Unrealistic 787 Wing Flex...on PMDG 777 + Main Landing Gear Does Not Lift On Rotate

[anden145 2,273]

Quite frankly, I don't see anything wrong with Kyle's response... seemed professional to me - I don't really know what it was, that stroke you as unprofessional or condescending... 

[JD396 38]

 

I was just out at LAX spotting last Friday and thought I'd re-create this pic I took in FSX.

 

Leon, would you mind explaining to us how distractingly unrealistic the wing flex is again?

[hopskip 253]

Pity FSX/P3D doesn't have such amazing reflections

[anden145 2,273]

 

I was just out at LAX spotting last Friday and thought I'd re-create this pic I took in FSX.

 

Leon, would you mind explaining to us how distractingly unrealistic the wing flex is again?

 

Nice comparisson! 

Can't find anything wrong with the wing-flex - seems PMDG got it spot-on... 

 

If I HAVE to say something in this regard, I would say that PMDGs 777 don't bend enough - although that could be (and quite possibly is) the angle is a little bit different... 

[Boeing or not going 578]

 

I was just out at LAX spotting last Friday and thought I'd re-create this pic I took in FSX.

 

Leon, would you mind explaining to us how distractingly unrealistic the wing flex is again?

 

Even though the OP's argument is not right, you really can't re-create a flight unless you have the same data like weights. - David Lee

[Jetstream96 20]

I was just out at LAX spotting last Friday and thought I'd re-create this pic I took in FSX.

So you said this is a recreation of the flight when the location of clouds are so incredibly obviously incorrect?

[JD396 38]

Even though the OP's argument is not right, you really can't re-create a flight unless you have the same data like weights. - David Lee

 

Well, you can guesstimate it based on fuel rules and how airlines load up planes like the 77W for long haul flights. At any rate OP said to take a long haul flight and compare it to the PMDG 777 to see how mind-blowingly bad the wing flex was on landing. So I did!

 

So you said this is a recreation of the flight when the location of clouds are so incredibly obviously incorrect?

 

Wow! What an oversight on my part! I re-ran my simulation and turns out OP is right:

[Mike777 163]

 

 

Wow! What an oversight on my part! I re-ran my simulation and turns out OP is right:

 

Thanks for settling it once and for all!    I never realized before that the T7 actually flies by flapping its wings.

 

Haven't laughed this hard for awhile.

 

Mike

[HighBypass 2,339]

 

...... thought I'd re-create this pic I took in FSX....

 

 

The real one appears to be using less flap that the sim one  (Trailing edge device, not literally wing flap!)

[ahsmatt7 1,199]

First off. No it doesn't. The cantilevered gear does not rise off, it simply locks and does not allow for extra rotation in an effort to add a little extra protection against tail strikes. This is, in fact, actually modeled.

Second, the wing flex is modeled correctly. If you believe it is incorrect bring facts and evidence.

Welcome to the forum. Full names are required to be placed in your posts. This helps ensure that forum discussions are a bit more civil. Something decidedly lacking in your rant...er...post...which is backed up by so much evidence that I'm quite compelled to go rouse up the team to fix the non-issues that you've dragged up out of nowhere.

 

You care about placing your own expectations of realism, over...actual realism?

Out of curiosity, how does the protection in the landing gear work to prevent an over rotation situation?

 

I can't picture how it would prevent it. Anyeho, carry on!

[scandinavian13 5,192]

 

 

Out of curiosity, how does the protection in the landing gear work to prevent an over rotation situation?

 

Note the verbiage used - "extra protection" - and not prevention. I'm assuming you're getting hung up on the "and does not allow for extra rotation [...]," which is a reference for rotation about the gear truck's attachment point, and not rotation of the aircraft about the pitch axis.

 

Basically, on most large aircraft, you rotate on the connection point where the gear truck attaches to the gear leg. On the 777-300ER, it essentially locks the rotation point such that instead of pivoting where the gear assembly would normally rotate, it pivots on the back axle. This shifts the pivot point back by about 5', which gives a little extra room on the tail as you rotate.

 

Here's the Boeing patent ("semi-levered" is the technical term):

https://www.google.com/patents/US8448900

[ahsmatt7 1,199]

Note the verbiage used - "extra protection" - and not prevention. I'm assuming you're getting hung up on the "and does not allow for extra rotation [...]," which is a reference for rotation about the gear truck's attachment point, and not rotation of the aircraft about the pitch axis.

 

Basically, on most large aircraft, you rotate on the connection point where the gear truck attaches to the gear leg. On the 777-300ER, it essentially locks the rotation point such that instead of pivoting where the gear assembly would normally rotate, it pivots on the back axle. This shifts the pivot point back by about 5', which gives a little extra room on the tail as you rotate.

 

Here's the Boeing patent ("semi-levered" is the technical term):

https://www.google.com/patents/US8448900

the CRJ only has one set of main gear and doesn't have 3 axels obviously, I never knew the 777 had that feature. Cool stuff.

 

You can tell I don't have expert landing gear knowledge because I don't fly a big enough airplane around to care hahaha

[anden145 2,273]

Very nice explanation, Kyle! Thanks for that. Interesting feature.

Is it only a feature of the -300 or this also installed on the -200? (or is tail-strike not as-a-serious concern in that model?)

[Jet Tech 31]

Anders,

 

It was only put on the 777-300 due to the extra 15.5 feet behind the gear as compared to the 777-200LR

[HighBypass 2,339]

Thanks Kyle. A complex piece of engineering (mind you a whole airliner is a complex piece of engineering). The back axle also has a pivot mechanism to help alleviate tyre scrub and assist in tight turns when manoeuvring on the ground.

 

EDIT - but I digress. Back to the flappy wings...