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  • Rolls Keeps Vectored-Thrust Ideas Coming
    Posted by Graham Warwick 3:25 PM on Nov 16, 2010

    With the UK to end Harrier operations after 30-plus years, in 2011, and the specter of cancellation hanging over the AV-8B's intended replacement, the F-35B Joint Strike Fighter, STOVL could soon be relegated to history. So it's interesting to see Rolls-Royce continuing to dabble in vectored thrust, as evidenced by a couple of new US patents awarded to the UK engine manufacturer.

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    All patent graphics: USPTO

    The first (patent number 7823826) is for a "VSTOL aircraft" (above) that looks Harrier-like - with a wrinkle. The design has Pegasus-style cold and hot vectoring nozzles, but the forward (cold) nozzles can be swung into an upward position where they discharge into ducting in the wing. The air is then ducted to slots in the wing to increase lift at lower airspeeds through circulation control. Slot blowing also produces thrust, the patent says, augmented by the hot nozzles.

    A second patent illustration (below), of a twin-engined transport concept, shows how the cold nozzle would mate to the wing ducting. While wing blowing may be a more efficient way of providing propulsive lift for STOL operations, and the vectoring nozzles provide VTOL capability, I'm not quite convinced the idea is practical.

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    The second patent (number 7823828) is for an "aircraft with improved lift". In this design (below) the engine is mounted under the wing so that, while the forward cold vectoring nozzles are retained, the aft hot nozzle is integrated with the high-lift flaps on the wing trailing edge.

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    In STOL mode (lower left, above), the flaps and nozzle are deflected partially. Part of the nozzle exhaust is ejected into a passage between the flaps to entrain additional freestream air and increase their effectiveness. In VTOL mode (lower right, above), both the cold and hot nozzles are deflected vertically downwards, while the flaps continue to operate in ejector-augmentor mode.

    How the 2D nozzle would integrate with the aircraft is illustrated below, and could bring a tear to the eye of anyone who fondly remembers Hawker's P.1216 advanced V/STOL concept of the early 1980s.

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    Tags: ar99, STOVL, propulsion

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