Reading the chat about the wing in Lou's thread reminded me of some video I shot last year on my trip to China. I have some video of takeoff, cruise and landing. All interesting to me, there is a lot of stuff going on with that wing. Here is the takeoff roll out of PEK - totally packed 777-300. Seemed to take forever. What is the small surface in the center of the wing? It seems to slowly rise as we pick up speed, and then at some speed it drops. After we are airborne, and the plane is making a right turn, it looks to me like it is resisting that turn. What it is doing during the initial part of the roll, and when it shifts down while still on the ground, etc? [ame]http://www.youtube.com/watch?v=H0VIXw_kWHI[/ame]
I think that you are referring to the spoilers and perhaps the inboard aileron. When the spoiler and aileron rise , it depresses the wing to make a turn.
Typically, on a Boeing wing trailing edge, going inboard to outboard is: flap, aileron, flap, aileron. That has been true since the 707.
So the two ailerons move independent of each other? I don't see the outboard aileron moving, but then again I guess being that far out on the wing it doesn't have to move much to have some effect. Any idea why the inboard aileron moves as it does during different phases of the takeoff roll?
Inboard aileron is often referred to as a flaperon. It can serve dual purpose of acting as a flap and aileron. Hence when the flaps are deployed the flaperon also as a drooped configuration. During cruise most of roll control is via the outbd spoilers. Outbd aileron is locked out during cruise.
Addition At low speeds the inboard aileron works in conjunction with the outboard aileron. So, if the pilot inputs a bit of aileron on take off, both of them will move. At high speeds (cruise), the outboard aileron is locked out and only the inboard aileron works. This has to be done because the outboard aileron is on the thinner part of the wing and would twist the wing when it was moved, acting as a tab instead of an aileron and would produce opposite reaction. At lower speeds, like landing, the spoilers act along with all of the ailerons when they move in an upward direction. This produces powerful roll control when it's needed the most. The spoilers do exactly what their name implies, it spoils the flow over the wing and is used at high speed. They don't move very much then but they do produce the desired effect. On landing when the flaps are down all of the spoilers pop up to increase drag and to kill the lift. The ailerons move together but in opposite directions, one wing up, the other wing down to produce a rolling motion and that produces a turn. Near the ground they will keep the wing tips off the runway. Hope this helped a bit.
Thanks for the replies. So do you think that movement between 0 and 35 seconds in my video has no specific intent? Maybe just the pilot getting a grip on the yoke awaiting time to rotate?
Here is another of the same flight, a couple of hours out of PEK, starting to get a little bumpy. I like the "flapping" wing. You can see in the last part of the video (the moving map display) that is wasn't all that bumpy. Argh, still more than 11 hours to go.. [ame=http://www.youtube.com/watch?v=-SAVoDF2oj4]Air China 777-300 PEK-IAH April 2014 - YouTube[/ame]
And my last clip - landing at IAH. Everything is moving, first time I could see the outboard aileron move. It is interesting to see the wing basically come apart after touchdown. Doesn't seem like there should be that many "pieces". [ame]http://www.youtube.com/watch?v=f-k7ISHHycU[/ame]
Your comment about "so many pieces" reminds me of the 727 trailing edge with triple slotted flaps, spoilers, and ailerons. I was giving stour of the mock up to airline customer pilots and the flaps and slats were deployed on the mock up, leaving only the spar box (main wing structure)intact. One of the tour members after looking at everything hanging out commented, " You'll NEVER get all that S***t to work at the same time!" Later on there was a statement that "it was the only airplane that assembled its wing after take off". I didn't mention that the inboard (high speed) aileron also operated as a flap on landing. At one point on the 727 design they were considering drooping both ailerons with the flaps but the mixing mechanism was very complex and heavy.
I was once sitting behind the wing in a 767 coming in to land at PHL on a very gusty day with a crosswind. Those inboard ailerons were flapping like crazy as the pilot fought to keep the wings as level as he could!
Just to justify my fascination with the wing, there wasn't much to think about with the meals. "Chicken rice or shrimp rice?" Image Unavailable, Please Login
Had this on a Cessna 206 (Robertson STOL kit). You end up losing a bit of aileron travel, but it does work well adding low speed lift.
I used to rig all that stuff up at Paine field on a lot of those Fedex 727's. Still have all my special made tools for doing mid flap cable changes and making all that turnbuckle adjusting easier. Should toss it all I guess, not likely to work a 27 again.
Isn't it just amazing? It seriously puts me in awe every time I fly watching the wings and the plane work.
Tim, I'm going to make an educated guess that the cable of which you speak was the one slaved to wing structure that rotated the bell crank that deployed the aft flap. Is my old head still working? Haven't got a cable to crank it up but i think that it still tries. I recently was going through the drafting and illustrating tools and equipment that I used 55 years ago and realized that no one would recognize some of it now and would find no way to use it even if they knew how. What do I do with it? My last cutaway, the B-29, soon to be released with annotations. Image Unavailable, Please Login
Been meaning to say for a long time that it is good to see someone still salute Mark over here on F'chat. That motor is almost in the car!! John
Hi John, The last time I checked on Mark's progress, which was a couple of years ago, it appeared that he had stopped work on the project for good. Could you P.M. me with info and link possibly? Thanks, DJ
