Bell Aerosystems developed its first jetpack project with military funding. After conducting all the necessary tests and determining the real characteristics of the new product, the Pentagon decided to close the project and stop funding due to the lack of prospects. For several years, Bell specialists, led by Wendell Moore, continued to work on an initiative basis until a new customer appeared. The creation of another personal aircraft was ordered by the National Aeronautics and Space Administration.
Since the early sixties, NASA employees have been working on a host of projects under the lunar program. In the foreseeable future, American astronauts were to land on the moon, which required a large number of special equipment for various purposes. Among other things, astronauts needed some means of transportation with which they could move along the surface of the Earth's satellite. As a result, several LRV electric vehicles were delivered to the moon, but other transport options were considered in the early stages of the program.
At the stage of working out preliminary proposals, NASA specialists considered various options for moving on the moon, including with the help of aircraft. They probably knew about Bell's projects, which is why they turned to her for help. The subject of the order was a promising personal aircraft that could be used by astronauts in the conditions of the moon. Thus, W. Moore and his team had to use the available technologies and developments, as well as take into account the peculiarities of the satellite's gravity, the design of spacesuits and other specific factors. In particular, the design of the spacesuits available at the time forced the engineers to abandon the proven "jetpack" layout.
Robert Kouter and the first version of the Pogo product
The project of the "lunar" flying machine was named Pogo after the name of the toy Pogo stick, also known as the "Grasshopper". Indeed, some versions of this product looked very much like a children's "vehicle", although they had a number of characteristic features directly related to the technologies and technical solutions used.
For the third time, Wendell Moore's team decided to use proven ideas involving a hydrogen peroxide jet engine. For all its simplicity, such a power plant provided the required thrust and made it possible to fly for some time. These engines had some drawbacks, but there was some reason to believe that they would be less noticeable under conditions of the lunar surface than on Earth.
During the work on the Bell Pogo project, three variants of the aircraft for the lunar mission were developed. They were based on the same principles and had a high degree of unification, since the same components were used in their design. However, there were some layout differences. In addition, options were offered with different carrying capacities: some versions of the "Pogo" could carry only one person, while the design of others provided space for two pilots.
The first version of the Bell Pogo product was a redesigned version of the Rocket Belt or Rocket Chair with major changes to the overall layout. Instead of a knapsack corset or a chair with a frame, it was proposed to use a metal rack with attachments for all major units. With the help of such a unit, it was planned to ensure the convenience of using the apparatus in a heavy and not very comfortable spacesuit, as well as to optimize the balancing of the entire product.
At the bottom, a part was attached to the base strut that served as a footboard for the pilot and the base of the landing gear. This time, the pilot had to stand on the power element of the apparatus, which made it possible to get rid of the complex system of seat belts, leaving only a few necessary. In addition, there were mounts for small wheels on the sides of the footrest. With their help, it was possible to transport the device from place to place. A small beam with an emphasis was provided on the front of the frame. With the help of wheels and a stop, the apparatus could stand upright without support.
The device is in flight. Behind the Levers - R. Courter
In the central part of the rack, a block with three cylinders for compressed gas and fuel was attached. As in the previous Bell technology, the central cylinder served as a storage of compressed nitrogen, and the side ones were to be filled with hydrogen peroxide. The cylinders were connected to each other by a system of hoses, taps and regulators. In addition, hoses leading to the engine departed from them.
The engine of the "classic" design was proposed to be mounted on the upper part of the strut using a hinge that allows control of the thrust vector. The engine design remains the same. In its central part there was a gas generator, which was a cylinder with a catalyst device. The latter consisted of silver plates coated with samarium nitrate. Such a gas generator device made it possible to obtain energy from fuel without the use of an oxidizer or combustion.
Two bent pipelines with nozzles at the ends were attached to the sides of the gas generator. To avoid heat loss and premature cooling of reactive gases, the pipelines were equipped with thermal insulation. Control levers with small handles at the ends were attached to the engine pipes.
The principle of operation of the engine remained the same. The compressed nitrogen from the central cylinder was supposed to displace the hydrogen peroxide from its tanks. Getting on the catalyst, the fuel had to decompose with the formation of a high-temperature vapor-gas mixture. Seven with temperatures up to 730-740 ° C was supposed to exit through nozzles, forming a jet thrust. The apparatus should be controlled using two levers and handles mounted on them. The levers themselves were responsible for tilting the engine and changing the thrust vector. The handles were associated with mechanisms for changing the thrust and fine adjustment of its vector. A timer has also been preserved to warn the pilot about fuel consumption.
Double version of "Pogo" in flight, piloted by Gordon Yeager. Passenger Technician Bill Burns
During the flight, the pilot had to stand on the step and hold on to the control levers. In this case, the engine was at the level of his chest, and the nozzles were located on the sides of the hands. Due to the high temperature of the jet gases and the great noise produced by such an engine, the pilot needed special protection. His equipment consisted of a soundproofed helmet with a timer buzzer, goggles, gloves, heat-resistant overalls and matching shoes. All this allowed the pilot to work without paying attention to the dust cloud during takeoff, engine noise and other unfavorable factors.
According to some reports, in the design of the Bell Pogo product, slightly modified units of the "Rocket Chair" were used, in particular, a similar fuel system. Due to the slightly less weight of the structure, the engine thrust at the level of 500 pounds (about 225 kgf) made it possible to slightly increase the performance of the device. In addition, the Pogo product was intended for use on the moon. Thus, without being distinguished by high performance on Earth, a promising aircraft could be useful on the Moon, in low gravity conditions.
Design work on the first version of the Bell Pogo project was completed in the mid-sixties. Using the available components, W. Moore's team made an experimental version of the apparatus and began testing it. The test pilot team remained the same. Robert Kourter, William Sutor and others were involved in checking a promising personal aircraft. Also, the general approach to checks has not changed. At first, the device flew on a leash in a hangar, and then free flights began in an open area.
As expected, the Pogo apparatus was not distinguished by its high flight characteristics. He could rise to a height of no more than 8-10 m and fly at speeds up to several kilometers per hour. The fuel supply was enough for 25-30 seconds of flight. Thus, in earthly conditions, the new development of Moore's team was not much different from the previous ones. Nevertheless, with the low gravity of the Moon, the available parameters of thrust and fuel consumption gave hope for a noticeable increase in flight data.
Soon after the first version of the Bell Pogo, the second appeared. In this version of the project, it was proposed to increase the payload, providing the ability to transport the pilot and passenger. It was proposed to do this in the simplest way: by "doubling" the power plant. Thus, to create a new aircraft, it was only required to develop a frame for attaching all the main elements. The engine and fuel system remained the same.
Yeager and Burns in flight
The main element of the two-seater vehicle is a simple frame design. At the bottom of such a product there was a rectangular frame with small wheels, as well as two steps for the crew. In addition, the power plant struts were attached to the frame, connected at the top with a jumper. Between the racks were fixed two fuel systems, three cylinders in each and two engines, assembled in one block.
The control system remained the same, its main elements were levers rigidly connected to the swinging engines. The levers were brought forward to the pilot's seat. At the same time, they had a curved shape for optimal mutual position of the pilot and handles.
During the flight, the pilot had to stand on the front step, facing forward. The control levers passed under his arms and flexed to provide access to the controls. Due to their shape, the levers were also an additional element of safety: they held the pilot and prevented him from falling. The passenger was asked to stand on the rear step. The passenger seat was equipped with two beams that passed under his hands. In addition, he had to hold on to special handles located near the engines.
From the point of view of systems operation and flight control, the two-seater Bell Pogo was no different from the one-seater. By starting the engine, the pilot could adjust the thrust and its vector, making the necessary maneuvers in height and course. By using two engines and two fuel systems, it was possible to compensate for the increase in structural weight and payload, while maintaining the basic parameters at the same level.
William "Bill" Sutor is testing a third version of the apparatus. The first flights are carried out using a safety rope
Despite some complication of the design, the first two-seater aircraft, created by W. Moore's team, had significant advantages over its predecessors. The use of such systems in practice made it possible to transport two people at once without a proportional increase in the weight of the aircraft. In other words, one two-seater device was more compact and lighter than two single-seater ones, which provided the same possibilities for transporting people. Probably, it was the two-seat version of the Pogo product that could be of the greatest interest to NASA in terms of its use in the lunar program.
The two-seater Pogo apparatus was tested according to an already worked out scheme. First, it was tested in a hangar using safety ropes, after which free flight tests began. Being a further development of the existing design, the two-seater device showed good characteristics, which made it possible to count on a successful solution of the assigned tasks.
In total, within the framework of the Bell Pogo program, three variants of aircraft were developed with the maximum possible unification. The third version was single and was based on the design of the first, although it had some noticeable differences. The main thing is the mutual placement of the pilot and the fuel system. In the case of the third project, the engine and cylinders were to be located behind the pilot's back. The rest of the layout of the two devices was almost the same.
The pilot of the third version of the "Pogo" had to stand on a step equipped with wheels and rest his back on the main post of the apparatus. In this case, the engine was behind him at shoulder level. Due to the change in the general layout, the control system had to be redone. The levers connected to the engine were brought out towards the pilot. In addition, for obvious reasons, they have been lengthened. The rest of the management principles remain the same.
The tests carried out according to the standard methodology again showed all the pros and cons of the new project. The flight duration still left much to be desired, but the speed and altitude of the vehicle were quite sufficient to solve the assigned tasks. It was also necessary to take into account the difference in gravity on the Earth and on the Moon, which made it possible to expect a noticeable increase in characteristics in the conditions of real use on a satellite.
Tests with the participation of an astronaut and using a spacesuit. June 15, 1967
It can be assumed that the third version of the Bell Pogo system was more convenient than the first in terms of control. This can be indicated by a different design of control systems with an increased leverage. Thus, the pilot had to make less effort to control. Nevertheless, it should be noted that the layout of the third version of the apparatus seriously impeded or even made it impossible to use it by a person in a spacesuit.
The development and testing of three variants of the Pogo apparatus was completed by 1967. This technique was presented to customers from NASA, after which joint work began. It is known about the holding of training events, during which astronauts, dressed in full-fledged spacesuits, mastered the control of personal aircraft of a new type. At the same time, all such ascents into the air were carried out on a leash, using a special suspension system. Due to the peculiarities of the layout of spacesuits and aircraft, Pogo systems of the first type were used.
The joint work of Bell Aerosystems and NASA continued for some time, but did not give real results. Even taking into account the expected increase in performance, the proposed aircraft could not meet the requirements associated with their intended use in the lunar program. Personal aircraft did not appear to be a convenient means of transport for astronauts.
For this reason, the Bell Pogo program was closed in 1968. NASA experts analyzed various proposals, including those of the Bell company, after which they came to disappointing conclusions. The proposed systems did not meet the requirements of the lunar missions. As a result, it was decided to abandon attempts to fly over the surface of the moon and start developing a different vehicle.
Drawings from US patent RE26756 E. Fig 7 - Rocket Chair. Fig 8 and Fig 9 - Pogo devices of the first and third versions, respectively
The vehicle development program for lunar expeditions culminated in the creation of the LRV electric vehicle. On July 26, 1971, the Apollo 15 ship departed to the Moon, carrying such a machine. Later this technique was used by the crews of the Apollo 16 and Apollo 17 spacecraft. During the three expeditions, the astronauts traveled about 90.2 km on these electric vehicles, spending 10 hours 54 minutes.
As for the Bell Pogo devices, after the completion of joint tests, they were sent to the warehouse as unnecessary. In September 1968, Wendell Moore applied for a patent for a promising individual vehicle. It described the earlier Rocket Chair project, as well as two variants of the single-seat Pogo apparatus. After filing the application, Moore received patent number US RE26756 E.
The Pogo project was Bell Aerosystems' latest development in jetpacks and similar technology. Over the course of several years, the company's specialists have developed three projects, during which five different aircraft appeared based on common ideas and technical solutions. During the work on the projects, the engineers studied various features of such equipment and found the best options for its design. However, the projects did not progress beyond testing. The equipment created by Moore and his team did not meet the requirements of potential customers.
By the end of the sixties, Bell had completed all the work on what it once seemed to be a promising and promising program and no longer returned to the topic of small personal aircraft: jetpacks, etc. Soon, all the documentation on the implemented projects was sold to other organizations, which continued their development. The result was the emergence of new modified projects, and even small-scale production of some jetpacks. For obvious reasons, this technique never received widespread adoption and did not make it to the army or space.