How Geese Will Save the Air Force Millions of Dollars
What’s good for the goose is good for the Air Force’s gander, apparently. The Air Force is seriously considering flying planes in formation like geese in order to potentially trim hundreds of millions of dollars off its staggeringly high fuel bill. The idea has been studied and tested. But it may take as much ...
What’s good for the goose is good for the Air Force’s gander, apparently.
The Air Force is seriously considering flying planes in formation like geese in order to potentially trim hundreds of millions of dollars off its staggeringly high fuel bill. The idea has been studied and tested. But it may take as much as three years to operationalize the concept, Air Force officials told FP.
Technically, the process is known as "vortex surfing." And it is used to great effect today by bike and car racers who capture the energy of the vehicle zooming in front of it, capitalizing, literally, on the vortex created by the lead racer. The Air Force figures that flying its planes in such a way could help to trim up to 20 percent off each trailing plane’s fuel burn rate. The Air Force’s total fuel bill in 2012 topped $9 billion-with-a-B. Officials at the service are eager to take the next step.
Here’s how it works: A cargo aircraft headed from the U.S. to Ramstein, Germany, say, joins with another jet headed in the same direction. One flies in the lead, and the other, the trail bird, assumes a position as much as 6,000-7,000 feet behind it, taking advantage of its tail wind and using far less energy. Last week, the Air Force did its first real test of vortex surfing, flying two jets from Edwards Air Force Base, Calif. to Hickam Air Force Base, Hawaii and back again, from July 9-11. Flying this way on the way home cut fuel consumption by as much as 7 percent on the way to Hawaii, according to Air Force officials.
Although the proof of concept was demonstrated last fall, this was the first time the Air Force had been able to test the human factor in the project: what the ride was like; how tired it made the crew; and how able they were to stay vigilant. The test also demonstrated the two planes’ ability to rejoin, descend, cruise and do night flight operations, as well as fly at sunrise and sunset, according to the chief scientist at the Air Force’s Air Mobility Command, Donald Erbschloe.
"People have been looking at how can we fly like birds probably since the earliest stages of aviation," Erbschloe said in a phone interview with FP. Some years ago, however, a DARPA official approached him and suggested trying a jet’s autopilot to fly in such a way. "That intrigued us quite a bit," he said.
Now jets like C-17s can create "wingtip vortex" and the trail planes get a free lift. "By riding that vortex, by surfing that vortex, we can transfer the energy that is lost by the lead aircraft and you can recapture some of that energy."
More than two jets flying in formation can be difficult — both operationally and logistically, since commanders have to find the jets all flying in the same direction at the same time. More than two planes flying together can also be a rough ride unless they are staggered, Air Force officials said.
Erbschloe says that the trail plane can reduce its fuel burn between 10 and 20 percent under optimal conditions. For AMC, which gobbles up two-thirds of the Air Force’s $9 billion fuel bill, "that’s significant," he said.
Air Force officials say vortex surfing is the future, so why didn’t anyone do it before now? One answer: avionics. Jet instrumentation is better than it once was. Another: incentive. After years of being handed a blank check from Congress, its money is drying up. Congress just doesn’t greet huge fuel bills when they come across its desk with the same indifference as it once did. The Defense Advanced Research Projects Agency, the Air Force Research Lab, NASA and Boeing all contributed to the project. Now it’s up to the Air Force to take the project and run with it. But Erbschloe said it could take up to three years before the concept is implemented across AMC.
Safety is the obvious concern, but Erbschloe said that those issues have been addressed and he’s confident in the concept. Part of the challenge will be socializing the concept to the layman. Some may believe that vortex surfing is akin to aerial refueling, in which an aerial re-fueler hovers freakishly close to the cockpit of the plane getting the top-off. But vortex surfing gives plenty of distance between planes — and plenty of time to react.
"The closure rate at that altitude and airspeed — you’ve got minutes to react," said Erbschloe, who is himself a retired pilot with 3,900 flying hours under his flight suit.
And the Air Force two-star who retired as the Air Force’s chief of safety agrees that vortex surfing passes safety muster.
"As long as the procedure is well-written, clear and the training is in place, then no, it wouldn’t be any different from any other Air Force operations," Frederick Roggero told FP. "I don’t see an issue."
The next step will be to create something called an advance technology demonstrator for the Department of Defense. Those tech "candidates" are currently under review and vortex surfing — Air Force acronym officials came up with Surfing Aircraft Vortices for Energy, or $AVE — is one of them. Last week’s test provided data in terms of fuel savings critical to its consideration. That process, which could begin as early as next year, will be the bridge to taking it from a nice idea to one that is operationalized across the Air Force and perhaps the military.
Roggero, who knows Erbschloe well and is familiar with what he’s trying to do at AMC, marvels at what the Air Force can learn from just looking at the sky.
"In essence, his basic philosophy is that the best, innovative ideas are found out in nature," said Roggero, who retired in 2010. "When you see the geese and ducks fly, some are working pretty hard and some of them are just cruising."