SURFING AIRCRAFT VORTICES FOR ENERGY (SAVE): SETP ANNUAL SYMPOSIUM SEP 2014

摘要

The C-17 has engaged in an attempt to harness energy from surfing aircraft vortices. Using the formation flying system software as the foundation, the SAVE software transmitted the lead aircraft's position, altitude, heading, and airspeed to the wing aircraft. The SAVE software on the wing aircraft provided guidance inputs to the autopilot that positioned the aircraft relative to the core wake vortex generated by lead. The SAVE software also included wake-crossing prevention functionality. Two phases of this program have been completed. The first phase, conducted by developmental test crews, researched potential fuel savings and demonstrated that a 5 to 10 percent reduction in fuel consumption for the wing aircraft can be achieved fully autonomously. The second phase, conducted by combined operational and developmental test crews, evaluated the human-systems aspects of SAVE software and potential fuel savings during operationally representative extended-duration flights. Cruise fuel savings of more than 10 percent were realized during extended durations with wing aircraft positioned 7,000 ft. aft and around 155 ft. laterally from the lead aircraft's wake vortex. An altitude source error in the SAVE software caused numerous guidance dropouts, however good vortex prediction and tracking allowed the wing aircraft to take larger longitudinal spacing, which provided continuous tracking. The SAVE software showed significant potential as a viable means to save fuel with good crew usability and minimal fatigue. This paper presents those results from a pilot perspective.