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YukonPete

Wing flex during turbulence

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Is it just me or does the wing flex during turbulence seem a little extreme? I am not criticizing PMDG. For all I know it could be 100% correct. But to me it just looks extreme!   

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I also wondered. The outboard engines go up and down quite a big distance even in relatively light turbulence. But I have no real life references as I never flew with it

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Have flown on the 744 many times an have seen the wing flex what seems even more than the video depicts.. The engine looks as if it should depart the structure! It really is something else to see. PMDG have created this flexing admirably within the P3D engine ( see what I did there...? :)  

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The 747's wing is designed to flex 13ft either side of centre. I really think we have to trust PMDG that they did their homework on stuff like this.

 

Glenn Davy

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Well, I was about to agree that it seemed "exaggerated" but after seeing that video, I can only say my respect for Boeing engineers (and PMDG) has gone up a notch. I did reduce ASN turbulence from 70 (default) to 50 however, as at 70 it was uncontrollable.

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Well, I was about to agree that it seemed "exaggerated" but after seeing that video, I can only say my respect for Boeing engineers (and PMDG) has gone up a notch.

 

This, ladies and gentlemen, is why when we say "we're going to rest on the data that we have, along with the experience of our Tech Team," we mean it, and place value in those facts and that experience.

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I rest my case, too. What I see on the video is exactly that I've experienced in mid flight today...so big grats to the tech guy at Boeing and PMDG!

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Also just a heads up to ASN users and maybe AS2016( i dont have as2016). Move the turbulence scalar slider back. For some reason, asn makes turbulence so much more unrealistic and obnoxious than it really needs to be. I moved mine back to 25 and everything works well with the 74u arondnd the other pmdg birds. Light turbulence is actually light turbulence....not severe.

 

Some food for thought.

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Im no expert but I have crossed the Pacific between North America & Australia dozens of times on Qantas 747-400 over the last 20+ years and I never seen wings flex on a 747 like they do on my PC! Yes you get the occasional severe turbulence like the video above maybe 5% of the time. I have done 3 flights in the PMDG 747 and everyone has had the plane flapping its wings like a bird! Again I am not saying PMDG data is wrong however something on my system must be!

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Don't know what PMDG's numbers state, but that video looks a lot like something I experienced on return to Johannesburg from Sydney. Those wings can flap around a lot, which is very reassuring when you see cabin crew rushing to their seats.

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I never seen wings flex on a 747 like they do on my PC!

 

Simulated turbulence is nothing like the real thing.

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Also just a heads up to ASN users and maybe AS2016( i dont have as2016). Move the turbulence scalar slider back. For some reason, asn makes turbulence so much more unrealistic and obnoxious than it really needs to be. I moved mine back to 25 and everything works well with the 74u arondnd the other pmdg birds. Light turbulence is actually light turbulence....not severe.

Some food for thought.

Thanks for the tip. i will ill take a look at AS16 when i get home.

Raw Boeing image of the 747 wing load test:

 

www.boeingimages.com/archive/Second 747 Wing Bend Test-2F3XC5K05FD.html

 

And then we have QOTS II during a normal approach to land:

 

kB7kUyHl.jpg

 

Guys, I understand that you coded based on feedback from people with the type rating and technical documentation, but that doesn't mean there isn't a problem.

Exactly what mine does in cruise. but mine flaps up and down to that same extreme. it literally looks like a bird flapping away in flight!

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And then we have QOTS II during a normal approach to land:

 

Normal approach to land includes full deflection of the elevator like that? I'd be interested to hear who your DE was. Someone was playing with (/abusing) the plane, g-loaded the wing, took a funny screenshot, and people are using a corner case as 'evidence' that we screwed up. The elev is clearly at full deflection. Yes, it looks a bit odd fully loaded up like that, but keep in mind that the behavior to cause it (as is clear in this very screenshot) is about as normal as a 744 doing a Blues run at a local airshow.

 

 

 


Exactly what mine does in cruise. but mine flaps up and down to that same extreme. it literally looks like a bird flapping away in flight!

 

Sounds like your turbulence settings need to be dialed down a bit.

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Normal approach to land includes full deflection of the elevator like that? I'd be interested to hear who your DE was. Someone was playing with (/abusing) the plane, g-loaded the wing, took a funny screenshot, and people are using a corner case as 'evidence' that we screwed up. The elev is clearly at full deflection. Yes, it looks a bit odd fully loaded up like that, but keep in mind that the behavior to cause it (as is clear in this very screenshot) is about as normal as a 744 doing a Blues run at a local airshow.

 

Bingo - there is serious G loading on the wing in that shot.

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Normal approach to land includes full deflection of the elevator like that? I'd be interested to hear who your DE was. Someone was playing with (/abusing) the plane, g-loaded the wing, took a funny screenshot, and people are using a corner case as 'evidence' that we screwed up. The elev is clearly at full deflection. Yes, it looks a bit odd fully loaded up like that, but keep in mind that the behavior to cause it (as is clear in this very screenshot) is about as normal as a 744 doing a Blues run at a local airshow.

 

 

 

Sounds like your turbulence settings need to be dialed down a bit.

Thats what i am thinking. thanks for the reply

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Guys, I understand that you coded based on feedback from people with the type rating and technical documentation, but that doesn't mean there isn't a problem.

 

I agree the motion is a little exaggerated for any given level of turbulence, but in your screenshot, it's clear from elevator position you were putting the 744 thru some extreme maneuvers. ;)

 

Cheers, Rob.

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Welcome.

It was AS2016 turbulence setting causing the problems. I turn them down 50% and now its as I would expect. Thanks

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It was AS2016 turbulence setting causing the problems. I turn them down 50% and now its as I would expect. Thanks

 

Glad to hear it. You're welcome. If you're interested, there's a notional chart in the Intro Manual that shows some of the crazy g forces weather programs will throw at planes in the sim.

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I have AS2016 and actually my turbulence setting was on 70 before and 2 days ago when I've installed the QOTSII and tuned down the turbulence setting to 35 (it was recommended by EZCA 2.0) and the bird still twerking around more than I've ever seen 737/777 before during cruising. Gonna test lowering it a bit more to see if it helps. 

It's not disturbing or anything like that....only so much twerking I havent seen since my days flying PA28 in real life. :)

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Erik,

 

If it matters at all:  I find ASN's turbulence model to be so ridiculous that it almost doesn't even warrant leaving it running.

 

I have mine set to 15...  and it is still a bit too much.

 

The problem is that ASN does not appear to apply any appreciable smoothing or gust control to their injection model, so you can get wind gusts that would sever the wing in real life...  even at very modest settings.

 

I have voiced my opposition to this ridiculousness for years- as it hampers our ability to give you a truly valid flight model.  I think about 1/2 of our development time in the modeling/behaviors arena is spent on "how to we keep the weather engines from exceeding the actual, real world limitations and capabilities of this model?"

 

It is fraught with dangers...  As we can't possible stop all of it.

 

So try 15 and see what you think.  I think you will find it to be far more reasonable.

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