Wings breaking off in AV8B and F14 realistic?

[truebrit]

Or limitation on the damage model?

[Gambit21]

I think it's a limitation of your wrist/yanking our stick to full deflection suddenly and immediately with no resistance, thus resulting in much more deflection that would be possible in real life. 

 

I've never once ripped the wings off an F-14 nor felt like I was close to it, and I've flown her to the limit... but I'm used to flying WWII aircraft so it comes naturally.

Be a bit more conscious, listen to the aircraft, and stop yanking the stick...it's not a FBW aircraft.

 

 

 

[truebrit]

1 hour ago, Gambit21 said:

I think it's a limitation of your wrist/yanking our stick to full deflection suddenly and immediately with no resistance, thus resulting in much more deflection that would be possible in real life. 

 

I've never once ripped the wings off an F-14 nor felt like I was close to it, and I've flown her to the limit... but I'm used to flying WWII aircraft so it comes naturally.

Be a bit more conscious, listen to the aircraft, and stop yanking the stick...it's not a FBW aircraft.

 

 

 

 

Thanks for the reply, but that wasn't really my question. I was wondering more if the wings coming off was a realistic consequence of too much force or just a limitation in the damage model. So instead of major fatigue and some damage needing attention after landing, a limitation in the damage model just has the wing rip right off instead. I would think that there was no amount of pull on the stick that could tear the wings off a fighter. But being a noob about such things I don't know.

 

Cheers.

[Mars Exulte]

In real life you can physically damage or destroy a plane by being stupid, careless, or otherwise unsafe, yes. It would take a lot to rip a wing off, but it's theoretically doable. Thing is in real life pilots are trained, have a sense of self preservation, and have controls that aide them in rudimentary tasks like not dying. A gamer rarely has much if any training, no concern about dying, generic placeholder controls with no feedback, and literally ZERO self discipline, combined these factors add up to mean gamers die to or doing stupid shit waaaay more frequently than is the case in real life.

Edited August 5, 2021 by Mars Exulte

[truebrit]

7 hours ago, Mars Exulte said:

In real life you can physically damage or destroy a plane by being stupid, careless, or otherwise unsafe, yes. It would take a lot to rip a wing off, but it's theoretically doable. Thing is in real life pilots are trained, have a sense of self preservation, and have controls that aide them in rudimentary tasks like not dying. A gamer rarely has much if any training, no concern about dying, generic placeholder controls with no feedback, and literally ZERO self discipline, combined these factors add up to mean gamers die to or doing stupid shit waaaay more frequently than is the case in real life.

 

 

Well sure, gamers don't die, they respawn. 

[silverdevil]

i had done this with f14 once. i was just messing around. i was going pretty fast at about 5000 feet. i just yanked the stick back and everything went black on screen for a second and jester said "we've taken serious damage!!". i toggled the exterior view and sure enough the wings were replaced by flames. i posted in heatblur but i did not have a vid of it and have not tried since. 

[Mars Exulte]

Sarcasm aside, the extreme edges of the envelope are where the simulation breaks down anyway because there's no data for it. ''What happens if you yank the stick all the way back at mach 2?'' asked no one ever. Other scenarios are similar. They don't usually test things in regimes where serious damage (or risk thereof) is a certainty because... why would you? Nobody's trying to kill test pilots or destroy planes ''just because''. So, in the simulation you simply hit a proverbial ''brick wall'' where structural limits are exceeded and the plane goes ''WTF IS HAPPENING?!!1!!'' and explodes. In real life the details might be different, but end result is likely to be similarly disastrous.

 

So, in conclusion, don't fly like a nublet and it won't be an issue in the first place. You will not routinely rip wings off any plane without serious negligence, regardless of developer, plane, or regime.

[truebrit]

2 hours ago, Mars Exulte said:

Sarcasm aside, the extreme edges of the envelope are where the simulation breaks down anyway because there's no data for it. ''What happens if you yank the stick all the way back at mach 2?'' asked no one ever. Other scenarios are similar. They don't usually test things in regimes where serious damage (or risk thereof) is a certainty because... why would you? Nobody's trying to kill test pilots or destroy planes ''just because''. So, in the simulation you simply hit a proverbial ''brick wall'' where structural limits are exceeded and the plane goes ''WTF IS HAPPENING?!!1!!'' and explodes. In real life the details might be different, but end result is likely to be similarly disastrous.

 

So, in conclusion, don't fly like a nublet and it won't be an issue in the first place. You will not routinely rip wings off any plane without serious negligence, regardless of developer, plane, or regime.

 

I'm sure they do much stress testing to simulate extreme forces, testing wings etc to breaking point, do you not think?

 

I don't have the modules btw, I was just wondering about the realism, as the more I learn about DCS the more I find certain things are not simulated correctly or at all. Like I stated in my op, a limitation of the sim maybe.

 

[jonsky7]

On 8/6/2021 at 10:26 PM, truebrit said:

 

I'm sure they do much stress testing to simulate extreme forces, testing wings etc to breaking point, do you not think?

 

I don't have the modules btw, I was just wondering about the realism, as the more I learn about DCS the more I find certain things are not simulated correctly or at all. Like I stated in my op, a limitation of the sim maybe.

 

 

They definitely do test them to destruction, edit: but on the ground, then from the data gained they draw up the flight envelope limits.

 

The problem with sitting in your chair at home is that there's no way to simulate the force needed to yank the stick back. Even with hydraulic powered flying controls, the feel of the stick can be changed by increasing or decreasing the load of a centring spring using an actuator, or other device, this is called q-feel nowadays.
(I have no idea if an F14 or Harrier had a Q-feel system)

 

Then there's the amount of G you'd be pulling to break the wings off. In most cases the pilot would probably black out due to G-LOC before the wings came off, but yanking back on the stick with all one's might at supersonic speed might.

 

It's probably one of the reasons fly-by-wire is the go-to choice today, the flight computer system will limit controls surface deflection to prevent the wings snapping off.
 

 

Not a fighter but a stress test to destruction

 

Edited August 8, 2021 by jonsky7

[Mars Exulte]

10 hours ago, jonsky7 said:

They definitely do test them to destruction, then from the data gained they draw up the flight envelope limits.

  Yes, but those are much more controlled and scientific in nature than a live pilot in a live aircraft deliberately self destructing.

 

10 hours ago, jonsky7 said:

The problem with sitting in your chair at home is that there's no way to simulate the force needed to yank the stick back.

  Very true, also our home controls (and usually the ingame sim) have no real limitations on your behavior. You have to do your own idiot proofing.

 

10 hours ago, jonsky7 said:

 Even with hydraulic powered flying controls, the feel of the stick can be changed by increasing or decreasing the load of a centring spring using an actuator, or other device, this is called q-feel nowadays.

  Very true.

 

10 hours ago, jonsky7 said:

(I have no idea if an F14 or Harrier had a Q-feel system)

  I think as soon as they started getring away from manually actuated controls (ie old WWII stuff mostly) where pilot physical strength was no longer the determinant for how far a surface could deflect, they'd pretty much be required to implememt artificial limits, warnings, etc etc because the aircraft systems would be perfectly capable of doing something disastrous. NOT doing something like that would have virtually guaranteed the occasional self destruct when somebody ''oops''d.

 

10 hours ago, jonsky7 said:

Then there's the amount of G you'd be pulling to break the wings off. In most cases the pilot would probably black out due to G-LOC before the wings came off, but yanking back on the stick with all one's might at supersonic speed might.

  Yeah

 

10 hours ago, jonsky7 said:

It's probably one of the reasons fly-by-wire is the go-to choice today, the flight computer system will limit controls surface deflection to prevent the wings snapping off.

  Yeah, among other things. Makes uncontrollable aircraft controllable and helps keep pilots from doing anything too unreasonable.

 

11 hours ago, truebrit said:

I'm sure they do much stress testing to simulate extreme forces, testing wings etc to breaking point, do you not think?

  They do, but in a controlled ground test (see above videos), not by flying a plane at Mach 2 and yanking the stick to see if it disintegrates.

 

11 hours ago, truebrit said:

I don't have the modules btw, I was just wondering about the realism, as the more I learn about DCS the more I find certain things are not simulated correctly or at all.

  DCS in general simulates the overwhelming majority of key points of aerodynamics, to produce aircraft that fly approximately like the real thing. It is in general an order of magnitude more detailed than most/all other publicly available simulations.

 

  That said, it's still a video game, with a video game budget, and video game priorities. It's not a 1-to-1 recreation, and while they frequently add new features and modeling, it does indeed lack certain things, and always will. Literally every piece of software out there available to the public will, even if the only limitation on them is processing power, becauss whatever they produce has to run passibly on a midrange home computer of the last 5 years or so at least.

 

  It's POSSIBLE to do a 1-to-1 recreation of real world aerodynamics in digital format, they use such things to develop some of the aerodynamics on some of this stuff, but they can't run that kind of indepth simulation dynamically for the game itself because you wouldn't be able to run it.

 

 

  As for damage models themselves (which is what this has more to do with in general) the core modeling is fairly simplistic. Major components and airframe parts are tracked, with a variety of damage states, but it's also not a 1 to 1 dynamic simulation for all the same reasons. 

 

  That said, they have overhauled the modeling for the WWII stuff now, and are supposed to do so for the jets next, so I'd say this part will improve substantially in the future, although as always, it won't be perfect and you'll still be able to find anomalies.

[Basher54321]

11 hours ago, truebrit said:

 

I'm sure they do much stress testing to simulate extreme forces, testing wings etc to breaking point, do you not think?

 

I don't have the modules btw, I was just wondering about the realism, as the more I learn about DCS the more I find certain things are not simulated correctly or at all. Like I stated in my op, a limitation of the sim maybe.

 

 

 

No they don't need to test to breaking point.

 

Ultimately the customer (eg USN/USAF) writes a spec that includes all the required limits for the desired aircraft including lifetime and intended usage etc. If say they specify 8G clean at X weight then that is what the aircraft will be built to.

 

However there is a standard safety margin that means a part must not break at 150% over the required load limit. So simplistic example - say I want my plane to be 8G then parts will be stress tested to 150% of that (12G).

My take from the 777 video is you can hear them cheer when the part hits 150% - but the part fails however at only 4% past this  that is why you got to see it break. Often they never see the part break because it only needs to not break up to 150% - so they don't continue stressing it because 150% meets the requirement.

 

This means that if someone pulls say 12G+ in your 8G jet you would expect loss of aircraft but there is no simple answer as to what breaks because they usually don't know - These things are on a time and cost budget of course.

 

If you pull say 10G well it might be okay on one occasion but another time someone pulls it at a different weight they can put the jet out of action when you need it - again there is no simple answer.

 

All aircraft are designed and built to specification - and that is the entire aircraft not just the engine or whatever - for example F-14/15 might be able to go through their design limit of 800kts but nothing on the jet is certified to do it so a pilot going over the limits is usually nothing more than a test pilot. 

 

Source is an ex structural engineer who worked on some very iconic USAF/USN Jet fighters. 

 

 

 

 

 

[Lace]

V_A is the manoeuvring speed, i.e the maximum speed for full control deflection.  Below this and you can pull any single control to the stops and will not overstress the aircraft.  Above it and you will exceed the design loading for the aircraft.  Whether this will break stuff depends on a lot of factors, but it is not something done routinely.  The reality is that it is easy to do in the sim (no physical resistance to control movement) and hard to do unintentionally IRL (lots of physical resistance to control movement).

[Rex]

On 8/4/2021 at 6:38 PM, Gambit21 said:

I think it's a limitation of your wrist/yanking our stick to full deflection suddenly and immediately with no resistance, thus resulting in much more deflection that would be possible in real life. 

 

I've never once ripped the wings off an F-14 nor felt like I was close to it, and I've flown her to the limit... but I'm used to flying WWII aircraft so it comes naturally.

Be a bit more conscious, listen to the aircraft, and stop yanking the stick...it's not a FBW aircraft.

 

 

 

 

I've ripped the wings off of the F-14 a whole bunch of times.  Then again, I don't really know how to fly it.    I flew it like the F-18, figuring the FCS would save me from doing anything I wasn't supposed to do.

 

Of course, that didn't happen, and I kept ripping the wings off while performing high-G maneuvers.

 

So, yeah, I think it goes without saying that it was due to my awful F14 piloting skills.   That said, if you've NEVER ripped the wings off, I gotta say, I'm a little surprised.  You must be a natural born F14 pilot, because it seemed not that hard to do, and if you have access to this awesome sim and don't try every now and then to over-stress it to the point point that they come unglued, might I suggest you do so?

 

The first thing I do in a new plane is try to destroy every which way I can. Not only  is it fun to break things without repercussions, but dare I say it helps you understand the plane's strengths and weaknesses much better.  And come on, have you never found yourself out of ammo, and decided to go out in a blaze of glory kamikaze-style? Of course you have! And why wouldn't you, it's quite fun.

 

And, at least a couple of times, so is flying the F-14 to shreds.  If you honestly have never even come close to doing so, then egads man, run, don't walk to your computer and do it now.  If I may offer one more suggestion, play that Kenny Loggins piece while doing so. You know the one, "High-way to the Danger Zone!", and when it gets to that "Danger-Zone" part just yell it out with reckless abandon. Make the neighbors think you've lost your mind.  Really feel it!

 

Climb to 10,000ft. Get up to, oh, Mach 1.4-ish, thne grab that stick and pull it like your're 13  again and the Victoria Secret catalog just came in the mail.   Prepare to say goodbye to your wings, because they're gonna go off and do their own thing.  Before they snap off, think of all the good times you had together. You had good times with those wings.  You had bad times with those wings, but you had times, man!  You had times and that's what counts!  

 

Then watch yourself fall to earth as a metal meteorite and slam into the ground at terminal velocity.  Screem "Woo-Hoo!" when you smack into terra firma and disintegrate.  Go ahead, hurry, go, make it happen, you can thank me later.

 

 

Edited August 8, 2021 by Rex

[silverdevil]

1 hour ago, Rex said:

grab that stick and pull it like your're 13  again and the Victoria Secret catalog just came in the mail.

lmao. nice analogy.

 

like i stated in my earlier post i was just fooling around. i would not try to destroy the plane if i was trying to win in a dogfight. the whole point is winning. its a sim and it is supposed to be enjoyable. to infer that someone pushing the sim to a limit is somehow inferior is misplaced at best. take those spent doritos bags and sew yourself a flight jacket. dont make any sudden moves so not to damage the jacket or the plane.

 

/s

[cfrag]

On 8/5/2021 at 12:14 AM, truebrit said:

Or limitation on the damage model?

 

Well, there are a couple of partial questions that warrant a look. 

 

First, is it realistic that g-load or aerodynamic stress can rip the wings off of a plane?

Definitely, and many engineers enjoy watching these demos at University. I certainly did (way back when - I dimly seem to recall a grainy super-8 color video being played by my professor). That being said: any object can and will break up under enough stress in the atmosphere. Just look at what happens to solid rocks (meteorites) when they hit our air. At sufficient velocity (energy), air is as dangerous as any other matter.

 

Can g-load/aerostress rip wings off of a Harrier or Tomcat?

Yes. It simply follows from above.

 

Can a plane reach such a dangerous state under own power?

Most can, other can't. Obviously, a paper glider can't. But surprisingly (to me) enough, even gliders can depart the envelope enough to break off their wings (usually when they overspeed in a dive and/or get into IMC).

 

Can this situation be induced by a human at the controls?

Outside of overspeeding, I'm not entirely sure, but I think yes - while ignoring warnings and behaving irresponsibly - just like it's possible to overspeed an airframe into situations that allow overstressing the airframe and break the wings off as a result. An FCS may limit a human's exposure to that risk, but neither eliminates the risk; nor does the Tomcat nor Harrier have an FCS that can influence control surface deflection. 

 

Is this modelled correctly in DCS, i.e. does DCS accurately model reality:  1) will the wings break off exactly when they would in a real-world Tomcat/Harrier, and 2) will they break off in the same way?

I find this highly doubtful, as DCS's damage model is not an output function of modelling the physical frame (if it's internal stress is modelled at all; it seems to me that structural damage is simply a lookup-table based on some calculated index derived from a small number of flight parameters). So while the wings can break off in both reality and game, and while there may well be a good overlap, it's highly unlikely that DCS manages to model this correctly: there will be cases where a wing breaks of in model or reality, while it doesn't in the other. Also, I highly suspect that the modules don't have the capability to model the parts dynamically in a way for the 3D engine to be displayed correctly. Most probably they only have a limited amount (one?) of broken-off wing models to display in-game. So no matter how a wing would break off (at the root, at some other place), it will always look the same in-game.

 

 

Edited August 8, 2021 by cfrag

[Rex]

1 hour ago, cfrag said:

 

 

 

Can this situation be induced by a human at the controls?

Outside of overspeeding, I'm not entirely sure, but I think yes - while ignoring warnings and behaving irresponsibly - just like it's possible to overspeed an airframe into situations that allow overstressing the airframe and break the wings off as a result. An FCS may limit a human's exposure to that risk, but neither eliminates the risk; nor does the Tomcat nor Harrier have an FCS that can influence control surface deflection. 

 

 

 

 

 

 

I'm inclined to think the pilot would lose consciousness before he could tear it apart by G-forces alone.

 

I mean, the wings won't come off at 9Gs, it would probably be closer to what, 15?  Maybe 20?   It probably depends on how long it's held there.  But a pilot won't be able to pull those Gs for more than a few seconds.

 

The meatbag is far more fragile than the airframe, so barring metal fatigue or some other problem, I have some doubts if the bucket o'flesh would successfully be able to pull it off just with acceleration.

 

Then again, hitting the ground is a type of G-damage, so technically I suppose I'm wrong.  In a collision with the ground, isn't it the hyper-rapid 500G deceleration that does you in?

Edited August 8, 2021 by Rex

[cfrag]

54 minutes ago, Rex said:

I'm inclined to think the pilot would lose consciousness before he could tear it apart by G-forces alone.

 

I agree - unless it's a sudden movement, and g-build-up is faster than blackout (if that is even possible). Can a sudden, harsh yank on the stick do that? I don't know, and would think that dampeners in the hydraulic may counter-act. From the pure physical standpoint it should be possible, and when the pilot keeps their death-grip after blackout, break-up of the air frame is conceivable. That's pure conjecture on my part, though.

 

59 minutes ago, Rex said:

In a collision with the ground, isn't it the hyper-rapid 500G deceleration that does you in?

 

Very likely. That's the point when we reach 'rapid unscheduled disassembly', right?

 

[Basher54321]

1 hour ago, Rex said:

 

I mean, the wings won't come off at 9Gs, it would probably be closer to what, 15?  Maybe 20?   It probably depends on how long it's held there.  But a pilot won't be able to pull those Gs for more than a few seconds.

 

 

 

Simplistically if max design G was 7.5 then all bets would be off over 11.3G and anything could structurally fail (on a new aircraft)

 

But if anyone can get an F-14 structural engineer to confirm the design (and not Mike Ciminera who doesn't appear to know)