The US Air Force (USAF) Air Mobility Command (AMC) has conducted the surfing aircraft vortices for energy ($AVE) programme flight tests using two C-17 Globemaster III aircraft to validate its ability to reduce annual fuel costs.
Carried out from Edwards Air Force Base in California, to Joint Base Pearl Harbor-Hickam, Hawaii, and back, the tests involved one C-17 trailing directly behind another to recapture energy that would otherwise be lost, which eventually lowers its fuel consumption.
Representing follow-on tests from the October 2012 test flights at Edwards AFB, the latest trials, featuring an actual operational mission, including night time flying sorties, assure the air force fuel savings of up to $10m a year.
Air Force Research Laboratory $AVE programme manager Bill Blake said the aircraft performed in-flight rendezvous, day and night operations, and also flew several hours in each direction in $AVE formation.
"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," Blake said.
Air Mobility Command chief scientist Dr Donald Erbschloe said the C-17’s autopilot can sustain $AVE position at safe distances ranging from 3,000ft – 6,000ft between the lead and trailing aircraft, with minor software modifications such as reducing aircrew workload, unlike the fighter aircraft from earlier test that required close flying at fingertip intervals, and ultimately more pilot intervention.
Following testing and concept validation, the command will request funding for a DOD Advanced Technology Demonstrator to determine exact procedures and processes required for the introduction of the $AVE concept to other air force aircraft, Erbschloe added, noting that the two- to three-year project may commence as early as next year.
62nd Airlift Wing weapons and tactics director major Kyle Clinton said, "Across the board, I believe the potential benefits could be worthwhile for the aviation community – not just for C-17 formations but also for mixed formations, such as tankers (accompanying) fighters."
$AVE represents a combined effort between AMC, Air Force Research Laboratory, 412th TW, Air Force Life Cycle Management Center, Defense Advanced Research Projects Agency, Boeing and NASA Dryden Flight Research Center.
Image: Two C-17 Globemaster III aircraft were used for $AVE programme flight test. Photo: courtesy of USAF.