"ttyymmnn" (ttyymmnn)
01/25/2020 at 12:37 • Filed to: None
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"ttyymmnn" (ttyymmnn)
01/25/2020 at 12:37 • Filed to: None | 1
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Looks like they are trying again today. Yesterday’s flight was scrubbed due to high winds.
http://www.boeing.com/commercial/777x/first-flight
Spaceball-Two
> ttyymmnn
01/25/2020 at 13:10 |
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I drove up there yesterday to watch the take off but yeah the weather was garbage.
Jake - Has Bad Luck So You Don't Have To
> ttyymmnn
01/25/2020 at 13:14 |
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how many aoa sensors does it have tho
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ttyymmnn
> Spaceball-Two
01/25/2020 at 13:14 |
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Just took off. Gorgeous. Those engines sounded amazing.
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ttyymmnn
> Jake - Has Bad Luck So You Don't Have To
01/25/2020 at 13:14 |
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All of them.
Thomas Donohue
> ttyymmnn
01/25/2020 at 13:15 |
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Folding wingtips??? Do we trust Boeing on this one?
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ttyymmnn
> Thomas Donohue
01/25/2020 at 13:17 |
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The folding wingtips were manufactured by Liebherr Aerospace, so we should be good.
facw
> Thomas Donohue
01/25/2020 at 13:18 |
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Seems easy to get right, and folding wingtips/wings have been a thing forever in naval aviation (including Boeing’s own Super Hornet).
I think the question is do we trust pilots to remember to fold them up when they are on the ground, and down when they are ready to takeoff? I’m sure they will do so the vast majority of the time, but you’re going to have a bad day if you forget.
lone_liberal
> ttyymmnn
01/25/2020 at 13:52 |
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It’s heading right for me! Incoming! I thought it would go toward Moses Lake but it stayed north of there.
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ttyymmnn
> lone_liberal
01/25/2020 at 15:05 |
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It took off to the north to avoid population centers. That’s why it couldn’t fly yesterday. The winds were too strong out of the south for a downwind takeoff.
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lone_liberal
> ttyymmnn
01/25/2020 at 15:28 |
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Makes sense. It looks like it flew to the outskirts of Fairchild and then turned and is flying circles above a whole lot of nothing.
Highlander-Datsuns are Forever
> ttyymmnn
01/25/2020 at 15:42 |
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Doing a good job going around and around again.
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ttyymmnn
> Highlander-Datsuns are Forever
01/25/2020 at 16:04 |
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gmporschenut also a fan of hondas
> facw
01/25/2020 at 19:24 |
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the winglet is mostly to reduce highspeed drag. I’d be more worried if there was some interfernce wiht a control surface or forgetting a control lock in place.
I would say there would be a pokeyoke, but this is boeing so who knows
You can tell a Finn but you can't tell him much
> Thomas Donohue
01/25/2020 at 22:32 |
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It will fly just fine with the wing ti ps folded. It just won’t be as efficient. I suspect at some point in the flight testing program they will do some testing to quantify the differences between having the wing s folded and extended. Possibly they’ll even test with one folded and one extended.
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Thomas Donohue
> You can tell a Finn but you can't tell him much
01/26/2020 at 09:19 |
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Source? I can’t see any reason to ever fly with the tips folded.
The FAA has some pretty strong language regarding the wingtips:
https://interestingengineering.com/the-boeing-777-xs-folding-wings-are-they-safe
This document has some pretty sobering language regarding the 777-8's and the 777-9's new design:
“Boeing has determined that a catastrophic event could occur if the Model 777-8 and 777-9 airplane wingtips are not properly positioned and secured for takeoff and during flight. In service, numerous takeoff operations with improper airplane configurations have occurred due to failures of the takeoff warning systems, or inadvertent crew actions
Full FAA Document
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You can tell a Finn but you can't tell him much
> Thomas Donohue
01/27/2020 at 13:58 |
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I’m making a bit of an educated guess regarding the planes ability to fly regardless of the position of the wing tips. The ends of the wings are designed to minimize the amount of air that “ spills” from the bottom to the top of the wing. This air spillage results in wingtip vortices and induced drag . In the case of the 777X Boeing has designed the wing with an extremely long span and a tapered shape at the ends ( raked wingtip ). The tapered shape actually makes it so the 777X wings are making very little lift right at the end of the wings which reduces the wingtip vortices . Other aircraft like the 737NG reduce wingtip vortices by using blended winglets . The winglets on the 737NG act as a wall that reduces the amount of air that spills from the bottom of the wing to the top. Both the raked wingtip and the winglets are designed to reduce the wingtip vortices and the drag associated with them .
If the 777X wing tips are folded up they should be aerodynamically similar to the winglets on other aircraft, though the wing would not be as aerodynamically efficient as it would be with the wing tips in the proper position. Folded wingtips shouldn’t have a huge effect on the takeoff or landing speed as none of the high lift devices are placed on the folding part of the wingtip. There would likely be some difference in handling characteristics due to the increased vertical surface of the airplane, but there would still be full control authority since none of the control surfaces are affected.
I think in the case of the 777X wing tips the FAA is being very cautious (as they should be) since they have no experience certifying commercial aircraft with folding wings. Nobody has done this before, and given the current public perception of both Boeing and the FAA, both entities should want to perform robust testing. There is no reason for the 777X to ever fly with the wingtips folded, but that doesn’t mean it shouldn’t be tested in that configuration. Boeing and the FAA should very much want to verify that the 777X will take off, fly and land acceptably if the wingtips are either incorrectly configured, or a cascade of failures results in something causing the tips to fold in flight.
In a similar case, Grumman tested the F-14 with asymmetric sweep on the wings before the Navy was OK with the design. They locked the right wing forward at 20° of sweep and flew the plane with the left wing at 35 , 50, 60 and 68 degrees of sweep to determine its flight characteristics. In the end they determined that landing was feasible with one wing at 60° of sweep while the other was extended to 20°.
http://www.grummanpark.org/content/tomcat-tales-f-14a-aircraft-no-3-buno-157982