On 3 November last year tourists visiting the Statue of Liberty were startled to see a man in a jetpack flying around it.
It wasn’t a stunt scene from an Iron Man film but a promo. The man in the grey suit was Australian inventor David Mayman, the founder of Jetpack Aviation. Watching Mayman careen and pirouette through the sky with seemingly effortless control makes you want to rush online to place your order. But although the company’s marketing material tells us “the personal jetpack is here” you’ll have to wait a little longer for a jetpack of your own.
Jetpacks first entered the popular imagination when they were depicted on the covers of pulp science fiction magazines in the 1920s. The United States military made a serious attempt to build one in the 1950s, during the Cold War. By 1961, US president John Kennedy was treated to a working display of a jetpack prototype known as the rocketbelt (it consisted of a rocket strapped to the back with a belt). But although the demonstration was successful, the army was unimpressed with the rocketbelt’s 20-second maximum flight time and the project was shelved. Since then, men with jetpacks have zoomed about on stage and rudimentary screen: think of the 1965 James Bond flick Thunderball, the 1984 Olympics opening ceremony in Los Angeles or Michael Jackson’s glitzy 1992 tour.
Jetpack Aviation won’t be the first company to go to market with a jetpack. A New Zealand-based firm, Martin Jetpack, announced their product will go on sale in late 2016. But the 200-kilogram Martin is more like a personal aircraft than a jetpack; far too bulky for a pilot to carry around. Instead of a jet engine, it uses ducted fans for thrust like a quadrotor drone. But it can fly for 30 minutes. In 2015, Dubai Civil Defence placed an order for 20 Martin Jetpacks at US$200,000 a pop. They plan to use the devices for “reconnaissance and rescue” missions across the towers in the City of Gold.
Jetpack Aviation’s JB-9 is the first jetpack to use a jet engine light enough to be carried on the pilot’s back.
It’s the brainchild and passion project of Mayman, an aviator, inventor and businessman who made his fortune in mining and software. To make his childhood dream come true, Mayman hooked up with fellow dreamer Nelson Tyler in the 1990s. A multi-award-winning Hollywood camera engineer and pilot, Tyler designed the rocket belt that flew during the opening ceremony of the 1984 Olympics.
As self-described jetpack purists, Mayman and Tyler were determined to use a jet engine for thrust. And with the JB-9 (their ninth prototype), they’ve succeeded. The JB-9, powered by two small turbojet engines that run on kerosene, is as light and portable as the old rocketbelt but can fly 30 times longer. With a top speed of 100 kilometres per hour, it’s also much faster than any previous design.
The jetpack is light enough for Mayman to jog several hundred metres while wearing it, even when it’s loaded with fuel, and its compact size allows him to pirouette in mid-air or land in tight spaces.
To build a jet small enough to fit on somebody’s back, the engine has to compensate by revving very fast to achieve lift off. As a result, the JB-9 guzzles four litres of fuel per minute, limiting flying time to 10 minutes. That’s not great for touring but enough for some medical emergencies. The jetpack could give a new meaning to the phrase “flying doctor”.
With its greater manoeuvrability and ability to land in tighter spots, the JB-9 is set to give Martin Jetpack some stiff competition. But JB-9s are not for sale. Would-be customers will have to wait for the JB-10, which will include a parachute to make the jetpack safer and auto-stabilisation systems such as those used in drones, that will make it easier to fly.
The first application the designers have in mind is a high thrills air-race. It may be a few more years yet before the jetpack rises beyond its established role of stunt spectacle entertainment.
When the pilot wants to speed up, he can tilt the whole pack forward to redirect the thrust. The ability to tilt or ‘vector’ the engine is one reason the pack can cover ground so much faster than the rest.
The huge 38-litre tank comprises most of the pack’s bulk. And at more than 30 kilograms, the fuel makes up most of the weight. As fuel is used up in flight, climbing speed can increase dramatically.
The right hand controls throttle via a twist-grip, like on a motorcycle. The left hand grip helps with steering, controlling little flaps that deflect the airstream from each jet.
Air rushes in at the top and is compressed by the turbine into a chamber at the engine’s heart, where a controlled explosion shoves it through the back end, generating tremendous thrust.
Fuel: Kerosene (38 litres)
Flying time: 10 minutes
Range: 8 kilometres (return)
Thrust: Two turbojet engines
Fuel consumption: 4 litres/minute
Top speed: 100 kilometres/hour
Peak altitude: 3,000 metres
Climb rate: 150 to 300 metres/minute
The video of the JB-9’s flight over New York City can be viewed here
Cathal O'Connell is a science writer based in Melbourne.
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