The catapulting of planes in the fleet is such a commonplace event that one seldom stops to realize the steps that have gone towards making such a maneuver possible. Not so in the commercial world. The arrival in New York of a mail plane which has been catapulted from a liner several hundred miles at sea is still news for the front page of any metropolitan daily. Although the modern application of the catapult is relatively new, the Greeks preceded us by hundreds of years in their knowledge of utilizing stored-up Power for propelling missiles or heavyweights. David’s sling shot and the hunter’s bow are further examples of this age-old knowledge of stored energy.
The modern catapult enables an aircraft to reach flying speed in a relatively short run by the application of external Power. Variations in the method of applying this power have furnished the main differences in design as the device evolved from its early crude state. Aircraft have increased in weight and their minimum flying speeds have steadily mounted. Yet so excellent has been the development work of the United States Navy that the present-day seaplanes which accompany the fleet are catapulted regularly and without difficulty.
Probably the first use of a catapult for launching aircraft occurred in 1896 among the sand dunes bordering Lake Michigan. At this time Octave Chanute was carrying on extensive experiments with gliders. Although his efforts contributed little of material value to the almost unknown science of aeronautics, he did find time to write encouraging letters to the Wright brothers who later carried their own experiments to a successful conclusion. Among the many devices the professor designed was one which assisted materially in launching his Butusov glider. He merely constructed two sloping wooden rails which he greased with tallow. The glider was mounted at the top of this incline and easily took to flight when lashed to the end of a line which was pulled by man power. This device is properly classified as a catapult, for it enabled an aircraft to take the air with a reduced run by the application of external power.
Professor Samuel Pierpont Langley faced serious difficulties when he considered the problem of getting his aircraft into the air. Landing gear, as such, was unknown. Wheels for landing had not been yet visualized and this brilliant investigator decided that some form of a float or sponson would be the solution to the problem. The available power plants did not permit a take-off from the water. Hence he made plans to initiate the flight of his models from a houseboat anchored in the Potomac River. Obviously, the length of the take-off was restricted, but he constructed a most satisfactory type of catapult. His craft was mounted on a small car which ran down a track when released. As the car was pulled back to battery it compressed a nest of powerful springs and was held in position by means of a manila line. When ready to launch the aircraft, the line was severed with a sharp knife. As is known only too well, Langley’s full-scale model piloted by Charles M. Manley crashed on the take-off on December 8, 1903.
When the Wright brothers finished their glider experiments and turned their attention to power-driven aircraft they were aware of the need of a more powerful engine than was then available. Even when running full out, their first power plant developed only a little over 15 horsepower. Obviously, this would not enable the craft to take off even though it might sustain the plane once in the air. As wheels were not used, wooden skids had to suffice. It became necessary for the inventors to devise some method of contributing external power during the trying moment of the take-off. Their solution of the problem was to construct a monorail track by securing steel strips to the upper surface of planks set on edge. On this track there ran two small rollers about the size of skate wheels to which was secured a cross beam upon which the plane rested. At the base of the track was a portable tripod mast. By means of blocks, a manila line was run from the peak of the mast to its base, then out to the far end of the track where it was turned back through another block and led to the plane’s crossbeam.
When preparing for a take-off the plane was backed into the battery position on the rail. A heavy weight was hoisted to the peak of the mast and secured by a restraining line. The propelling line was then secured to the plane at one end and to the weight at the other end. When the pilot was ready with his engine turning up full he nodded to the catapult operator who released the weight. The falling mass imparted sufficient velocity to the aircraft to insure flying speed by the time the end of the track was reached.
Obviously, this was one of the simplest possible catapults and, fortunately, one which was unusually successful. Its capacity depended entirely upon the weight and upon the height of the tower. By 1909 the Wrights had lengthened their track to about 40 feet, and had increased the weight to 1,400 pounds. By 1910 the use of more powerful engines and the adoption of wheels for landing gear made it possible for the Wright planes to take off under their own power, and the catapult was abandoned.
The year 1909 saw the first official navy interest in aviation when Lieutenant G. C. Sweet, U. S. Navy, and Naval Constructor Mclntee were designated as official observers to witness Orville Wright’s demonstration of the airplane at Fort Myer, Virginia. This was followed up by Captain Washington Irving Chambers, U. S. Navy, who witnessed the aviation meet at Belmont Park in October, 1910, as well as the meet held at Halethorpe, Maryland, shortly afterwards.
All of these observers saw the airplane through naval trained eyes and they visualized its possible use in naval warfare. Its application to seagoing vessels was another matter, and in his efforts to solve this problem Captain Chambers arranged for Eugene Ely to fly a plane from a platform rigged up on the forecastle of the U.S.S. Birmingham. This flight was successfully accomplished on November 14, 1910, and, to complete the experiment, Ely flew his craft aboard a platform erected on the quarter-deck of the U.S.S. Pennsylvania in San Francisco Bay on January 18, 1911.
The result of these two flights was to convince naval authorities that aviation must be accepted by the navies of the world. But here their agreement ceased. It was obvious that the erection of platforms aboard men-of-war would not permit the full use of the main battery. Therefore, although airplanes might contribute a certain amount of information as scouts, they were not worth the sacrifice of so much gun power.
One school of thought maintained that if aircraft were to go to sea with the fleet they must be concentrated on one vessel with a large platform. Here we see the forerunner of the airplane carrier of today. A second school of thought headed by Captain Chambers argued that it was essential for an aviator to be a member of the crew of the ship for which he scouted and spotted gunfire. It was thought that the ship should know him and his capabilities and the flyer should know the ship’s organization and methods. The result would be closer teamwork.
While Ely’s second flight showed that a landplane could be used on board a battleship, it further demonstrated that it was somewhat impractical owing to the long and bulky platform necessary for safe operation. Some other means of operating airplanes with ships had to be devised. To the naval officer of today the answer seems Perfectly obvious, but it must be recalled that a hydroplane had never been flown in the United States until eight days after Ely flew aboard the Pennsylvania.
At this point it becomes necessary to digress slightly in order to follow the various steps leading to the catapult development in the United States Navy.
The idea of a hydroplane was anything hut new. Experiments on them had been carried out through the last half of the nineteenth century. In 1905 the Archdeacon glider, when towed by a motor boat, succeeded in lifting itself from the River Seine and gained an altitude of 50 feet. Although it is little known, the Wright brothers undertook a series of experiments with pontoons on the Miami River near Dayton. Unfortunately, the dam maintaining the level of the water broke and they were forced to discontinue their Work. Otherwise, the first engine-driven flight might have taken place from the water’s surface.
Curtiss equipped his second plane, the Red Wing, with floats as far back as 1909. A wide float was used to protect the propeller from the spray. Choppy water proved to be too much for the craft, however, for the short float contributed a bucking motion which prevented its gathering headway. Even then it was thought that the long pontoon would probably be the final solution. Although flight was not attained from the water at this time, Curtiss was sufficiently confident about his experiments to make a trip to Washington, where he conferred with the Navy Department about the possibilities of a seagoing airplane.
Curtiss became more than ever convinced that the hydroplane was a necessity. As he flew down the Hudson River on his Albany-New York prize-winning flight in May, 1910, he definitely determined to proceed with the problem of constructing such an aircraft. As a safety precaution for this flight he had lashed a canoe to the landing gear of his plane, but even then the prospects of a forced landing in the cold waters of the Hudson were far from inviting. Augustus Post records that shortly afterwards while attending a play in New York, Curtiss interrupted the climax by leaping to his feet and loudly shouting, “I’ve got it!” On the theater program he had sketched what later proved to be the design for his first successful hydroplane.
In the meantime, the first flight of a hydroplane had been accomplished. The machine was designed and flown by Henri Fabre at Martigues Bay, France, March 28, 1910. Powered with a 50-horsepower Gnome engine it flew a thousand feet at an altitude of six feet. Numerous short flights were made, but the machine had many limitations which served to discourage its further development.
Inspired by Fabre’s work, Curtiss carried on his experiments at Hammondsport, N. Y., during the remainder of 1910. He attached crude floats to his standard land biplane but, as before, he was unable to gain sufficient speed to fly. That winter, however, saw him and his flight class at North Island. Here he determined to carry his experiments to a successful conclusion in addition to undertaking the burden of teaching a group of students to fly.
The men under instruction were eager to help their mentor, and the work progressed rapidly. Especially helpful was Lieutenant T. G. Ellyson, U. S. Navy, who was one of his first students. Ellyson’s naval background and knowledge pulled the group over rough spots in design and, in addition, he instructed the students. Curtiss wrote of him at that time:
He makes an excellent instructor, being conservative and using rare judgment as to what the aviator should and should not attempt to do.
The new float gear was developed piece by piece. Any new ideas advanced by one of the group received attention from all hands. From time to time the floats were mounted on one of the land planes. Taxiing around the bay the inventor sought to discover errors in design. The most difficult task was to give the floats such a shape that they would ride up over the bow waves instead of trying to plunge through.
On January 26, 1911, Curtiss was trying out a new set of floats, but had made no plans for actual flight. As the machine gathered speed it rose higher and higher out of the water. At last it was barely skimming the surface. Enthusiastic with the results and with his interest concentrated on the float’s reactions to the water, the pilot failed to notice his rapid approach to the shore. Looking up, he quickly realized the danger of wrecking his craft by running aground. Instinctively he eased back on the controls and lifted the plane into the air, where he was enabled to turn to safety. The faith of the early naval observers had been justified.
Many changes and improvements were soon made in the original design. The pontoons were particularly clumsy. The main float was 7 feet long and 6 feet wide, while the forward float was of the same width, but only a foot in length. These were replaced by a single main pontoon similar to those in use today. Less weight was ininvolved and the already overtaxed engine was able to give considerably better performance. In order to eliminate the eroding action of the spray, and to remove the engine from directly behind the pilot’s head, as well as for increased efficiency, the propeller and engine were placed forward of the pilot. The hydroplane now was rapidly assuming the form of the modern seaplane.
Captain Chambers felt that it was necessary to go further to prove the adaptability of the hydroplane for naval use. If a plane could be hoisted over the side, it could take off from the water, and if it landed alongside the vessel at sea it could be taken aboard. Curtiss felt sure of being able to comply with this requirement and when the Pennsylvania returned to San Diego following the Ely experiment in San Francisco, he sent word to the ship that he was ready to fly out and be taken aboard. Captain Pond promptly signaled, “Come on out.” Within a few minutes Curtiss had landed alongside the vessel where his plane was attached to one of the boat cranes by means of a sling and hoisted on deck. After a short visit, the aviator and his machine were lowered over the side and from there flew back to North Island.
Here was definite proof that men-of-war with no special apparatus could carry and operate aircraft, for Curtiss had shown how it was possible to eliminate the cumbersome platform necessary for landplane operations at sea. As a matter of fact, this demonstration impressed the naval authorities so strongly that two machines of this design were ordered. In spite of this the navy personnel had no illusions about the ability of a seaplane to take off in a rough sea. Unless some means were developed for launching the craft in flight the hydroplane was doomed to remain a fair weather craft. It was obvious that a method must be devised which would launch the plane from the deck of a ship without touching the water.
Ellyson worked on the problem for some time, but was unable to perform any experiments until the flight school had been moved back to Hammondsport, N. Y. In September, 1911, he erected a tripod 16 feet high on the shores of Lake Keuka. From this platform a 250-foot length of three-quarter inch steel rope was run out in the lake and secured to a submerged pile. In the keel of the plane’s pontoon was cut a 1-inch groove which was lined with metal. The regulation navy type Curtiss hydroplane was then backed up to the cable and on to the platform. When ready to attempt the launching the plane was pushed forward on to the cable which had approximately a 10 per cent incline. The craft was kept from sliding down the wire by means of a toggle. Lateral equilibrium Was maintained by two wires running parallel to the main cable on which the wings with special fittings rode. In addition, men with wing lines were to run with the plane as far as they could keep up with it. Ellyson took his place in the machine and warmed up his engine thoroughly. The 10-mile wind shifted slightly out of the line of the cable shortly before the preparations for the flight were completed. Sure of his plans, however, Ellyson was determined to go through with the experiment. He opened this throttle wide and signaled for the release of the plane. Rapidly gathering speed he slid down the incline, faster and faster Until the men on the wing lines had to let go. After a run of 150 feet he eased back on the controls and his craft gracefully took the air—the first naval catapult.
Many trials followed and not a single accident occurred to mar this new development. It was soon discovered that only a short run was required. Such a device mounted aboard ship had the added advantage that it could be headed into the wind at will, and that this wind and that created by the forward speed of the ship would reduce the length of cable required. It was optimistically predicted that the next year would see a hydroplane aboard each American battleship.
Many crank inventors heard of the navy’s search for a launching device and novel designs flooded the Navy Department. Among these was one which has perhaps rightfully found its proper place in amusement parks. It was proposed to swing the aircraft from a mast which could be revolved. As more and more speed was attained the plane would be swung higher and higher and finally released in what is now known as a flipper turn.
In the meantime Captain Chambers had been working on another idea. It would appear as though the elements of this plan had been proposed by Glenn Curtiss, for in September, 1911, Chambers wrote Curtiss,
. . . now I have had in mind a long time and intended to speak to you yesterday about the new “get away” experiment. Have been enamored all along with that pigeon trap idea with parallel motion. Have you given it up?
In addition, Chambers also wrote to Orville Wright from whom he received a favorable reply concerning the possibility of building short platforms on battleship turrets supplementing the normal run by the application of external power. The development of this idea now began and soon the compressed air type of catapult assumed first importance, relegating Ellyson’s wire launching device. In January, 1912, Chambers wrote Curtiss:
In regard to the launching device, I don’t think I would lose any time with the cable from the cliff. Ellyson’s flights at Hammondsport seem enough to assume its practicality and if the catapult idea is not in shape for trial before the ships leave, it might be a good idea to try the cable upon the ship . . .
This was the end of the wire launching device. It never went to sea. Work on the catapult progressed somewhat slowly, but by the summer of 1912 it had been completed and mounted on the old Santee Dock at the Naval Academy. Ellyson was eager to attempt the flight and to his joy was selected for the experiment. Much discussion arose as to the likelihood of the pilot becoming unconscious during the rapid acceleration. Moreover, no one was entirely certain that the metal fittings on the plane would withstand the initial shock. At last, however, on July 31 everything was ready and Ellyson climbed into the pilot’s seat.
Unfortunately, the catapult track was stationary and could not be trained. Just before the flight was to begin the wind shifted slightly across the track. Nothing daunted, Ellyson gave the signal to shoot. With his engine wide open he started moving. His plane, being mounted on the car, was being pushed faster and faster as the compressed air moved a piston down the cylinder of the device. When the craft was about halfway down the 30-foot track with everything proceeding according to schedule the plane began to fly. The forward end of the pontoon raised well clear but the rear end was held in place by the acceleration of the car. As this attitude of the plane became aggravated the forward end rose rapidly and the aircraft performed the first part of a loop. Assisted by the slight cross wind, it fell clear of the catapult and crashed into the water to end the first shot of the compressed air catapult. Neither the pilot nor machine were any the worse for the ducking and it was gratifying to all hands to discover that the fittings of the plane and engine showed no signs of weakening due to the sudden acceleration. Ellyson declared that he had been perfectly conscious at all times during the maneuver and that he was more than willing to repeat the experience. Much was learned from this experiment. Obviously, provisions for securing the plane to the car and likewise the car to the catapult track must be made if safety in operations were to be attained. It was apparent that the aircraft should be released only when the end of the track was reached.
Lieutenant Commander Holden C. Richardson (C.C.), U. S. Navy, undertook the further development of the crude design which made its debut at Annapolis. The scene of this work was the Washington Navy Yard. Little money was available for this specific purpose, but a large scrap heap was close at hand and out of the waste material was constructed a much improved catapult. For one thing the acceleration was made more constant, thus easing the strain on both the machine and the pilot. Reverse flanges and small wheels held the car on the under side of the track. Moreover, the airplane was held down to the car by iron straps, the ends of which were tripped automatically at the end of the run by means of elevated studs on the track. The runway was 30 feet in length and 3 feet in width. The outer end of the track was curved slightly upward in order to throw the machine into the air. The plane was to be released at the end of the runway and the car was then free to drop off into the water. Mounted on a barge 2 feet above the water line the catapult could be swung into the wind.
On October 12, 1912, all preparations had been made. The car was first loaded with bags of sand which served as a dummy load. When the compressed air charge was released the car went flying down the track in a most encouraging fashion. The hydroplane was then towed alongside the barge and hoisted on to the catapult car. All available torpedo air compressors were cut into the line in order to build up the air banks for a second shot. At last the engine was warmed up and everything ready. In spite of the memory of a bath which he had received on his last attempt, Ellyson was eager to have a try at it.
With the engine roaring with all the strength of its 50 horsepower, and his propellers thrashing and flailing the air, the pilot nodded his head as a signal to open the air valve. With a mighty swish the catapult action began. The plane tried to fly before the end of the track was reached, but being secured indirectly to the rails, if was unable to do so. Realizing that his craft had flying speed, Ellyson pulled back on the controls as he reached the end of the run and his hydroplane soared beautifully into the air without so much as kissing the water. A speed of nearly 40 miles an hour had been reached in a distance of 30 feet and in a period of but 1.5 seconds.
Here was a further application of the hydroplane to the navy. Battleships and cruisers could make use of the observing power of aircraft without cluttering up the decks with obstructing runways. Curtiss, who viewed these tests, said, “This device is the most important achievement since wheels were put on land machines—Captain Chambers has given the world something that will be eagerly taken up by every navy.” As a matter of fact, Chambers had already made tentative designs for placing permanent catapults on the tops of turrets of all battleships.
Further tests of this catapult insured its reliability, and it was decided to install one on board some vessel in order to investigate its action under actual seagoing conditions. Several modifications were made on the design as the construction progressed. Among these was the lengthening of the track in order that the device could accommodate a larger and heavier plane. The new catapult as installed measured 103 feet in length. It was completed at about the same time it was decided to transfer the navy’s aviation unit from Annapolis to the practically abandoned navy yard at Pensacola, Florida. Accordingly the new catapult was sent along to the aviation station as freight aboard the U. S.S. Mississippi which had been assigned to carry out aeronautical experiments.
Although the device reached Pensacola in January, 1914, little was done with it Until the following year. It must be remembered that the primary mission of the aviation detail was to train aviators and they had their hands full with this assignment. In addition, trouble broke out with Mexico and two of the few planes were sent to the fleet at Vera Cruz; one was detached to naval forces at Tampico. In 1915, however, under the direction of Lieutenant Commander H. C. Mustin, U. S. Navy, work along this line began anew. Mr. W. M. Fellers, then a civilian draughtsman who has since become an officer in the navy, took an important part in this design work. The catapult was modified in several respects. Some of the old parts were used while in other cases new machinery was manufactured. During that year the device was fitted to a barge and was successful in launching Lieutenant Bellinger into the air at the controls of a Curtiss flying boat. After rather extensive experiments this catapult was further modified with the primary object of fitting it to the cruiser, U.S.S. North Carolina, which had replaced the Mississippi when that ship was sold to Greece. First of all the track had to be reduced to 65 feet to fit the quarter-deck of the ship. This made possible a speed of 45 miles per hour at the end of the plane’s run.
The stem of the ship was selected as the location of the catapult for two reasons. The boat cranes could not handle the planes in either extremity, so that it was necessary to insert a temporary boom in the muzzle of a turret gun and use this for a crane. The turrets aft best suited the plans of the designers. Also, the longest possible runway was essential and since it had to be stationary, a catapult mounted forward would train directly over the bow. It was thought undesirable to take the chance of running down a pilot and his plane should it fail to take the air at the end of its run.
The modified catapult was installed on board the U.S.S. North Carolina during the late summer of 1915. The first test was made with a plane which carried no pilot, with the controls lashed in flying position. The experiment was successful so far as the catapult was concerned, although the plane stalled at the end of the track and spun into the water. This was sufficient proof for Lieutenant Commander Mustin, commandant of the station, and he ordered the second plane aboard to be prepared for a catapult shot. Climbing in and warming up the engine he flew the first plane off a catapult mounted on a ship. After several live shots, the next attempt was to catapult a plane while the ship was definitely under way. Lieutenant A. A. Cunningham, U. S. Marine Corps, was selected for this experiment. This shot, however, failed and the plane struck the water with one wing and turned over. Fortunately, the pilot swam out from under and was picked up by a boat.
Further modifications were now made to the catapult and Lieutenant Commander Mustin was the next to essay a flight from it while the ship was moving ahead. In February, 1916, while flying a Curtiss AB-2, he was successful. Captain Chambers’ original thought had arrived at a successful conclusion, and it was generally thought that finally aircraft had been successfully applied to our battleships and cruisers.
Shortly afterward catapults were installed on board the U.S.S. Huntington and the U.S.S. Seattle. The tracks were elevated considerably above the decks and the structure restricted the free use of the after turrets. It should be recorded, however, that the guns were free to elevate fully except when trained within a few degrees of directly astern. Catapult operations continued intermittently during the remainder of the year and on into 1917. At this time a small group of Coast Guard pilots, headed by Lieutenant E. F. Stone, was assigned the task of becoming proficient in the use of the catapult. On July 19 they were successful in launching an R-6 torpedo plane carrying two 50-pound bombs. An end speed of 53 miles per hour was reached on this shot. This shows clearly the advance made during the experimental period, because the aircraft used weighed approximately 5,000 pounds. It is interesting to note that the catapult cars were still permitted to continue overboard, although a line secured to them prevented their loss.
By this time the United States was well into the war and all cruisers were needed to convoy troopships to France. The submarine menace had begun in reality. Consequently, the Huntington, along with her planes and aviators, was ordered to this duty. Unfortunately for the aircraft the ship held target practice while proceeding northward from Pensacola and two of the four planes aboard were hopelessly damaged by the concussion resulting from the gunfire. The cruiser made her first trip across the Atlantic in October, 1917, with two planes mounted on the catapult and with two 50-pound bombs attached for business. The engines were kept warmed up during daytime in anticipation of enemy activity, but on the entire round trip no submarine was sighted. Not all of the older officers were in sympathy with the new weapon offered by aeronautics, especially when part of the main battery was restricted by the catapult. Consequently, the track was removed when the Huntington reached the United States.
In 1917 the Navy Department let a contract with the Sperry interests for a launching device for aircraft. Called in on this project was Mr. Carl Norden, a well-known engineer. The result of this work was the Norden flywheel catapult which was installed at the Naval Proving Ground, Dahlgren, Virginia. This device was very successful although the war ended before it had been fully developed.
Although England had begun to think about airplane carriers no nation had even begun the development of a catapult. When in need of planes to accompany the Grand Fleet to sea the British used light scout landplanes. Temporary platforms were constructed on the tops of the high turrets and the planes had to fly off this short runway as best they could. With the turret trained into the wind the planes were unable to fly by the time they tumbled off the end of the runway and had to depend upon the resulting dive before tutting the water to give them the required air speed. The wastage of machines was rather high. Nevertheless, the year 1919 saw similar platforms erected on turrets of many United States battleships. Among these vessels were the Pennsylvania, Arizona, Oklahoma, Nevada, Idaho, Mississippi, and Texas. The platforms could only be as long as the turret guns. This alone made operations precarious and never certain. Crude canvas hangars were provided as protection to the aircraft. The platforms were designed to be portable and easily disassembled, but this proved to be an illusion. The airplanes interfered with the vision of the turret range finders, they tended to unbalance the guns, and, on the whole, the system was entirely unsatisfactory.
It became imperative that a satisfactory location for a catapult be found. It was desirable to design the device to handle planes weighing up to 3,500 pounds and to give them a speed up to 55 miles an hour. Moreover, it was decided that the catapult car must be retained on the firing ship. Work was now pushed in earnest. Commander Kenneth Whiting suggested a turntable type of construction which Would permit the device to train in any direction, thus permitting the aircraft to be launched directly into the wind. Under the direction of Lieutenants W. M. Fellers and E. F. Stone, the development went ahead at such a high rate of speed that on October 26, 1921, an airplane was successfully fired off the newly designed catapult.
During the following year this device was installed on the quarter-deck of a battleship and it proved entirely satisfactory. As fast as they were constructed they Were mounted on vessels in the fleet until today all of our major ships carry an efficient force of aircraft—thanks entirely to the development of the catapult.
It is interesting to note that it was proposed to mount the original Norden catapult upon the Langley which was nearing completion. This project was discontinued, however, and one of the old catapults which had been previously mounted on the cruisers at Pensacola was installed on the new carrier after several modifications.
Shortly after the Washington conference plans were made for the installation of catapults on board the airplane carriers Saratoga and Lexington. It was desired to accommodate planes weighing up to 10,000 pounds, and Norden was again called upon to handle the project. He designed a much improved flywheel-type catapult which was accepted. Although these units are now installed in our large carriers, they have not been used to any extent.
As early as 1921 Commander Hamlet of the Coast Guard suggested to Lieutenant Stone the possibility of a powder catapult. By using a slow burning powder for a propellant instead of compressed air, much simplicity in construction would result. There would be no air lines to produce leaks and to be shot away. No time would be needed for recharging the air flask. A definite and accurate force could be applied to the plane on each shot for the powder could be weighed out in charges. Working in conjunction with Mr. Carl Jensen, Lieutenant Stone produced a working model of the device and a full-scale catapult was built in 1923 and successfully used. It was first mounted on the U.S.S. Mississippi where an MO type of observation plane was launched more or less regularly from it. Since that time many improved catapults of this type have been installed on board vessels of the fleet.
The trend of naval aviation in England, both during and after the war had been toward the airplane carrier. However, many experiments were made with the catapult idea in an effort to apply aircraft to vessels of war. Little was accomplished at first and it was not until 1922 that serious efforts were devoted towards developing a catapult for fleet use. Most of these efforts centered around a hydraulic device. The result of this work was to mount the first catapult aboard H.M.S. Vindictive in 1925. More were added to other ships from time to time, but their use has been somewhat limited. In 1928 experiments were made to use cordite to propel the aircraft down the track. Efforts along this line were distinctly successful. English designers have gone so far as to construct a catapult with a folding runway in order to conserve deck space. The English have also applied the catapult in a very interesting manner to the submarine. It is obvious that the range of visibility offered by the conning tower is limited. If a plane were available to act as a scout the submersible could perform its duties much more efficiently. Such a small aircraft, however, would probably have insufficient power to permit its taking off from the normal swells encountered in the open sea and it became imperative to launch the plane by means of a small catapult. Such a device was mounted in the ill-fated M-2 which sank recently.
The English have also devoted considerable attention toward launching landplanes by means of the catapult. They have reached the state of development where an airplane weighing 18,000 pounds can be accelerated to a speed of 60 miles an hour at the end of a 120-foot run. The United States Navy has also devoted some thought and effort along this line, and it is not unreasonable to think that in a time of war both land and seaplanes will be carried on board battleships—that is, unless an extremely light and satisfactory type of amphibian gear is developed. If the naval battle be long, it is questionable whether the spotting seaplanes can be recovered. To stop the vessel is to invite attack by submarine. If landplanes had been catapulted from battleships they, at least, could land aboard a carrier, refuel, and again take the air to carry out their mission. This would decrease to some extent the hazard which would result if the commander in chief were to be feinted into catapulting his aircraft too soon to be effective. Picture the spotting planes in the air, but practically out of fuel at the beginning of a naval engagement!
In addition to flying planes off steamships at sea, there is another possible field for commercial development of the catapult. Land and property become more expensive as time goes on. Especially is this true of the areas that are desirable for the establishment of airports. In an effort to get reasonably priced land in sufficient quantities for landing fields the aviation companies are forced to go farther and farther from the center of a city. Naturally this is undesirable, for the speed advantage of the airplane diminishes as the length of the flight decreases. To eliminate such an undesirable feature it is not unlikely that we will see further use of the catapult. A short landing platform with arresting gear will be built over a railway station or dock which will permit the plane to land its passengers and mail close to the heart of the city. A catapult will enable the loaded aircraft to take the air again. To prevent adding too much weight to large transport planes it is probable that smaller planes will be rigged for this shuttle work. They will operate between a large terminal airport on the outskirts of the city and the overhead platform landing field situated within the city. Once again the United States Navy will have done the pioneering work and have done it well.