leading edge flaps

"John Mullen" wrote in message
...
Ed Rasimus wrote:

On 10 Jan 2004 08:44:32 -0800,
(Arquebus257WeaMag) wrote:


This questions has been killing me, what is the name of the leading
edge flaps that you find on airliners for example. Ive heard the name
slats, but I know there is another name for it.


Leading edge flaps are called leading edge flaps. That wasn't so
difficult was it?

Seriously, flaps are powered devices that change the airfoil shape
(increase camber) to offer greater low speed lift. They retract to
reduce drag at high speed. They CAN, but don't always extend to
simultaneously increase wing area--most airline trailing edge flaps do
this. They may also be segmented into successively extending
sections--again airliner trailing edge flaps are a good example.

Slats are typically UN-powered devices on the leading edge that extend
simply by the reduced dynamic pressure against them as airspeed slows.
Example would be the leading edge extensions of the F-86 and F-100.

Some leading and trailing edge flaps are "slotted" meaning they create
a gap in the airfoil when extended. This reduces turbulence and keeps
airflow laminar over the entire top surface by allowing a bit of air
through the slot from the bottom of the flap to the top surface.

There are all sorts of variations including Krueger flaps, Fowler
flaps, "BLC" (boundary layer control) blown flaps, flaperons that
combine both flap and aileron functions, and spoilers which disrupt
airflow across the top of the wing to reduce lift/increase drag.

Not to mention 'splaps', but that's getting a bit technical...

Ed did not address the use of spoiler flap as used to cancel adverse Yaw,
produced by roll steering. Ed's description of the spoiler is refers only
to a spolier flap in a speedbrake configuration and while textbook in
nature, has been false for airliners since the 707; except twins. (engine
out regulations for twins require a tall tail, so the mechinisation of a
spoiler flap carrys too large a weight penalty to be practical)

Glad to educate you, John Mullin.