Behind the engine exhaust the B777 has a flaperon. It droops with the flaps, but is used as an aileron as well. This is possible because of FBW.
Next time you fly a B777, get a window seat behind the wing and watch it during take off. When the flaps are extended for taxy, it comes down. When the engines are opened up for take off it goes up again and fluctuates in the engine exhaust. It is actually uncontrolled during this time and is pushed up by the exhaust. Then at about 80kts, it comes back down again. It is in the fan exhaust flow, but for as short a time as is necessary.
|Quoting Prebennorholm (Reply 9):|
And with modern FADEC engines spool up time is not the same issue, even if it may still be slow. At least spool up from flight idle is no longer a delicate manual thing, but a fully predicable automated thing.
Engine spool up is mandated by regulation. The engine must go from flight (or approach) idle to max thrust in 6 secs. This has been the case as long as I can remember. On older engines it was achieved by having a high flight idle to achieve this.