Greetings all.
I have been doing some reading last night trying to understand the wing flex that we have seen on the first few flights of the Dreamliner.
I am interested to know about how Boeing has gone around with the design of the wing and till what extent will the flex on the Dreamliner be, while fully laden with cargo and pax at its cruising altitude.
How much is the official wing deflect of the 787 against the 777 wing? I know the composition of both wings is completely different and a comparison as such should not be done but it will be interesting to see how the two different composites behave in operational environment.
But I have tried to gather some information with almost every article/study telling different stories.
Open court for discussion.
By: old shape - 6th February 2010 at 10:25
You absolutely sure about that? Even the middle of the wing seems to flex much more than any 747 or 777 I’ve seen! I could well be wrong but having seen plenty of videos and photos of it I just can’t believe it’s an illusion. More than happy to be proved wrong though!
Paul
It has to be stiff enough for the job! erm, I’ll start again.
Beyond the Lump attachment mounts there could very well be more flex but somehow I doubt it’s very much. I hope it isn’t moving in opposite sync. with the tip, like an Indian Dancers arms!
By: PMN - 4th February 2010 at 23:43
The flex is actually no worse than a 777 or 747.
You absolutely sure about that? Even the middle of the wing seems to flex much more than any 747 or 777 I’ve seen! I could well be wrong but having seen plenty of videos and photos of it I just can’t believe it’s an illusion. More than happy to be proved wrong though!
Paul
By: old shape - 4th February 2010 at 23:39
The flex is actually no worse than a 777 or 747. The tip is riding higher by about 3 metres in normal flight. What makes it look worse is that the wing tip is almost already at the level of the top of the fuse, so the normal flex takes it above the fuse, which is giving us an uncomfortable illusion. IIRC the “expected” max load will flex it about 8 metres up.
I presume you have seen pictures of test rigs where they complete all the appropriate load iterations, then take it to 150%, then take it to snap/destruction? I saw the A310 wing with the tip pointing vertically, it snapped that afternoon, which I unfortunately didn’t see or hear.
As for the Winglets, this wing has been designed with the “New knowledge” of wingtip vortice control in mind, so the devices are less prominent. The beautiful curly winglets from APB are retrofit or added new to a wing that was designed without the “New Knowledge”.
Of course we new about the tip vortices, the new knowlege I refer to is the desire to do something about them.
By: Distiller - 4th February 2010 at 18:40
Noticed that it doesn’t have winglets? Well, the curved/flexing outer wing does the same job as the winglets, but over a wider speed range and with less drag. All about lift/drag optimization.
By: Arabella-Cox - 4th February 2010 at 06:38
I’m afraid I am not that technically minded, but the wing flex on the first flight aircraft was unreal.
I wonder what nervous passengers will make of it?
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February 4, 2010 at 5:51 am