Air Force C-17 Globemaster IIIs like these are unique among airlifters because they have winglets, vertical add-ons to the wings to reduce drag. (Tech. Sgt. Shane A. Cuomo / Air Force)
- Filed Under
Vertical add-ons to the wings of massive C-5Ms could save about 2.8 million gallons of fuel per year, according to a team of researchers who just completed wind tunnel tests on the aircraft.
The team, from Lockheed Martin, the Air Force Research Laboratory and the Arnold Engineering Development Complex at Arnold Air Force Base, Tenn., attached winglets, the vertical add-ons, to the wings of a 10-foot-wide model of a C-5M Super Galaxy. Winglets reduce drag on an aircraft by altering the airflow off the plane's wingtips, which can improve fuel efficiency during takeoff and cruising. After completing the wind tunnel tests in November, Lockheed officials predicted a fuel savings of 4 percent, or 2.8 million gallons of fuel per year, if the winglets were installed on the Air Force's 52 C-5Ms.
"This looks like it would be a good enhancement for the airplane if the Air Force would like to take the next step," said Jack O'Banion, Lockheed's director of air mobility improvements and derivatives.
The idea came through testing of similar winglets on the C-130 Hercules, O'Banion said. Winglets are already on C-17 Globemaster IIIs and many commercial jets.
The program came from an energy efficiency contract from the Air Force to collect data on the aerodynamics, reduction of stability control and pressure changes from adding winglets, said Eddie Fletcher, the electronic principal engineer for the program at Lockheed Martin. During the test, the C-5M model was placed in a 16-foot wind tunnel at the Arnold Engineering Development Complex.
The winglet designed by Lockheed Martin would not increase the width of the C-5, important given that there are few facilities large enough to fit the large plane.
The Air Force has been flying the C-5 Galaxy since it was first operational in 1970, and the jumbo jet has undergone little change since then, other than the engine and cockpit upgrades for C-5M Super Galaxys.
"We have not fundamentally altered the shape of the C-5 since it was created in the '60s," O'Banion said.
The Air Force flies 88 C-5s of all variants. Long-term plans call for flying 52 of the upgraded C-5Ms with an expected service life of beyond 2040.