displayed for demonstration at the Luscomb Aircraft Agency in New York City during some part of the period from September 1940 to January 1, 1941. The models, above referred to, were empirically constructed and it is readily understood that improvements were made as experience dictated. That the Aerostructor, as a machine, existed prior to Dehmel and was operated by “variable electrical means” is beyond argument. It is also beyond argument that the device was intended to provide flight training by the use of a visibly rotating artificial horizon while the Dehmel device provided such training by the reading of simulated flight instruments. In other words, the Aerostructor was a visual trainer while Dehmel is dedicated to blind flight training. This distinction in purpose loses its importance because the controversy here involves the means for producing the results rather than in a distinction in the form of the results themselves. In one important respect, the history of both devices may be said to be similar. Neither concept produced a subsequent commercially successful airplane flight trainer. We are then interested in the internal mechanism of the Aerostructor and the extent of its public use in order to determine whether or not Dehmel was anticipated thereby or whether or not Dehmel discloses a patentable invention over same. In view of the rule applicable to evidence as to prior invention or prior use, the evidence must be scrutinized as to the Aerostructor mechanism and the extent to which it was disclosed to the public prior to Dehmel. Anderson Co. v. Trico Products Corp., 2 Cir., 267 F.2d 700. We turn then to the evidence disclosing the history and structure of the Aerostructor device. The first model of the Aerostructor, constructed and displayed as above, was apparently a crude device. It however afforded the basis.for a patent application filed August 7, 1940. This application was continued in part by a subsequent patent application filed December 15, 1942. A British application, similar thereto, was filed October 12, 1943 and a patent .issued thereon on May 23, 1946. In the meantime Aerostructor device No. 2 had been constructed and displayed at the Luscomb Agency, as above indicated. The time of the completion of the construction of Aerostructor machines, models 3 and 4, does not clearly appear. They had been completed by June 1941 and did not differ materially from the model displayed in the New York show room in the latter part of the year 1940. Sometime apparently in the latter part of the year 1940, a trailer was purchased for convenience in conveying the Aerostruc-tor for display purposes. In the winter of 1940-1941 and extending into the spring thereof, the Aerostructor device was exhibited in several places and in February 1941 an article concerning the device appeared in a magazine known as “Air Facts”. During the period, above mentioned, the device was exhibited to government officials at Washington. It was used for some three weeks at Floyd Bennett Field. It was exhibited to the Canadian Air Force at Ottawa, Canada. It was demonstrated at the Flushing Airport, at the Teterboro Airport and at Valhalla. The device was also tested by the military at Randolph Field, Texas, and at Tulsa, Oklahoma. Such demonstrations were essentially negative in their results insofar as obtaining orders or contracts for the construction of the device is concerned. The Navy, however, indicated a definite interest therein for the purpose of teaching aerial gunnery. To exploit such interest, a change was made therein which principally consisted in photographically imposing a simulated target upon the rotating artificial horizon, the operating mechanism of which remained substantially unchanged. By requisition, dated June 12, 1941, the Navy ordered two items or devices described as “Item 1”, “Aerostructor, Model Kl” and “Item 2”, “Aerostructor, Special Gunnery Model, which is essentially an extension of the principles utilized in Item 1”. Thereafter the manufacturers appeared to consider the device for gunnery training as a separate instrument which was called the Gunair-structor. The devices, called for in the requisition, were delivered on May 3, 1942 and further contracts led to the production of about 500 Gunairstructors during the war period. Emphasis upon the construction of the Gunairstructor led to differences among the three persons who conceived, financed and built the original Aerostructor device. At the conclusion of World War II, all manufacturing ceased and the principals involved apparently lost interest in further perfecting or manufacturing either device and the United States patent applications, referred to above, were abandoned. The above statements are made because the circumstances and the abandoned applications indicate a lack of motive to exaggerate or to color the witnesses’ oral testimony as to the concept and the structure of the device above referred to. It is very evident that the personal relationship of the above three persons tended to destroy any inference of collaboration in the matter of their testimony as given in this action. The above history is important only if the Aerostructor, as conceived, manufactured, displayed and sold, contains such a disclosure of electrical components and their operable action as to constitute an item of prior use or as to constitute an anticipation of Dehmel. In this respect, an appraisal of the electrical components is difficult by one lacking skill in the art. It should be first stated that the circumstances afford no reason to consider the evidence relating thereto at anything other than the best effort of the witnesses to present the facts in a truthful manner. The passage of time alone and its effect upon the memory of the witnesses is the only detracting circumstance. The witness, Polhemus, who testified upon the trial, gave every indication that his testimony was entirely trustworthy and same appears to be corroborated by documentary references. We can start with the fact that this particular witness, with only a high school education, appeared to find no novelty in 1939 in the use of electrical means to summarize the effect of the movement of simulated airplane controls. The Aerostructor contained interconnected electrical circuits, potentiometers, electrical means and resistances which control the operation and speed of reversing motors. The operation of such means accomplished integration of the effects of the movements of the controls. Fundamentally, it combined electrical and mechanical means so as to give visual evidence of the control movements to the trainee. The Aero-structor accomplished in a visual manner with imperfections the same thing that Dehmel accomplished (also imperfectly) except that in the case of the Aerostructor, the result appeared upon a moving horizon while in Dehmel the result appeared in the simulated airplane instruments. A detailed comparison of the combined elements and the method of operation found in 508, 603 and the Aero-structor requires lengthy discussions unnecessary to this decision. It is sufficient to conclude that the Aerostructor contained combinations similar to those found in the claims in dispute here and that means of operation were similar, as were the results obtained. The oral proof offered beyond that summarized in the description of the Aerostructor, above, need not be further elaborated. It is, however, important that same be fortified by contemporary physical evidence. Such evidence exists here. The patent applications and the British patent afford such corroboration especially since Fig. 9 in each, which is a diagram of electric circuits and components, seems to be substantially similar in each document. The Air Facts article, the pamphlet outlining the operational procedure, the photographs and the diagrams, prepared for the use of the patent attorney, are likewise corroborative as is the application previously referred to. The conclusion is inescapable that the Aerostructor was an actual electrically operated airplane training device, conceived, built and displayed to the public prior to Dehmel. The technical procedural objections, raised by the plaintiff, to the evidence relative to this subject, do not appear to be substantial. Plaintiff shows no prejudice and the evidence will be received and given the weight and effect to which it is entitled. Plaintiff’s contention that the electrically operating means were foreclosed from public view and inspection is likewise rejected. Reliance seems to be placed upon the following testimony referring to the Luscomb showroom display — “Yes, people came in, as I say, off the street and ran it all the time. Lots of people wanted to know what was in it. We put this lock on it afterwards to keep people from opening it all the time to see what made it tick”. The above indicates a free and open public inspection prior to the lock being placed thereon and, taken together with the evidence of demonstration, use and sale above referred to, constitutes public use within the meaning of the statute. Armour & Co. v. Rath Packing Co., D.C., 154 F.Supp. 54. Defendant urges that the Aerostructor should be considered as an item of prior art which anticipates the claims of Dehmel or invalidates them for lack of invention. Reliance is based upon the decision in Alexander Milburn Co. v. Davis, 270 U.S. 390, 46 S.Ct. 324, 70 L. Ed. 651, to avoid the holding in Interurban Ry. & Terminal Co. v. Westinghouse Electric & Mfg. Co., 6 Cir., 186 F. 166 to the effect that an abandoned patent application cannot anticipate. The particular facts here, together with the fundamental rule that the patentee must be the first inventor, lends force, at least equitably, to the contention but such a decision as in Monarch Marking System Co. v. Dennison Mfg. Co., 6 Cir., 92 F. 2d 90 is highly persuasive that the rule of the Interurban case is still the law and if change is to be made therein, an appellate court may more appropriately decide. The Aerostructor may be used however in determining the skill of the art. Wilson Athletic Goods Mfg. Co. v. Kennedy Sporting Goods Mfg. Co., 2 Cir., 233 F.2d 280 and as an invention known or used by others in this country before the Dehmel disclosure. 35 U.S. C.A. § 102(a). The abandoned patent is likewise available as evidence of disclosure of the Dehmel invention. United States Blind Stitch Machine Corp. v. Reliable Machine Works, Inc., 2 Cir., 67 F. 2d 327. The facts as to the concept, embodiment and use of the Aerostructor are so similarly comparable to those disclosed in the decisions of Smith v. Hall, 301 U.S. 216, 57 S.Ct. 711, 81 L.Ed. 1049, affirming 2 Cir., 83 F.2d 217 as to require a finding that any invention found in the flight claims of Patents 508 and 603 are not patentable under the provisions of the statute referred to above. Both devices simulated by electrical means the effect of the operation of airplane controls. If invention is found in one, it exists in the other. Both machines had their imperfections with a consequent lessening of usefulness. Both machines used electrical components long known in the art and the structures were subject to a variation of electrical components as experimentation dictated. Neither machine wholly solved the problem of complete and true simulation. Success in the particular field is relative. Neither became commercially successful but same is not essential if invention exists. Smith v. Hall, supra, 301 U.S. at page 233, 57 S.Ct. at page 718. The Aerostructor was most certainly both known and used as the terms appear in the above statute. Its many public displays and demonstrations with a testing or measuring of the results, constitute both knowledge and use. It would be naive to conclude that the Navy placed its requisition without knowledge or experience. It may also be said that the electrical operating structure of the Aerostructor became commercially successful in the form of the device known as the Gunairstructor. This court finds that the Aerostructor antedated Dehmel whose invention was known and used by others in this country and in public use or sale therein more than one year prior to the Dehmel applications and that the flight claims of Patents 508 and 603 are therefore 'invalid. It would seem to follow that the-claims are also invalid in that they fail to reveal creative genius. Such is a requirement of patentability. Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84, at page 91, 62 S.Ct. 37, at page 40, 86 L.Ed. 58. The concept of such a machine was known long-prior to Dehmel. Its reduction to practice awaited the suitable materials rather than creative genius. If the builders, of the Aerostructor could, without extensive experience or specialized education except that'obtained in a technical high school, so arrange electric circuitry, potentiometers, rheostats, and available' electrical components so as to show even in an imperfect manner, the effect of the-movement of the controls upon an artificial horizon, the substitution by Dehmel of dial instruments for the horizon would' seem to be well within the expected skill of the art. For this reason also, the claims are found to be invalid. Vagueness and Indefiniteness. The defense that flight simulating-claims of the 508 and 603 patents are' vague and indefinite becomes more impressive upon a review of the evidence relating to the language of the claims involved and their application to the-structure of the infringing device. The-defense is based upon the statutory provisions which require that each claim shall particularly point out and distinctly claim the subject matter which the applicant regards as his invention. 35-U.S.C.A. § 112. The problem involves an understanding of those skilled in the art to be appraised and applied by one-unskilled therein. To state the problem is to disclose the difficulty. This is especially true where the patent application was pending over a period of years-during which the science of electronics-probably had its greatest advancement and during which also the patent claims were amended in a manner which must have reflected the advancements in the-art. The court is aided by judicial de-cisions and our Circuit, having recently-discussed the subject at some length in the case of Georgia-Pacific Corp. v. United States Plywood Corp., 2 Cir., 258 F.2d 124, it would seem unnecessary to refer to precedents other than those cited therein. Each claim involved must disclose a structure which, when read in the light of the specification, will enable one skilled in the art to construct same without experimentation. Turning now to the claims involved here, we find that they are replete with such terms as “responsive to”, “operated by”, “controlled by”, “operably responsive”, “operably connected”, “electro-mechanieally interconnected” etc. Each of the terms appears to speak in terms of function rather than in terms of structure. They indicate what is done by the elements rather than how it is done. The use of such terms are not to be condemned in themselves but they “call for no particular type of association”, (Application of Wright, supra, 256 F.2d at page 589), and are vulnerable to the contentions that the claims using same are indefinite, too broad, and that they overclaim the invention. Each patent claim would seem to present its own particular problems. The difficulty encountered here is pointed up in testimony as to the meaning of certain of the above terms. The substance of plaintiff’s own testimony as to the meaning of “operatively connected” is that it is directly connected but it does not necessarily mean a direct connection. Plaintiff’s expert, in defining and applying the terms indicating •responsiveness as found in the claims, stated that there was no formula that the court could use and that the words might mean a responsiveness occasioned by a direct, single connection or that which occurs indirectly after the use and action of any number of remote interconnected devices. In substance, the witness states that the terms must be understood and applied with enough elasticity so as to meet the particular circumstances encountered. The element or item referred- to in the claims as a servo-motor is troublesome in its meaning and application. The term, like others discussed here, is not defined in the specifications. It first appears in the amended claims of 508 filed April 17, 1945. Plaintiff defines the term as a “control motor” which would apparently supplement a primary motor or control. Plaintiff’s expert testifies that while the term lacked specific definition prior to 1943 that thereafter it was understood in the art as a motor whose output was fed back thereto through a feedback loop or negative feedback. Defendant’s expert witnesses agree with that definition but they assert that the term always was understood in the art as embodying the negative feedback mechanism. In any event, after 1943 the term was so defined and understood in the art. This seems to be confirmed by the language and drawings of Patent 314 in which plaintiff uses the term servo-motor and indicates that same embodies such a feedback loop. The term, as used in claims under discussion and disclosed in the mechanism, is applied to motors having no such mechanism. It would seem to follow that either the term is misdeseriptive or indefinite. The term “variable electrical devices” is as limitless as the electrical art itself. It includes, according to plaintiff Dehmel, such items as a rheostat, potentiometer, cam relay, motor, meter or light switch. “Variable electrical means” and similar expressions must be likewise interpreted. Broadly interpreted and applied, the claims, containing the language discussed or referred to above, would seem to pre-empt the field of electrically operated airplane flight trainers. Such a result cannot be reconciled with the statutory particularity required of patent claims. An element in a claim may be expressed as a “means” (35 U.S.C.A. § 112) but if so expressed, the specifications must describe the structure (Stearns v. Tinker & Rasor, supra, 252 F.2d 597). A study of the specifications does not help; they speak in terms of function rather than of structure. Claim 11 of Patent 508 is illustrative of the claims involved. “Clause No. 11. in an aircraft training apparatus for ground training to indicating and controlling one or more simulated flight conditions, the combination of 1. a plurality of manually operable control members corresponding to those of an actual aircraft operable conjointly to produce said conditions, 2. an electrical motor, 8. a flight condition indicator operably responsive to said motor, 4. a plurality of variable electrical devices for controlling the operation of said motor, certain of said variable electrical devices being operatively connected respectively to certain of said manually operable flight control members for individually adjusting said variable electrical devices, 5. a servo-motor operably responsive to at least one of said flight control members, 6. and an operative connection between said servomotor and at least one of said variable electrical devices for adjustably operating the same.” Here we have (1) aircraft controls; (2) an electrical motor; (3) a dial which responds to the action of the motor; (4) electrical devices which control the motor and are connected with the aircraft controls for their adjustment; (5) a servo-motor which responds to one or more of the controls; (6) a connection between the servo-motor and some adjusting electrical device. There seems to be no disclosure of an essential relationship between the elements. Application of Wright, supra, 256 F.2d 589. The dial may respond to the motor and the servo-motor may respond to the controls either directly or remotely after any number of refinements or alterations. It may be that the servo-motor contains a feedback mechanism or is simply any auxiliary motor of any type providing a supplementary measure of control. The operative connection referred to in clauses 4 and 5 may mean any type of connection capable of conveying operative force or nothing at all. In re Fessenden, 56 F. 2d 669, 19 CCPA 1048. Claim 13 seems to differ from Claim 11 principally in that it provides for a plurality of servo-motors. Claim 29 refers to and depends upon “voltage deriving means” and “electro-responsive means” which may be defined like “variable electrical devices” as being limited only by the skill of the art. They, like the word “controlled” as used in the claim, are so broad as to be indefinite and are functional rather than structural. Claim 32 embodies responsiveness and the discussion of Claim 11 would apply. Its indefiniteness appears in its applications both to the patent and to the alleged infringing device. As far as Claims 33, 35, 38 and 45 are concerned, the same similar terms, referred to in the comment on Claim 29, are found therein. In addition, the statement of responsiveness is found in Claims 33 and 45, the indefinite meaning of which has already been discussed. Flight Claims 3, 40, 52 and 101 of Patent 603 need no individual discussion. Each contains terms similar to those discussed above. The claims above mentioned, as interpreted and applied, leave such a “zone of uncertainty” (United Carbon Co. v. Bin-ney & Smith Co., 317 U.S. 228, at page 236, 63 S.Ct. 165, at page 170, 87 L.Ed. 232), which requires that they be found to overclaim the invention and to be vague and indefinite and therefore invalid. The Prior Art. Some of the items urged as anticipating or disclosing the Dehmel combination will be briefly discussed. The Link C-2 Trainer was manufactured by the defendant and in use in 1940 and prior thereto. Generally speaking, the C-2 was constructed and operated in accordance with the pre-war features of the Link trainer. It features a movable chassis responsive to the operation of the controls. This responsiveness was accomplished for the most part through pneumatic means and the results of movements of the controls were reflected in instruments or means observable by the operator. While the machine may be referred to by the layman as a pneumatic device, there were certain electrical components located therein which were a part of the operating apparatus but same do not invalidate the assertion that the device was operated primarily pneumatically. Further discussion of the C-2 is not required since it is understood that it is defendant’s principal contention relative thereto that the flight claims in suit are vague, indefinite and invalid since they read upon the C-2 structure. It should also be noted that a Link patent, disclosing substantially the same type of trainer, was considered by the Patent Office in its processing of Dehmel patent 508. The Roeder patent, issued in Germany on April 21, 1933, is entitled “Training Apparatus for Piloting of a Craft Which is Freely Movable in Space”. The device, shown in this patent is operated through mechanical and hydraulic mechanisms. No electrical components are shown although it is suggested that “electrical means” may be used. The embodiment of the device shown in the patent appears to show a mechanism intended to afford training in the operation of airships (lighter than air) and Roeder goes on to state that no fundamental difference exists in the case of airplane training apparatus from the embodiment shown except that the “airplane pilot has a substantially larger number of control adjustments to make”. Just what the adjustments are and how they are to be reflected for the education of the student is not disclosed. Roeder does disclose in schematic form the interaction of forces of flight, all of which are capable of computation by mathematical formula by long known aerodynamic equations. In other words, he shows the mathematical approach to the building of an airplane trainer which was followed by the alleged infringing device rather than the empirical approach followed by Dehmel. Roeder definitely did show an appreciation of the problem, a knowledge of the art of computing and a familiarity with aerodynamics. He also showed a knowledge of integration (Claim 2) and the existence of servo-motors (Claim 5) which are sometimes used in supporting the claim of invention in the Dehmel device. This patent however cannot operate as prior art or as an anticipation. A foreign patent to be anticipatory must be so clear as to enable a person skilled in the art to practice it without the necessity of making experiments. Carson v. American Smelting & Refining Co., 9 Cir., 4 F.2d 463; Becket v. Coe, 69 App.D.C. 51, 98 F.2d 332, at page 335; Technical Tape Corp. v. Minnesota Mining & Mfg. Co., 2 Cir., 247 F.2d 343. No such disclosures appear here. Roeder conceived an idea involved here, but he did not practice it. He went no farther than to pose the problem and suggest a solution. The Chedister Patent No. 2,341,312, filed March 7, 1941 and issued February 8, 1944, is a training device intended to acquaint trainees with the operation of automobiles. It is a visual trainer containing electrical components such as potentiometers, rheostats and electrically controlled motors, so arranged and interrelated as to indicate visually to the trainee the effect of the operation of the controls. The Reymond Patent No. 2,080,186, filed July 25, 1934 and issued May 11, 1937, is entitled “Latitude and Longitude Meter for Ships”. The device automatically records latitude and longitude as same changes in accordance with the position of a moving vessel. It uses electrical components, potentiometers, motors and integrators, so arranged and interrelated so as to compute to the observer the result or effect of such movements. Other prior art patents, writing and texts, advanced by the defendants in the course of the trial, have not been overlooked. It is not necessary to discuss same at length here. Here they are collectively assembled and altered to disclose the Dehmel machine. The result does not constitute an anticipation. Block v. Nathan Anklet Support Co., 2 Cir., 9 F.2d 311; Davison v. Alexander Smith & Sons Carpet Co., D.C., 22 F. Supp. 461. The claims involved are not invalidated by the showing of the prior art here and this court repeats a statement previously made in Consolidated Car Heating Co. v. Chrome-Gold Alloys Corp., D.C., 109 F.Supp. 652, at page 655— “The disclosure of prior art may not be gathered piecemeal from prior public disclosure and then combined in such a manner as to destroy subsequent invention.” The defense of invalidity by reason of the disclosures of prior art is not established. Infringement. It might be sufficient to say that since invalid claims may not infringe that plaintiff has failed to establish this essential element of his cause of action. This facet of the case was so exhaustively tried and extensively briefed that it is deemed advisable to briefly discuss same assuming, for the purpose of the discussion, that the claims above referred to are valid. It can be said generally that the flight claims of 508 and 603 may be read literally upon the defendant’s E 600 machine. Such readings are made possible by the great breadth given thereto and the elasticity of meaning attributed to the language. Even so construed and applied, such a “word by word correspondence is not alone enough”. Grubman Engineering & Manufacturing Co. v. Goldberger, 2 Cir., 47 F.2d 151, at page 152. As in the above decision, an. examination of the patent device and the E 600 discloses that they are unlike in detail. This is illustrated by the-opposite arrangement of the pitch and roll mechanism implicit in claim 40 of 603 with a consequent different indication under given conditions. The devices are built on two entirely different principles. Plaintiff's own expert testifies that in the E 600, there is a mathematical computation showing what occurs in an actual plane while in the 508 the apparatus is not designed or assembled along the lines of the equations of motions. Again plaintiff’s expert testifies that the rationale of the-computation process is entirely different in the two devices, and that the modes of computation therein are not directly comparable. The testimony, given by plaintiff’s expert, illustrates the court’s-conclusion that the E 600 is so far changed in principle from the Dehmel device as to escape a finding of infringement. “The E 600, having been designed from a set of mathematical relations to begin with, have naturally followed a pattern conforming to the mathematical formulation of the problem. It could do no other. The 508 does not do that in the same way”. It would seem unnecessary to further discuss the evidence on this point. Plaintiff’s contention as to infringement (including also the radio aid claims hereinafter discussed) seems to assume too broad a range of equivalents, including those old in the art, those not known at the time (Halliburton Oil Well Cementing Co. v. Walker, 329 U.S. 1, at page 13, 67 S.Ct. 6, at page 12, 91 L.Ed. 3) and to lean too heavily upon the identity of the result obtained. The different mode of operation is overlooked or ignored. Air Devices, Inc. v. Air Factors, Inc., 9 Cir., 210 F.2d 481. It is concluded that the legal principles expressed in Westinghouse v. Boyden Power-Brake Co., 170 U.S. 537, at pages 568, 569, 18 S.Ct. 707, at pages 722, 723, 42 L.Ed. 1136 and in Grubman Engineering & Manufacturing Co. v. Goldberger, supra, 47 F.2d at page 153 are applicable and that plaintiff has failed to establish that defendant has infringed the claims ■under discussion. The Defense of Inoperability. This defense is directed to the ■flight claims of the 508 and 603 Patents. It is based upon the co