delivered the opinion of the court: *
The Eastern Rotorcraft Corporation, a Pennsylvania corporation owning the patent involved in this litigation, sues, under 28 U.S.C. § 1498, to recover the “reasonable and entire compensation” for the Government’s allegedly unauthorized use of its patented invention. Only the question of liability is now before the court.
The patent in suit is the Campbell Patent No. 2,705,461 entitled “Cargo Net Fabricated From Flexible Cable.” It discloses a cargo net that, when spread out, extends in a zigzag fashion and produces diamond-shaped parallelogram meshes throughout the body of the net. Ring or hook fittings are attached along the sides and ends of the nets and at the exterior corners of the peripheral parallelograms. A net made in this manner has a high degree of flexibility and is readily adaptable to retain different shaped cargo. When not in use, the net may be collapsed by stretching it horizontally and returning the zigzag runs of cable to a parallel relationship and it may be rolled into a bundle for easy storage.
*302I
In December 1950, plaintiff entered into a contract with the Department of the Air Force for the production of six airplane cargo nets. The contract stipulated that plaintiff would grant the Government a non-exclusive, royalty-free license to any invention that was “first reduced to practice” either during the performance of the contract or “upon the understanding that a contract would be awarded.” 1 Since the invention was not reduced to practice “upon the understanding that a contract would be awarded,” the Government is only entitled to a license if the reduction to practice was not completed prior to the contract.
Deduction to practice occurs when the workability of an invention can be demonstrated. Workability means that a physical form of the invention has been constructed which functions. Nash and Lasken, “Patent Eights Under Government Contracts” in Patents and Technical Data (Gov’t Contracts Monograph #10) 42-52. And this requires testing the invention. The amount of testing necessary is based upon the needs of the particular art. Sinko Tool and Mfg. Co. v. Automatic Devices Corp., 157 F. 2d 974 (2d Cir. 1946). Some devices are so simple and their purpose and efficacy so obvious that their complete construction is sufficient to demonstrate their workability. Mason v. Hepburn, 13 App. D.C. 86 (1898); Buchunan v. Lademann, 54 F. 2d 425 (C.C.P.A. 1932). Other devices required laboratory testing; others, service testing in their intended environment. E.g., Elmore v. Schmitt, 278 F. 2d 510 (C.C.P.A. 1960); *303Paivinen v. Sands, 339 F. 2d 217 (C.C.P.A. 1964). In all these situations, the inquiry is not what kind of test was conducted, but whether the test conducted showed that the invention would work as intended in its contemplated use. Elmore v. Schmitt, supra; Gaiser v. Linder, 253 F. 2d 433 (C.C.P.A. 1958). Proof of the invention’s utility for its intended purpose does not require proof of its flawlessness; it is only necessary to show that the invention is able to perform its intended purpose beyond a probability of failure. Taylor v. Swingle, 136 F. 2d 914 (C.C.P.A. 1943).
In November, 1949, the inventor, during a conference at Wright-Patterson AFB on cargo tie-down equipment for airplanes, was informed that the Air Force, having experienced difficulty holding down miscellaneous loads inside airplanes during the Berlin airlift, was considering the use of a new type of cargo net. The nets under consideration used square mesh cable nets made from transversely intersecting cable members. They did not have the flexibility to adapt to mixed loads. Nor could they be collapsed and stored in a bundle. Soon thereafter the inventor thought of the net which is now the. patent in suit. He requisitioned the necessary components and constructed a sample net. On April 16, 1950, he successfully placed the net over a load of miscellaneous items placed on a pallet. After seeing that the net adapted to the contour of the items, he removed the net, collapsed it, and placed it rolled up inside his briefcase. The following week he took the. cable net to interested Air Force personnel at Wright-Patterson AFB. Application for a patent was not filed until June 19,1951.
The cargo net patent has two primary purposes. One is to provide flexible nets that can cover and hold a large number of varied objects during transit. Campbell Specification at col. 1, ls. 15-18. The other is “to provide a net construction which may be readily folded for storage purposes” so that it “may be conveniently stored in a rack or rolled into a compact coil.” Id at col. 1, ls. 35-40. The tests performed by the inventor on April 16, 1950, sufficiently demonstrated the workability of the net for tire purposes stated in the patent specification. The invention was thus reduced to practice *304prior to the Government contract; therefore, the Government does not have a license under the patent.
Several months after the inventor gave the Air Force the sample nets, plaintiff was awarded a contract for six cable nets. During the performance of the contract, the inventor improved the structural pattern of the nets so that they could be more easily manufactured. Plaintiff filed a patent application for the improved structure and in January, 1952, granted an express license to the Government on the improved invention.
Defendant contends that this express license gives it an implied license under the original patent in suit. Since the patent in suit is the dominant patent, it claims that its license is without value unless it has an implied license. Factually, this contention is not true because when the patent in suit expires, defendant will be able to freely make nets using both patents. And contractually, it is not sound inasmuch as the contract states that the Government will not obtain a license either “directly or by implication” to inventions made outside the contract.
II
Defendant and third-party defendants contend that the patent is not valid because “the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains.” 35 U.S.C. § 103. In support of its defense of obviousness, defendant first presented sixteen prior art patents. During the trial, it relied principally upon the Clark Patent No. 926,242 in view of either the Swift Patent No. 631,910, the Elia Patent No. 1,772,888, or the Brickman Patent No. 2,462,432 and the Netherlands Patent No. 32,401 in view of the Lee Patent No. 1,365,511. After the trial, defendant shifted its reliance to the Swift Patent No. 631,910 in view of the Henry Patent No. 830,320. Upon briefs and oral argument to the court, defendant shifted back to the Brickman Patent No. 2,462,432. The third-party defendants also chose at this time *305to rely on tbe Bricktnan Patent.2 In determining tbe obviousness of tbe patent in suit, only tbe Bricktnan patent will be considered.
In Graham v. John Deere Co., 383 U.S. 1, 17 (1966), tbe Supreme Court set forth the guidelines to follow in determining the obviousness of a patent under 35 U.S.C. § 103:
* * * tbe scope and content of tbe prior art are to be determined; differences between tbe prior art and tbe claims at issue are to be ascertained; and the level of ordinary skill in the pertinent art resolved. Against this background, the obviousness or non-obviousness of tbe subject matter is determined. * * *
Tbe Brickman patent provides a “method for securing fit-ings to wire structures.” Its sole concern is with a method; it makes no references to any potential use for tbe wire structures after the fittings have been attached. See Brickman Specification at col. 1, ls. 1-28. The patent in suit provides a cable cargo net that is more flexible and compact than earlier nets. See Campbell Specification, sufra. It achieves its purposes by fastening load attachment terminals to the cable runs at the external comers of the peripheral parallelograms. The Brickman patent differs from the patent in suit in that it makes no reference to (1) the location of attachment terminals 3 and (2) the fact that the net can be rolled into a compact bundle.4
The level of skill in this pertinent art did not make these two teachings of the patent in suit obvious. The problems of terminal attachment and net storage were not easily solved. Often terminals were only placed at the corners of the net. This approach lessened the net’s adaptability to cargo of dif*306ferent sizes. Compact storage of the net was usually not possible because of border cables circumscribing the net. If the patent in suit made non-obvious advances over earlier cargo nets, it follows that its differences with a method for making wire mesh are also non-obvious. Therefore, the patent in suit is valid.
Ill
As stated in Autogiro Company of America v. United States, No. 50328, decided today, ante at 55:
* * * the determination of patent infringement is a two-step process. First, the meaning of the claims in issue must be determined by a study of all relevant patent documents. Secondly, the claims must be read on the accused structures. In doing this, it is of little value that they read literally on the structures. What is crucial is that the structures must do the same work, in substantially the same way, and accomplish substantially the same result to constitute inf ringement. * * *
The claims of the patent in suit5 are not restricted to a net structure in which each cable run is made from a separate cable. They can be read to cover a net structure formed by a plurality of runs of cable in which a single cable is doubled back to form two of the cable runs. This interpretation of the claims finds support in both the patent drawings and the specification. Figure 4 of the patent depicts a cable that is doubled back to form two runs. The specification states at col. 1, ls. 19-22:
In constructing nets for use in retaining or handling cargo, it is the normal practice to provide members which run longitudinally and transversely with respect to the edges of the net proper.
In the accused structure, the interior runs of cable are formed by folding the cable in half so that one cable forms two runs. The terminal attachments are fastened at the exterior corner of each peripheral parallelogram. Since the function and mode of operation of the accused structure is the same as that claimed in the patent in suit, there is infringement by defendant.
*307IV
In summary, we find: (1) defendant and third-party defendants do not have a license under the patent, (2) the patent is valid, and (3) it has been infringed by structures made for defendant. Plaintiff is entitled to recover for the unauthorized use by defendant of its patent and judgment is entered to that effect. The amount of recovery will be determined pursuant to Rule 47(c) (2).
Campbell Patent No. 2,705,461—The Patent in Buit
1. A net device constructed from flexible cable including a plurality of generally longitudinal runs of cable, each run extending in zig-zag fashion when the net mesh is in open position, each interior run being attached to the adjacent run on one side at spaced points by a swaged fitting at each point and being similarly attached to the adjacent run on the other side at alternately spaced points to form a series of parallelograms with their sides lying in diagonal relationship with respect to the longitudinal direction, said swaged fittings having their longitudinal axes lying in the longitudinal direction of the cable runs, a plurality of load attachment terminals located at the ends of inside cable runs, each of said terminals being connected to the ends of two runs of cable at the external comer of a peripheral parallelogram.
2. A net construction according to claim 1 wherein each load attachment terminal has a looped portion of cable formed by a swaged fitting.
3. A net device constructed from flexible cable including a plurality of generally longitudinal runs of cable, each ran extending in zig-zag fashion when the net mesh is in open position, each interior run being attached to the adjacent run on one side at spaced points by a swaged fitting at each point and being similarly attached to the adjacent run on the other side at alternately spaced points to form a series of parallelograms with their sides lying in diagonal relationship with respect to the longitudinal direction of the net device, said swaged fittings having their longitudinal axes lying in the longitudinal direction of the cable runs, a plurality of load attachment terminals each located at the ends *308of two inside cable runs, each of said terminals being connected at the external corner of a peripheral parallelogram, the sides of the net also being provided with a plurality of load attachment terminals, each located at an external corner of a peripheral parallelogram.
4. A new device constructed from flexible cable including a plurality of generally longitudinal runs of cable, each run extending in zig-zag fashion when the net mesh is in open position, each interior run being attached to the adjacent run on one side at spaced points by a swaged fitting at each point and being similarly attached to the adjacent run on the other side at alternately spaced points to form a series of parallelograms with their sides lying in diagonal relationship with respect to the longitudinal direction of the net device, said swaged fittings having their longitudinal axes lying in the longitudinal direction of the cable runs, a plurality of load attachment terminals located along the side of the net, each located at an external corner of a peripheral parallelogram and each having a loop portion of cable formed by a swaged fitting whose longitudinal axis lies in a transverse direction with respect to the swaged fittings which form the corner points of the inside parallelogram.
FINDINGS OF FACT
The court, having considered the evidence, the report of Trial Commissioner Donald E. Lane, and the briefs and argument of counsel, makes findings of fact as follows:
1. This is a patent suit arising under the provisions of Title 28 U.S.C. § 1498 for reasonable and entire compensation for unauthorized use or manufacture by or for the United States of an article of manufacture disclosed and claimed in U.S. Letters Patent No. 2,705,461 entitled “Cargo Net Fabricated From Flexible Cable” which issued April 5, 1955, to plaintiff based on an application filed June 19, 1951, by Harris S. Campbell.
2. Plaintiff, Eastern Rotorcraft Corporation, is a corporation organized and existing under the laws of the Commonwealth of Pennsylvania, having its principal office and place of business at Doylestown, Pennsylvania. Plaintiff is the owner of the entire right, title, and interest of the patent in suit.
*3093. Intervenor-defendant is a partnership consisting of Sidney G. Sandnes, Edward S. Sandnes, and Arnold G. Sandnes, doing business as Sandnes’ Sons, New Cumberland, Pennsylvania. The accused cargo nets were procured by the defendant from the intervenor-defendants. There was no appearance for intervenor-defendants at trial on the merits.
4. The cargo net disclosed and claimed in the patent in suit is formed by a number of parallel runs of cable. Each run of cable is attached to adjacent runs by swaged fittings alternately spaced along the length of the run. When the attached runs of cable are spread out sideways, the runs extend in zigzag fashion, producing meshes of diamond-shaped parallelograms which extend throughout the body of the net including its margin or periphery, as illustrated in Fig. 4 of the patent drawings reproduced herein. Attachment fittings (rings or hooks) are provided at frequent intervals along the sides and ends of the net and are attached at the exterior corners of the peripheral parallelograms. The advantage of cargo net made in this manner is that it has a high degree of flexibility to adapt itself readily to retain assorted items of cargo having different shapes. When not in use, the net may be collapsed and folded or rolled into a compact bundle for storage by simply stretching the net in the longitudinal direction so that the zigzag runs of cable return to their parallel relationship, and then rolling the net into a circular bundle.
5. In describing the prior art the description states: “In constructing nets for use in retaining or handling cargo, it is the normal practice to provide members which run longitudinally and transversely with respect to the edges of the net proper.” [Emphasis added.] The drawings are also part of the patent description and in Fig. 4 of the patent in suit it is shown that cable 10c has more than one run since it is doubled back after connecting with a terminal hook 14.
6. The Brickman ’432 patent disclosure shows a netting or fencing construction which is formed by a plurality of longitudinal runs that are fastened together at spaced points by fittings. However, it does not show any load attachment terminals for the peripheral structure of the net.
*310
*311
7. Defendant admits that it has used more than one of the accused net devices purchased from the third-party defendants, d.b.a. Sandnes’ Sons. An illustration of a portion of the accused net construction is reproduced in the illustration following finding 6. However, defendant contends that the patent claims in issue do not read on the accused devices because a run of cable as referred to in the claims in issue should be restricted to mean a single length of cable, and because the accused net includes one length of cable forming two runs of cable with the terminals attached in the middle of a length of cable and not at the ends. As previously mentioned, Fig. 4 of the patent in suit shows a *312cable having more than one run. In construing the claims in issue in light of the total patent specification, it is found that the claims in issue are not restricted to a net in which each cable run is formed by a single cable, but are sufficiently broad to encompass a net in which several cable runs are formed from a single cable.
8. The accused net device is illustrated in plaintiff’s exhibit 30. The interior runs of cable are formed by folding the cable in half so that one cable forms two runs. The ends of the cables are attached to adjacent cables near the middle of the adjacent cables. Each of the runs extends in a zigzag fashion and is attached to the adjacent runs at alternately spaced points to form diamond-shaped parallelograms. The terminal hooks are attached to the ends of two rims of cable at the exterior corner of each peripheral parallelogram. The function and mode of operation of the accused net device are identical to the net device disclosed and claimed in the patent in suit. The accused device contains every element and limitation recited in the claims in issue.
9. Defendant contends that it has a license under the patent in suit in view of contract AF-33 (038)-17838 entered into on December 14, 1950, between the Department of the Air Force and the plaintiff. Said contract called for the production of six cargo nets. The contract provided that the plaintiff would grant to the Government a nonexclusive royalty-free license to use any invention that was conceived or “first actually reduced to practice” either during the performance of said contract or “upon the understanding that a contract would be awarded.” The contract further expressly provided that the Government would not receive a license, either directly or by implication flowing as a consequence of the contract, to use any other invention owned by the plaintiff.
10. In November 1949, Campbell made a trip to Wright-Patterson AFB concerning cargo tiedown equipment for airplanes, where he was informed that the Air Force was working on airplane cargo nets for holding down miscellaneous bulk items. The Air Force was considering using cable nets that had square meshes with the cables transversely intersecting each other. In this configuration each *313cable member was held in direct tension between holddown hooks which prevented flexibility. Furthermore, the Air Force square mesh cable nets were difficult to fold and had to be rolled up somewhat like a rug. Soon thereafter Campbell conceived the invention recited in the patent in suit. Campbell requisitioned the necessary parts and on weekends he, with the help of his son David, constructed a cable net that when expanded measured approximately 8 feet by 6 feet. This net was fully constructed by April 16, 1950. Campbell placed this cable net over a load of items placed on a pallet to see how the net would adapt to the contour of the miscellaneous cargo load. Campbell then collapsed the net and rolled it up and placed it in his briefcase and on April 21, 1950, took it to Wright-Patterson AFB and gave it to the personnel in the Equipment Laboratory Branch. It is found that the construction of said net and the placing it over a miscellaneous load to test its usefulness on April 16, 1950, constituted an actual reduction to practice of the invention recited in the patent claims in issue. Said invention was not reduced to practice “upon the understanding” that an Air Force contract would be awarded to the plaintiff for the procurement of cargo nets embodying the invention.
11. In August 1950, plaintiff received a request for proposal for six cable nets, six rope nets, and six web nets and the necessary engineering data. In September 1950 the plaintiff submitted a proposal for the cable and web nets, but not for the rope nets. The proposal contained Sketch 4001 which is substantially identical with Fig. 2 of the patent in suit. The Air Force accepted plaintiff’s proposal for the six cable nets and on December 14, 1950, the parties signed the contract AF-33 (038)-l7838. During the course of performing this contract, Campbell made improvements in the structural pattern of the cable nets so that they could be more easily manufactured and eliminated the necessity of splicing any of the cables to form the complete pattern. In May 1951 plaintiff informed the Air Force that this improvement invention had been made during the performance of the contract, but that the general or background invention (disclosed and claimed in the patent in suit) had been reduced to practice prior to the contract. In January 1952 *314plaintiff granted the Government an express license under tbe improved invention which is disclosed and claimed in patent No. 2,854, 931, application filed in January 1952. The patent in suit is dominant to the 2,854,931 patent. The six cargo nets and the engineering data provided for in the contract were delivered to the Air Force prior to June 1951.
12. In March 1953, the Air Force issued an open bid invitation for 45 nets. The accompanying drawings were identical except for the title block with the drawings furnished to the Air Force by the plaintiff under the AF-33 (038)-17838 contract. Plaintiff objected to the open invitation on the basis that it disclosed proprietary information and that the nets called for under the open bid invitation embodied the invention claimed in the patent in suit. Campbell contacted the legal personnel of the Office of the Judge Advocate at Wright-Patterson Air Force Base concerning the matter, whereupon the Air Force withdrew the open invitation to bid and negotiated a contract with the plaintiff for the 45 cables. These facts indicate that the Air Force did not consider at that time that it had a license to use the invention claimed in the patent in suit.
13. During the trial, defendant’s expert witness testified that the defendant had an implied license to use the invention recited in the dominant patent in suit for the reason that the plaintiff granted a license to the defendant under the improvement 2,854,931 patent. However, the contract between the parties specifically stated that the defendant was not to receive a license directly or by implication to inventions not made in the performance of the contract.
Conclusion or Law
Upon the foregoing findings of fact, which are made a part of the judgment herein, the court concludes as a matter of law that all the claims of patent 2,705,461 are valid and infringed and that the plaintiff is entitled to recover for the unauthorized use by defendant of the invention defined in said patent claims. Judgment is entered to that effect. The amount of recovery will be determined pursuant to Pule 47(c) (2).
At the direction of the court, Trial Commissioner Donald B. Lane prepared an opinion which has been of substantial assistance.
The contract read:
“The contractor agrees to and does hereby grant to the Government an irrevocable, nonexclusive, non-transferable and royalty-free license to practice, and cause to be practiced for the Government throughout the world * * * any Subject Invention conceived prior to any performance of this contract as set forth in paragraph (a) above but first actually reduced to practice in the course of any such performance * *
Subject Invention is defined as: “any invention, improvement or discovery (whether or not patentable) conceived or first actually reduced to practice either (A) in the performance of the experimental developmental or research work called for under this contract, or (B) in the performance of any experimental, developmental or research work relating to the subject matter of this contract which was done upon the understanding that a contract would be awarded.”
The third-party defendants made no appearances at the trial and filed no requests for findings. They only took an active part in the defense of this suit after the issuance of the commissioner’s report. Prior to their briefs and oral argument before the court, they presented no prior art references to support the obviousness defense.
The loop in figure 5 of the Brickman patent is neither referred to as an attachment terminal nor is a location for it described. In fact, no mention is made of any relationship between the loop and a net. It is only shown as a way to secure fittings to wire loops.
Figure 2 of the Brickman patent does not show the capacity of the net to be easily rolled up; instead, it shows the initial step in making wire mesh according to the patent. See Brickman Specification at col. 1, Is. 33-34.
3>he claims are in the appendix.