608 Reporter's Statement of the Case This desired operation presented many problems. The problem of landing in the restricted area of a ship's deck was difficult, and additional difficulties were presented by the disturbance of the air created by the ship's movement, the discharge of combustion gases from its power plant, and the roll and pitch of the deck, all of which factors were variable. The pilot had to be able to fly through more or less turbulent air and to follow more or less the roll and pitch of the moving deck and still achieve a landing in an extremely restricted area. 4. Prior to July 14, 1922, the filing date of plaintiff's patent application which matured into the patent in suit, the Navy had produced no satisfactory solution of this problem, and was still conducting experiments. In 1919 the United States Navy had no airplane carriers. The British Navy then had at least one. American naval officers realized that the development of aircraft carriers was desirable, although many officers were skeptical of the possibility of successfully landing airplanes on carriers. In that year Congress appropriated funds for the conversion of the collier Jupiter into an aircraft carrier, which was subsequently renamed the Langley. The Langley was intended primarily to be used for experimental purposes and the training of personnel. For the purpose of trying out various methods of arresting airplanes in a restricted landing area, an experimental landing platform or "dummy deck" was built on land at Hampton Roads in the summer of 1920, but it was built on soft ground and settled so badly that it had to be rebuilt. The rebuilding was not completed until late in 1921. On this platform a number of different forms of airplane arresting apparatus were constructed and tested. The Langley was commissioned March 20, 1922, at which time the experimental activities were transferred from the "dummy deck" at Hampton Roads to the Langley. Many of the devices tried were found to be impractical or inoperative and were abandoned. 5. The patent in suit discloses mechanism for hooking an airplane while in flight to a stationary arresting apparatus, Reporter's Statement of the Case 95 C. Cls. which applies a gradual retarding force to the airplane, lands it, and brings it to a stop in a very short distance. The mechanism consists of two cooperating parts one carried by the airplane, the other mounted upon the landing area, which the patent states may be a ship's deck. The mechanism at the landing area will hereafter be referred to as the "landing-area mechanism" and that upon the aircraft as the "airplane mechanism." The landing-area mechanism comprises an arresting cable wound on a drum or drums and passing through pulleys and having a portion stretched transversely across the landing area and elevated above the surface thereof. The drum or drums upon which the cable is mounted are rotatable to pay out a limited amount of cable, but their rotation is resisted by springs. The airplane mechanism consists of a pole mounted below the fuselage of the airplane and extending longitudinally thereof, pivoted at one end, having the other end releasably held against the fuselage so that the free end may be dropped to a predetermined position well below the landing gear, this being the position for engaging the arresting cable. When the pole is in landing position it extends obliquely downwardly from the airplane, with its lower end projecting some distance below the bottom of the landing wheels. On the aft end of the pole in landing position there is a stout hook, and a connection is provided from the hook to the airplane fuselage at a point some distance in the rear of the center of gravity of the airplane and approximately in fore-and-aft alinement therewith. In one form of the invention (Pratt, fig. 5, reproduced herewith) the hook D' is removably held on the pole B' and is detached from the pole when it hooks on to the arresting cable, and the arresting force is transmitted from the detached hook to the fuselage by a cable G. In another form (Pratt, fig. 9, reproduced herewith) the hook D" is not detachable, and the pole B" itself serves to transmit the retarding force to the fuselage at a point in the rear of the center of gravity of the airplane and approximately in foreand-aft alinement therewith. 608 Reporter's Statement of the Case In making a landing with the apparatus disclosed in the patent in suit, the pilot flies toward the arresting gear and drops the free end of the pole, which, after being dropped, is in position to strike the arresting cable. The pilot flies sufficiently low so that the pole will strike the arresting cable as the airplane crosses it, whereupon the cable is guided by the pole into the hook and, as the airplane flies on, the arresting cable is paid out against the force of the retarding springs. The retarding force so applied gradually reduces the speed of the airplane without any substantial tendency to tilt or upset it, and as its speed diminishes it sinks to the landing surface and stops. The retarding force is greater the greater the speed and weight of the machine and the shorter the landing run desired, other things being the same. The application of the retarding force to the plane below the center of gravity would introduce a positive force, tending to cause the plane to nose over, this nosing-over force being the greater the heavier the airplane, the greater the speed at the time of hooking on, and the farther below the center of gravity the retarding force is applied, other things being the same. When the force is applied in the rear of the center of gravity and approximately in fore-and-aft alinement therewith, not only is there no force introduced tending to tip the plane, but should such a force be introduced for any reason, such, for instance, as by the landing wheels striking an obstruction, the retarding force applied by the arresting cable tends to hold the tail down and prevent nosing over. Similarly, should the plane tend to be slued around, as by only one landing wheel striking an obstruction, or by a cross wind, the force applied by the arresting cable tends to straighten the machine out and hold it in proper alinement. 6. Prior to the date of filing his patent application, whicn matured into the patent in suit, plaintiff had devoted much time and thought to the problem of landing airplanes in a restricted area. He was acquainted not only with the theoretical aspects of the problem, but with certain of its practical aspects as well. He had been trained as a naval aviator, commissioned and been made a flying instructor, and his experience included operation of both seaplanes and land planes. During the summer of 1918 he was injured in an airplane crash and later |