Innovators at NASA's Armstrong Flight Research Center have applied a novel peak-seeking control algorithm to improve performance during formation-flight-for-drag-reduction by optimizing an airplane's spanwise lift distribution. During stabilized flight within the energy-rich portion of a lead aircraft's wake vortices, variations in the upwash field along the trailing aircraft's wing produce a strong rolling moment. Modern aircraft control trim schedules are not designed to recover fuel-saving energy from this rolling moment. The Armstrong innovation optimizes the trimmed spanwise lift distribution of a wing in formation flight for minimum drag by:
- Controlling discrete trailing-edge effectors along the wing to alter the lift distribution
- Using a Kalman filter algorithm to estimate the gradient and curvature of the drag vs. trim space
- Relying on a peak-seeking controller to adjust the trim for minimum drag based on real-time measurements
While formation-flight-for-drag-reduction can reduce fuel burn by 10% or more, optimizing the spanwise lift distribution in this operating environment can further reduce fuel use.
- Robust: Overcomes the uncertain nature of wake vortex upwash fields with a real-time, onboard solution
- Easily implemented: Improves wing efficiency in formation flight without requiring a wing redesign, using existing control surfaces
- Flexible: Enhances formation-flight-for-drag-reduction without sacrificing performance during solo flight
- Streamlined: Increases drag reduction by an additional 2% to 3% over formation-flight performance with traditional roll trim schedules
- Military (formation flight, unmanned aerial vehicles)
- Commercial aircraft (for cargo transport carriers, commercial passenger aircraft operators, makers of unmanned aerial vehicles)
NASA has one patent pending for this technology.
This technology is part of NASA's technology transfer program. The program seeks to stimulate broad commercial use/application of NASA-developed technologies. NASA is flexible in its agreements, and opportunities exist for licensing and joint development. Armstrong is interested in a partnership to commercialize this technology.
If you would like more information about this technology or about NASA's technology transfer program, please contact:
Technology Transfer Office
NASA's Armstrong Flight Research Center
PO Box 273, M/S 1100
Edwards, CA 93523-0273
Phone: (661) 276-3368