Wake Turbulence and Formation Flying
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Wake Turbulence and Formation Flying
I posted this on Sunday, but it seems not to have worked for some reason, however:
If two large aircraft are flying in close proximity, say USAF's B52 Bombers or airliners on a photo shoot, is there a large effect caused by the wake turbulence from each aircraft?
Many thanks,
Patsy
If two large aircraft are flying in close proximity, say USAF's B52 Bombers or airliners on a photo shoot, is there a large effect caused by the wake turbulence from each aircraft?
Many thanks,
Patsy
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Since wake turbulence usually decends behind the aircraft that creates it, I believe that one of the methods of dealing with it is to fly slightly above the lead aircraft. I do know from talking to C5 Galaxy pilots that when they perform in-air refueling from KC-135's, the bow wave of the C5 actually pushes the tail of the KC-135 up, causing the aircraft to nose down. The KC-135 pilot has to be ready to make an immediate correction when refueling a C5. Since most of the wake turbulence comes from the wing tips, I would imagine that as long as you stay inboard or outboard of the wingtips, it is less of an issue.
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Patsy001, since you asked about large aircraft and bombers in formation in a photo shoot...
That reminds me of the XB-70 crash in the 60s. An XB-70 AV2 (test air vehicle 2) was in a photo shoot with four other aircraft (fighters), all of which were equipped with GE engines. The fact that all 5 aircraft were GE engine equipped was the reason for the photo shoot, as a promotion for GE. A learjet was being used as the photo plane.
During the photo shoot, with all the aircraft in a tight formation (XB-70 leading) for the photo op, one of the fighters (an F104) flew in too close to the right wing tip of the XB-70. When it did, it got caught in the heavy wing tip wake vortex of the bomber, and was "blown" by the vortex over the top of the bomber and it struck both vertical stabilizers. The F104 was severed in half and decended in a ball of flames. The XB-70 flew on for a very brief time, then became unstable without the vertical stabs (which were torn off by the fighter) and decended in a dive and crashed.
So I think your question is a very good question from a safety perspective. This type of thing has to be watched carefully in photo shoots of aircraft in formation. Good planning with wake turbulance in mind, should prevent a safety problem from developing.
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Safe flying to you...
That reminds me of the XB-70 crash in the 60s. An XB-70 AV2 (test air vehicle 2) was in a photo shoot with four other aircraft (fighters), all of which were equipped with GE engines. The fact that all 5 aircraft were GE engine equipped was the reason for the photo shoot, as a promotion for GE. A learjet was being used as the photo plane.
During the photo shoot, with all the aircraft in a tight formation (XB-70 leading) for the photo op, one of the fighters (an F104) flew in too close to the right wing tip of the XB-70. When it did, it got caught in the heavy wing tip wake vortex of the bomber, and was "blown" by the vortex over the top of the bomber and it struck both vertical stabilizers. The F104 was severed in half and decended in a ball of flames. The XB-70 flew on for a very brief time, then became unstable without the vertical stabs (which were torn off by the fighter) and decended in a dive and crashed.
So I think your question is a very good question from a safety perspective. This type of thing has to be watched carefully in photo shoots of aircraft in formation. Good planning with wake turbulance in mind, should prevent a safety problem from developing.
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Safe flying to you...
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Patsy, it depends what your position is in regard to the aircraft you are formating on.
Line abreast or vic should result in very little turbulence at all.(unless you are flying very close, a la red arrows).
Line astern depends on how close to the centre line of the preceeding aircraft you are and the distance from it. Some aircraft are very smooth to fly behind, some quite violent and some have a turbulent area that doesn't disappear until you get within 60 - 100 ft of them. It helps if you avoid flying directly behind the engines or wing tips.
Line abreast or vic should result in very little turbulence at all.(unless you are flying very close, a la red arrows).
Line astern depends on how close to the centre line of the preceeding aircraft you are and the distance from it. Some aircraft are very smooth to fly behind, some quite violent and some have a turbulent area that doesn't disappear until you get within 60 - 100 ft of them. It helps if you avoid flying directly behind the engines or wing tips.
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Steve757 is right.
The thing about photo shoots is that it's like your family. When you want to take a picture of them, you get them all together, then you tell them to move in close, so you can get all of them in the frame.
It's the same with aircraft. It's that desire to get them in close together for the right shot, that can get you in trouble. If you could get some wake turbulence info on each aircraft you want in the shoot, then you can figure out the best way to arrange the aircraft in formation, to accommodate both the visual effect you're looking for and the wake turbulence safety issues.
If you're going to do a close formation for the photo op, then you'll need pilots with good formation flying skills, as crashes occur all too often with pilots (mostly GA pilots) who try formation flying, and don't have the special skills and training that safe formation flying requires. In fact, I think it would be good wisdom to confirm that each pilot participating in formation flying, has the necessary skills and training before you allow them (or encourage them) to participate.
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Safe flying to you...
The thing about photo shoots is that it's like your family. When you want to take a picture of them, you get them all together, then you tell them to move in close, so you can get all of them in the frame.
It's the same with aircraft. It's that desire to get them in close together for the right shot, that can get you in trouble. If you could get some wake turbulence info on each aircraft you want in the shoot, then you can figure out the best way to arrange the aircraft in formation, to accommodate both the visual effect you're looking for and the wake turbulence safety issues.
If you're going to do a close formation for the photo op, then you'll need pilots with good formation flying skills, as crashes occur all too often with pilots (mostly GA pilots) who try formation flying, and don't have the special skills and training that safe formation flying requires. In fact, I think it would be good wisdom to confirm that each pilot participating in formation flying, has the necessary skills and training before you allow them (or encourage them) to participate.
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Safe flying to you...
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There's an interesting point that this reminds me of. If you have a formation in the V shape it cuts down on lift induced drag. This happens because the wingtip behind the wingtip of the aircraft in front has its vortices effectively cancelled or reduced.
Apparantly this is why migratory birds fly in this formation . Every now and again they change the leading bird as he is the only one feeling the full effects of induced drag on both wings.
How jolly interesting What What!!!!
Apparantly this is why migratory birds fly in this formation . Every now and again they change the leading bird as he is the only one feeling the full effects of induced drag on both wings.
How jolly interesting What What!!!!
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Since we're off on tangents...
I read the other day that the newly realeased avionics software package (Block 5.3) to be loaded on the Lockheed/Martin C-130J Hercules systems, now includes "fully automatic formation flying". I wonder how that works?
Honest, it's true, read it here.
http://news.lmasc.com/article.htm?article_id=307
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Safe flying to you...
I read the other day that the newly realeased avionics software package (Block 5.3) to be loaded on the Lockheed/Martin C-130J Hercules systems, now includes "fully automatic formation flying". I wonder how that works?
Honest, it's true, read it here.
http://news.lmasc.com/article.htm?article_id=307
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Safe flying to you...
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FS, the C130H can be fitted with station keeping radar. Essentially a secondary radar which gives a plan view of a group of aircraft. Additionally, by inputs to the pitch and bank bars of the ADI and by use of a 'fore/aft' distance indicator it is possible to fly an accurate position displaced from the formation leader. The auto system probably couples the autopilot to the SKe Radar. What it will not do is allow aircraft to fly Blue Angel typr formations 'hands off' !
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Done a bit of that stuff myself. The punch line is, the more lift the a/c needs to produce to stay airborne, the further you stay away from it (behind and below) If you fly close formation in a vic position and the lead increases the g-load during a maneuver, the downwash from his wing increases and you tend to roll towards him, if you do not counter the effect. So, if its big, stay beside, above or infront(not when its faster than you)
