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  • Flexrotor - ScanEagle Goes Vertical?
    Posted by Graham Warwick 5:00 PM on Mar 03, 2010

    A new UAV from the designer of the Aerosonde and ScanEagle is not to be ignored, and is likely to be an extraordinary performer. After all, the Aerosonde was the first unmanned aircraft to cross the Atlantic and the ScanEagle extracts more than 24h endurance from a 20kg airframe. The Aerovel Flexrotor doesn't disappoint: a 19.2kg vehicle with 40h-plus endurance - that takes off and lands vertically.

    blog post photo
    Photo: Aerovel

    Aerovel was founded by Tad McGeer, who helped form Insitu and designed the Aerosonde and ScanEagle. McGeer says he was "pushed out" of Insitu in late 2005 and formed Aerovel in 2006 to develop the Flexrotor, which is designed to tackle one of the disadvantages of the ScanEagle - the size of its launch and recovery equipment.

    The Flexrotor is a tailsitter, and designed for automatic retrieval, refueling and launch using one lightweight base station, details of which are still under wraps. McGeer says a tailsitter configuration allows the airframe to be designed for wingborne efficiency. The low disc loading - half that of a helicopter - means the Flexrotor is essentially a powered sailplane in forward flight and keeps the power-to-weight ratio low.

    The vehicle is powered by the same 3W-28 single-cylinder two-stroke engine as the ScanEagle, driving the 1.85m-diameter two-blade rotor through a reduction gearbox. That gearbox is one of the penalties of VTOL; another is a slight reduction in top speed, says McGeer. To land, the aircraft pitches from horizontal to vertical flight and uses helicopter-style collective and cyclic pitch control, electric thrusters on the wing tips counteracting rotor torque. The payload is in the nose.

    blog post photo
    Art: Aerovel

    Aerovel has completed the prototype, is now testing the drive train and hopes to fly the Flexrotor by mid-year. The prototype will be used for testing on the propulsion system, hover and transition flight control and automatic turnaround. The company hopes to have a production-standard aircraft available for user trails by late 2011.

    Tags: ar99, UAV, VTOL

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