Small new devices meant to save money spent on gas by reducing aerodynamic drag are inching closer to fleetwide adoption for the Air Force’s 222 C-17 transport jets.
Microvanes are 3D-printed out of composite materials into thin blades about 16 inches long. When attached to the rear exterior of the C-17 fuselage, microvanes reduce drag, and thereby fuel consumption, by 1 percent compared to unmodified C-17s.
Though 1 percent may not sound like much, the Air Force said it will save up to $14 million annually over the frequent flights C-17s take around the world.
“Every gallon of fuel saved strengthens our readiness and operational effectiveness,” Roberto Guerrero, deputy assistant secretary of the Air Force for operational energy, safety, and occupational health, said in a Jan. 14 press release. “By adding modern technology like microvanes to our legacy aircraft, we’re saving millions in fuel costs and building capability critical for maintaining our competitive edge in the era of great power competition.”
The Air Force Research Laboratory (AFRL) has been working on the technology as far back as 2014. In 2021, the Department of Defense awarded a contract to Metro Aerospace, which holds the license to Lockheed Martin’s patent on the technology, to explore putting microvanes on Air Force C-130s and “help validate drag-reduction concepts that can be developed and applied to commercial aircraft, other aircraft such as the C-17, KC-135, and future vertical lift.” An official said at the time that the microvanes had cost about $5 million to develop.
Cargo planes often have high drag where the fuselage sweeps upward to accommodate a rear cargo door. Reducing that drag means transports can carry troops, equipment, and supplies to farther flung operations.
“It’s about ensuring that we remain agile and capable in a rapidly evolving global environment,” Guerrero said. “What’s more, through recent legislation, we can use the savings realized by this technology to fund other initiatives that increase combat capability.”
In 2022, AFRL and the Air Force Life Cycle Management Center were in the process of certifying the microvanes for airworthiness. The next year saw the start of final flight-testing, including air refueling and assault strip operations, where C-17s land on shorter, narrower runways to simulate combat landings.
Now, Air Force Operational Energy and Air Mobility Command “are entering the final phase of evaluation” according to the release. The C-17 used in testing is assigned to Stewart Air National Guard Base, N.Y. Lt. Col. Eric Durkins, commander of the 105th Aircraft Maintenance Squadron at Stewart, said the aircraft “has supported our worldwide missions now for over a year without an issue[.]”
Six C-17s are modified with microvanes, with two more expected to receive them at Joint Base Charleston, S.C., this month. That will kick off a six-month logistics service assessment, which the release said is the final step before fleetwide fielding.
Microvanes complement a wider Air Force effort to make its energy use more efficient. The branch’s 2023 Climate Campaign Plan called for using drag reduction, enhanced engine sustainment practices, and other tools to boost its “lethality per gallon,” i.e., the number of test events, weapons released, or other objectives accomplished per gallon of gas or other energy metric.
The plan aims to make operational energy usage for Air Force flying missions 5 percent more efficient by fiscal year 2027 and 7.5 percent by 2032. The service is also testing out a more efficient blended wing body prototype for possible future air lifters and looking into microgrids and small nuclear reactors to make its bases less reliant on nearby grids in times of crisis.