Single Wing Flight

[Anatoli-Kagari9]

Been following this great thread here and at the IL2 BOS Forum, where I also "flamed" the theme :-)

 

Here's a well known video about an accident with an F-15 which lost it's right wing from the root!!!

 

[Bucic]

Neither of the posted examples ...

Let me get back to you sometime later.

I think you misread some of my wording. For example nowhere did I say your model is outright wrong. I would be stupid to actually post such a statement. I know who you are and what you do for a living ;)

 

For example. When I commented on the severity of wing loss it was not strictly my argument for your model being incorrect. I simply opposed ignoring the factor. Same with contemporary jets. I oppose liberties in extrapolating RL examples that are vastly off with regard to OP's case, especially by non-professionals.

 

Now, let me also state why I initially thought the OP's case was very fishy in terms of FM and now I don't think it's fishy after all, I.e. what was my mistake in looking at the problem. It's rather simple:

 

Lateral momentum balance:

Initially I would always 'consider' the forces with regard to CoG as a fulcrum. It should be CoP (center of pressure). While it's the mistake I suspect most people here made That's embarrassing for someone with my education. On my defence I don't get much sleep during the recent... month but I'd say it's more me getting rusty in my current non-engineering job :/

 

EDIT:

Yo-Yo, could you perhaps say how much of the remaining aileron deflection is needed now vs pre-patch for the OP's case? An estimate is fine. I'm curious.

Edited September 26, 2014 by Bucic

[Anatoli-Kagari9]

BTW, and taking always my hat off to Yo-Yo for is superb work in the p51d, Dora, and certainly my next acquisition - bf109k4 - I would like to comment on a different subject that last weekend while talking to a fellow pilot, who flies agricultural aircraft ( powerful Cessna and Piper low wing, with radial and even turboprop engines... ) I commented on a feature I noticed for the first time on a flightsim with DCS's p51d and Dora... The effect of strong crosswind on the initial takeoff run, and the apparently illogical need to use downwind aileron and rudder while you build up speed....

 

He confirmed this as a tricky thing powerful taildragger pilots learn when operating near ( sometimes above ... ) the published x-wind takeoff limits for their aircraft, when the slipstream dflected downwind can indeed cause that effect we feel so well modeled specially on the Dora!

 

Unique DCS World... UNIQUE!

[Aeons]

this thread keeps going in loops. im not interested in a jet fighter losing some of its wing- completely different dynamics.

 

 

Im talking about the flight model in the DCS Dora module. So going by the constant replies by ED and constantly showing us different types of planes/aerofoils and how it can fly (but never anything related to the DCS Dora model). im guessing they believe that the DCS Dora model is 100% correct and doesn't need to be changed.

 

So be it. my 20 years as a pilot tells me otherwise ( I confess though, flying turbines isn't anything like a Dora - never flown a dora in real life). I guess in the end, this platform/module is only a game, and games are not real life (unless you live in Asia and play WoW)

 

thanks for all the input everyone

[Anatoli-Kagari9]

this thread keeps going in loops. im not interested in a jet fighter losing some of its wing- completely different dynamics.

 

 

Im talking about the flight model in the DCS Dora module. So going by the constant replies by ED and constantly showing us different types of planes/aerofoils and how it can fly (but never anything related to the DCS Dora model). im guessing they believe that the DCS Dora model is 100% correct and doesn't need to be changed.

 

So be it. my 20 years as a pilot tells me otherwise ( I confess though, flying turbines isn't anything like a Dora - never flown a dora in real life). I guess in the end, this platform/module is only a game, and games are not real life (unless you live in Asia and play WoW)

 

thanks for all the input everyone

 

Aeons, this is Dejá Vue... :-) No critic! I appreciate your OP, and this thread is great to read...

 

Last April a similar thread was started at the IL2 BOS Forums - the other sim I use for feeling closer to the sensation of flying a powerful prop aircraft :-)

 

This is the thread at the IL2 BOS Forums, but I would like to call your attention to this particular post on it and this article it links to.

 

Same story here.

Edited September 26, 2014 by jcomm

[Yo-Yo]

this thread keeps going in loops. im not interested in a jet fighter losing some of its wing- completely different dynamics.

 

 

Im talking about the flight model in the DCS Dora module. So going by the constant replies by ED and constantly showing us different types of planes/aerofoils and how it can fly (but never anything related to the DCS Dora model). im guessing they believe that the DCS Dora model is 100% correct and doesn't need to be changed.

 

So be it. my 20 years as a pilot tells me otherwise ( I confess though, flying turbines isn't anything like a Dora - never flown a dora in real life). I guess in the end, this platform/module is only a game, and games are not real life (unless you live in Asia and play WoW)

 

thanks for all the input everyone

 

I wrote that our case has nothing to deal with airfoil because this is a matter of wingspan lift distribution that does nt depend on the certain airfoil, Re, etc.

What you experience can tell about asymmetric wing flight? How often you have this situation in your practice?

So, no prognosis to the board plane flight ability? Let's wait for remaining FM critics, though... if they fail to bet - it would be a good argument for correct FM in DCS...

[Bucic]

So, no prognosis to the board plane flight ability? Let's wait for remaining FM critics, though... if they fail to bet - it would be a good argument for correct FM in DCS...

I'm out already :D

I'd appreciate some details on the actual influence of the fix in the recent update though.

Edited September 26, 2014 by Bucic

[Abburo]

The board plane will drop on it's broken wing and if is high enough it will go into stall dive, going down in spiral, keeping the right wing higher.

To counter that effect it needs enough right rudder authority in order to compensate the loss of left lift.

If it would be a remote control plane it could be recovered, if not it is lost.

 

I saw RC planes with one wing completely ripped off that have been saved from fatal crash. But that depends first of all to engine power and equaly to it's control surfaces authority, especially the rudder.

 

[Anatoli-Kagari9]

http://bbs.hitechcreations.com/smf/index.php?topic=365671.0

[NineLine]

http://bbs.hitechcreations.com/smf/index.php?topic=365671.0

 

Nice!

[Yo-Yo]

http://bbs.hitechcreations.com/smf/index.php?topic=365671.0

 

Thank you very much!

[Bucic]

...

Yo-Yo, could you take a look at my by-the-guts figure? I'm curious whether I get something wrong. I'd really appreciate it. It doesn't show any specific values but the force vectors length represents values, they sum up to 0. I wanted to create a figure that would roughly show what happens after loss of a significant part of a wing, with an emphasis on what are relative changes to values and locations of the vectors.

Not taken into account:

- slipstream

- use of rudder

- empannage positive influence on lateral controllability

 

https://onedrive.live.com/redir?resid=66CF2646234394FC!24744&authkey=!AM1VGG9blxAlNFw&ithint=folder%2csvg

 

There's a vector graphics file (SVG) included so if anyone wants he can easily move things around.

Edited September 26, 2014 by Bucic

[OutOnTheOP]

While I have no doubt that an aircraft can fly with significant portions of a wing missing *in theory*, the paper airplanes are entirely unconvincing to me, as are the RC aircraft, for a number of reasons:

 

1) RC aircraft generally have huge control authority, with vast sweeps of deflection available to their control surfaces. The paper airplanes have essentially infinite. You can push their ailerons and rudder through 90+ degrees of deflection. This is simply not true on a FW190 (or just about any other real, full-scale aircraft). It begs the question: how much wing can a FW lose before it runs out of control authority to counter it?

 

2) the RC and paper airplanes have parts deliberately, surgically removed. In combat, things are a bit different: if the wing of a metal-construction aircraft is violently removed, I would bet odds are pretty good that the twisted and crushed remains would bind up control rods, and the pilot would no longer be able to control even the remaining aileron.

 

3) even assuming that there was enough control authority, and that the controls remained unbound, how much stick force would be required, could the pilot put that much stick force in for an extended period, and would the aileron tolerate such high deflection angles at combat speeds (which the aircraft was presumably at when it lost the wing)?

 

None of the "real-world" example photos yet shown have illustrated any more than perhaps 30% wing loss on a conventional tube-with-wings design (F-15 doesn't count; it has significant body lift that the WW2 designs just don't share). The FW190 photo posted earlier was particularly unimpressive; if you look closely, you'll see the picture was deliberately angled to ensure that perspective foreshortening made the wing look more damaged than it actually is; only the portion of wing outboard of mid-aileron is missing; perhaps two-three feet at most.

[Yo-Yo]

Yo-Yo, could you take a look at my by-the-guts figure? I'm curious whether I get something wrong. I'd really appreciate it. It doesn't show any specific values but the force vectors length represents values, they sum up to 0. I wanted to create a figure that would roughly show what happens after loss of a significant part of a wing, with an emphasis on what are relative changes to values and locations of the vectors.

Not taken into account:

- slipstream

- use of rudder

- empannage positive influence on lateral controllability

 

https://onedrive.live.com/redir?resid=66CF2646234394FC!24744&authkey=!AM1VGG9blxAlNFw&ithint=folder%2csvg

 

There's a vector graphics file (SVG) included so if anyone wants he can easily move things around.

 

This graph represents forces on the wing as you imagine it. In real world the lift distribution is close to elliptical, so the lost part of lift will be less. By the way, even for the rectangular wing this distribution is not rectangular.

 

If you want to have true picture of the forces/moments you must calculate and integrate them along the wingspan regarding real distribution

Edited September 27, 2014 by Yo-Yo

[Yo-Yo]

While I have no doubt that an aircraft can fly with significant portions of a wing missing *in theory*, the paper airplanes are entirely unconvincing to me, as are the RC aircraft, for a number of reasons:

 

1) RC aircraft generally have huge control authority, with vast sweeps of deflection available to their control surfaces. The paper airplanes have essentially infinite. You can push their ailerons and rudder through 90+ degrees of deflection. This is simply not true on a FW190 (or just about any other real, full-scale aircraft). It begs the question: how much wing can a FW lose before it runs out of control authority to counter it?

Do you really think that 90 degree of deflection gives 6 times more effect than 15%?

 

2) the RC and paper airplanes have parts deliberately, surgically removed. In combat, things are a bit different: if the wing of a metal-construction aircraft is violently removed, I would bet odds are pretty good that the twisted and crushed remains would bind up control rods, and the pilot would no longer be able to control even the remaining aileron.

Referring to 777 decision? :) For sure, the controls CAN BE damaged. But they must not be damaged in 100% as well as they CAN BE damaged without ripping the wing off.

 

3) even assuming that there was enough control authority, and that the controls remained unbound, how much stick force would be required, could the pilot put that much stick force in for an extended period, and would the aileron tolerate such high deflection angles at combat speeds (which the aircraft was presumably at when it lost the wing)?

 

Do you think about the fact that only one aileron remains to apply force to? FW-190, by the way, has very efficient ailerons with very effective compensation, don't you think that this is the reason of differencies with P-51 and Fw-190 operating with a wing partly lost?

 

None of the "real-world" example photos yet shown have illustrated any more than perhaps 30% wing loss on a conventional tube-with-wings design (F-15 doesn't count; it has significant body lift that the WW2 designs just don't share). The FW190 photo posted earlier was particularly unimpressive; if you look closely, you'll see the picture was deliberately angled to ensure that perspective foreshortening made the wing look more damaged than it actually is; only the portion of wing outboard of mid-aileron is missing; perhaps two-three feet at most.

 

The wing has distinctive construction details that allow to understand what part of the wing is lost.

 

The matters of faith against real world and science...

Edited September 27, 2014 by Yo-Yo

[OutOnTheOP]

Do you really think that 90 degree of deflection gives 6 times more effect than 15%?

 

Did I ever say that? I said that the range of sweep on a cardboard/ paper airplane is whatever you want it to be (and, for that matter, you can use the ENTIRE wing surface as aileron by twisting it, and can do the same to use the horizontal stabilizers for roll control), and cannot be compared to a real airplane where the deflection angle and surface area of aileron is limited.

 

Referring to 777 decision? :) For sure, the controls CAN BE damaged. But they must not be damaged in 100% as well as they CAN BE damaged without ripping the wing off.

 

No, I am not referring to any decision; I am pointing out that the loss of a wing is not likely to occur without also incurring other damages.

 

Do you think about the fact that only one aileron remains to apply force to? FW-190, by the way, has very efficient ailerons with very effective compensation, don't you think that this is the reason of differencies with P-51 and Fw-190 operating with a wing partly lost?

 

Yes, I did think about that. It's why I asked the question; no one has addressed it. It is not necessary to be quite so antagonistic about it; how about if instead you simply post the math on how much force it would require? Also, as to "efficient ailerons"... they're not THAT much better than a P-51, because the P-51 rolls damn near as well as the FW190, despite having weight distribution WAY further toward the wingtips, and much higher roll inertia.

 

 

The matters of faith against real world and science...

 

No, the matters of faith IN science... but ONLY when the experiment is properly constructed. As yet, it has not been. A small-scale RC plane flying with 80% wing lost (but surplus thrust on the order of likely 2:1 TWR, and control authority vastly beyond that of a FW190) is not an equal comparison to a full-scale FW190. ...Particularly if roll control on that F-18 model is done with all-moving tailplane, in which case it hasn't even lost any control responsiveness, unlike a FW190 with a missing aileron. You can quit with the ad hominem inferences that I do not understand how science works.

 

Your posts have shown that a paper airplane missing half its wing can be made to fly generally straight, so long as it has effectively unlimited control authority. It has not shown that a Dora, within it's control authority and distributions of lift and weight, can do the same with 2/3 it's wing missing, as shown in DCS in the original post.

 

The fact remains that none of the real-life examples (despite other very impressive damage!) have been shown to be recovered with more than maybe 30-40% of the wing surface removed, while in DCS, the Dora appears flyable with as much as 60-70% removed. This does not align to what has been observed in reality, and is therefore open to questioning.

 

To prove it could do so, you must show: 1) that the aileron on the remaining wing is capable of cancelling the lift produced by the portion of wing missing on the other side, less the force equal to the *weight* of the missing portion (so as to balance the lift on each side), and that 2) the aircraft is capable of remaining airborne with the lift force produced by what's left.

 

As I see it, if you have lost 60% off one wing, you must then cancel out the lift on the same 60% of the other wing (again, it would in fact be somewhat under 60%, as you don't have to account for the weight of the now-missing portion). So... with 40% the effective lift, a Dora would be flying at something slightly over 100-120 pounds per square foot effective wing loading. That sounds REALLY high to me; we're talking half again higher loading than an F-16! It would be equivalent, wing-load/ AOA-wise, to flying a perpetual 3-ish G turn. I'm not entirely certain it would be sustainable (particularly with all the drag from the aileron at high deflection)

Edited September 27, 2014 by OutOnTheOP

[airdoc]

you may find this interesting regarding lift distribution (the site has the equations, integrals, etc, so if you 're looking for a crude calculation of the forces after partial wing loss and are patient enough you could try it out ) :

 

 

this one depicts the calculation of the total wing load distribution (after taking into account lift, wing weight and fuel weight)

 

 

http://www.mathworks.com/products/symbolic/code-examples.html?file=/products/demos/symbolictlbx/Wing_load_model/analytical-model-of-aircraft-wing-loads.html

Edited September 27, 2014 by airdoc

[OutOnTheOP]

you may find this interesting regarding lift distribution (the site has the equations, integrals, etc, so if you 're looking for a crude calculation of the forces after partial wing loss and are patient enough you could try it out ) :

 

[ATTACH]105109[/ATTACH]

 

this one depicts the calculation of the total wing load distribution (after taking into account lift, wing weight and fuel weight)

[ATTACH]105110[/ATTACH]

 

 

http://www.mathworks.com/products/symbolic/code-examples.html?file=/products/demos/symbolictlbx/Wing_load_model/analytical-model-of-aircraft-wing-loads.html

 

Ok, I'll bite: the argument seems to keep coming up that the loss of the outboard section of the wing is less important, because the inboard portion produces a higher amount of lift per foot of span.

 

This is true... however, how much of the relatively low lift produced by the tip portion of the span is due to the loss of efficiency due to spanwise flow? Keep in mind, if mid-wing BECOMES the tip (due to the loss of the outboard panels), it TOO loses a lot of lift to spanwise flow. How much, I don't know; I don't have those equations at hand.

[effte]

The (main) issue isn't the amount of lift generated, but the amount of torque around the roll axis. The outboard portion proportionally provides a lot of torque due to the moment arm. The lift distribution will change with the loss of the outboard portion of the wing, making the remaining stub the new outboard portion with less lift per foot due to spanwise flow. Hence, the lift loss will be greater than the lift on the now departed outboard section.

 

An aircraft can fly with X % of one wing removed. The opposite (remaining) aileron 'simply' has to deflect up to dump enough lift for the total moment contribution of the outer part of the remaining complete wing to equal zero.

 

The overall alpha then has to be increased in order to make the remaining lift equal the weight of the aircraft.

 

The limitations will be

a) When you cannot increase alpha to keep lift equal to weight any more without exceeding the critical AoA (stalling)

b) Running out of aileron authority, ie when the fully deflected remaining aileron is not able to dump enough lift to give you zero rolling moment.

 

Both of these will be airspeed dependant, i e you can generate more lift and have more aileron authority at a higher airspeed. To put it another way, you will stall at a certain airspeed (which will be higher than your normal airspeed) and at another airspeed you will run out of control authority to counteract the roll.

 

The question is: How much wing can you lose at the airspeed you are able to maintain - not "can it fly".

 

Any anecdotal evidence of the feasability of flight less part of one wing is pretty much useless (F-15, FW-190 with a smaller wing section lost, model aircraft), as it tells us only that it is indeed possible within certain parameters - and we already knew that. We cannot extrapolate to the case of losing the amount of wing depicted in the OP.

 

If we remain within reasonable limits, the estimate of an aeronautical engineer and pilot is that there would be no way for the aircraft in the OP to fly, even if restricting it to the flight dynamics perspective and leaving systems damage aside. Unload and enter a near-vertical high-speed dive, yes, some resemblance of control may just be maintained until the rather violent impact with the ground. I do not believe anyone will be able to show calculations showing otherwise.

[OutOnTheOP]

*snip*

 

That pretty much sums it up, yes

[NineLine]

Just a simply question, how many of you involved in this discussion have tried flying the Dora as pictured in the original post?

[Anatoli-Kagari9]

Just a simply question, how many of you involved in this discussion have tried flying the Dora as pictured in the original post?

 

I tried, and on two occasions I got completely different results, as I expected...

 

1) Diving, accelerating to 800km/h IAS, and then pulling and breaking my wing, which immediately initiated a highspeed roll and dive into the ground - no recovery was possible, and I guess a pilot would have his neck broken anyway...

 

2) colliding with a p51d, after following him all the way up until we both almost stalled, which ripped a good part of my right wing... I was recovering but crashed because I began to get stable bellow 600m alt I guess... but then entered a spin :-/ Anyway, should it have happened at a much higher alt, I believe I would be able to stabilize the Dora...

 

Just out of curiosity, yesterday while flying a Bf109 F4 in IL2 BOS I also collided with a Yak-1. The other guy broke his prop, I lost part of my right wing... Was not able to recover because, again, I was very low...

 

Some interesting videos from IL2 BOS ( sorry for bringing another sim to this discussion, but it looks pertinent in this case...):

 

http://www.youtube.com/watch?v=yACauO2IF5k

 

Love this one :-) :

Edited September 28, 2014 by jcomm

[NineLine]

I set a mission to have an explosion blow my wing off, there isnt much in the way of control available to me... but then I am not the greatest pilot either :) Point is though... its not like the aircraft flies like a dream with this kind of damage :)

[NineLine]

Love this one :-) :

 

FYI, if you are going to bring BoS into this, I would like to point out that my 2 year old landed a Stuka in a snowy field with no damage.... just saying ;)

 

I dont think BoS is all that relevant :P Anyways... lets keep this based on real accounts and DCS.... thanks.

[VIMANAMAN]

I encountered this a second time a few weeks ago (for the same embarrassing reason :) ) and the % of 'wing off' was much greater than the track I posted on p1 - I remember thinking 'that's up to the gear' (much like the OP, although no damage at all to 'good' wing IIRC) - I was able to catch the roll initially, but couldn't keep the nose up - I was low so (stupidly) gave it full power in one swift move... and spun in :)

 

Right wing lost + Power on = right roll - which makes sense as that's the direction she 'squirms' under power on take off.

 

I don't think I kept the track - but will check - If I did we can all have a go :)