Thomas M. Moore, as well as his colleagues Herman F. Beduerftig and Werner Voss, who gave new impetus to the promising direction, worked in the team of Werner von Braun in the first post-war years. Working with the German design documentation, American engineers familiarized themselves with developments in the field of liquid rocket engines operating on hydrogen peroxide and a liquid catalyst. Such systems were used on various techniques, for example, on the Me-163 Komet rocket fighter. Moore became interested in an interesting technology and soon presented his version of its non-standard use.
According to the American expert, the engine thrust on hydrogen peroxide was quite sufficient to create an individual aircraft capable of carrying a person with a small additional load. In addition, a similar power plant could be made in the form of a relatively compact unit. As a result of preliminary calculations and conceptual design, there appeared a proposal to make a jet aircraft in a backpack form factor, which facilitated its use.
Mock-up of "JetWest" by Mark Wells. Photo Rocketbelts.americanrocketman.com
According to some information, the idea of manufacturing the apparatus in the form of a knapsack Moore could have peeped in the patent for the invention of A.F. Andreeva. Some sources mention that the American engineer knew about the development of the Soviet inventor and took into account some of its features.
The first proposal to create a jet pack appeared in 1947 year. At the same time, Moore discussed the possibility of creating such a technique with more experienced specialists. However, over the next few years, the project almost did not develop. Only in 1950, did von Braun help Moore to offer a promising project to the military department and obtain funding for its implementation. Specialists received 25 thousand dollars for carrying out the necessary research and prototype assembly. The project received the symbol Jetvest ("Jet Vest"). The development of the project was carried out in Arsenal Redstone.
As follows from the patent US3150847, obtained by the inventors in 1964, the military was offered a promising vehicle that could be used to solve a mass of various tasks. The most obvious is the transfer of soldiers across the battlefield, as well as overcoming various obstacles, both natural and artificial. With the help of jet vests fighters could climb on high ground, fly rivers, etc.
Other ways to use the new development were also proposed. With the help of "Jetvest" people could fly from ship to ship or from ship to shore and back. It could be used as a means of saving pilots for low-altitude ejection. In addition, the jet vest could be used by scuba divers to quickly move from the water to the desired point of the shore. Finally, in the long term, such systems could be included in the equipment of lunar expeditions. Under conditions of low gravity of the moon, jetpacks could show increased efficiency.
Layout of the work of Mark Wells, right-rear view. Photo Rocketbelts.americanrocketman.com
Apparently, all such arguments attracted the attention of the military, resulting in government funding for the development. For several years, specialists led by Thomas Moore had to master 25 thousand dollars. In the future, additional funding was not excluded. In addition, the Pentagon could order a number of serial equipment of a new type.
According to the results of preliminary studies, the overall appearance of a promising individual vehicle was formed. The main element of the Jetvest system was to become a vertical support platform with fixtures for all other components. On the platform was provided a system of seatbelts, with which the "Vest" was to be mounted on the pilot's body. On the rear surface of the platform were tanks for fuel and catalyst, as well as a cylinder for compressed air. On top of the platform there was a horizontal bar with elements of jet engines. On the pilot's chest was fastened box housing with controls.
The principle of "Jetvest" was quite simple. Compressed air from a cylinder had to squeeze liquid hydrogen peroxide from the tanks and feed them into the combustion chambers of the two engines. Under the action of the catalyst, also supplied to the combustion chambers, the peroxide was supposed to ignite and burn to form a large volume of the vapor-gas mixture. According to the calculations of Moore and his colleagues, the amount of gaseous substance formed was sufficient for the appearance of the desired thrust.
Jet engines with a combustion chamber and an expanding nozzle were located at the ends of the support rod. The main task of this unit was to remove the engine at a safe distance from the pilot. In the first prototype of the jet pack, a straight bar was used, but in a later patent, a curved tubular detail was proposed. By bending and moving the engines forward, it was proposed to ensure that the thrust vector passes through the center of gravity of the pilot and the knapsack. In this case, according to the calculations of the authors of the project, the maximum possible flight stability was ensured with the minimum risk of unbalancing.
Thomas Moore with his invention. Photo Rocketbelts.americanrocketman.com
The design of the engines provided throttle to change the amount of fuel entering the combustion chamber. With the help of these devices, the pilot could change the thrust of engines for take-off, landing or height maneuver.
For other maneuvers it was proposed to use a deflected thrust vector. To this end, the engines were made movable and could swing within a small sector of the vertical plane. Due to the synchronous or differential deviation of the nozzles, it was possible to fly forward or backward, turn in place, etc.
Management was proposed to carry out with the help of a box console mounted on the chest belts of the harness system. On the console all the necessary controls were located. For the flight, the pilot should use only three mobile flywheels. On the right side of the console there was a flywheel controlling the throttle valves. Under the pilot's left hand there were two coaxial flywheels mechanically connected to the rocking nozzle drives. Thus, the pilot could regulate the thrust of the engines with his right hand, and with the left - the direction of flight and other parameters.
Due to the simultaneous rotation of both left flywheels forward or backward, synchronous deflection of nozzles for translational flight in the desired direction was provided. To turn in the right direction, it was necessary to change the thrust vector of one of the nozzles by turning the corresponding flywheel. After that, according to calculations, the device with the pilot had to turn in the right direction. Probably, with the help of simultaneous rotation of the flywheels in different directions, it was possible to turn around on the spot, but the layout of the console made such a turn extremely difficult or even impossible.
Preparing for the tests. Moore help put on a "jet vest". Photo Rocketbelts.americanrocketman.com
The flywheels of the control panel were connected to throttle valves and nozzle drives using flexible shafts and a set of mechanisms in the console and on the engine bar. For all its simplicity, this design provided the required reliability and ease of management. In addition, it almost did not affect the overall weight of the entire apparatus.
The first sample of the promising "Jet Vest" designed by Moore, Beduerftig and Foss, designed with the assistance of V. Von Braun, was assembled in 1951-52. Soon after the end of the assembly, the specialists began to test the apparatus. In order to test the performance of individual systems and the entire product as a whole, it was decided to start tests without the use of flammable hydrogen peroxide. Attempts to take off should take place only after checking the systems for tightness and serviceability.
The test pilot was the author of the project, Thomas Moore. Despite the minimal risks, all necessary precautions were taken during the tests. The pilot used protective overalls, a helmet and goggles. In addition, in order to avoid an unplanned ascent into the air, the pilot and his “Jet Vest” were tied to a test bench. The system of additional belts and cables limited the movement of the pilot and the JetWest. Fortunately, all tests passed without accidents, but precautions were not superfluous.
The first tests of the Jetvest apparatus were carried out in order to check the tightness of the fuel system and power plant. To do this, the tanks were filled with compressed air, which was subsequently vented through nozzles in a regular manner, simulating the supply of hydrogen peroxide. Subsequently, compressed nitrogen was used for testing, which also served as an imitation of full-fledged fuel. Only after all the checks, the device was planned to be filled with hydrogen peroxide and to carry out comprehensive tests with the supply and combustion of fuel.
Testing apparatus. Photo Rocketbelts.americanrocketman.com
Verification of the “Jet Vest” with full fueling was carried out at a special stand with a pit for venting jet gases and a tethered system for the pilot’s insurance. Also, the test bench was equipped with instruments for measuring aircraft thrust. During this phase of testing, Moore made several small short-term ascents into the air, using up quite a large amount of fuel. The lifting height did not exceed 0,5-1 m, however, in this case Jetvest showed its capabilities well. According to some reports, during the tests, two small-sized engines developed thrust at the level of 300 pounds (about 135 kg), which was enough for the pilot with jet apparatus to lift into the air and a small load.
After the completion of preliminary tests, the work of the promising jet apparatus was demonstrated to the military. Those appreciated the success of engineers, but did not approve the continuation of work. The project Jetvest considered too complicated and unsuitable for practical operation. Such systems, according to experts, could be used only in the distant future. The Pentagon has stopped funding the project. Having no money to continue the work, Moore’s team was forced to take up other projects.
After the official cessation of work on the "jet vest" Thomas Moore and his colleagues continued to participate in the creation of rocket technology. In particular, Moore himself after that was engaged in combat missile guidance systems. However, the inventor did not give up a promising direction, although he was forced to carry out all the work on his own initiative.
Over the next few years, Moore and his enthusiastic colleagues continued to develop the design of the Jetvest in order to improve performance and usability. Only in the 1961 year, after a mass of project refinements, Moore and Beduerftig applied for a patent. The corresponding document, confirming their authorship and merit, was issued in September 1964-th.
Due to the lack of support from the potential customer, all new works by Moore and his colleagues did not lead to any noticeable results. Jetpacks were still considered devices of the distant future, the development of which currently does not make sense. The flights of the early fifties have remained the biggest success of the Jetvest project. The late modernized version of this device, which was distinguished by an improved power plant and some other features, was not manufactured or tested.
Like other innovative projects, Jetvest Mura had positive and negative features. The first, of course, can be attributed to the viability of the project and the fact of the existence of a prototype. In addition, American engineers were able to create a fairly successful power plant with built-in control systems. In combination with a relatively simple rocket engine for hydrogen peroxide, all this could give the jet apparatus a start in life.
However, the device was not without flaws. The most notable of them is the specific and not the most convenient design of controls. It was proposed to operate two nozzles with the help of three flywheels, and the left hand was responsible for controlling the course. Right-handed pilots would hardly have approved it. In addition, the communication of controls with nozzle mechanisms was carried out through flexible shafts. Because of their importance, these mechanisms should have been highly reliable.
For obvious reasons, the total weight of the structure in the working position was limited by the physical capabilities of the pilot. Therefore, Moore's “Jet Vest”, as well as other similar devices, had a relatively small amount of fuel. A few liters of hydrogen peroxide, placed in two tanks on the pilot's back, was enough for no more than a few tens of seconds of flight with a minimum load. When lifting or maneuvering fuel consumption increased. Because of this, the maximum speed, altitude and duration of the flight left much to be desired.
Finally, the high-grade practical operation of the “Jetvest” was hampered by the high cost of fuel. Hydrogen peroxide was not a convenient fuel from an economic point of view. In addition, the mass development of such equipment by the army would require to change the logistics of the troops in order to provide units with fuel for jetpacks.
The specific list of positive and negative features as a result affected the future of the promising project. The existing disadvantages outweighed the expected benefits, which is why the military did not dare to continue funding the work. As a result, the army did not purchase Jetvest products, but at the same time it did not receive a lot of problems associated with their operation.
It should be noted that the experiments of Thomas Moore and his colleagues already in the fifties led to the emergence of a new similar project, the author of which was the namesake of the inventor. In the mid-fifties, a group of Bell engineers led by Wendell Moore began work on their own project, but that’s another story.
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