The Jetpack concept is surely mans ultimate fantasy of flight, the ability to climb vertically from a standstill, hover, fly forwards, backwards and turn, all with little more than an oversized rucksack on your back has inspired features in films & books for almost a century, few other device's capture quite the same fascination. Many attempts have been made over the years to bring this fantasy to reality but most have failed. However the successful efforts made under US military contract by Bell Aerospace and Williams International (formally Williams Research) in the 1960's + a few copies of the rocketbelt flown since provide the inspiration and proof that the concept can be realised.
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| Bill Suitor flying the NelsonTyler rocket belt, star of the 1984 Olympic opening ceremony. |
The Bell Aerospace developed rocket belt is by far the best known, staring in "Thunderball" with James Bond flying it to escape the enemy and the phenomenal appearance at the 1984 LA Olympics + many breath taking appearances before & since it continues to be a real crowd puller. But it does have one huge draw back, its 20-25 second flight duration. The reason for this is simply the use of a fuel thirsty rocket engine to provide lift. Whilst the rocket engine is superior for certain applications this is certainly not one of them. In propulsive terms it gives a large acceleration to a small mass, furthermore this mass is stored in chemical form - Hydrogen peroxide, for best efficiency you would chose to give a small acceleration to a large mass, better still if most of this mass is air, as would be by using an air breathing jet engine. However it should be recognised that as a means to demonstrate the jet or rocketpack principal this type of rocket belt initially designed by Wendell Moore is unrivalled in terms of compactness, simplicity & reliability. Bell developed the original design and a few successful copies have been produced & demonstrated since.
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| Simply a "work of art" - the Williams Jet Belt. |
Recognising the limitation imposed by this very short duration, in the mid/late 1960's Bell began design studies with Williams for an air breathing Jet powered version that would provide 10 minutes flight time! After about 4 years design, development and testing, (much of which was funded by the military) in 1969 Robert Courter piloted the Williams powered belt in glorious free flight for several minutes. This is the only successful Jet-Pack ever demonstrated. It still exists (I am told it is on display at Williams HQ), but is never flown & rarely photographed, a real shame for such a Masterpiece of engineering. However as it's engine is the powerplant used in all US military long range cruise missiles, and the original jet belt development was under a Military contract it's almost secret status is not surprising.
At the heart of the Williams belt is a WR19 twin spool contra-rotating, co-axial turbofan engine that despite having been developed in the late 60's is still one of the most impressive small gas turbine (jet) engines ever produced, this complexity is also probably the main reason why no other true Jetpacks/Jetbelts (same thing) have been demonstrated by others since. The basic layout of the Williams unit is air intake facing down with mixed (hot & cold) exhaust efflux fed to vector nozzles either side of the pilot's shoulders. These nozzles & throttle are manipulated by hand and arm movements. This coupled with weight shift provides stable flight control, a similar system as was developed for the rocket belt. The fuel tanks are transparent and mounted either side of the engine and an emergency rocket deployed parachute is included.