leading edge flaps

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.

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.


Droops?


John

Not sure if this applies, but the Tornado used to have Krueger (think thats
how its spelt) on the leading edge where the wing pivots.

"Arquebus257WeaMag" wrote in message
m...
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.

krueger flaps

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.


Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
Smithsonian Institution Press
ISBN #1-58834-103-8

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...

John

On Sat, 10 Jan 2004 17:46:52 +0000, John Mullen
wrote:


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

John

I wondered how long it would take. Mere minutes...

Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
Smithsonian Institution Press
ISBN #1-58834-103-8

"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.

On Sat, 10 Jan 2004 10:07:10 -0800, "Tarver Engineering"
wrote:


Ed Rasimus wrote:


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.

Ed did not address the use of spoiler flap as used to cancel adverse Yaw,
produced by roll steering.

One can only say so much in a newsgroup response. There's little time
to address all possible options of control surfaces at all times. But,
since you brought it up, let us note that some aircraft use "spoilers"
(not spoiler flaps) as a control surface. It is an effective way to
counter adverse yaw--the tendency of the drag of a downward deflected
aileron to be greater than that of the upward deflected one, which
causes the aircraft to way opposite the direction of intended roll.

The B-52 for example uses spoilers for roll control and the F-105 had
eight spoilers on the top of the wing on each side for the same
purpose.

Not sure what "roll steering" is. Roll is defined as rotation around
the longitudinal axis of the aircraft. Yaw as rotation around the
vertical, and pitch as rotating relative to the horizontal. One
"steers" the aircraft by inducing bank, which then creates a lift
component to divert the aircraft from straight ahead flight.

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;

Spoilers, surfaces that extend from the top surface of the wing are
used to "spoil" lift. They disrupt the smooth, accelerated flow over
the top surface of the wing which causes the low pressure area which
is different than the high pressure area on the bottom surface (maybe
wings don't lift, they "suck" the airplane up?) When these
lift-destroying devices are deployed, they help an aircraft descend
without gaining a lot of airspeed. Speedbrakes, are traditionally drag
devices, used to increase the form or parasite drag on the airframe.
Same thing gets accomplished but spoilers operate through induced
drag/destruction of lift while speedbrakes operate by parasite drag.
Got nothing to do with aircraft specific types.


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)

What does tail size have to do with weight lifting capability? Twins
don't always have a tall tail, and regardless, the mechanics of a
flight control system, whether spoilers, flaps, slats, slots,
speedbrakes, ailerons, flaperons, spoilerons, stabilizers,
stabilators, or whatever is about the same.

Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
Smithsonian Institution Press
ISBN #1-58834-103-8

"Ed Rasimus" wrote in message
...
On Sat, 10 Jan 2004 10:07:10 -0800, "Tarver Engineering"
wrote:


Ed Rasimus wrote:


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.

Ed did not address the use of spoiler flap as used to cancel adverse Yaw,
produced by roll steering.

One can only say so much in a newsgroup response. There's little time
to address all possible options of control surfaces at all times. But,
since you brought it up, let us note that some aircraft use "spoilers"
(not spoiler flaps) as a control surface.

I think aircraft use spoiler flaps as a control surface, as opposed to a
fixed spoiler. Just as I might write the full name of a kreuger flap, or a
fowler flap. (nice description in your post, by the way, Ed) If you mean to
claim that the introduction of aerodynamics to the discussion is
problematic, you can't possibly know the depths of the buffarilla operator's
consternation that USAF had mislead him as to how his short tail B-52 wing
works. I don't really mean to bust anyone's bubble, but I think the real
answer is important too.

It is an effective way to
counter adverse yaw--the tendency of the drag of a downward deflected
aileron to be greater than that of the upward deflected one, which
causes the aircraft to way opposite the direction of intended roll.

Yet, the spoiler in such a configuration is not intended to "spoil lift",
but only to cancel the drag and lift difference between the right and left
aileron.

The B-52 for example uses spoilers for roll control and the F-105 had
eight spoilers on the top of the wing on each side for the same
purpose.

Here is a question for you, did my sploiler flap discussion with Buff get
the USAF to teach the real aerodynamics of the short tail B-52 wing? I
think it would be interesting to note if it relly matter whether a pilot
knows how their wing works.

Not sure what "roll steering" is. Roll is defined as rotation around
the longitudinal axis of the aircraft. Yaw as rotation around the
vertical, and pitch as rotating relative to the horizontal. One
"steers" the aircraft by inducing bank, which then creates a lift
component to divert the aircraft from straight ahead flight.

The error between selected course and actual course is roll steering.(or
more correctly, the output of a mode slector) On the output side of the
roll computer is roll command, which you may have seen dispalyed on a flight
director attitude display.

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;

Spoilers, surfaces that extend from the top surface of the wing are
used to "spoil" lift.

Not in the application we are discussing here. The spoiler flap actually
pushes down on the wing and induces drag. Although I can understand why it
is simpler for an operator to parrot some string of words.

They disrupt the smooth, accelerated flow over
the top surface of the wing which causes the low pressure area which
is different than the high pressure area on the bottom surface (maybe
wings don't lift, they "suck" the airplane up?)

Sometimes, but right now we are not discussing a speed brake.

When these
lift-destroying devices are deployed, they help an aircraft descend
without gaining a lot of airspeed.

Yes, Ed knows what a speed brake is.