September 09, 2013
Credit: Martin Aircraft
Border patrols, first responders and bungee jumpers looking for a new thrill are all potential users of what developer Martin Aircraft says will be the first practical Jetpack when deliveries begin in 2014. The military is also interested, for use on manned or unmanned missions ranging from radio relay to personnel insertion and cargo resupply.
The Auckland-based company has conducted initial manned test flights of the latest prototype of its ducted-fan Jetpack after receiving a permit to fly from New Zealand's Civil Aviation Authority. The single-pilot machine is being developed to comply at first with rules governing microlights, but new CEO Peter Coker acknowledges Martin will have to work with individual regulators around the world if the Jetpack is to fulfill its promise as a “motorbike in the sky.”
Designed for a cruise speed of 30 kt., range of 30 km (19 mi.) and endurance of 30 min., the vertical-takeoff-and-landing Jetpack is attracting interest for uses as disparate as search and rescue, pipeline inspection, corporate events, flying displays and a “jetpack experience” for thrill seekers. As an unmanned heavy lifter, with the ability to carry a 150-kg (330-lb.) payload, the machine is being looked at by the agricultural and film industries, Coker says.
Flight tests of the company's 12th and latest prototype are underway. After initial manned hops, prototype P12 is being flown unmanned to expand the low-altitude envelope as Martin modifies the engine, after which manned flights are planned to resume. The modification adds a balance shaft to reduce vibration inherent in the 200-hp. V4 two-stroke, designed and built by Martin itself after it could not find an engine powerful, light or compact enough.
Mounted behind the pilot, the engine powers a pair of ducted fans that provide both vertical thrust and flight control. Compared with P11—the previous prototype that had center-of-gravity challenges, says Coker—the ducts have been moved down and increased in size, and a “robust” fly-by-wire system added to increase flight performance. Martin is aiming for a maximum speed of 40 kt. Empty weight manned is 180 kg and maximum takeoff weight 330 kg, for a payload with full fuel of 100 kg.
Altitude is limited to 3,000 ft. by microlight rules but, in May 2011, P11 was flown unmanned to 5,000 ft. to show the machine could fly out of ground effect and “prove this is an aircraft,” Coker says. That flight ended with the first deployment of the ballistic recovery parachute, a standard safety feature of the Jetpack. “The parachute is part of the system, and is connected to the engine so that, if it is not performing correctly, it will deploy automatically,” he says.
“We are developing an active parachute to get the dead-man's curve down to a very low level,” he adds. Normally associated with helicopters, the dead-man's curve is the lower corner of the height/velocity chart where a power failure can be fatal. “We'd like the parachute to be usable down to 6 meters or so.” Below that, the carbon-fiber landing gear would absorb the impact. “The undercarriage can withstand a fairly reasonable arrival, and the pilot is enclosed in carbon fiber for safety,” Coker says. A flotation collar will provide buoyancy in a water ditching.