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Jet Models Will Push the Envelope for Safety's Sake
05.27.04
They can fly as fast as 200 miles per hour and push the flight envelope to a place most pilots never want to go.
Generic Transport Model taxi test
"They" are turbine-powered, dynamically-scaled remote control models, a new research capability being developed at NASA's Langley Research Center in Hampton, Va.
Image at right: Langley's Reggie Kidd oversees the Generic Transport Model (GTM) trainer as it taxis before a group of NASA and industry onlookers at a recent demonstration. Photo credit: NASA.
The first engineers to use this unusual tool are doing "refuse to crash" technology research for NASA's Aviation Safety and Security Program (AvSSP). "Using a sophisticated flying model will allow us to test flight regimes beyond normal envelope operations in an in-flight environment," said Christine Belcastro, head of the Control Upset Prevention Recovery element of the AvSSP.
Belcastro and her team are designing computer software and control systems to prevent airliners from going into steep dives and other extreme flight conditions (or upsets), The technology would also help aircraft automatically return to level flight if the on-board systems detect an upset condition which can be caused by extreme weather, damage, equipment malfunction or pilot error.
"It wouldn't be safe to put a real aircraft into unusual attitudes to test our software and there are limits to wind tunnel testing," added Belcastro. "We needed to find a way to validate not only our control systems research but also realistic in-flight scenarios that can be used in simulators to help better train pilots."
"The team is developing a unique testbed, not just for Langley, but for NASA," said Butch Watkins, project manager in Langley's Advanced Model and Sensor Systems Branch. "We are creating a cost-effective capability to do research that can't be done in wind tunnels or with full-scale aircraft."
Generic Transport Model remote control unit Image at left: A close-up look at the GTM remote control
Langley technicians built the Generic Transport Model trainer, a five-and-a-half percent scale version of a commercial airliner that weighs 50 pounds. It has an 82-inch wingspan, is remotely piloted and has turbine engines. Builders would have liked to construct a larger model, because it would have been easier to equip with all the gear needed to make it realistic. Instead they used already existing molds to help keep the cost down and because they had wind tunnel data for the same sized model.
"Building a dynamically scaled flying model is quite a challenge," said Watkins. "It has to have the same attributes as the real plane. That includes scaled weight and dimensions and accurate inertia characteristics of roll, pitch and yaw."
Once technicians conquered the complexities of construction the team turned to Langley research engineers who understand aerodynamics. Four of them have spent hours learning to fly the sophisticated machines.
"We started our training with commercial remote control propeller models," said Jeff Hill, model flight systems safety pilot. "We have worked our way up to off-the-shelf jets. And then this summer we plan to conduct the first flights with the first Generic Transport Model trainer. That's in preparation for the full-up research flight tests with instrumentation of Generic Transport Model trainer two that's under construction."
Pilots do their practice flying at Fentress Field in Chesapeake and at Smithfield Foods' private airfield in Smithfield. The team plans to do its flight tests at a newly developed runway at NASA's Wallops Flight Facility near Chincoteague, Va.
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Aceasta postare a fost editata de MIG-29: 27 May 2004 - 05:02 PM
