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.

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.

From: Ed Rasimus

snip

Not sure what "roll steering" is.

snip

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


The only place I have ever seen the terms "roll steering" and "pitch steering"
was in reference to the bars on an ADI.

Dan, U.S. Air Force, retired

"B2431" wrote...

The only place I have ever seen the terms "roll steering" and "pitch steering"
was in reference to the bars on an ADI.

To those you can add "roll-summed steering," which is how Grumman described the
steering commands on the ADI in the A-6.

On 11 Jan 2004 01:19:53 GMT, (B2431) wrote:

From: Ed Rasimus

Not sure what "roll steering" is.

The only place I have ever seen the terms "roll steering" and "pitch steering"
was in reference to the bars on an ADI.

Dan, U.S. Air Force, retired

Not even there, Dan. The ADI terminology was "bank steering" and
"pitch steering".


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

"Ed Rasimus" wrote in message
...
On 11 Jan 2004 01:19:53 GMT, (B2431) wrote:

From: Ed Rasimus

Not sure what "roll steering" is.

The only place I have ever seen the terms "roll steering" and "pitch
steering"
was in reference to the bars on an ADI.

Not even there, Dan. The ADI terminology was "bank steering" and
"pitch steering".

That would be because most INSs produse "roll command" and you would not
have "roll steering" in an F-4.

On Sun, 11 Jan 2004 09:50:00 -0800, "Tarver Engineering"
wrote:


"Ed Rasimus" wrote in message
.. .
On 11 Jan 2004 01:19:53 GMT, (B2431) wrote:

From: Ed Rasimus

Not sure what "roll steering" is.

The only place I have ever seen the terms "roll steering" and "pitch
steering"
was in reference to the bars on an ADI.

Not even there, Dan. The ADI terminology was "bank steering" and
"pitch steering".

That would be because most INSs produse "roll command" and you would not
have "roll steering" in an F-4.


Dan's post refers to the nomenclature for the Attitude Director
Indicator. The two bars, one horizontal and one vertical, provide cues
for flying instruments, similar to the "bug" in more current displays.
They can offer commands related to navigation guidance such as turns
to headings or cues for flying ILS approaches or even be linked to
weapons release computers for fly up for lofted weapons deliveries.

The vertical bar on the display was called the bank steering bar
because it displaced left or right of center and when the proper
amount of bank was initiated, it returned to center. When your course
change was complete it displaced the opposite direction to return you
to wings level flight.

The horizontal bar was termed the pitch steering bar and it commanded
pitch inputs to achieve the proper climb or dive angles.

The nomenclature has nothing to do with the Inertial Navigation
system. The ADI is not specific to the F-4, but is the generic
attitude indicator display and was the same in the F-105, F-4, and
T-38, as well as a a number of other US aircraft which I don't have
several thousand hours in.


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

"Ed Rasimus" wrote in message
...
On Sun, 11 Jan 2004 09:50:00 -0800, "Tarver Engineering"
wrote:


"Ed Rasimus" wrote in message
.. .
On 11 Jan 2004 01:19:53 GMT, (B2431) wrote:

From: Ed Rasimus

Not sure what "roll steering" is.

The only place I have ever seen the terms "roll steering" and "pitch
steering"
was in reference to the bars on an ADI.

Not even there, Dan. The ADI terminology was "bank steering" and
"pitch steering".

That would be because most INSs produse "roll command" and you would not
have "roll steering" in an F-4.


Dan's post refers to the nomenclature for the Attitude Director
Indicator. The two bars, one horizontal and one vertical, provide cues
for flying instruments, similar to the "bug" in more current displays.
They can offer commands related to navigation guidance such as turns
to headings or cues for flying ILS approaches or even be linked to
weapons release computers for fly up for lofted weapons deliveries.

What roll steering refers to is a navigational error signal. From which the
flight director roll computer would use roll steering and other parameters
to produce roll command, usually displayed as a CMD bug on a flight director
attitude display.

The vertical bar on the display was called the bank steering bar
because it displaced left or right of center and when the proper
amount of bank was initiated, it returned to center. When your course
change was complete it displaced the opposite direction to return you
to wings level flight.

Or a bug can be used to play pilot chase the needles, or just have George do
it.

The horizontal bar was termed the pitch steering bar and it commanded
pitch inputs to achieve the proper climb or dive angles.

Same idea, except roll steering is only part of the equation that produces
command.

The nomenclature has nothing to do with the Inertial Navigation
system. The ADI is not specific to the F-4, but is the generic
attitude indicator display and was the same in the F-105, F-4, and
T-38, as well as a a number of other US aircraft which I don't have
several thousand hours in.

Ed, an INS usually produces roll command directly and does not use the
flight director calculation for roll command. The nomenclature is
different.

Let me give you an example of some 747 navigation changes we have
facilitated:

A certain head of state aircraft wants to have a glass cockpit and selects a
company with an FMS that integrates several flight management systems into
their computer. (PMS, Flight Director, DADC, Primary Display) For this
system integration we provided a converter from digital to Analog Roll
Command, so that the FMS could drive the aircrft's roll command input.

Another head of state has a 747 where there was a desire to integrate a
Trimble 2101 I/O for approach. In this case, we provided a signal such that
the HSI could output "roll steering" from signals derived from the GPS and
the DG.

So, it is a matter of where the signal is in the system as to what it is
named and you would not normally use roll steering with an INS, but I have
heard of some INSs that are the other way.

From: Ed Rasimus
Date: 1/11/2004 9:45 AM Central Standard Time
Message-id:

On 11 Jan 2004 01:19:53 GMT, (B2431) wrote:

From: Ed Rasimus

Not sure what "roll steering" is.

The only place I have ever seen the terms "roll steering" and "pitch
steering"
was in reference to the bars on an ADI.

Dan, U.S. Air Force, retired

Not even there, Dan. The ADI terminology was "bank steering" and
"pitch steering".


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


You are correct. I guess I am not as perfect as tarver g

Dan, U.S. Air Force, retired