Thrill seeker
The lure of doing something different results in a jet-powered push bike
By Ray Cleaver
Photographs: Rob Tucker
Paul Jury likes going fast. He enjoys the world of speed so much he’s attached a micro jet engine to a push bike. Paul’s bike has been cranked up to 120kph and he thinks it can go as fast as 150kph.
The New Plymouth man, who runs Floorcoat Taranaki, said he and his mates like speed and a bit of danger. They’re into activities such as drift triking, wake boarding, kite surfing, snowboarding, and skydiving.
Checking out a few YouTube clips they decided to up the ante and use jet power.
“The jet motor was originally attached to planks of wood and when we first cranked it up, it tried to take off in the workshop, showering anyone behind it with gravel,” says Paul.
The next step to check out its capabilities was attaching it to a go-kart but Paul said the kart was a bit heavy to realise the maximum potential of the jet.
Attaching it to the bike worked a treat. There’s plenty of pickup and speed. Go to YouTube and look up Jet bike vs Audi R8 to see the bike cranked up.
Jeremy Clarkson rode a similar 112kph jet bike on Top Gear. The world record for such a jet-powered pushbike is 333kph, dragging off a Ferrari!
Paul built a bracket on the rear of the bike for the motor and the fuel – jet kerosene – is in a fuel container in a basket on the front. The jet turbine chews through the fuel. Paul said it uses about a litre a minute.
Loud noise
The jet bike made a public appearance down the main street of New Plymouth in the Americana car festival in February this year, ridden by Paul’s mate Frenchy.
It was a standout entry, especially with the noise it made.
These jet engines are not recommended if you have close neighbours, or even not so close neighbours. They make a very loud noise. A piercing scream in fact. Paul was loathe to fire it up when we first arrived due to a preschool 100 metres away. “If we wake up the sleeping kids I’m in trouble,” he grinned. “It’s not really all about speed. You can get a fast motorbike for that. There’s the thrill of doing something different.”
Snow jet
But putting the jet engine on the bike is just a trial. Paul plans to mount the engine on a special frame and use it while snowboarding this winter.
“I figure you could possibly get up to 100kph on a flat paddock of snow and then, of course, you could snowboard down a slope, then jet power your way back up.
“I think it would be quicker than the bike. It’s all about the power-to-weight ratio.”
Paul has designed a special frame, made of carbon fibre and fibreglass by mate Peter Wilson for snowboarding.
The frame is designed to hold the engine, has Velcro straps to attach to the body, and it is hand held. The container of fuel straps to the rider’s back.
“Two of these engines can lift a man off the ground. Guys have put these engines on wing suits and can hover and fly at 150kph,” says Paul.
Engine specs
The micro jet engines are made by a Dutch company, AMT, and are mainly used for remote-control model jet planes. Paul’s model, the Titan, is not very big at only 385mm long and just 147mm across. It weighs a mere 3.6kg.
It winds up to a maximum 96,000 rpm and moves a staggering 36,000 litres of air per minute.
Paul said measuring the speed of the bike and eventually the powered snowboard is done by GPS readings through a phone app.
The engines cost $25,000 off the shelf but Paul purchased his for considerably less. It is second hand and was used for a project in Australia.
The motor has an ignition starter, a thermostat sensor probe, an rpm sensor, and a small computer system for analysing temperature and speed of the motor to adjust the fuel mix through the electric fuel pump.
Bobber bike
Pauls workshop and shed holds more than just his business equipment.
A black 2013 Lamborghini Gallardo shares the shed with a boat for wakeboarding, various jobs under construction and a strange looking motorbike.
The bike, once a Yamaha X5650 is a ‘bobber’. A bobber is a custom stripped-down bike with excess bodywork removed and the front fender removed, the rear fender shortened (bobbed), and all superfluous parts removed. Paul made up the bike in the shed, using his TIG welder and a metal lathe with a 600mm bed.
“It’s really just a fun bike. I use it to go and get a cup of coffee.”
Innovation
Another unusual object Paul has is a bath he had a friend make up.
Made from carbon fibre and kevlar the bath is suspended between two walls
It was made by Peter Wilson using yachting construction techniques. Peter made a reverse mould first, then made the bath from double foam layers.
New design
The AMT website says the miniature Titan Electric start gas turbine has been constructed from a single radial compressor and an axial flow turbine stage. The Titan owes much of its excellent performance and superb power/weight ratio to a new design diffuser stage. This revolutionary type of diffuser also allows the relative small engine diameter.
The time required for the Titan to spool up and down is also positively influenced by the low mass of the axial turbine wheel, taking less than 4 seconds and from minimum to maximum rpm and only 3 seconds from max. rpm to min. rpm.
