The Air Force is currently pursuing next-generation aircraft structure research programs with the help of NASA and other federal and commercial partners, Kevin Geiss, Deputy Assistant Secretary of the Air Force, Energy, said in an interview with Military.com
“A blended wing-body is one example. Instead of a monocoque where you have the fuselage and the wings coming off, the wing is conformal with the aircraft. The lifting part of the aircraft blends right into the cargo or storage part,” said Geiss.
This design is configured to optimize fuel efficiency by decreasing the “drag” or airflow passing around the aircraft while still achieving maximum lift and cargo-carrying capacity.
Fuel efficiency is a huge part of the Air Force’s future energy strategy, as the service uses more than 2 billion gallons of aviation fuel every year, according to a March 2012 service report titled “Energy Horizons – A Science and Technology Vision for Air Force Energy.”
The report mentions non-traditional airframes or “blended-wing body” technology along with other aerodynamic improvements such as conformal antennas and winglets, or shaped curves at the end of an aircraft’s wings designed to optimize air flow over the wings.
“Center of gravity controls and lift-distribution control systems enhance performance by ensuring that lift is efficiently appropriated across the aircraft in relation to the location of the carried weight,” the essay states.
Another fuel-efficiency enhancing technique is something Geiss referred to as “Mission Index Flying,” a technique designed to help an aircraft optimize its route by using sensors and meteorological technology to take advantage of the weather conditions in real time.
In some cases, such as with the Air Force’s C-17, fuel efficiency can be improved by slightly decreasing airspeed while flying, thus reducing drag, Geiss said.
The Air Force has also learned how to be more efficient with palates and develop methods of weight distribution and packing designed to lower flight weight of cargo planes, Geiss said. This too results in increased fuel efficiency.
Also, although the Air Force is not currently acquiring any alternative fuels for operational use, the service does hope to be able to purchase about one-half of its fuel as cost-competitive alternative, drop-in fuels by 2020, Geiss explained.
The Air Force could wind up acquiring large quantities of biofuels, alternative fuels or synthetic blend fuels, Geiss added.
“This depends on industry to figure out a way to make these fuels cost-competitive. We are not going to get out in front of industry so it is up to them to figure out how to develop their processes. We’re not going to ask for an increase in the fuel budget because alternative fuel should be the same price,” Geiss said.