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Aircraft to fly in formation 1.8 nm apart to save fuel like geese do

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Aircraft to fly in formation 1.8 nm apart to save fuel like geese do

Old 20th Nov 2019, 12:13
  #41 (permalink)  
 
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Originally Posted by jimjim1

……….. and the only modification required would be flight control systems software. …
Yeah, because that control software scheme has worked out so well in recent months?
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Old 20th Nov 2019, 12:32
  #42 (permalink)  
 
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For some airlines this would not be hard to achieve on certain routes. I regularly fly from HKG to the USA, Europe and AUS. Almost every time we are in a cluster of other company aircraft. It is not unusual to have 5+ company aircraft within 100 miles of each other on the same airway. On 8-15+ hr flights it would not take up a huge amount of time to close gaps between adjacent pairs. If you have doubts look at flight radar24 at 1800z at the line of CX aircraft heading to Europe and also the USA.
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Old 20th Nov 2019, 16:19
  #43 (permalink)  
 
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Why don't we do formation take offs/landings too? double runway capacity with immediate effect! Narrow bodies only for now though I'd guess.
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Old 20th Nov 2019, 17:00
  #44 (permalink)  

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Codswallop!

Moderate/severe turbulence, engine problems/shutdowns, depressurisation, sick pax/crew, formating and deformating of aircraft, all would make the idea untenable. Plus the first collision between 2 airliners would bring hundreds of dramatic deaths and an end to the silly concept.

Just a smokescreen from manufacturers to virtue-signal their green credentials.
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Old 20th Nov 2019, 17:14
  #45 (permalink)  
 
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Originally Posted by compressor stall
If you're a pilot you'd know that wake vortices tend to stay directly behind the wing tips, they don't expand outwards (much).

The plan here is not to fly in the vortex or the wake, much the same way geese don't.

Here's the source info from the public project release at Dubai this week.

https://www.airbus.com/newsroom/pres...rformance.html

Honk
How far away was that CRJ that ran into the vortice from the 380 heading the opposite direction?
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Old 20th Nov 2019, 17:17
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Old 20th Nov 2019, 21:07
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Originally Posted by b1lanc
How far away was that CRJ that ran into the vortice from the 380 heading the opposite direction?
From a briefing I saw a couple of years ago the 604 was some 15nm behind and 1000' underneath on a reciprocal track, so rather irrelevant for this discussion. But to indulge your digression, it was going to be an unpleasant ride, but there's a bit more to the cause of the severity of that accident that hasn't been coherently published yet (but the data is public). One can infer what it's about from the BFU interim report and the "what not to do in wake turbulence encounters" information promulgated in more recent times.

Funnily enough the formation being proposed would actually have the surfing aircraft further away from the lead aircraft's vortices than an aircraft on a 1nm lateral SLOP recommendation to avoid descending vortices.
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Old 20th Nov 2019, 22:17
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Hmm. Most of the guys I know who have formation cards have, at least once in their training 1) fully stalled an airplane to a break, 2) know how to do a chandelle and a lazy eight, 3) can land something with a tail wheel, and 4) can reliably hand fly some sort of a non-precision approach.

I really wouldn’t trust most of the regional jet jocks who learned to “fly” in a Cirrus without ever having to consider the vagaries of power, pitch, and mixture, and who did a commercial in something that was only “complex” by virtue of a glass panel to do the job...
(flame on)

Last edited by 421dog; 20th Nov 2019 at 23:02.
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Old 20th Nov 2019, 23:02
  #49 (permalink)  
 
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Originally Posted by 421dog
Hmm. Most of the guys I know who have formation cards have 1) fully stalled an airplane, 2)know how to do a chandelle and a lazy eight, and 3) can land something with a tail wheel.
I really wouldn’t trust most of the regional jet jocks who learned to “fly” in a cirrus and did a commercial in something that was “complex” by virtue of a glass panel to do the job...
(flame on)
Autopilot would be doing the flying anyway.

I think this is far easier to implement than replacing Jet A1 with biofuel.

Of course there's plenty of people saying it's all too hard, but the fact is 99%+ of cruise flight is a non-event and could easily manage this. Hit bad turbulence or there's an operational issue? Ok fine break out of formation, it's not the end of the world you'll just burn use fuel you would have burned anyway.

If these cost savings are as high as implied then there is a huge low-hanging fruit for airlines to work together here.
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Old 20th Nov 2019, 23:09
  #50 (permalink)  
 
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Originally Posted by chuboy
Autopilot would be doing the flying anyway.

I think this is far easier to implement than replacing Jet A1 with biofuel.

Of course there's plenty of people saying it's all too hard, but the fact is 99%+ of cruise flight is a non-event and could easily manage this. Hit bad turbulence or there's an operational issue? Ok fine break out of formation, it's not the end of the world you'll just burn use fuel you would have burned anyway.

If these cost savings are as high as implied then there is a huge low-hanging fruit for airlines to work together here.

Yup, and my point is, that, when I am flying, maybe closer to another airplane than IFR seperation might dictate, but still with visual separation, I am fairly comfortable with not flying into a guy buzzing along beside me.

i am worried that those who are not accustomed to the direct control of their craft might represent a hazard.
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Old 20th Nov 2019, 23:22
  #51 (permalink)  
 
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Go back and read the original article - 12% saving at 55 ft. Let me repeat that - 55 FEET! It wouldn't take much of a system malfunction to result in a mid-air at 55 ft. - especially given it would be on auto-pilot so the crew reaction time to a malfunction wouldn't be good.
Airbus has said 1.8 nautical miles - which is doable, but the potential benefit would be a tiny - less than 1% - and things like turbulence and cross winds mean that the 'sweet spot' would be constantly moving around so staying in the right spot for hours on end would be non-trivial.
There may be some potential benefit for military - where close formation flying is the norm.
For passenger service, it's a pipe dream...
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Old 20th Nov 2019, 23:37
  #52 (permalink)  
 
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And Altas - as for formation flying skills - are you allowed to fly above FL290 without and autopilot?
No. Of course not.

I understand the point you are making, but there is no such thing as something that cannot fail.

The reality is that when the automatics fail, which they can do quite readily, some aircraft can be quite a bit more difficult to operate and more importantly, because the automatics are almost always engaged, some drivers won't have recent practice to fall back on.

And that's the problem. Every day there would be thousands of events around the world where the automatics drop their bundles, and it's simply fixed by the pilots. If you stopped those fixes, it would start raining aluminium.
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Old 21st Nov 2019, 03:03
  #53 (permalink)  
 
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[img]blob:https://www.pprune.org/5b2d80f1-2225-4890-b213-6103dca187f2[/img]

Goosed or Ducked, take your pick.

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Old 21st Nov 2019, 03:18
  #54 (permalink)  
 
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Salute!

Tnks for the reminder , TDracer. Ya gotta be close to have help. but you can be a half mile behind a heavy and see some serious roll and such.

We "lights" saw the effects of the wing downwash/upwash/vortex on a daily basis in close formation. Figure ten to fifteen feet or so.

As an experiment on a cross ocean mission I tried to use the vortex of the KC-135 tanker while maintaining nose-tail seperation ( B-70 crash fully on my mind). Sure enough, as I closed from the stern I had to hold left stick , although I was on the starboard side. So I was riding the "wave" like a surfer. Pulled back power a bit and stayed right with the tanker. My fuel flow went down a few hundred pounds per hour. So those geese have figured it out prolly a few hundred thousand years ago, ya think?

Gums recalls....
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Old 21st Nov 2019, 08:30
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Lead aircraft will have a higher fuel burn than following aircraft, thus will want to climb to a higher optimum altitude early than the following one. What then?
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Old 21st Nov 2019, 12:16
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Originally Posted by DroneDog
Will it be mandatory for the following pilots to "honk" to encourage the lead aircraft?
I assume that the externally fitted Horn thus fitted will be fully FAA approved.
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Old 21st Nov 2019, 14:14
  #57 (permalink)  
 
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Salute!

@ cog....

Lead aircraft will have a higher fuel burn than following aircraft, thus will want to climb to a higher optimum altitude early than the following one. What then?
Well, you follow the procedure that the geese do. Just watch a migration formation and see the lead goose change positions and a new one takes over for awhile, then another and so forth. Dem geese ain't dumb!

My tanker buddies tell me that refueling Air Force one and other big planes "pushes" them due to the "bow wave".

In the final analysis, it is actually possible to get "help" from a buddy to reduce fuel flow or even stay up due to an engine loss. But you need to be fairly close and have done it before when not under duress. Of course, then there's "Pardo's Push" as a last resort.

Gums sends...
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Old 21st Nov 2019, 14:31
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Originally Posted by gums
Salute!

@ cog....



Well, you follow the procedure that the geese do. Just watch a migration formation and see the lead goose change positions and a new one takes over for awhile, then another and so forth. Dem geese ain't dumb!

My tanker buddies tell me that refueling Air Force one and other big planes "pushes" them due to the "bow wave".

In the final analysis, it is actually possible to get "help" from a buddy to reduce fuel flow or even stay up due to an engine loss. But you need to be fairly close and have done it before when not under duress. Of course, then there's "Pardo's Push" as a last resort.

Gums sends...
We got a little nudge from the B-52s...enough to be noticeable. Basically nothing, from another -135. Nose is too pointy. But a C-141 had a significant bow wave, with that broad nose, and the C-5 was like wintertime at Steamer Lane; a great big wave. My 19-year-old Boom Operator gave me very accurate range calls as a C-5 moved in, and I would give little anticipatory bursts of trim, based on his calls. The old autopilot would often kick off, with C-5s, so I just did it all manually.

Another neat thing that the Old Boeing did was design the -135 and the B-52 to work together aerodynamically. The B-52 wingtips were outside of our downwash and vortices. If the Buff moved right, he had more wing outside the downwash on the right side, and the plane naturally wanted to ease back to the left. I wouldn't be surprised if the combo of the two airplanes wasn't a little more fuel efficient...with 12 motors running, I don't think we would have noticed much. But if 55 feet is an optimum distance, we were right in that range (not counting the boom, which of course was touching the other airplane).

Squawk was a pretty simple matter. Lead tanker squawked, anyone on the boom or the wing went STBY, and the farthest trailer behind also squawked. At times we had five tankers in trail, each with a flock of receivers. The formation would be more than 5 miles long. Lots of metal between those two transponder returns.
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