The Dragonfly DF1 is a helicopter that uses rockets attached to the tips of its blades to power it instead of a conventional fixed motor attached to the body. The rockets produce no pollution and are fueled by 70 percent hydrogen peroxide (H202) supplied by a pair if fuel tanks surrounding the pilot’s seat. They are capable of propelling the DF1 to a top speed of 185 km/h (115 mph) and can send the craft climbing to a ceiling of 4,000m (2.485 miles) at a rate of 700 m (2,300 ft) a minute.
The rocket chopper is apparently simpler and safer to fly than conventional helicopters as there are less flight controls and moving parts. It also offers improved stability as propelling the rotors directly results in less vibration. Plus, because there is no motor torque, the tail rotor is only required to rotate the helicopter and not for stability.
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Tip-jet powered helicopters are nothing new. The Percival P.74 was a British experimental helicopter designed in the 1950s that employed tip-jet powered rotors but was unable to get off the ground due to its inadequate power source. The Hiller YH-32 Hornet built for the US Army and Navy also in the early 1950s exhibited powerful lifting capacity providing some hope for military uses, but the high noise, poor range, and high night-time visibility of the ramjet flames from the ramjet engines mounted on the blade tips also doomed this craft.
Tucson-based company, Swisscopter America’s Inc. has been able to overcome these shortcomings by using a pair of H2O2 rocket motors made by Tecaeromex that use a penta-metal catalyst in the motors to instantly dissociate the peroxide into 600 degree Celsius high pressure steam and drive the blades. The DF1 retains the traditional collective/throttle lever but steers via a motorbike-like control bar for tilting the rotor head. The DF1 also does away with any foot controls.
Although probably still not suitable for military uses the DF1 does boast some impressive specs. Its tanks hold 70 liters (18.5 gal) of fuel to provide up to 50 minutes of flight time at a cruising speed of 65 km/h (40 mph). This can be extended to 100 minutes with an optional extra 60-liter (16 gal) fuel tank. Empty the helicopter weighs a mere 106 kg (234 lbs) and can carry up to 227 kg (500 lbs) including pilot and fuel.
Other options include a windshield canopy, crop spray system, rescue hammock, cargo compartment, fire extinguisher, autopilot, winch, more powerful engines and navigation and landing lights.
Swisscopter has conducted test flights of the DF1 and obtained airworthy certificates ahead of an expected commercial launch of the DF1 this year. Interested parties can reserve their place in line for the DF1 on the Swisscopter website now. The company is also testing an experimental two-seater prototype using the same technology.
Via Red Ferret.