The method is called $AVE, or surfing aircraft vortices for energy and involves one C-17 trailing directly behind another, with the C-17's autopilot sustaining the $AVE position at safe distances ranging from 3,000-6,000 feet between the lead and trailing aircraft.
"Creatures in the wild do this all the time -- exploiting conditions which give them an energetic advantage -- just that slight edge," said Dr. Donald Erbschloe, Mobility Command's chief scientist. "Dolphins and human surfers ride the 'bow waves' off ships, hawks circle in thermals to gain altitude and energy, and geese fly in V-shaped formations to reduce their exertion during long migrations."
The tests were conducted on flights from Edwards Air Force Base, Calif., to Joint Base Pearl Harbor-Hickam, Hawaii, and back – last month, Data from the tests projected savings of up to $10 million a year.
"We were very pleased with the results of the long-range demo. We demonstrated in-flight rendezvous, day and night operations, and flew several hours in each direction in our $AVE formation," said Bill Blake, the Air Force Research Laboratory $AVE program manager
"With only minor changes, we were able to attain double-digit fuel savings, which exceeded what we measured during our 2012 proof-of-concept test."