Spoilers, no spoilers?

On Feb 8, 9:25*am, Peter Clark
wrote:
On Fri, 8 Feb 2008 07:40:33 -0800 (PST), "F. Baum"
wrote:



. If there truly was a physical reason why
spoilers should not come out in the air, it would have been an
engineering requirement to systematically disable their mechanism
unless, say, the gear is down and the wheels rolling.

Actually, this is the way it works. Only some of the spoilers deploy
inflight (Either through the spoiler handle or the Aileron/Spoiler
mixer ). The rest of the spoilers will not deploy until the plane is
on the ground.

Or an airspeed lockout. *If memory serves they won't deploy, even for
roll assistance, above a certain speed either.

Not too sure on this. On all the jets I have experience with, the
boards are usable to VMO/MMO. On some some of the older ones, like the
727 they will blow down a bit as you approach the pole.


*Don't they also
deflect at different angles depending on what system is activating
them? *Highest angle off the wing is for full in-flight spoiler handle
(and some don't even come up for that), inboard segments deflect at a
greater angle than outboards for roll assistance (which is about 1/2
the angle off the wing compared to full spoiler), and everything comes
up at full for weight-on-wheels spoiler system?

They deploy proportionate to the roll or spoiler input. On several of
the newer airliners there is a flight detent and full range for ground
deployment. Exceeding the flight detent results in buffeting. As an
interesting side note, on the Boeings, if you have the boards about
half way extended and then try a turn, you get a dramatic increase in
the roll rate.