Bell Rocket Belt


The Bell Rocket Belt is a low-power rocket propulsion device that allows an individual to safely travel or leap over small distances. It is a type of rocket pack.

Overview

began development of a rocket pack which it called the "Bell Rocket Belt" or "man-rocket" for the US Army in the mid-1950s. It was demonstrated in 1961. Its of hydrogen peroxide fuel provided only 21 seconds of flight-time so it did not impress the army. After was applied for in 1964 and granted in 1966, development was cancelled.
This concept was revived in the 1990s and these packs can provide powerful, manageable thrust. This rocket belt's propulsion works with superheated water vapour. A gas cylinder contains nitrogen gas, and two cylinders containing highly concentrated hydrogen peroxide. The nitrogen presses the hydrogen peroxide onto a catalyst, which decomposes the hydrogen peroxide into a mixture of superheated steam and oxygen with a temperature of about 740 °C. This was led by two insulated curved tubes to two nozzles where it blasted out, supplying the propulsion. The pilot can vector the thrust by altering the direction of the nozzles through hand-operated controls. To protect from resulting burns the pilot had to wear insulating clothes.
The Bell Rocket Belt was successful and popular but was limited in its potential uses to the Army due to limited fuel storage. As a result, the Army turned its attention to missile development, and the Rocket Belt project was discontinued.
One Bell Rocket Belt is on display at the Smithsonian Institution's National Air and Space Museum annex, the Steven F. Udvar-Hazy Center, located near Dulles Airport. Another resides at the State University of New York at Buffalo's Department of Industrial and Systems Engineering. It has been used in presentations at Disneyland and at the 1984 Summer Olympics and 1996 Summer Olympics opening ceremonies. It has also been seen in movies and on television. This type of rocket belt was used in the 1965 James Bond film Thunderball. It also made an appearance in the Lost in Space television series as well as the 1976 CBS Saturday morning children's live action TV show Ark II.

History

Wendell F. Moore began working on a rocket pack as early as 1953 while working as an engineer at Bell Aerosystems. Experiments began in the mid-1950s. Developing the engine did not present difficulties — the application of hydrogen peroxide was well developed by missilemen. The main problem was achieving stable and steady flight; for this, a reliable and convenient control system had to be developed.
In 1959 the U.S. Army contracted Aerojet General to conduct feasibility studies on a Rocket Belt and contracted Bell Aerosystems to develop a Small Rocket Lift Device. The experimental rig, which worked on compressed nitrogen, was prepared. Its steel tubing frame allowed a tester to be attached to the rig. Two hinged nozzles were set on the frame. Nitrogen at 35 atmospheres was supplied to the nozzles by flexible hoses. An engineer-operator on the ground regulated the supply of nitrogen through a valve. Additionally, the tester regulated the thrust using levers under his shoulders. The tester inclined the nozzles forward and backward, trying to reach stable hovering at a limited height. A safety tether was attached from below, so that the rig and tester could not fly too high.

Testing

The first tests showed that the human body was a very unstable platform. Testing found the best arrangement for the jet nozzles relative to the center of gravity of both the pilot and pack that allowed for directional control. Wendell Moore and other members of his group participated in the test flights. These first flights were just sharp leaps, but proved the concept and persuaded the military to fund development. The Bell company was awarded a contract to develop, flight test, and demonstrate a practical SRLD.
A rocket motor with a thrust of 280 pounds-force was chosen. The pack with its fuel weighed. The pack had a fiberglass frame contoured to fit the operator's body, secured with straps, and cylinders of fuel and nitrogen were attached to the frame. The motor was fastened using a hinged assembly that was controlled by levers under the shoulders while thrust was controlled through a regulator assembly connected to a throttle handle on the right lever of the device. The handle on the left lever governed the slant of the nozzles. Tests of the pack began toward the end of 1960 and were performed in a large hangar with a safety tether. Wendell Moore completed the first 20 tethered takeoffs while making incremental improvements.
On 17 February 1961, the pack veered sharply, reaching the end of the safety tether, which then broke, causing Moore to fall approximately 2.5 meters, breaking his kneecap and rendering him unfit for further flights. Engineer Harold Graham took over as test pilot and testing resumed on 1 March. He then carried out 36 more tethered tests which enabled them to achieve stable control of the pack.
On 20 April 1961, on a vacant spot near the Niagara Falls airport, the first free flight of a rocket pack was performed. Harold Graham reached a height of approximately, and then flew smoothly forward at a speed of approximately 10 km/h for a distance of 108 feet and then landed. The flight lasted 13 seconds.
In subsequent flights Graham learned how to control the pack and perform more complex maneuvers: flying in a circle and turning on a spot. He flew over streams and cars, ten-meter hills, and between trees. From April through May 1961 Graham carried out 28 additional flights. Wendell Moore worked to achieve reliability from the pack and confident piloting from Graham in preparation of presenting the rocket pack to the public. In the course of testing, maximums of duration and distance were achieved: duration 21 seconds; range 120 m; height 10 m; speed, 55 km/h.

Demonstrations

On 8 June 1962, the pack was publicly demonstrated for the first time before several hundred officers at the Fort Eustis military base. Other public demonstrations then followed, including the famous flight in the Pentagon courtyard. On that day Harold Graham flew before 3000 members of the military department, who observed with enthusiasm.
On 11 October 1961, the pack was demonstrated personally to President John F. Kennedy in the course of experimental maneuvers on the military base Fort Bragg. Graham took off from an amphibious LST, flew over a strip of water, and landed in front of the President.
Harold Graham and a support crew travelled to many cities in the USA. They visited Canada, Mexico, Argentina, Germany, and France, as well as other countries. Each time they successfully demonstrated the rocket pack in action before the public. However, the army was disappointed. The maximum duration of flight of the rocket pack was 21 seconds, with a range of only 120 m. A large contingent of service personnel needed to accompany the rocket pack. During flight of hydrogen peroxide was expended. In the opinion of the military, the "Bell Rocket Belt" was more a spectacular toy than an effective means of transport. The army spent $150,000 on the Bell Aerosystems contract. Bell spent an additional $50,000. The army refused any further expenditure on the SRLD program, and the contract was cancelled.

Design

The rocket could carry a man over 9-m-high obstacles and reached a speed of 11 to 16 km/h. However, its flying time was limited to 20 seconds. A later advancement during the years 1995–2000 could not improve the flying time to any more than 30 seconds.
Apart from the extremely limited working time, this rocket belt did not allow for a controlled landing should its drive fail, as it would operate at altitudes far too low for a parachute to function. This represents a substantial safety risk and differentiates the rocket belt from airplanes and helicopters, which can land safely without power by gliding or autorotation.

Operating principle

All existing rocket packs are based on the construction of the "Bell Rocket Belt" pack, developed from 1960 to 1969 by Wendell Moore.
Moore's pack has two major parts:
  • Rigid glass-plastic corset, strapped to the pilot. The corset has a tubular metallic frame on the back, on which are fixed three gas cylinders: two with liquid hydrogen peroxide, and one with compressed nitrogen. When the pilot is on the ground, the corset distributes the weight of the pack to the pilot's back.
  • The rocket engine, able to move on a ball and socket joint in the upper part of the corset. The rocket engine consists of a gas generator and two pipes rigidly connected with it, which end with jet nozzles with controlled tips. The engine is rigidly connected to two levers, which are passed under the pilot's hands. Using these levers the pilot inclines the engine forward or back and to the sides. On the right lever is the thrust control throttle, connected via a cable to the regulator valve to supply fuel to the engine. On the left lever is the steering handle, which moves the tips of the jet nozzles, allowing the pilot to control his yaw.
The whole construction is simple and reliable; except for the regulator valve and steerable nozzles, the rocket engine has no moving parts.
  • The figure shows the engine, hydrogen peroxide cylinders and compressed nitrogen cylinder.
  • The pilot turns the engine thrust control handle, opening the regulator valve.
  • Compressed nitrogen displaces liquid hydrogen peroxide, which is piped to the gas generator.
  • There it contacts the catalyst and decomposes.
  • The resulting hot high-pressure mixture of steam and oxygen gas enters two pipes, which emerge from the gas generator.
  • These pipes are covered with a layer of insulation to reduce heat loss.
  • Then the hot gases enter the jet nozzles, where they are first constricted, then allowed to expand, thereby accelerating them to supersonic speed and creating reactive thrust.