In the early fifties, a team of engineers led by Thomas Moore designed and built their own version of the jetpack called Jetvest. This system has passed preliminary tests and became the first representative of the technique of its class, which managed to take off. However, the potential customer did not want to finance the continuation of the work. Because of this, enthusiasts were forced to continue developing Jetvest on their own initiative and did not achieve any noticeable success. In 1953, there was a new proposal for the construction of a jetpack. This time, Bell Aerosystems specialists took the initiative.
Project start
Wendell F. Moore, the namesake of Thomas Moore, was the initiator of the work at Bell. Apparently, he had some information about the first project and also decided to participate in the development of a promising direction. Moore formed the general look of his jetpack, but until a certain time the project did not leave the stage of preliminary discussions. Just at this time, the Pentagon refused T. Moore to continue funding its development, which made the prospects for other similar projects dubious. As a result, no one wanted to support W. Moore in his work.
General view of the finished Bell Rocket Belt apparatus. Photo Airandspace.si.edu
Until the end of the fifties, W. Moore completed an analysis of the available information about the work of his namesake and identified the disadvantages of his project. In addition, the existing developments have made it possible to form the optimal appearance of a promising jetpack. Moore originally suggested using a hydrogen peroxide engine. Such systems, for all their simplicity, could provide the required thrust, and also did not differ in their design complexity. At the same time, it was required to create a simple, reliable and easy-to-use control system. For example, the T. Moore control panel with three flywheels, which existed at that time, did not provide the necessary comfort for the pilot and made it difficult to control the flight, since it had not the most convenient design.
Consideration of the project and preliminary design work proceeded on an initiative basis until the very end of the fifties. In addition, by 1958, experts led by W. Moore were able to build a simplified experimental jetpack that could demonstrate the correctness of the selected ideas and decisions. With the help of a simplified apparatus, it was planned to test the existing ideas, as well as confirm or refute their viability.
First experiments
The experimental prototype was only supposed to demonstrate the fundamental possibility of solving the assigned tasks, which is why its design was seriously different from that originally proposed for a full-fledged jetpack. A system of hoses and a pair of nozzles were mounted on a frame of a simple design. In addition, a harness system was attached to the frame. For maneuvering, two swinging nozzles were provided, located on one beam associated with the control levers. The prototype did not have its own fuel tanks or other similar units and had to receive compressed gas from third-party equipment.
The device, view from the side of the pilot's seat. Photo Airandspace.si.edu
The hoses of the experimental apparatus were connected to an external source of compressed gas. Nitrogen was proposed as a means of creating jet thrust, which was supplied with a compressor at a pressure of 35 atmospheres. The gas supply and thrust control of such an "engine" were handled by a tester on the ground.
The first tests of the prototype knapsack designed by W. Moore were as follows. One of the testers put on the apparatus, in addition, it was tied to the test bench with safety cables, which did not allow to rise to a significant height or lose a stable position in the air. A second tester operated a compressed gas supply valve. Upon reaching the desired thrust, the first tester, together with the apparatus, rose into the air, after which his task was to keep the entire system in a stable position.
At the disposal of the pilot were two levers associated with the nozzles of the apparatus. By moving them, the pilot tilted the nozzles and thereby changed the direction of the thrust vectors. Due to the synchronous deflection of the nozzles forward or backward, the pilot could change the direction of the forward flight. For more complex maneuvers, it was necessary to tilt the beam and nozzles in other ways. A similar control system was proposed to be used on a full-fledged jetpack. In theory, it made it possible to obtain a fairly high maneuverability.
The pilots of the experimental apparatus were various Bell engineers, including Wendell Moore himself. The first test flights were similar to jet thrust jumps. The testers did not immediately learn to hold the apparatus in a stable position, which is why uncontrolled maneuvers in roll and height began. Therefore, it was necessary to reduce the pressure of the compressed gas and lower the pilot to the ground in order to avoid emergency situations, injuries and damage to the equipment.
Despite some setbacks, the experimental prototype made it possible to solve several critical problems. The specialists were able to confirm the capabilities of the used control system. In addition, an optimal nozzle configuration was selected. Finally, based on the results of these tests, the most convenient design of pipelines and engines was chosen, in which the thrust vector passed through the center of gravity of the "pilot + vehicle" system and ensured its maximum stable behavior. The main load in the form of fuel and pilot cylinders was located between the two nozzles.
The absence of restrictions on the amount of compressed gas supplied by the compressor made it possible to determine the potential capabilities of the apparatus. At the final stage of testing, the pilots managed to rise to a height of 5 m and stay in the air for up to 3 minutes. At the same time, they completely controlled the flight and did not face any serious problems. Thus, after several modifications, the experimental prototype fully completed the tasks assigned to it.
Tests of the experimental prototype, as well as its demonstration to specialists from other departments, had a positive effect on the further fate of the project. In 1959, Bell specialists managed to convince a potential customer in the person of the military department of the prospects for a new development. The result of this was a contract for a feasibility study of such equipment, as well as the development and construction of a prototype jetpack.
Complete sample
The jetpack development program has received the official designation SRLD (Small Rocket Lift Device). The development company used its own designation - Bell Rocket Belt ("Bell missile belt"). It should be noted that the internal corporate designation of the project did not fully match the design of the device. Outwardly, the "Small Rocket Lifter" looked more like a knapsack with a mass of unusual and even strange units. Due to the mass of complex assemblies, the apparatus did not at all look like a belt.
Drawing from the patent
Having received an order from the defense department, Moore and his colleagues continued to work on the project and, as a result, created its final version, according to which several jet vehicles were eventually built. The finished "Rocket Belts" differed markedly from the products of the preliminary design. During the design, the specialists took into account the test results of the experimental product, which had a noticeable effect on the design of the finished knapsack.
The main element of the SRLD / Bell Rocket Belt device is a metal frame fixed to the pilot's back. For ease of use, the frame was equipped with a rigid fiberglass corset attached to the pilot's back. The harness belts were also attached to the frame. The design of the frame, corset and harness was designed to evenly distribute the weight of the jetpack onto the back while on the ground or to transfer the pilot's weight to the structure in flight. In view of the availability of an order for the military, Bell engineers took into account the convenience of future users of promising technology.
Three metal cylinders were vertically mounted on the main frame. The central one was intended for compressed gas, the side ones - for hydrogen peroxide. To save weight and simplify the design, it was decided to abandon any pumps and use positive displacement fuel supply to the engine. Above the cylinders, a pipeline was installed in the form of an inverted V with a gas generator in the center, which served as a hydrogen peroxide engine. The central part of the engine was pivotally connected to the frame. Nozzles were located at the ends of the pipes. Due to the bending of the support pipes, the jet engine nozzles were at the level of the pilot's elbows. In addition, they were moved forward and located on the plane of the center of gravity of the "pilot + vehicle" system. To reduce heat loss, it was proposed to equip the pipes with thermal insulation.
In the course of operation, compressed nitrogen from the central cylinder under a pressure of 40 atmospheres was supposed to displace liquid hydrogen peroxide from the side tanks. That, in turn, entered the gas generator through hoses. Inside the latter there was a catalyst made in the form of silver plates coated with samarium nitrate. Under the action of the catalyst, hydrogen peroxide decomposed, forming a vapor-gas mixture, the temperature of which reached 740 ° C. Then, the mixture passed through curved side pipes and escaped through Laval nozzles, forming a jet thrust.
The controls of the "Rocket Belt" were made in the form of two levers rigidly connected to the swinging engine. There were small consoles at the ends of these levers. The latter were equipped with handles, buttons and other equipment. In particular, the project provided for the use of a timer. According to calculations, the supply of hydrogen peroxide was only enough for 21 s of the flight. For this reason, the device was equipped with a timer, which was supposed to warn the pilot about fuel consumption. When the engine was turned on, the timer started counting down and gave a signal every second. 15 seconds after turning on the engine, the signal was applied continuously, which meant the need for an early landing. The signal was given by a special buzzer mounted in the pilot's helmet.
Traction control was carried out using a rotary knob on the right panel. Turning this knob activated the nozzle mechanisms, resulting in a change in thrust. It was proposed to control the course and maneuver by tilting the V-shaped pipeline of the engine. In this case, the vector of the thrust of the jet gases changed its direction and shifted the apparatus in the right direction. Thus, to move forward, one had to press the levers, to fly backward, raise them. It was planned to move sideways by tilting the engine in the right direction. In addition, there were drives for finer control of the nozzles, connected to the lever of the left control panel.
Astronomer Eugene Shoemaker "tries on" a jetpack. Photo Wikimedia Commons
It was assumed that the pilot of the Bell Rocket Belt system would fly in a standing position. However, by changing the posture, it was possible to influence the flight parameters. For example, raising the legs a little forward, it was possible to provide an additional displacement of the thrust vector and increase the flight speed. However, the authors of the project considered that control should be carried out only with the help of the regular means of the apparatus. Moreover, new pilots were taught to operate exclusively with levers, while maintaining a neutral body position.
Several design features of the new rocket pack forced the engineers to take special measures to ensure the safety of the pilot. So, the pilot had to use a suit made of heat-resistant material, a special helmet and goggles. The overalls were supposed to protect the pilot from hot jet gases, the goggles protected the eyes from the dust raised by the jet jets, and the helmet was equipped with hearing protection. Due to the noise generated by the engine, such precautions were not redundant.
The total weight of the structure with a full supply of fuel at the level of 19 liters (5 gallons) reached 57 kg. A jet engine powered by hydrogen peroxide gave a thrust of about 1250 N (127 kgf). Such characteristics allowed the "Rocket Belt" to lift itself and the pilot into the air. In addition, there was a small amount of traction left for transporting a small load. For obvious reasons, during the tests, the device carried only the pilot.
Testing
The first sample of a full-fledged SRLD / Bell Rocket Belt apparatus was assembled in the second half of 1960. His trials soon began. For greater safety, the first test flights were carried out on a special stand equipped with tethered ropes. In addition, the stand was located in a hangar, which protected the pilot from wind and other adverse factors. To determine the parameters of the apparatus, some measuring instruments mounted on the stand were used.
W. Moore himself became the first test pilot of the Rocket Belt. Over the course of several weeks, he made two dozen short flights, gradually increasing the altitude and mastering the control of the apparatus in flight. Successful flights continued until mid-February 1961. The authors of the project rejoiced at their successes and made plans for the near future.
Pilot William P. "Bill" Sutor at the opening of the Los Angeles Olympics. Photo Rocketbelts.americanrocketman.com
The first accident happened on February 17. During the next ascent, Moore lost control, as a result of which the device rose to the maximum possible height, broke the safety cable and collapsed to the ground. Having fallen from a height of about 2.5 m, the engineer broke his kneecap and could no longer participate in tests as a pilot.
It took several days to repair the damaged Rocket Belt and find out the causes of the accident. Flights resumed only on March 1. This time the test pilot was Harold Graham, who also participated in the development of the project. Over the next month and a half, Graham completed 36 flights, learned how to operate the apparatus, and also continued the test program.
April 20, 1961 G. Graham performed the first free flight. The site for this phase of testing was Niagara Falls Airport. After starting the engine, the pilot climbed to an altitude of about 4 feet (1, 2 m), then smoothly switched to level flight and covered a distance of 108 feet (35 m) at a speed of about 10 km / h. After that, he made a soft landing. The first free flight of the Rocket Belt lasted only 13 seconds. At the same time, a certain amount of fuel remained in the tanks.
From April to May 61st G. Graham performed 28 free flights, during which he improved the piloting technique and found out the capabilities of the apparatus. Flights were carried out over a flat surface, over cars and trees. At this stage of testing, the maximum characteristics of the apparatus in the existing configuration were established. Bell Rocket Belt could climb to a height of 10 m, reach speeds of up to 55 km / h and cover distances of up to 120 m. The maximum flight duration reached 21 s.
Outside the polygon
Completion of design work and preliminary tests made it possible to show the new development to the customer. The first public demonstration of the Rocket Belt product took place on June 8, 1961 at the Fort Eustis base. Harold Graham demonstrated the flight of a promising apparatus to several hundred servicemen, which seriously surprised everyone present.
Subsequently, the promising jetpack was repeatedly demonstrated to specialists, government officials and the general public. So, shortly after the "premiere" at the military base, a show took place in the courtyard of the Pentagon. Ministry of Defense officials appreciated the new development, which was considered almost impossible a few years ago.
In October of the same year, Graham took part in a demonstration maneuver at Fort Bragg, which was attended by President John F. Kennedy. The pilot took off from an amphibious assault ship located at a distance from the coast, flew over the water and successfully landed on the shore, next to the president and his delegation.
Later, a team of engineers and G. Graham visited several countries where demonstration flights of a promising aircraft were carried out. Each time the new development attracted the attention of specialists and the public.
Sean Connery on the set of Fireball. Photo Jamesbond.wikia.com
In the mid-sixties, Bell Aerosystems had the first opportunity to take part in filming. In 1965, another James Bond film was released, where the "Rocket Belt" was included in the arsenal of the famous spy. At the beginning of the film "Fireball", the main character escapes the pursuit with the help of a jetpack designed by W. Moore and his colleagues. It is noteworthy that the entire flight of Bond lasts about 20-21 seconds - apparently, the filmmakers decided to make this scene as realistic as possible.
In the future, the development of Bell was repeatedly used in other areas of entertainment. For example, it was used in the opening ceremonies of the Olympic Games in Los Angeles (1984) and Atlanta (1996). The device also took part in the Disneyland park show several times. In addition, "Rocket Belt" has been repeatedly used in the filming of new films, mostly in the fantasy genre.
Results of the project
The 1961 demonstrations made a big impression on the military. However, they were unable to convince the Pentagon of the need to continue the work. The SRLD program cost the military department $ 150,000, but the results left much to be desired. Despite all the efforts of the developers, the Bell Rocket Belt device was distinguished by too high fuel consumption and "ate" all 5 gallons of fuel in just 21 seconds. During this time, it was possible to fly no more than 120 m.
The new rocket pack turned out to be too complicated and expensive to operate, but did not give the troops any clear advantages. Indeed, with the help of this technique, fighters could overcome various obstacles, but its mass operation was associated with a large variety of problems. As a result, the military decided to stop funding and close the SRLD program due to the lack of real prospects in the current situation and with the existing level of technology.
Flight of James Bond. Stills from the film "Ball Lightning"
Despite the refusal of the military department, Bell Aerosystems for some time continued to try to modify its jetpack and create an upgraded version with increased performance. The additional work took several years and cost the firm about $ 50,000. Due to the lack of noticeable progress, the project was closed over time. This time the management of the company also lost interest in him.
In 1964, Wendell Moore and John Hubert applied for a patent, soon receiving document number US3243144 A. The patent describes several versions of the jetpack, including one used in tests. In addition, this document contains a description of various units of the complex, in particular a helmet with a signal buzzer.
During the first half of the sixties, Bell specialists collected several samples of promising technology with some minor differences. All of them are currently museum exhibits and are available for viewing by everyone.
In 1970, all the documentation for the Rocket Belt project no longer needed by Bell was sold to Williams Research Co. She continued to develop an interesting project and even achieved some success. The first development of this organization is considered the NT-1 project - in fact, a copy of the original "Rocket Belt" with minimal modifications. According to some reports, this particular device was used in the opening ceremonies of two Olympiads and other festive events.
With some tweaks, the new engineering team was able to significantly improve the performance of the original jetpack. In particular, later versions of the device could stay in the air for up to 30 seconds. Nevertheless, even such a significant increase in characteristics could not open the way for the device to practical use. Bell's "rocket belt" and further developments on its basis have not yet reached mass production and full-fledged practical operation, which is why they remain an interesting but controversial example of modern technology.
