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NAS FEATURED NEWS
Columbia Helps Validate Innovative Control Concepts for Supersonic Aircraft
NASA researchers are using the Columbia supercomputer to identify new flight control concepts for tailless supersonic aircraft.
05.31.07
For the past year, NASA Langley researcher Lewis Owens has used more than 200,000 processor-hours on the Columbia supercomputer, screening various new control concepts for a tailless supersonic aircraft. Exploration of non-conventional controls today may someday translate to better fuel economy, increased flight range, or decreased weights for tomorrow's aircraft.
Caption: (Above right) NASA Langley researchers are using Columbia to screen non-traditional control concepts for supersonic aircraft.
(Click on image to enlarge)
The main goal of this work is to develop innovative ways to provide vehicle yaw control.
Yaw is the left-right movement of the nose of an aircraft, traditionally controlled by a rudder.
"These advanced control technologies may provide ways to help improve supersonic cruise efficiency by reducing the portion of the cruise drag associated with gaps and breaks around conventional control surfaces," explains Owens. NASA is interested in this work, as it relates to one of the Fundamental Aeronautics Program goals to develop more efficient supersonic aircraft for high-speed civil transport -- capable of traveling at speeds approaching Mach 2.
Owens looked at four different non-traditional concepts for yaw control: surface bumps, surface porosity, jets of air, and fluidic thrust vectoring.
The surface bump control consists of bumps that deploy or retract depending on how the pilot wants the vehicle to move. During the normal flight of an airplane (that is, during cruise), the bumps are retracted. When the bumps are extended into the flow field, they create a local drag force and yawing moment that changes the flight direction.
Porosity uses small holes on the upper and lower surface of a wing to control the top-to-bottom pressure difference, or lift of the wing. Normally, the holes are closed for efficiency. Control is achieved by varying the number of holes that are open to reduce the local lift force on the wing by sliding plates under the surface.
Selective placement of jets of air on a vehicle to generate desired forces is another concept Owens considered. For example, placing jets on the bottom aft-end (rear) of a wing will give the same effect as if a flap were deflected, and will change the lift and drag forces. The air supplying these jets may be diverted from the engine flow and distributed to jet slots located in the aircraft wings.
Thrust vectoring results in a change in the force vector direction from the engine. Historically, this was accomplished by using mechanical surfaces to redirect the flow as desired. A different approach to thrust vectoring uses a small percentage of engine flow (about 3%) in certain places in the vehicle engine nozzle to vector the thrust for vehicle control. This concept, referred to as fluidic thrust vectoring, reduces the weight penalties associated with mechanical thrust vectoring systems.
For more information on non-conventional aircraft controls, contact: Lewis Owens, Lewis.R.Owens@nasa.gov
For more information on Columbia resources and NAS support services, contact:
William Thigpen,
William.W.Thigpen@nasa.gov
For information about NASA and agency programs on the Web, visit
http://www.nasa.gov/home/
Holly A. Amundson
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