Dara Aviation is applying to the US State Department for export approval for an innovative joined-wing, or box-wing, configured unmanned air vehicle (UAV) which is in development for long-endurance commercial missions ranging from remote sensing to communications relay.
The composite D-1 vehicle, with a span of 3.29m (10ft) and a length of 1.75m, has a maximum take-off weight of 25kg (55lb), of which up to 2kg can be payload. The joined wing has been flying since September 2000 and is demonstrating "very high levels of efficiency", says Dara chief engineer Shahin Afshari. "We are several steps ahead of Lockheed Martin [which is studying joined-wing concepts], and our aircraft will be available at a fraction of the cost of regular UAVs," says Afshari, adding that the $50,000 price will include an autopilot system.
The D-1 is offered with a variety of small two-stroke commercial engines ranging in power from 0.9kW (1.3hp) to 2.9kW, producing a top speed of 68kt (125km/h) and a cruise speed of 55kt. "At 70mph [60kt], it will fly for 20h with a 10lb payload, and use only 4USgal [15 litres] of fuel," says Afshari. The Seattle-based company has built 17 D-1s and plans to flight test an autonomous version in California next month. Flight tests in remote-piloted mode have taken place at Monroe, Washington.
The D-1 has moveable trailing edges on both wingsets, the forward set acting as flaps and the aft set as elevons. "For take-off it can use elevators and flaps, and for pitch control it can use the flaps if necessary," says Afshari. Yaw stability is provided by end plates, or "rotary rudders". Dara says of this patented design: "The hinges are not in the usual configuration and only one rudder moves to turn the aircraft."
Initial potential customers include a mining company which is considering using the D-1 as a remote sensing platform for mineral surveying.
Source: Flight International
