leading edge flaps

"Ed Rasimus" wrote in message
...
On Sat, 10 Jan 2004 17:46:52 +0000, John Mullen
wrote:


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

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

It is what the troll is about, Ed.

I wrote kreuger and fowler flaps, as full names of wing extensions, and so
the discussion came here. Surely you must understand the sweet irony I am
enjoying.

"Ed Rasimus" wrote...

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.

There are powered examples as well, such as the A-6 and EA-6B.


Some leading and trailing edge flaps are "slotted" meaning they create
a gap in the airfoil when extended.

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.

Just so there is no confusion, flaperons and spoilers are not [normally] used as
leading edge devices.

It may be a matter of semantics on different airplanes types, but "flaperons" as
used by Grumman on the A-6 and EA-6B serve as spoilers and ailerons, but NOT as
flaps. There ARE several aircraft such as the F-4 that used drooped ailerons as
flaps, but I have not heard or seen them called "flaperons."

"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.

In general, they can be called "leading edge flaps."

Some of them are specific designs, such as the "Kreuger flaps" on 727s and the
inboard segment of 747s. Others, such as the outboard segments of the 747s,
look like, and perform the same function when extended, as the "leading edge
slats" on the F-86, A-4, and A-6. However, because of the manner in which they
are stowed and deployed on the 747, they are still called "leading edge flaps."

"John R Weiss" wrote in message
news:9WYLb.15782$na.12393@attbi_s04...
"Ed Rasimus" wrote...

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.

There are powered examples as well, such as the A-6 and EA-6B.


Some leading and trailing edge flaps are "slotted" meaning they create
a gap in the airfoil when extended.

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.

Just so there is no confusion, flaperons and spoilers are not [normally]
used as
leading edge devices.

It may be a matter of semantics on different airplanes types, but
"flaperons" as
used by Grumman on the A-6 and EA-6B serve as spoilers and ailerons, but
NOT as
flaps.

I like the B-52 contrast in tail heights as an excellnt demonstration of the
advantages of spoilers as a control surface, as opposed to the speed brake
configuration.

"Tarver Engineering" wrote...

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)

I don't think any of us have ever seen any documentation in any book or
technical publication that refers to a "spoiler flap" -- so far, the term
appears to have been created by Tarver, here in the newsgroup. OTOH, through
the years I have seen several just-as-ridiculous descriptions of aeronautical
equipment and their [alleged] functions in the popular press (newspapers and
non-technical magazines, apparently written by people not familiar with
airplanes.

The statement "a spoiler flap in a speedbrake configuration and while textbook
in nature, has been false for airliners since the 707; except twins" sounds like
a new Tarverism, worthy of archiving. Its actual meaning escapes me, though the
misinterpretations and misinformation that could easily be drawn from it by
people looking for information are numerous. Just a few examples:

I have never read about "a spoiler flap in a speedbrake configuration" in
any textbook. Anyone else?

From "false for airliners since the 707; except twins" it is possible to
infer that the L-1011, DC-10, MD-11, 747, and other 3- and 4-engine airliners do
not have spoilers or speedbrakes. Of course, we all know that is false.

The statement that "engine out regulations for twins require a tall tail" is
clearly false in the general case, as evidenced by the DC-9, MD-80, and B-717,
as well as numerous business jets with fuselage-mounted engines.

And finally, "...require a tall tail, so the mechinisation of a spoiler flap
carrys too large a weight penalty to be practical" makes no sense whatsoever,
because: (1) we don't yet know what a "spoiler flap" is; (2) spoilers
"mechani[zed]" as speedbrakes are in fact used on virtually every modern
airliner; and (3) the height of an airplane's tail has no bearing on whether or
not spoilers "mechani[zed]" as speedbrakes are practical -- they are apparent on
both tall-tail (e.g., 777) and short-tail (e.g., MD-80) airliners.

"John R Weiss" wrote in message
news:0nZLb.16052$na.13316@attbi_s04...

snip of Weiss way behind the power curve

I have never read about "a spoiler flap in a speedbrake configuration"
in
any textbook. Anyone else?

You might want to look at the recorded parameters for the DFDR on your
747-400.

Flaps and slats increase the wing camber which produces obvious advantages.
Extensible flaps and slats increase the wing area which produces obvious
advantages.

The slat (not to be confused with the leading edge flap) energizes the upper
surface boundary layer, thus delaying upper surface flow separation and stall.
This effect increases the stall angle-of-attack, increases directional
stability, but sometimes increases or decreases the coefficient of lift,
depending on the wing system design.

The net effect of both slat and flap extension working in unison is to increase
lift, increase stall angle-of-attack, and increase directional stability. This
serves to reduce the landing speed. It also serves to increase aircraft "G"
(normal acceleration) above the clean wing value at a given airspeed.




Kurt Todoroff


Markets, not mandates and mob rule.
Consent, not compulsion.

Remove "DELETEME" from my address to reply

"Kurt R. Todoroff" wrote in message
...
Flaps and slats increase the wing camber which produces obvious
advantages.
Extensible flaps and slats increase the wing area which produces obvious
advantages.

The slat (not to be confused with the leading edge flap) energizes the
upper
surface boundary layer, thus delaying upper surface flow separation and
stall.
This effect increases the stall angle-of-attack, increases directional
stability, but sometimes increases or decreases the coefficient of lift,
depending on the wing system design.

The net effect of both slat and flap extension working in unison is to
increase
lift, increase stall angle-of-attack, and increase directional stability.
This
serves to reduce the landing speed. It also serves to increase aircraft
"G"
(normal acceleration) above the clean wing value at a given airspeed.

Very nice, Kurt.

"Tarver Engineering" wrote...

I have never read about "a spoiler flap in a speedbrake configuration"
in any textbook. Anyone else?

You might want to look at the recorded parameters for the DFDR on your
747-400.

Sorry, but they don't let me bring home a DFDR. Exactly where would I find a
reference to "a spoiler flap in a speedbrake configuration," and in what
context?

"John R Weiss" wrote...
I have never read about "a spoiler flap in a speedbrake configuration"
in any textbook. Anyone else?

You might want to look at the recorded parameters for the DFDR on your
747-400.

Sorry, but they don't let me bring home a DFDR. Exactly where would I find a
reference to "a spoiler flap in a speedbrake configuration," and in what
context?


Also, I just looked through 14CFR Part 121 -- including 121.343, 121.344, and
Appendices B and M (the FAA standards for Flight Recorder and DFDR operational
parameters) -- and found absolutely no reference to "spoiler flaps" in ANY
configuration.