The Bell Rocket Belt jetpack project turned out to be generally successful. Despite the short flight duration associated with the insufficient volume of fuel tanks, this device confidently lifted off the ground and could fly freely, maneuvering with the help of a movable engine. The refusal of the military department from the further development of the project did not lead to a complete stop of work on a promising direction. In 1964, Bell Aerosystems specialists, led by Wendell Moore, Harold Graham and other participants in the previous project, proposed another version of an individual aircraft with a jet engine running on hydrogen peroxide.
The main goal of the new project was to increase the flight duration. The jet engine used, running on hydrogen peroxide, made it possible to increase this parameter only by increasing the volume of the fuel tanks, which could lead to an increase in the weight of the entire structure and, as a consequence, the impossibility of maintaining the existing form factor of the knapsack. Nevertheless, engineers have found a simple and elegant way out of this situation. The solution to the problem was to be a chair, which was proposed to be used instead of a frame and corset with a belt system. For this reason, the new project has received a simple and understandable name Bell Rocket Chair ("Rocket Chair" or "Rocket Chair").
Robert Kouter and the Rocket Chair in Test
The main element of the new aircraft was an ordinary office chair of acceptable size and weight, bought by specialists at the nearest thrift store. The chair was fixed on a small frame with wheels, which made it possible to transport this device, and also to some extent facilitate takeoff and landing. The seat was provided with fastenings for the pilot's seat belts. In addition, a small frame with assemblies for installing the elements of the fuel system and the engine was attached to the back.
It should be noted that the development and assembly of the "Rocket Chair" did not take much time. This device was a direct development of the previous "Rocket Belt" and a number of existing units were used in its design. Engine type, how it works, etc. have not changed. Thus, the new aircraft was actually a deep modernization of the existing one, carried out using a seat and some other components.
A small frame with attachments for several cylinders of fuel and compressed gas was fixed on the back of the chair. In addition, a small shield was provided at the top of the frame to protect the pilot's back of the head from impacts and high engine temperatures. As before, the cylinders were placed vertically in one row. In the central pressurized nitrogen was stored for the displacement fuel supply system, in the lateral - hydrogen peroxide. The total fuel tank capacity has been increased from 5 gallons to 7 gallons (26.5 L). This made it possible to speak of a slight increase in the flight time.
In free flight
The engine design remains the same, although some changes have been made to improve performance. The main element of such an engine was a gas generator made in the form of a metal cylinder with several inlets and outlets of pipelines. A catalyst in the form of silver plates coated with samarium nitrate was located inside the cylinder. Two curved tubes with nozzles at the ends exited the side of the catalyst. The pipes were equipped with thermal insulation. The Rocket Chair engine was an upgraded version of the power plant of the previous aircraft with increased thrust.
The engine assembly was attached to the frame of the apparatus on a hinge. In addition, two levers were connected to it, which were brought forward at the level of the pilot's hands. It was proposed to control the apparatus by moving the levers in the right direction. Moving the levers led to a corresponding displacement of the nozzles and a change in the direction of the thrust vector, followed by maneuvering. When the levers were pressed, the nozzles tilted back and provided a forward flight, lifting the levers led to the opposite result.
Also, as part of the control system, there are two consoles installed at the ends of the main levers. On the left, a swinging handle was provided for fine control of the nozzles, on the right, a rotating handle for controlling the thrust. There was also a timer that warned the pilot about flight time and fuel consumption. The timer was associated with a buzzer in the pilot's helmet and was supposed to give a continuous signal during the last few seconds of the estimated flight time, warning of the running out of fuel.
Demonstration flight around the obstacle, September 2, 1965
The pilot's equipment, as before, consisted of a helmet with hearing protection and a buzzer, goggles, heat-resistant overalls and appropriate footwear. Such equipment protected the pilot from noise, dust and hot jet gases, the temperature of which could reach 740 °. Thanks to the characteristic relative position of the pilot and the engine nozzles, it was possible to dispense with special protective boots. In many of the surviving photographs, the pilots of the Chair are wearing ordinary sneakers.
The principle of operation of the engine used was relatively simple. Compressed nitrogen from the central tank was fed into the tanks with hydrogen peroxide and displaced it from there. Under pressure, the liquid entered the gas generator, where it fell on the catalyst and decomposed, forming a high-temperature vapor-gas mixture. The resulting substance had a high temperature and large volume. The mixture was removed to the outside through the Laval nozzles, forming a jet thrust. By changing the amount of hydrogen peroxide entering the gas generator, it was possible to change the engine thrust. The direction of flight was changed by tilting the engine and changing the direction of its thrust vector.
Due to some modifications, the engine thrust was increased to 500 pounds (about 225 kgf). This thrust made it possible to compensate for the increase in weight of the entire structure associated with the use of a chair and larger tanks. In addition, the increase in the capacity of the fuel tanks should have led to an increase in the maximum possible flight duration. According to calculations, the Rocket Chair could remain in the air for up to 25-30 seconds. For comparison, the original Bell Rocket Belt could fly no longer than 20-21 seconds.
General diagram of the Bell Rocket Chair from the patent
Design work was completed by early 1965. At the very beginning of the year, a prototype of the device was made, the basis for which, as already mentioned, was an armchair from the nearest store. The use of existing products and other design features greatly simplified prototype assembly. Its construction was completed in February 65th.
On February 19, the Bell Rocket Chair took off for the first time in one of Bell's hangars. For the safety of the pilot, the first test flights were carried out on a leash. With the help of safety cables, the device was not allowed to fall to the ground too quickly, and the pilot did not have to climb to a great height. Flying on a leash in the hangar allowed us to clarify the optimal balancing of the product and make some other changes to its design. In addition, during preliminary tests, the pilots were able to master the technique of piloting the new device. A series of flights inside the hangar continued until the end of June.
Engine design and control system. Drawing from the patent
Several pilots who already had experience with a similar system of the previous type participated in the test program of the "Rocket Chair". They were Robert Courter, William Sutor, John Spencer and others. Wendell Moore, as far as we know, after the accident during the tests of the previous device no longer dared to fly on his developments. Nevertheless, there were enough people who wanted to test the new technique without it. Preliminary tests on a leash helped determine the main features of the aircraft's behavior in the air. Also, the pilots were able to master the management of it. Testers who flew both designs of Moore's team noted that the new Chair was noticeably easier to control than the previous Belt. He behaved more stable and required less effort to hold in the desired position.
On June 30, 1965, the last tethered flight took place. By this time, the finalization of the structure was completed. In addition, the test pilots learned all the features of piloting and were ready to fly freely. On the same day, the tanks of the apparatus were again filled with hydrogen peroxide and compressed nitrogen, after which it was taken out to an open area. Without any problems, the device first took to the air without belay and covered several tens of meters.
Testing of the Bell Rocket Chair product continued until early autumn. On September 2, the last flight took place, during which the maneuverability of the device was checked during flight in an airfield with appropriate buildings. For more than two months, specialists conducted 16 test flights lasting up to 30 seconds. The general characteristics of the new device, despite the increase in weight and engine thrust, remained at the level of the base Bell Rocket Belt.
Rocket Chair (left) and two Bell Pogo variants. Drawing from the patent
The promising aircraft was developed by Bell Aerosystems specialists on an initiative basis, without an order from any government agency or commercial enterprise. The development company paid for all work independently. No attempts were made to offer a new development to potential customers. Remembering the end of the previous project, American engineers did not even try to promote the new one.
The Rocket Chair made it possible to test the fundamental possibility of increasing the fuel reserve and flight duration. 7 gallons of hydrogen peroxide tanks were enough for half a minute of flight. Thus, the "Rocket Chair" flew one and a half times longer than the "Belt". Nevertheless, even this duration of the flight did not allow considering the new development as a vehicle suitable for full-fledged operation in practice.
According to reports, after the completion of tests in September 1965, the only sample of the "Rocket Chair" went to the warehouse as unnecessary. The project completed all the tasks assigned to it, thanks to which it could be closed and move on to other work.
Modern "Rocket Chair" by Key Hes
In September 1966, Wendell Moore applied for another patent. This time, the subject of the document was a "Personal Aircraft" based on a frame, a chair and an engine powered by hydrogen peroxide.
In the future, Bell Aerosystems was engaged in the development of other promising projects in the field of aviation and missile technology. As for the idea of a "flying chair", it has not disappeared. Several years ago, the American enthusiast Key Hes built an analogue of the Bell Rocket Chair. His version of the product has a similar design, but differs in some details. For example, the design of the support frame, which serves as a chassis, has been changed. In addition, additional fuel tanks were installed under the seat of the chair. Finally, instead of a two-nozzle engine, the new aircraft uses a four-tube-and-nozzle design for more stable flight behavior. In addition, the design of the control lever associated with the rocking motor has been redesigned.
Hes's apparatus has been tested and demonstrated its capabilities. From time to time, an amateur engineer and his apparatus participate in various events, where they show all the possibilities of unusual rocketry.
William Sutor and K. Has's apparatus
It should be noted that one of the drawings, attached to the patent application US RE26756 E, depicted not only the "Rocket Chair", but also another version of an individual aircraft based on the same developments. By the time the application was submitted, Bell's design team had developed a new upgrade option for the Rocket Belt system with a change in the overall layout and some improvement in performance. The new project later became known as Bell Pogo and even interested NASA. We will look at this development by Moore and colleagues in the next article.
