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  • When I Grow Up I Want To Be A JSF
    Posted by Bill Sweetman 2:28 PM on Aug 26, 2010

    Lockheed Martin has been showing off its Various (VTOL advanced reconnaissance insertion organic unmanned system) UAV for some years now, usually in the form of wall charts and videos, but is now showing a detailed scale model and talking about the concept. The model was unveiled at the Association of Unmanned Vehicle Systems International show in Denver this week. Better yet, the company was in a mood to talk about how it is intended to work.

    blog post photo

    First of all, appearances are deceptive. Various is not a fast jet despite its swept wings and tails: it is designed for a 220 knot cruise speed, mainly to address a Marine requirement for a UCAV that can match the speed of the V-22. Top speed is 320 knots and it can loiter efficiently at 160 knots.

    So why the swept wings?  The semi-blended design with the long-chord inner wings is needed to provide a home for the lift fans on the vehicle's center of gravity. At the same time, sweepback is needed to balance the vehicle properly. And the big V-tails are not there for high-g maneuvering, but to provide adequate control authority during transition. Here's a Lockheed Martin video that shows a little more detail:

    Various has shaft-driven lift fans, like the JSF, but with a much lower specific thrust -- the two fans together must have almost as much area as the JSF fan, but support 8300 lb in take-off weight (think AT-6B) versus 18,000 lb thrust from the JSF's lift fan.

    The propulsion system is related to Lockheed Martin patents from the 1990s for special-operations transports, with a single compact core engine that drives both the lift fan and a cruise fan. The engine is mounted in the forward fuselage and the cruise fan could be either shaft-driven or gas-driven. The propulsion system has a very high effective-bypass ratio, which is the key to a competitive loiter time.

    The flight envelope of Various is not unlike a high-speed rotorcraft, with one difference - it is not intended to perform missions that involve hovering. But, Lockheed Martin argues, it has a key advantage over a small unmanned rotorcraft in terms of on-deck safety, and it also has the potential for stealth - including a very small infrared signature, without a separate suppressor. Part of the Various concept, too, is that it could be configured with different degrees of stealth to balance cost and survivability.

    Tags: ar99, unmanned, lockheed martin, various, auvsi, tacair

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