Heavies flying in formation to save fuel
Trash du Blanc
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Heavies flying in formation to save fuel
Aerospace Daily: Engineers See Fuel Savings From Formation Flight
By Jefferson Morris/Aerospace Daily
26-Nov-2001 3:53 PM U.S. EST
NASA is partnering with engineers at Boeing and UCLA to help aircraft mimic a practice migratory birds have perfected over millions of years -- flying in formation to reduce drag and conserve energy.
Autonomous Formation Flight (AFF), if proven, could eventually enable fuel savings as high as $2 million per large commercial transport aircraft per year, according to AFF Project Manager Gerard Schkolnik of NASA's Dryden Flight Research Center.
In fact, the bigger the aircraft, "the bigger the savings," Schkolnik told The DAILY. In the case of a 777 flying a transcontinental route, "for each trailing aircraft in formation you would save anywhere between half a million to two million dollars per trailing aircraft," he said.
"The emissions reductions are staggering as well -- on the order of 10 million pounds of CO2 reductions, and about 100,000 pounds of NOX reductions per trailing aircraft per year," he added.
The principle of AFF seems simple.
"Any bird or a trailing aircraft flying in formation experiences a drag reduction by taking advantage of energy which is shed by the lead aircraft or bird, via the wingtip vortex," explained Schkolnik. "What the trailing aircraft or trailing bird is trying to do is fly in a position that essentially generates an upwash, which then reduces the amount of energy that is required by the aircraft or bird to be able to maintain position."
By Jefferson Morris/Aerospace Daily
26-Nov-2001 3:53 PM U.S. EST
NASA is partnering with engineers at Boeing and UCLA to help aircraft mimic a practice migratory birds have perfected over millions of years -- flying in formation to reduce drag and conserve energy.
Autonomous Formation Flight (AFF), if proven, could eventually enable fuel savings as high as $2 million per large commercial transport aircraft per year, according to AFF Project Manager Gerard Schkolnik of NASA's Dryden Flight Research Center.
In fact, the bigger the aircraft, "the bigger the savings," Schkolnik told The DAILY. In the case of a 777 flying a transcontinental route, "for each trailing aircraft in formation you would save anywhere between half a million to two million dollars per trailing aircraft," he said.
"The emissions reductions are staggering as well -- on the order of 10 million pounds of CO2 reductions, and about 100,000 pounds of NOX reductions per trailing aircraft per year," he added.
The principle of AFF seems simple.
"Any bird or a trailing aircraft flying in formation experiences a drag reduction by taking advantage of energy which is shed by the lead aircraft or bird, via the wingtip vortex," explained Schkolnik. "What the trailing aircraft or trailing bird is trying to do is fly in a position that essentially generates an upwash, which then reduces the amount of energy that is required by the aircraft or bird to be able to maintain position."
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Sometimes I wish we could send these daft Einstein wanabees forward twenty years to evaluate their grand schemes in hindsight.
They could then read the news headlines that spoke of 1000 plus people dying in one accident involving the midair collision of two large civil airliners (A380's perhaps).
The catchline underneath would go something like:- "Airlines put their profits ahead of safety by flying dangerously close to save fuel."
Hijackers could bring down two (or more) airplanes by hijacking just the one.
Why not save weight by doing away with engines on the trailing aircraft and just towing them across the pond as giant gliders?
NOTOPS?
If something seems too good to be true....it probably is!
They could then read the news headlines that spoke of 1000 plus people dying in one accident involving the midair collision of two large civil airliners (A380's perhaps).
The catchline underneath would go something like:- "Airlines put their profits ahead of safety by flying dangerously close to save fuel."
Hijackers could bring down two (or more) airplanes by hijacking just the one.
Why not save weight by doing away with engines on the trailing aircraft and just towing them across the pond as giant gliders?
NOTOPS?
If something seems too good to be true....it probably is!
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weve been doing it for years in the mil. not to save gas but to ease nav and comms. And having dispenced and received fuel from heavy jets I can only say that I am a little worried about the claims of wake turb bringing down a heavy jet. I think we are in the process of learning about accumulative fatigue on bonded materials
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This is all fine in theory, but any tanker pilot will tell you that formation flying in a heavy uses LOTS of fuel. The extra fuel burn caused by throttle-pumping to stay in position more than offsets any savings to be made from upwash effects.
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Im no aviator, but I knew a guy who flew refuelers for SAC, he used to talk about the work involved to keep in formation with the B-52s. I recall it required some serious flying and jockeying ( read fuel burn) to stay in place.
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The AFF program as it was explained to me is to develop computerised controls that maintain aircraft position in optimum formation position to exploit energy savings. The idea is for the computer to do keep formation smoothing out the "human" tendency to jockey the throttles
Having said that it gives me great pause to think about two jumbos flying tight formation controlled by computers
Having said that it gives me great pause to think about two jumbos flying tight formation controlled by computers
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I can just see it "The Flying Jumbos" all with pretty little pictures of Dumbo and his big ears painted onto the aircraft, and how about the long arm of the law doing helicopter formation flying? They could have some of Capt P's flying pigs as their logo. 
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The USAF did something like it in the 60s by joining up two or more straight wing fighters wing tip to wing tip and it resulted in fuel savings of over 20%. The experiment was called off after a couple of accidents caused by a loss of control by the slave airplane which caused it to roll over onto the lead without decoupling.
Great video of it on the History channel in the US last year.
A good idea for the time, but not really practical for passengers.
Great video of it on the History channel in the US last year.
A good idea for the time, but not really practical for passengers.
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It sounds like a good idea, the only problem is that formation would have to be broken every time IMC was entered, and collision avoidance would become a bigger concern.
Also, what if one of the planes has a problem ? what he īs leaving a contrail behind ? what if he has to descend rapidly...Communication would go from the 5th or so step in the memory items to the 2nd one.
I donīt know...lotsa testing I guess before bringing 200 pax/million dollar planes within half a mile apart, I guess.
Good luck guys !!
Also, what if one of the planes has a problem ? what he īs leaving a contrail behind ? what if he has to descend rapidly...Communication would go from the 5th or so step in the memory items to the 2nd one.
I donīt know...lotsa testing I guess before bringing 200 pax/million dollar planes within half a mile apart, I guess.
Good luck guys !!
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What about Airport overload, imagine 4+ full pax 747's or even the A380 (one day) arriving at an airport all at once, the surge of pax would be incredible, it would cause caos, as it allready does. Its allready battle mode at heathrow/gatwick/manchester (definatly the latter) trying to get baggage.
And the wake, is there someway around that one, i.e fly in certain formation to create a perfect flight? Probs not!
And the wake, is there someway around that one, i.e fly in certain formation to create a perfect flight? Probs not!
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Flying multi-ship formations of C-141's, I can tell you that fuel burn increases dramatically for the follower/wingmen due to all the throttle jockeying to keep position, You'd have to have a hell of an auto-pilot to achieve very tight spacing between aircraft to achieve the desired results. Also the amount of fatigue induced by flying formation for long periods of time is incredible, like flying a CatII approach to a moving runway for 5 or 6 hours non-stop!!!just ask those B-17 drivers of yore.
