Por que os flaperons do 787 estão localizados até o momento?

Question

Por que os flaperons do 787 estão localizados até o momento?

#1 resposta do (3 votos)
#2 resposta do (1 votos)

1

Why are the flaperons positioned in between the outboard and inboard flaps (see 2nd picture)? Why not have them located as far outboard as possible to achieve maximum roll authority? I would think the order would be more efficient if the main flaps were both inboard, followed by the flaperons, followed by the ailerons. Thoughts?

In a previous post "How does the particular piece of flap behind an engine on a B777 work?", Peter Kampf explains the flaps would have a gap b/w them when extended because they extend perpendicular to the hinge line and the trailing edge is non co-linear. However, the 737 tackles this problem just fine (see 1st picture) so I don't think it fully captures why the flaperon is placed where it is on the 787 and 777.

estabilidade asa Controles de vôo

por Jason 12.07.2019 / 18:46

2 respostas

Tags estabilidade asa Controles de vôo

Como viajar de Cedar Rapids para Chicago de ônibus? Conto com navio e artefato antigo

score 3 · Answer 1

Citando o answer @fooot linked to:

At high speed, the outboard ailerons are locked and all roll control is achieved by deflecting the inboard ailerons (and spoilers, if needed). This helps to reduce wing torsion and twist.

Yes, roll authority will be larger once the force is applied further away from the fuselage (/ roll axis), but the cost at which this comes (wing twist) is larger than that benefit.

score 1 · Answer 2

I can't speak for the designers on the true rationale, but one of the considerations would be a balance between control reversal speeds and roll rate requirements at high speed. I strongly suspect that the locking of the ailerons is because the aileron aeroelastic reversal speeds don't meet the margins required under Part 25 of 14CFR.