Description: Airfoils produce more lift and less drag when the boundary layer is attached to the airfoil. With most aircraft there are combinations of airspeed and angle of attack where the boundary layer at least partially detaches from the airfoil. Reducing boundary layer detachment will increase lift and reduce drag. This will reduce fuel consumption saving money for the operator and improving control for the pilot. Two methods are known to improve boundary layer attachment: heating the air and supplying acoustic pressure at an airspeed and airfoil shape dependent frequency. Carbon nanotubes can be used to produce heating elements as thin as a layer of paint. Because they are thin they can be heated and cooled hundreds of times per second. This combination means that carbon nanotube heating elements can be thermoacoustic speakers to both heat the air stream and generate the appropriate acoustic frequency to maximize boundary zone attachment. All system components have been demonstrated individually achieving TRL 2. Phase I will demonstrate multifrequency sound generation on surfaces in a wind tunnel using nanotube heating elements, and achieving TRL 3. Phase II will include medium seals wind tunnel tests verifying the effects and achieving TRL 5.

Benefits: One of NASA's functions is to supply technology to the civilian and military sectors. Developing and dispersing this technology will be of greatest benefit outside of NASA, with improved safety and profitability for commercial aircraft operators at all levels, from private pilots to commercial airlines. The technology proposed here, if implemented, can reduce fuel consumption or increase payload. It will also improve the effectiveness of control systems. Either will make aircraft operation more profitable. Reducing fuel consumption will also reduce emissions, including aircraft produced CO2. Increasing boundary layer attachment will also make the aircraft more responsive to its controls, an added advantage.

One of NASA's functions is developing and demonstrating new flight technologies for both military and civilian use. The technology proposed here, if implemented, can reduce fuel consumption or increase payload. Either will make aircraft operation more profitable. Reducing fuel consumption will also reduce emissions, including aircraft produced CO2. Increasing boundary layer attachment will also make the aircraft more responsive to its controls, an added advantage.