Flight testing of the stealthy Lockheed Martin/ Boeing DarkStar long-endurance unmanned air vehicle (UAV) will resume in the second or third quarter of 1997, once the second prototype is completed.
Two further DarkStar systems, including two UAVs and associated payloads, are also being built. They will be delivered in the middle of 1998 for user demonstrations.
The revised Tier III Minus advanced-concept-technology-demonstration (ACTD) programme plan results from the review of the crash of the first DarkStar prototype in April 1996.
It was determined that the UAV loss was caused by changes made in flight-control software and take-off technique between the first and second flights.
The DarkStar prototype was extensively damaged after it pitched up, stalled and crashed moments after taking off from a runway at Edwards AFB, California, on its second test flight. The UAV was first flown on a successful 20min initial test flight on 29 March, 1996.
The accident was blamed on "deficiencies in the modelling and simulation of the flight vehicle", says the USDepartment of Defense (DoD). The contractors have since revised the simulations to model more accurately the expected flight characteristics in all the flight regimes.
Subsequently, the ACTD was extended from 24 months to 31 months. Fabrication of the third DarkStar has been accelerated. It will be used for ground tests and as the back-up flight-test airframe. The DarkStar air-vehicle 4 construction will remain on its current schedule.The DoD has yet to specify how many operational DarkStars would be deployed.
nThe first flight of the Alliant Techsystems Outrider tactical UAV might take place in the second half of this month, according to the Pentagon's UAV Joint Programme Office.
The initial test flight had been set for November 1996, but it was delayed because programme officials were not certain that a safe flight could be conducted. It was determined that additional risk- mitigation efforts were required to ensure a safe first flight.
The risk-reduction work included windtunnel tests on a scaled air- vehicle model, antenna testing, and additional tests to evaluate dynamic systems and flight parameters. The windtunnel data have shown that the wings are producing less lift than originally predicted.
Source: Flight International
