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  • Sikorsky's X2 - Collier Win, Commercial Next?
    Posted by Graham Warwick 7:27 PM on Mar 16, 2011

    Sikorsky's X2 Technology demonstrator, which set an unofficial helicopter speed record of 250kt, has won the 2011 Collier Trophy for achievement in aeronautics. And the competition was tough - two winners of this year's Aviation Week Laureates were runners up: the X-51A hypersonic vehicle and automatic ground-collision avoidance system (Auto-GCAS) teams.

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    Photo: Sikorsky

    A well-deserved win for the small X2 team. The 25 engineers assembled to undertake this rapid-prototyping initiative went from start to first flight in 43 months, and in just 18 flights and 17.4 hours of flying time achieved the four key performance parameters of 250kt in level flight, low pilot workload, low vibration and low noise. Total cost to Sikorsky was $50 million over five years. A bargain.

    And the 250kt level speed was acheived without all the rotor drag-reduction treatments planned, but Sikorsky has backed off the idea of one last high-speed flight to demonstrate its true potential. Apparently the blades are nearing the end of their short test life.

    But the question I always hear being asked is when will Sikorsky develop a commercial version? The company is already building two S-97 X2 Raider light tactical helicopter prototypes to fly in 2014, but we might have to wait a while for a civil X2. But here's what it might look like...

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    Corporate X2 (All concepts: Sikorsky

    "The commercial potential [of X2] is not readily apparent yet," Sikorsky president Jeff Pino said at the Heli-Expo show early this month. The issue is the cost of speed, and specifically the fuel consumpion associated with the power required to fly fast.

    The 220kt X2 Raider will be a 9,000-10,000lb helicopter powered by a single 3,000shp-class turboshaft driving the coaxial rotors and tail-mounted prop - a similar-sized commercial helicopter, AgustaWestland's new AW169, will has a pair of 1,000shp-class engines, but a traditional helicopter speed of around 140kt.

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    Tactical and utlity (rear) X2s

    The advantages of the X2 configuration to the military, as detailed by Sikorsky, are pretty compelling. Speed - the Raider can fly a 350km-radius mission in an hour, compared with 200km for a conventional helicopter. Hot-and-high - the Raider can hover out of ground effect above 10,000ft at 95F, compared with under 4,000ft.
    Signature - low noise (the prop can be disengaged) and high speed reduce the distance at which the Raider can be heard.

    And there are tactical advantages to the configuration. The Raider can use reverse thrust from the prop to stop quickly, then blend rotor and prop thrust to point the fuselage and weapons at the target. The Raider can then reverse and climb out while engaging the target, rather than having to climb over or turn away from it.

    If the X2 finds a commercial market it will likely be on longer missions, where higher speed can increase productivity by flying more missions per day (like offshore oil and gas) or save lives (like emergency medical services and search and rescue). Pino says the X2 could increase the range of the "golden hour" for medevac by a factor for 2.5.

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    Coast Guard X2

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    Attack X2

    Tags: awt, rotorcraft

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