Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
ltbewr
Topic Author
Posts: 15272
Joined: Thu Jan 29, 2004 1:24 pm

Airbus studing aircraft flying in formation

Mon Sep 21, 2020 2:43 pm

Airbus has been studying the concept of like flocks of birds, commercial aircraft flying in formation, taking advantage of the 'wake' of aircraft before them for fuel savings. It is counter-intuitive to usual flying concepts and could go very wrong as wake turbulence and reaction to it caused the AA 587 crash, but one has to wonder if it can work if carefully done. https://www.yahoo.com/finance/news/why- ... 00178.html.
 
User avatar
Starlionblue
Posts: 20092
Joined: Fri Feb 27, 2004 9:54 pm

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 2:50 pm

Nothing wrong in concept. It is pretty well-understood physics. The difficulty would be implementation. How do you coordinate? Plus you need aircraft going in the same direction at the same time.

The AA587 crash is not really applicable. This system would be applied in the cruise with the wake effects managed and expected. AA587 was at low level with no control over specific separation. Furthermore, the FO on that flight reacted entirely inappropriately, which resulted in the fin coming off.

IIRC, this has been studied by Airbus for years.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
CosmicCruiser
Posts: 2443
Joined: Tue Feb 22, 2005 3:01 am

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 2:54 pm

That was my thoughts Starlionblue. Just the logistics of this seems impossible.
 
FGITD
Posts: 1037
Joined: Wed Jun 15, 2016 1:44 pm

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 4:38 pm

CosmicCruiser wrote:
That was my thoughts Starlionblue. Just the logistics of this seems impossible.


It’s a fun idea to imagine. A 787 takes off from LAX to LHR, and as it crosses North America, more of that airline's flights form up on it and cross the Atlantic together.

In reality though...not so simple. If it's one airline, at what point are the flights flying inefficient routings to meet up with each other? If they're separate airlines on the same tracks, why would they help each other? I can't see LH letting a few AA flights trail them for their own efficiency, or AF leading a flock of Norwegians into CDG, etc etc etc the list goes on and on.

Also would be a logistical nightmare on the arrival end at a hub. Imagine all the BA north American flights arriving into LHR more or less one after another.
 
zuckie13
Posts: 312
Joined: Fri Mar 02, 2018 8:23 pm

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 4:40 pm

1) Can you logistically get a bunch of aircraft to hit the same point at the same time to get into formation?. How much fuel would you waste getting them into place/holding/waiting etc. and would the savings make up for it. You can try to get planes from several northeast airports to get together and fly information towards SFO, but good luck having each hit it's departure time perfectly to make it work.

2) Would you be able to maintain passenger comfort doing this or you be suffering from turbulence the whole way (well except for the lead plane)?

I agree, I think the AA587 type thing is not the big issue - you'd probably be on some type of cross-linked autopilot anyway while in formation. Just don't write the software to slam the rudder hard over and you'll be fine.

I agree
 
gloom
Posts: 476
Joined: Thu Jun 30, 2016 4:24 pm

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 6:09 pm

CosmicCruiser wrote:
That was my thoughts Starlionblue. Just the logistics of this seems impossible.


Difficult sure, but not impossible.

You can set airliners Mach speed to a 0.01 Ma at least (most of them with 0.001 step). On cruise, that's between 4 and 5 kts difference for 0.01Ma. When on NAT or Siberia route (Europe to Japan), there's plenty of traffic now separated by altitudes, or with lateral separation close enough to use hour or two to get within distance, then match speeds for the rest of the route. Sure, not as easy as I speak, and requires specific routes/LR ops, but I guess still quite possible. It's also/just something most pilots have been taught NOT to do. This could be the most difficult part.

Cheers,
Adam
 
GalaxyFlyer
Posts: 6252
Joined: Fri Jan 01, 2016 4:44 am

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 8:03 pm

Do six or eight hours of close formation and see how it works.
 
mxaxai
Posts: 1983
Joined: Sat Jun 18, 2016 7:29 am

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 8:05 pm

gloom wrote:
CosmicCruiser wrote:
That was my thoughts Starlionblue. Just the logistics of this seems impossible.


Difficult sure, but not impossible.

The difficult part is, how do you manage to make all these aircraft meet? Just a minute delay during takeoff or climb will result in several kilometers separation at the rendezvous point.

Does one aircraft circle and wait? Does the delayed aircraft speed up or the early aircraft slow down (both less efficient)?

What if one of the aircraft wants to climb higher, but the other is too heavy to follow?

What if different models have different optimal cruise speeds (e. g. A320 cruises at M.78, A330 cruises at M.82 and A350 cruises at M.85)?

How much of a detour are you willing to take to join a formation, assuming your departure and destination airports are different from the others?
 
dragon6172
Posts: 1128
Joined: Sat Jul 14, 2007 9:56 am

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 10:13 pm

How close of form does one have to fly to get the benefits? Can't imagine flying hours on end, at night, in close formation.
As someone else said, I'd imagine there would have to be some autopilot function for this to work.
Phrogs Phorever
 
GalaxyFlyer
Posts: 6252
Joined: Fri Jan 01, 2016 4:44 am

Re: Airbus studing aircraft flying in formation

Mon Sep 21, 2020 10:31 pm

I’ve done it at night, in cloud, it’s not fun. Well, at least, as I think of fun being fun.
 
User avatar
Starlionblue
Posts: 20092
Joined: Fri Feb 27, 2004 9:54 pm

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 12:07 am

The article talks about "over a mile apart". Not exactly close formation, but still much closer than airliners are allowed today.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
gloom
Posts: 476
Joined: Thu Jun 30, 2016 4:24 pm

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 4:55 am

mxaxai wrote:
The difficult part is, how do you manage to make all these aircraft meet? Just a minute delay during takeoff or climb will result in several kilometers separation at the rendezvous point.


And yet ATC manage to handle them all over the route. Delayed or not. "XXX, able to increase speed to .76? Increase .76 traffic ahead". Speed increase/reduction and directs/headings make up for plenty of opportunities to stack up traffic on operational basis, not pre-planned.

As I said, I imagine them mostly on already-busy LR routes, since some of these are even over capacity (see Siberia overfly). If you have 5 tracks over Altantic, you can expect planes at right hours to stack up. Then, it's only a matter of up to 1 hr to properly adjust distances. You don't need to plan ahead, really.

Cheers,
Adam
 
GogonAger
Posts: 11
Joined: Sat Aug 01, 2020 8:10 pm

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 8:14 am

I would guess that it is not meant to be manually formation flying like i image the stuff done by military but automated flying in specific locations relative to other aircrafts at closer distance then currently possible. That would most likely require some form of direct communication and therefore active participation between the aircraft.

As already mentioned one airline might not have so much planes going the same direction for a long enough route to make it work, so an industry wide standard would be required and those are usually either enforced to increase safety or pushed by industry because of customer wishes, developments etc. Later would have to the case in this scenario.

Unfortunately i think is it not that achievable for an airline to develop (or let a manufacturer develop) the standards for such a complex system if the savings would be shared with all their competitors. So i think that this is a very nice concept that has the potential to save some fuel on the highly used routes while also decrease the congestions but at the moment it is hard to me to imagine seeing something like that in more than experimental setups done by the larger manufacturers. But these are of course just my personal thoughts. Would be happy to be proven wrong....
 
User avatar
SheikhDjibouti
Posts: 2278
Joined: Sat Sep 30, 2017 4:59 pm

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 12:24 pm

mxaxai wrote:
gloom wrote:
CosmicCruiser wrote:
That was my thoughts Starlionblue. Just the logistics of this seems impossible.

Difficult sure, but not impossible.

The difficult part is, how do you manage to make all these aircraft meet? Just a minute delay during takeoff or climb will result in several kilometers separation at the rendezvous point.


With the indulgence of those in charge of a.net, I will post a link to FR24, showing the North Atlantic today at around 03:00 UTC
Note the multiple trains of westbound a/c all following each other. (ok, so the icons are often only estimated positions, but still...)
https://www.flightradar24.com/2020-09-2 ... 6,-28.92/5

As these flights approach leave Canada, or approach Ireland (<250 miles), the tracks change from estimated to actual, (which often makes little difference) so you can better see who is proximate to whom. I believe there is also some degree of satellite tracking being rolled out.

Take as an example Virgin VS4 (789) & BA294 (789) one from ORD, the other from JFK, both inbound to LHR. As they pass YYT they are maybe 50 miles apart. But as they arrive over Shannon the image on FR24 is of one a/c superimposed upon the other (FL380 vs FL410). They couldn't be any closer!

The different flight levels is at least in part due to ATC separation requirements; VS4 (the lower a/c) having reached a higher altitude (FL390) whilst still over Newfoundland several hours earlier.
And the 50 miles horizontal separation over Newfoundland could have been mitigated by a very slight course alteration from the ORD flight, to ensure a rendezvous.

So, on this particular occasion, these two a/c, from different airports, with departure times two hours apart from each other, could have formed a pair across the pond.

But not on any of the three previous flights, where VS4 crossed the Atlantic in splendid isolation! Where was BA294 on these days? I have no idea. :scratchchin:

So yes, logistically it could be a nightmare, with individual pairings being arranged ad hoc only after both aircraft were definitely airborne.
Sounds like a job for a supercomputer. :lol:

p.s. for those who aren't familiar with geography, these two a/c were both headed for London, but near identical tracks would also be used by a/c heading for Paris, Brussels, AMS, FRA, etc etc. Pairs of flights can be made from aircraft with different departure and different arrival points. The common elements must be speed, altitude, and ... timing!
Nothing to see here; move along please.
 
GalaxyFlyer
Posts: 6252
Joined: Fri Jan 01, 2016 4:44 am

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 2:52 pm

GogonAger wrote:
I would guess that it is not meant to be manually formation flying like i image the stuff done by military but automated flying in specific locations relative to other aircrafts at closer distance then currently possible. That would most likely require some form of direct communication and therefore active participation between the aircraft.

As already mentioned one airline might not have so much planes going the same direction for a long enough route to make it work, so an industry wide standard would be required and those are usually either enforced to increase safety or pushed by industry because of customer wishes, developments etc. Later would have to the case in this scenario.

Unfortunately i think is it not that achievable for an airline to develop (or let a manufacturer develop) the standards for such a complex system if the savings would be shared with all their competitors. So i think that this is a very nice concept that has the potential to save some fuel on the highly used routes while also decrease the congestions but at the moment it is hard to me to imagine seeing something like that in more than experimental setups done by the larger manufacturers. But these are of course just my personal thoughts. Would be happy to be proven wrong....


As we should we’ll know, if it’s an automatic flight mode, the pilots must be fully capable of taking over manually and continue flying. Lose sight of the “lead” airliner and automatics fail, the pilot needs to be ready to safely separate from the formation.
 
User avatar
SheikhDjibouti
Posts: 2278
Joined: Sat Sep 30, 2017 4:59 pm

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 3:12 pm

GalaxyFlyer wrote:
As we should we’ll know, if it’s an automatic flight mode, the pilots must be fully capable of taking over manually and continue flying. Lose sight of the “lead” airliner and automatics fail, the pilot needs to be ready to safely separate from the formation.

Losing sight of the lead airliner; does that happen often at FL390 or above?
Nothing to see here; move along please.
 
VSMUT
Posts: 4571
Joined: Mon Aug 08, 2016 11:40 am

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 3:27 pm

SheikhDjibouti wrote:
GalaxyFlyer wrote:
As we should we’ll know, if it’s an automatic flight mode, the pilots must be fully capable of taking over manually and continue flying. Lose sight of the “lead” airliner and automatics fail, the pilot needs to be ready to safely separate from the formation.

Losing sight of the lead airliner; does that happen often at FL390 or above?


Probably if you fly through the anvil of a massive CB of some sort, but then you have other more immediate things to worry about :duck:
 
GalaxyFlyer
Posts: 6252
Joined: Fri Jan 01, 2016 4:44 am

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 3:43 pm

SheikhDjibouti wrote:
GalaxyFlyer wrote:
As we should we’ll know, if it’s an automatic flight mode, the pilots must be fully capable of taking over manually and continue flying. Lose sight of the “lead” airliner and automatics fail, the pilot needs to be ready to safely separate from the formation.

Losing sight of the lead airliner; does that happen often at FL390 or above?


Hasn’t happened because nobody’s done it.

Ever fly formation at M.84 at F390? Trust me, it takes some attention. Ever fly in formation in cloud?
 
User avatar
SheikhDjibouti
Posts: 2278
Joined: Sat Sep 30, 2017 4:59 pm

Re: Airbus studing aircraft flying in formation

Tue Sep 22, 2020 6:50 pm

GalaxyFlyer wrote:
SheikhDjibouti wrote:
Losing sight of the lead airliner; does that happen often at FL390 or above?

Hasn’t happened because nobody’s done it.

Ever fly formation at M.84 at F390? Trust me, it takes some attention. Ever fly in formation in cloud?

Apologies; I didn't realize I had to spoon-feed you the question.

Here it is again, with all the bells & whistles.
Losing sight of the lead airliner aircraft {of any description}; does might that happen often at FL390 or above {if this procedure was ever introduced at some future date}?
[Notwithstanding VSMUT's reply about flying through the thick end of some CB]

It is a proper question; I would appreciate a proper answer.
If it helps;
GF wrote:
Do six or eight hours of close formation and see how it works.
SB wrote:
The article talks about "over a mile apart". Not exactly close formation



By way of an olive branch (if it's needed), here are my answers to your questions.
Ever fly formation at M.84 at F390?
No, but I have flown in formation at M.14 at FL001.
Ever fly in formation in cloud?
Does FOG count? In which case, I refer you to my previous answer.

GF; FWIW you already know I respect your wide range & depth of knowledge. :white:
Nothing to see here; move along please.
 
User avatar
LyleLanley
Posts: 254
Joined: Wed Dec 18, 2019 9:33 pm

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 2:36 am

~ A mile apart or so? Sure. Although you'd probably have to stay visual, and that would detract from the usual setting up of sunshades or high-charts in the windows. Not to mention a huge pain whilst flying west with the sun in your eyes the entire time.

Close formation? No. Fu**ing. Way. Passengers have a hard enough time with keeping their belts on normally. Let alone with another airliner =/<50 feet away. Lots of spilled champagne in 1st, and worse in steerage with that huge moment arm...
"I've sold monorails to Brockway, Ogdenville, and North Haverbrook, and, by gum, it put them on the map!"
 
GogonAger
Posts: 11
Joined: Sat Aug 01, 2020 8:10 pm

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 6:46 am

GalaxyFlyer wrote:
GogonAger wrote:
I would guess that it is not meant to be manually formation flying like i image the stuff done by military but automated flying in specific locations relative to other aircrafts at closer distance then currently possible. That would most likely require some form of direct communication and therefore active participation between the aircraft.

As already mentioned one airline might not have so much planes going the same direction for a long enough route to make it work, so an industry wide standard would be required and those are usually either enforced to increase safety or pushed by industry because of customer wishes, developments etc. Later would have to the case in this scenario.

Unfortunately i think is it not that achievable for an airline to develop (or let a manufacturer develop) the standards for such a complex system if the savings would be shared with all their competitors. So i think that this is a very nice concept that has the potential to save some fuel on the highly used routes while also decrease the congestions but at the moment it is hard to me to imagine seeing something like that in more than experimental setups done by the larger manufacturers. But these are of course just my personal thoughts. Would be happy to be proven wrong....


As we should we’ll know, if it’s an automatic flight mode, the pilots must be fully capable of taking over manually and continue flying. Lose sight of the “lead” airliner and automatics fail, the pilot needs to be ready to safely separate from the formation.


That's true but i would expect that in the assumed hypothetical scenario where such operations would be daily business some sort of TCAS-like functionality to enable coordinated and save separation maneuvers would not be the biggest deal compared to the overall changes in procedures required for that...
 
User avatar
SheikhDjibouti
Posts: 2278
Joined: Sat Sep 30, 2017 4:59 pm

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 10:34 am

LyleLanley wrote:
~ A mile apart or so? Sure. Although you'd probably have to stay visual, and that would detract from the usual setting up of sunshades or high-charts in the windows.
Nah, no need to stay visual all the time; just have the ability to check if required. The rest of the time you can relax and hand over to whatever version of ACAS/TCAS/PCAS or FLARM is introduced. Hell, at less than a mile apart, a bluetooth app on a cell-phone would probably suffice. :duck:

Besides, the analogy with geese provides for sweet spots both to the left and right of the lead goose.

The lead aircraft will probably not have visual on the aircraft behind it; hell, they cannot even see their own engines to see if they're still on the wing.

And surely the following goose/aircraft, can elect whether to go on the left or right quarter, to eliminate any problem of staring into the sun. No?


Not to mention a huge pain whilst flying west with the sun in your eyes the entire time.
Excuse me? Ignoring the points above, can you elaborate on that? Please.
I feel you have an interesting point, but I'm missing it for some reason.

I am under the weird impression that the majority of TATL flights are;
Westbound in the early morning (¹) (with the sun behind you)
Eastbound in the late evening (²), heading into darkness, until viewing the sunrise as they approach Europe and split formation for their individual destinations.
Either way I'm not seeing a problem.
(¹) London/Paris/Europe departure time
(²) New York departure time

This is only TATL; I cannot speak for TPAC or other heavy traffic routes.

Close formation? No. Fu**ing. Way.
:checkmark:
Nothing to see here; move along please.
 
User avatar
Starlionblue
Posts: 20092
Joined: Fri Feb 27, 2004 9:54 pm

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 12:52 pm

LyleLanley wrote:
~ A mile apart or so? Sure. Although you'd probably have to stay visual, and that would detract from the usual setting up of sunshades or high-charts in the windows. Not to mention a huge pain whilst flying west with the sun in your eyes the entire time.

..


If this required keeping visual track of the other aircraft in formation, it would not be feasible.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
User avatar
Faro
Posts: 2003
Joined: Sun Aug 12, 2007 1:08 am

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 2:08 pm

What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro
The chalice not my son
 
User avatar
Starlionblue
Posts: 20092
Joined: Fri Feb 27, 2004 9:54 pm

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 2:10 pm

Faro wrote:
What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro


This would be cruise only but IIRC migratory birds increase their range by up to 30% when flying in formation*. They swap lead bird position while flying in order to ensure everyone gets the benefits, which would be an added wrinkle to a scheme with aircraft.

* 30% number from some nature documentary I watched in the previous century.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
zuckie13
Posts: 312
Joined: Fri Mar 02, 2018 8:23 pm

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 6:16 pm

Starlionblue wrote:
Faro wrote:
What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro


This would be cruise only but IIRC migratory birds increase their range by up to 30% when flying in formation*. They swap lead bird position while flying in order to ensure everyone gets the benefits, which would be an added wrinkle to a scheme with aircraft.

* 30% number from some nature documentary I watched in the previous century.


I imagine it'd be like the cyclists in the Tour de France - fly in an echelon and when the lead plane gets "tired" (aka, has burned some extra fuel leading), it can peel off and fall back behind the rear one. Just an extra dimension to deal with.
 
GalaxyFlyer
Posts: 6252
Joined: Fri Jan 01, 2016 4:44 am

Re: Airbus studing aircraft flying in formation

Wed Sep 23, 2020 6:28 pm

I will add, it’s usually the wingmen who are short of fuel having been constantly adjusting thrust to stay with lead. I’ve never seen a huge difference, but wingies, esp number 4 are not saving fuel
 
LH707330
Posts: 2353
Joined: Fri Jun 15, 2012 11:27 pm

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 5:07 am

GalaxyFlyer wrote:
I will add, it’s usually the wingmen who are short of fuel having been constantly adjusting thrust to stay with lead. I’ve never seen a huge difference, but wingies, esp number 4 are not saving fuel

In this case, were you typically ahead of the vortices? I assume you're referring to military flying here, correct?

To address some of the broader questions:

What if your meetup time is off by a few minutes? -> Slow down or dogleg a bit. If you're going to spend 6 hours getting a ~10% benefit, then 10% of 360 minutes is 36 minutes, so wasting 10 minutes is 3% of your total and you're still 7% ahead.

Competitors always hanging off the back (we cyclists call this a "wheelsucker, so maybe "wingsucker?" :P ): Keep track and maybe get ATC to scramble the order or come up with a compensation scheme it gets too lopsided. There are a few benefits to being at the front of a conga line, when you get to the destination the taxiways will be clearer.
 
User avatar
SheikhDjibouti
Posts: 2278
Joined: Sat Sep 30, 2017 4:59 pm

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 11:30 am

LH707330 wrote:
What if your meetup time is off by a few minutes? -> Slow down or dogleg a bit. If you're going to spend 6 hours getting a ~10% benefit, then 10% of 360 minutes is 36 minutes, so wasting 10 minutes is 3% of your total and you're still 7% ahead.
You are assuming that "10 minutes" is 100% wasted fuel (which it would be if you literally performed a 360°, or a wide dog-leg). But if all you do is reduce throttle settings a tad to allow a following aircraft to catch-up, then I suspect you will save fuel ! (providing you don't end up stalling the aircraft and falling out of the sky). The trade off will be a slightly later arrival, some frustrated passengers (if they are awake and even notice), and a slight rush regarding aircraft turnaround times at the destination. Or in other words, the same effect as a marginal difference in headwind.

I would be very interested to hear comments from regular high-flyers as to whether cruising at M0.82 instead of M0.87 ( for a few minutes) is in any way really detrimental.


Competitors always hanging off the back (we cyclists call this a "wheelsucker, so maybe "wingsucker?" :P ): Keep track and maybe get ATC to scramble the order or come up with a compensation scheme it gets too lopsided.
Ha-ha, you've been watching too much Tour de France.

I am 100% sure the operations (& finance) boys & girls will be all over this, and before long there will be an international market in "formation credits".
i.e. Plus credits for being the lead aircraft, minus credits for being the follower.

And wherever scheduled departure times result in flight X (airline A) always dragging flight Y (airline B), such that over time airline B gets a lopsided benefit, then somewhere else in the world this will be balanced out, maybe involving airlines C, D, E and more.
i.e. there is no need for individual flight-pairs to switch lead aircraft half-way across the Atlantic.

And then there will be those airlines that abuse the system and end up on the "black-list", being forced to sneak up behind other aircraft whilst maintaining radio-silence, and then acting all innocent.
An adjustable wing-tip device to create some unpleasant turbulence for the cheeky follower should quickly put an end to that. :twisted:
Nothing to see here; move along please.
 
kalvado
Posts: 2896
Joined: Wed Mar 01, 2006 4:29 am

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 12:44 pm

Starlionblue wrote:
Faro wrote:
What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro


This would be cruise only but IIRC migratory birds increase their range by up to 30% when flying in formation*. They swap lead bird position while flying in order to ensure everyone gets the benefits, which would be an added wrinkle to a scheme with aircraft.

* 30% number from some nature documentary I watched in the previous century.

I suspect it depends on wing loading after all. And wing loading of a goose is less than A350. 20 kg/m2 for the goose vs 500-700 for a jet.
There may be other factors, but I wouldn't hold my breath for anything above 3-5% at best
 
GalaxyFlyer
Posts: 6252
Joined: Fri Jan 01, 2016 4:44 am

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 2:00 pm

LH707330 wrote:
GalaxyFlyer wrote:
I will add, it’s usually the wingmen who are short of fuel having been constantly adjusting thrust to stay with lead. I’ve never seen a huge difference, but wingies, esp number 4 are not saving fuel

In this case, were you typically ahead of the vortices? I assume you're referring to military flying here, correct?

To address some of the broader questions:

What if your meetup time is off by a few minutes? -> Slow down or dogleg a bit. If you're going to spend 6 hours getting a ~10% benefit, then 10% of 360 minutes is 36 minutes, so wasting 10 minutes is 3% of your total and you're still 7% ahead.

Competitors always hanging off the back (we cyclists call this a "wheelsucker, so maybe "wingsucker?" :P ): Keep track and maybe get ATC to scramble the order or come up with a compensation scheme it gets too lopsided. There are a few benefits to being at the front of a conga line, when you get to the destination the taxiways will be clearer.
.

If it close form, you feel the vortices as your wingtip is in it, basically. Spread combat formations are too distant to feel vortices- up to a mile or more apart.
 
User avatar
Faro
Posts: 2003
Joined: Sun Aug 12, 2007 1:08 am

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 3:36 pm

kalvado wrote:
Starlionblue wrote:
Faro wrote:
What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro


This would be cruise only but IIRC migratory birds increase their range by up to 30% when flying in formation*. They swap lead bird position while flying in order to ensure everyone gets the benefits, which would be an added wrinkle to a scheme with aircraft.

* 30% number from some nature documentary I watched in the previous century.

I suspect it depends on wing loading after all. And wing loading of a goose is less than A350. 20 kg/m2 for the goose vs 500-700 for a jet.
There may be other factors, but I wouldn't hold my breath for anything above 3-5% at best



I would agree with that...something like a super-PiP at best...but nothing revolutionary...


Faro
The chalice not my son
 
User avatar
Strebav8or
Posts: 6
Joined: Sat Aug 29, 2020 4:03 pm

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 8:16 pm

Just my .02 Cents....
RVSM airspace has aircraft on opposing headings flying at 1,000 foot separation. This theory just eliminated RVSM airspace, altogether.
Imagine three or more aircraft, stacked 1nm and 1,000 feet below the other, riding this 'wave" and othr aircraft trying to share the route coming the opposite way. I see havoc in this.
 
LH707330
Posts: 2353
Joined: Fri Jun 15, 2012 11:27 pm

Re: Airbus studing aircraft flying in formation

Thu Sep 24, 2020 9:21 pm

SheikhDjibouti wrote:
LH707330 wrote:
What if your meetup time is off by a few minutes? -> Slow down or dogleg a bit. If you're going to spend 6 hours getting a ~10% benefit, then 10% of 360 minutes is 36 minutes, so wasting 10 minutes is 3% of your total and you're still 7% ahead.
You are assuming that "10 minutes" is 100% wasted fuel (which it would be if you literally performed a 360°, or a wide dog-leg). But if all you do is reduce throttle settings a tad to allow a following aircraft to catch-up, then I suspect you will save fuel ! (providing you don't end up stalling the aircraft and falling out of the sky). The trade off will be a slightly later arrival, some frustrated passengers (if they are awake and even notice), and a slight rush regarding aircraft turnaround times at the destination. Or in other words, the same effect as a marginal difference in headwind.

I would be very interested to hear comments from regular high-flyers as to whether cruising at M0.82 instead of M0.87 ( for a few minutes) is in any way really detrimental.


Competitors always hanging off the back (we cyclists call this a "wheelsucker, so maybe "wingsucker?" :P ): Keep track and maybe get ATC to scramble the order or come up with a compensation scheme it gets too lopsided.
Ha-ha, you've been watching too much Tour de France.

I am 100% sure the operations (& finance) boys & girls will be all over this, and before long there will be an international market in "formation credits".
i.e. Plus credits for being the lead aircraft, minus credits for being the follower.

And wherever scheduled departure times result in flight X (airline A) always dragging flight Y (airline B), such that over time airline B gets a lopsided benefit, then somewhere else in the world this will be balanced out, maybe involving airlines C, D, E and more.
i.e. there is no need for individual flight-pairs to switch lead aircraft half-way across the Atlantic.

And then there will be those airlines that abuse the system and end up on the "black-list", being forced to sneak up behind other aircraft whilst maintaining radio-silence, and then acting all innocent.
An adjustable wing-tip device to create some unpleasant turbulence for the cheeky follower should quickly put an end to that. :twisted:

I guess I could have been more specific about the 10 minutes. Even when that is a worst-case scenario of total wastage, it still nets a 7% gain, so it's worth doing. If people are just slowing down, maybe that creeps up to 8-9% again.

I have actually not watched any TdF this year, but I've done my fair share of bike racing and have seen a number of wheelsuckers. As you said, the "formation credit" market could become a thing for the winsuckers, same way your riding buddies are responsible for buying beer if you pull them on the last upwind leg back home.

GalaxyFlyer wrote:
If it close form, you feel the vortices as your wingtip is in it, basically. Spread combat formations are too distant to feel vortices- up to a mile or more apart.


Thanks for that. Are the aircraft ever about a boat length back and maybe half a span across to be in the wake, or generally forward of that so that only the wingtip is in it?
 
User avatar
LyleLanley
Posts: 254
Joined: Wed Dec 18, 2019 9:33 pm

Re: Airbus studing aircraft flying in formation

Fri Sep 25, 2020 2:17 am

SheikhDjibouti wrote:
LyleLanley wrote:
~ A mile apart or so? Sure. Although you'd probably have to stay visual, and that would detract from the usual setting up of sunshades or high-charts in the windows.
Nah, no need to stay visual all the time; just have the ability to check if required. The rest of the time you can relax and hand over to whatever version of ACAS/TCAS/PCAS or FLARM is introduced. Hell, at less than a mile apart, a bluetooth app on a cell-phone would probably suffice. :duck:

Besides, the analogy with geese provides for sweet spots both to the left and right of the lead goose.

The lead aircraft will probably not have visual on the aircraft behind it; hell, they cannot even see their own engines to see if they're still on the wing.

And surely the following goose/aircraft, can elect whether to go on the left or right quarter, to eliminate any problem of staring into the sun. No?


Not to mention a huge pain whilst flying west with the sun in your eyes the entire time.
Excuse me? Ignoring the points above, can you elaborate on that? Please.
I feel you have an interesting point, but I'm missing it for some reason.

I am under the weird impression that the majority of TATL flights are;
Westbound in the early morning (¹) (with the sun behind you)
Eastbound in the late evening (²), heading into darkness, until viewing the sunrise as they approach Europe and split formation for their individual destinations.
Either way I'm not seeing a problem.
(¹) London/Paris/Europe departure time
(²) New York departure time

This is only TATL; I cannot speak for TPAC or other heavy traffic routes.

Close formation? No. Fu**ing. Way.
:checkmark:


You’re absolutely right. I wasn’t speaking only of the standard TATL flights - more just crossing in general. Having flown westbound, in close formation for a few hours with the sun beating, it’s not fun. My $0.02.
"I've sold monorails to Brockway, Ogdenville, and North Haverbrook, and, by gum, it put them on the map!"
 
kalvado
Posts: 2896
Joined: Wed Mar 01, 2006 4:29 am

Re: Airbus studing aircraft flying in formation

Fri Sep 25, 2020 12:32 pm

Starlionblue wrote:
Faro wrote:
What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro


This would be cruise only but IIRC migratory birds increase their range by up to 30% when flying in formation*. They swap lead bird position while flying in order to ensure everyone gets the benefits, which would be an added wrinkle to a scheme with aircraft.

* 30% number from some nature documentary I watched in the previous century.

And some better numbers:
Document considered by ICAO mentions "over 10%" fuel savings: https://www.icao.int/Meetings/a40/Docum ... 317_en.pdf
Another press article quotes "5 to 10%" : https://www.travelweekly.com/Travel-New ... ion-flying
 
kalvado
Posts: 2896
Joined: Wed Mar 01, 2006 4:29 am

Re: Airbus studing aircraft flying in formation

Fri Sep 25, 2020 12:42 pm

Starlionblue wrote:
Faro wrote:
What's the bottom line?...how much fuel burn can you save with formation flying?...


Faro


This would be cruise only but IIRC migratory birds increase their range by up to 30% when flying in formation*. They swap lead bird position while flying in order to ensure everyone gets the benefits, which would be an added wrinkle to a scheme with aircraft.

* 30% number from some nature documentary I watched in the previous century.

And some better numbers:
Document considered by ICAO mentions "over 10%" fuel savings: https://www.icao.int/Meetings/a40/Docum ... 317_en.pdf
Another press article quotes "5 to 10%" : https://www.travelweekly.com/Travel-New ... ion-flying

Who is online

Users browsing this forum: No registered users and 15 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos