Washout?

Morgans wrote:

"cavelamb himself" wrote


Which brings us all back to the question What Is It???
Rectangular wing or soemthing else?


I recall being told rectangular, but only after all of the stall strip
advice began flowing.

As Barnyard said, probably no need to do anything with rectangular, but I
would thing if it was found to be needed afterwards, adding a stall strip
would be easy enough.


Copy that.

And AFTER test flying to see if it's necessary...

Richard

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George Elliot

A few years ago I saw some photos from a company that made
strap on slats which could be placed on the outboard portion ahead
of the ailerons to delay stalling in that area of the wing and
preserve
roll control further into the stall.

On Wed, 26 Mar 2008 01:34:20 -0700 (PDT), scottperkinsusa
wrote:

A few years ago I saw some photos from a company that made
strap on slats which could be placed on the outboard portion ahead
of the ailerons to delay stalling in that area of the wing and
preserve roll control further into the stall.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Any idea where the inventor/test pilot is buried? vbg


- Barnyard BOb -

"Barnyard BOb" wrote in message
...
On Wed, 26 Mar 2008 01:34:20 -0700 (PDT), scottperkinsusa
wrote:

A few years ago I saw some photos from a company that made
strap on slats which could be placed on the outboard portion ahead
of the ailerons to delay stalling in that area of the wing and
preserve roll control further into the stall.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Any idea where the inventor/test pilot is buried? vbg


- Barnyard BOb -

My, my, you are such a lovable little fuzz ball! ;-)

In theory, something like that should be have an effect similar to the slats
on a Helio Courier--but locked in the open or deployed position.

However, I really don't know how well or poorly it may have worked, and I
suspect that it has been replaced by those little "delta" shaped leading
edge vortex generators.

I don't fully understand the theory on those either, although they certainly
seem more promising than the older method of degrading the inboard portions
of a wing to achieve the desired progression. If anyone has experience
and/or theoretical knowledge, I beg to be enlightened.

Peter

I believe the strap on slats you referred to, were actually
spoilers,strapped to the wing, to be used when the aircraft was tied
down in windy conditions, to eliminate lift ,and airframe damage.

On Mon, 24 Mar 2008 23:39:03 -0700, "Rich S."
wrote:

"cavelamb himself" wrote in message
...

Just checkin'

Some guys like to think it's the airfoil.

Gotcha. It's a bit ironic. You go to all the trouble to build a neat looking
elliptical wing (I love a Spit and a Jug for that reason) and you get a
sharper stall than a plain jane rectangular wing. 'Taint fair!

So, what's wrong with the sharper stall? You just learn to handle it.
According to Ball's Book on Bonanzas the Early Debs don't have any
washout (just a small stall strip) and they do have an abrupt stall
with a strong tendency to drop a wing in the landing configuration.
The stall is abrupt clean or in departure stalls, but predictable and
easily handled with no altitude loss.. They are a "rudder only"
airplane in the stall, but with practice you can learn to hold the
yoke back and keep it stalled while using the rudder to keep it
balanced. It does take practice and this is going far beyond stall
recovery.

When it drops a wing, you keep the ailerons neutral, ease off on the
back pressure and stand on the opposite rudder to stop the turn. You
do NOT shove the nose down unless you want every thing in back up
front with you or on the glare shield.

Departure stalls and accelerated stalls (clean) and approach (landing
configuration) can be handled nicely if done promptly with the
appropriate inputs at the break.

No, I'd not recommend them for student pilots, pilots who only do
things mechanically, and pilots who don't practice until the recovery
becomes instinctive. But these characteristics are pretty much a fact
of life for most high performance aircraft and particularly older
ones.

Rich S.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Tue, 25 Mar 2008 07:00:32 -0700 (PDT),
wrote:

Thanks for all the advice and discussion. Looks like stall strips
could be the way to go. I think I'll experiment with the VGs too.
BTW, the wing is rectangular.

As this is not where they are usually attached and the effect will
probably be greater toward the tips than at the roots I would think
you'd need to be very careful to make certain the effect was the same
on both wings. You don't wan't one wing stalled more than the other
with one having a more pronounced effect than the other ...unless you
are into aerobatics.


Or put a "triangle" shaped addition on the leading edge of the wing's root,
to trip that portion into stall, first.

That's all anyone is after with washout. Keep the outer portion flying,
while the root is stalling.

If it were me, I would probably do a bit of both! g

Advantages of keeping the wing with no washout is that the whole wing will
be lifting at cruise, instead of throwing away part of the outer wing's lift
with added washout.

big john and morgans have it with the triangular strips.

you just tape them on and keep shortening them until you have the
stall chracteristics you need. then you replace the temporaries with
permanent ones.
make both sides identical.
work out where the 3 degree angle of attack neutral point is on the
leading edge and stick them there.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

"Morgans" wrote in message
...

"Peter Dohm" wrote

I don't fully understand the theory on those either, although they
certainly seem more promising than the older method of degrading the
inboard portions of a wing to achieve the desired progression. If anyone
has experience and/or theoretical knowledge, I beg to be enlightened.

A piece of triangle on the inboard leading edge do not hurt the airfoil at
cruise, noticeably.

Think about it. If you put it on the leading edge where the air is
splitting going up or down, what difference would it make? Once the angle
of attack increases too much, then it causes the air to start burbling,
and lit you know to back off a bit. Sounds good to me!
--
Jim in NC

Jim, I think you may have read my question and statement too hurriedly.

I agree that the traditional "stall strips" have negligible effect on the
wing in cruise. However, in the slow flight regime, they only cause the
inboard portions of the wing to stall at a higher airspeed. In some cases
the degradation can be dramatic--as in the case of the Piper Tomahawk where
the version with 4 stall strips stalls at approximately 10% higher airspeed
than the version with 2 stall strips. (I am sorry that I can't locate the
POH to quote precisely)

The question, on which I begged enlightenment, was the preformance of the
little "delta" shaped vortex generators which are dewsigned to be placed as
a forward projection of the leading edge with the tip downward and their
widest portion at the top. Unlike the moveable slats on the Helio and the
fixed slats on the Swift, which work by enhancing the Coanda effect, the
leading edge vortex generators are open at the sides and create a double
vortex at high AOA and have negligible effect in cruise. Most of what I
think that I know about them is from hangar flying, and the builders/pilots
who have them seem to like them, but I still don't know whether the actual
stall speed is increased or decreased--although the stall is supposed to
occur at a slightly higher AOA.

Clear as mud, eh!
Peter

"Roger" wrote in message
...

So, what's wrong with the sharper stall? You just learn to handle it.
According to Ball's Book on Bonanzas the Early Debs don't have any
washout (just a small stall strip) and they do have an abrupt stall
with a strong tendency to drop a wing in the landing configuration.

Rog .........

I have a couple of hunnert hours in Vee-tails and Debs. Believe me, they do
not stall sharply compared with the Emeraude. I think if you read my later
postings in this thread, I was *not* complaining about not being able to fly
the airplane (sorry about the double negative. I will say that it is much
harder to become proficient at detecting an incipient stall. There is
virtually no warning burble.

There are other effects of the abrupt or "clean" stall as well, especially
in departure configuration. You soon learn to stay well away from that
attitude, but you are so uncomfortably pitched up to achieve one, that it's
easy to avoid.

Rich S.

Peter Dohm wrote:
"Morgans" wrote in message
...

"Peter Dohm" wrote

I don't fully understand the theory on those either, although they
certainly seem more promising than the older method of degrading the
inboard portions of a wing to achieve the desired progression. If anyone
has experience and/or theoretical knowledge, I beg to be enlightened.

A piece of triangle on the inboard leading edge do not hurt the airfoil at
cruise, noticeably.

Think about it. If you put it on the leading edge where the air is
splitting going up or down, what difference would it make? Once the angle
of attack increases too much, then it causes the air to start burbling,
and lit you know to back off a bit. Sounds good to me!
--
Jim in NC


Jim, I think you may have read my question and statement too hurriedly.

I agree that the traditional "stall strips" have negligible effect on the
wing in cruise. However, in the slow flight regime, they only cause the
inboard portions of the wing to stall at a higher airspeed. In some cases
the degradation can be dramatic--as in the case of the Piper Tomahawk where
the version with 4 stall strips stalls at approximately 10% higher airspeed
than the version with 2 stall strips. (I am sorry that I can't locate the
POH to quote precisely)

The question, on which I begged enlightenment, was the preformance of the
little "delta" shaped vortex generators which are dewsigned to be placed as
a forward projection of the leading edge with the tip downward and their
widest portion at the top. Unlike the moveable slats on the Helio and the
fixed slats on the Swift, which work by enhancing the Coanda effect, the
leading edge vortex generators are open at the sides and create a double
vortex at high AOA and have negligible effect in cruise. Most of what I
think that I know about them is from hangar flying, and the builders/pilots
who have them seem to like them, but I still don't know whether the actual
stall speed is increased or decreased--although the stall is supposed to
occur at a slightly higher AOA.

Clear as mud, eh!
Peter




I wnet looking for some "how it works" articles...
with varying degrees of sucess.

These were the more interesting

http://en.wikipedia.org/wiki/Vortex_generator

http://www.microaero.com/

http://www.zenithair.com/stolch801/d...vg-design.html
Chris Heintz 701 VG page

http://www.aerospaceweb.org/question...cs/q0009.shtml
Interesting description...

http://www.mitsubishi-motors.com/cor...004/16E_03.pdf
Mitsubishi is using them on automobiles now!
Interesting paper.

http://www.avweb.com/news/reviews/182564-1.html
The use of vortex generators is nothing new. First used in England, VGs
have been used on transport jets for decades, and on bizjets since Bill
Lear invented them. But historically they were used as an aerodynamic
"band-aid" to deal with localized mach buffet problems at the high end
of the airspeed envelope. MacDonnell Douglas engineers would routinely
scoff at the VGs on Boeing jets and brag, "see, we don't need those
things because we got our aerodynamics right in the first place."

http://cas.umkc.edu/physics/sps/proj...ex/vortex.html
Vortex rings - like smoke rings?
Dolphins make air vortex rings in the water and play games with them.

http://www.nasa.gov/centers/langley/.../Micro-VG.html
NASA paper about micro VGs on the FLAPS (way cool)

http://home1.gte.net/pjbemail/VortexGen.html
VGs used to enhance top speed of ice skaters???

http://www.flxsys.com/Applications/A...x%20Generator/
ACTIVE (dynamic) VGs developed for the Air Force?

http://www.physorg.com/news85159467.html
Silly things are even being used under water...


Richard
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(remove the X to email)

Now just why the HELL do I have to press 1 for English?
John Wayne