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  2. Airflow over the canard

Airflow over the canard

L Koutz <koutzl@...>
 

Ed

I read your theory.

Here is what I have found. This is on a Q-200 (LS-1) canard. I originally
tufted the whole wing and found the elevator portion of the canard "stalled"
first. Procceding the elevator stall (tufts lifting and flopping about) the
tufts all moved inboard in unison on the outboard portion of the canard
elevator (this is the only portion of the canard I can see from the cockpit
so I don't know what happens on the inboard portion). This indicated to me
that the air after it crossed the elevator gap was a different animal with a
lot less energy to drive it along the airflow shape. The air moving inboard
just prior to stall I assumed to be because of the anhedral of the canard. I
don't know if this is true but at the time it seemed to make sense. So I
don't think that air leaking between the elevator and fuselage would be
moving outboard and cause a bubble. I also filled up the canard gap with a
foam weatherstrip "seal" since I thought air was leaking through the gap and
disturbing the air. The gap seal didn't seem to make a difference as the
wing stalled the same.

I have put VG's on the canard starting at the outboard end (about 50% chord
and triangles 1/2" high X 1 1/2" long). these seemed to delay the elevator
stall. So I added more in 18" sections. The third section I put on caused
some of the tufts on the elevator to rise up during cruise flight at about a
30 degrees from the elevator. This really puzzled me! That's when I put in
the gap seals. No difference! So here I sit with no clue. Only more testing
can fill in my information gap and I have been working on some other areas
of the plane right now.

Does anyone have any theories on this?

Larry

----- Original Message -----
From: "Edward N. MacLeod" <ed@...>
To: <Q-LIST@...>
Sent: Tuesday, September 12, 2000 8:10 PM
Subject: [Q-LIST] A simple STOL mod for Qs?

For you bored aero intellects out there:

After reading through the archives regarding canard tuft testing and the
associated confusing results, I had a thought about what is going on.

What if high-pressure air, under the canard, at the root, is flowing
around the inboard elevator gap (not the hinge gap) when the elevator
is down? This higher pressure air would tend to fill the low-pressure
area above the elevator. The lower pressure laminar flow air on the top
of the canard would flow over this stationary longitudinal bubble of
higher pressure air, prematurely stalling the canard, root first. There
would be little tendency for the bubble to dissipate as it is not in the
slipstream. A relatively low volume flow through the inboard elevator
gap could maintain the stationary bubble.

It gets worse. I believe the shape of the gap on Qs when the elevator
is down (at least on my Q2) actually directs the air longitudinally
along the top of the elevator!

The hypothesis is: Seal the gap and you significantly reduce
elevator-down stall speed.

Does this make sense to anyone else?

Food for thought,

Ed m
Ed MacLeod <ed@...>
 

Hi Larry,

It sound like the inboard leak phenomenon is occurring at the
outboard end of the elevator. Does this agree with your observations?
Perhaps the prop is blasting away the air leaking in at the root and
the outboard leak becomes more significant.

Ed m


--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Ed

I read your theory.

Here is what I have found. This is on a Q-200 (LS-1) canard. I
originally
tufted the whole wing and found the elevator portion of the canard
"stalled"
first. Procceding the elevator stall (tufts lifting and flopping
about) the
tufts all moved inboard in unison on the outboard portion of the
canard
elevator (this is the only portion of the canard I can see from the
cockpit
so I don't know what happens on the inboard portion). This
indicated
to me
that the air after it crossed the elevator gap was a different
animal with a
lot less energy to drive it along the airflow shape. The air moving
inboard
just prior to stall I assumed to be because of the anhedral of the
canard. I
don't know if this is true but at the time it seemed to make sense.
So I
don't think that air leaking between the elevator and fuselage
would
be
moving outboard and cause a bubble. I also filled up the canard gap
with a
foam weatherstrip "seal" since I thought air was leaking through
the
gap and
disturbing the air. The gap seal didn't seem to make a difference
as
the
wing stalled the same.

I have put VG's on the canard starting at the outboard end (about
50% chord
and triangles 1/2" high X 1 1/2" long). these seemed to delay the
elevator
stall. So I added more in 18" sections. The third section I put on
caused
some of the tufts on the elevator to rise up during cruise flight
at
about a
30 degrees from the elevator. This really puzzled me! That's when I
put in
the gap seals. No difference! So here I sit with no clue. Only more
testing
can fill in my information gap and I have been working on some
other
areas
of the plane right now.

Does anyone have any theories on this?

Larry


----- Original Message -----
From: "Edward N. MacLeod" <ed@m...>
To: <Q-LIST@...>
Sent: Tuesday, September 12, 2000 8:10 PM
Subject: [Q-LIST] A simple STOL mod for Qs?

For you bored aero intellects out there:

After reading through the archives regarding canard tuft testing
and the
associated confusing results, I had a thought about what is going
on.

What if high-pressure air, under the canard, at the root, is
flowing
around the inboard elevator gap (not the hinge gap) when the
elevator
is down? This higher pressure air would tend to fill the
low-pressure
area above the elevator. The lower pressure laminar flow air on
the top
of the canard would flow over this stationary longitudinal bubble
of
higher pressure air, prematurely stalling the canard, root first.
There
would be little tendency for the bubble to dissipate as it is not
in the
slipstream. A relatively low volume flow through the inboard
elevator
gap could maintain the stationary bubble.

It gets worse. I believe the shape of the gap on Qs when the
elevator
is down (at least on my Q2) actually directs the air
longitudinally
along the top of the elevator!

The hypothesis is: Seal the gap and you significantly reduce
elevator-down stall speed.

Does this make sense to anyone else?

Food for thought,

Ed m
L Koutz <koutzl@...>
 

Ed

I don't read the tufts moving inboard together as a sign that air is leaking
through the outboard elevator/ canard gap. I don't know why they do this
just yet.
Larry

Hi Larry,

It sound like the inboard leak phenomenon is occurring at the
outboard end of the elevator. Does this agree with your observations?
Perhaps the prop is blasting away the air leaking in at the root and
the outboard leak becomes more significant.

Ed m
Ed

I read your theory.

Here is what I have found. This is on a Q-200 (LS-1) canard. I
originally
tufted the whole wing and found the elevator portion of the canard
"stalled"
first. Procceding the elevator stall (tufts lifting and flopping
about) the
tufts all moved inboard in unison on the outboard portion of the
canard
elevator (this is the only portion of the canard I can see from the
cockpit
so I don't know what happens on the inboard portion). This
indicated
to me
that the air after it crossed the elevator gap was a different
animal with a
lot less energy to drive it along the airflow shape. The air moving
inboard
just prior to stall I assumed to be because of the anhedral of the
canard. I
don't know if this is true but at the time it seemed to make sense.
So I
don't think that air leaking between the elevator and fuselage
would
be
moving outboard and cause a bubble. I also filled up the canard gap
with a
foam weatherstrip "seal" since I thought air was leaking through
the
gap and
disturbing the air. The gap seal didn't seem to make a difference
as
the
wing stalled the same.

I have put VG's on the canard starting at the outboard end (about
50% chord
and triangles 1/2" high X 1 1/2" long). these seemed to delay the
elevator
stall. So I added more in 18" sections. The third section I put on
caused
some of the tufts on the elevator to rise up during cruise flight
at
about a
30 degrees from the elevator. This really puzzled me! That's when I
put in
the gap seals. No difference! So here I sit with no clue. Only more
testing
can fill in my information gap and I have been working on some
other
areas
of the plane right now.

Does anyone have any theories on this?

Larry


----- Original Message -----
From: "Edward N. MacLeod" <ed@m...>
To: <Q-LIST@...>
Sent: Tuesday, September 12, 2000 8:10 PM
Subject: [Q-LIST] A simple STOL mod for Qs?

For you bored aero intellects out there:

After reading through the archives regarding canard tuft testing
and the
associated confusing results, I had a thought about what is going
on.

What if high-pressure air, under the canard, at the root, is
flowing
around the inboard elevator gap (not the hinge gap) when the
elevator
is down? This higher pressure air would tend to fill the
low-pressure
area above the elevator. The lower pressure laminar flow air on
the top
of the canard would flow over this stationary longitudinal bubble
of
higher pressure air, prematurely stalling the canard, root first.
There
would be little tendency for the bubble to dissipate as it is not
in the
slipstream. A relatively low volume flow through the inboard
elevator
gap could maintain the stationary bubble.

It gets worse. I believe the shape of the gap on Qs when the
elevator
is down (at least on my Q2) actually directs the air
longitudinally
along the top of the elevator!

The hypothesis is: Seal the gap and you significantly reduce
elevator-down stall speed.

Does this make sense to anyone else?

Food for thought,

Ed m



To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html
Ed MacLeod <ed@...>
 

--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Hi Larry,

I have a hard time dreaming up another expaination for the inboard
flowing tufts. With the elevators down, you get a strong wing tip
vortex at the outer elevator edge. The flow on the top would be
inboard. Seal the outer (and inner?) edges of the elevator and you
eliminate this vortex flow, the tufts should not flow inboard as
readily.
This is why they add droopy wing tips to stol aircraft, to make it
harder for the vortex to roll back onto the trailing edge of the wing
and disrupting the normal airflow over the wing.

As always, I could be wrong.

Ed m



Ed

I don't read the tufts moving inboard together as a sign that air
is
leaking
through the outboard elevator/ canard gap. I don't know why they do
this
just yet.
Larry

Hi Larry,

It sound like the inboard leak phenomenon is occurring at the
outboard end of the elevator. Does this agree with your
observations?
Perhaps the prop is blasting away the air leaking in at the root
and
the outboard leak becomes more significant.

Ed m
Jon Finley <finley@...>
 

Guys,

I've been reading your thoughts and pondering my experiences. I really do
not know what is happening so any ideas that I may offer are only GUESSES!!

I do not recall if my tuft "bank" moves one way or the other when airflow is
gone/degraded/disturbed/etc BUT I do know that I have one tuft that likes to
spin in circles almost all the time. It attached in the middle (both
horizontally and vertically) of the left (pilot side) elevator, is about
three inches long, and spins clockwise about the end that is attached to the
elevator (with a really small piece of fine tape). Next time I fly I will
pay attention to see if there is a direction that all tufts move.

Keep up the discussion - fun stuff!! For all those that are flying - put a
few tufts on your canard and tell us what they are doing!! It takes about
five minutes, is free (unless you don't have tape and yarn/string/whatever),
and you may learn something about your airplane!
Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html

-----Original Message-----
From: Ed MacLeod [mailto:ed@...]
Sent: Thursday, September 14, 2000 7:49 AM
To: Q-LIST@...
Subject: [Q-LIST] Re: Airflow over the canard



My Groups | Q-LIST Main Page | Start a new group!


--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Hi Larry,

I have a hard time dreaming up another expaination for the inboard
flowing tufts. With the elevators down, you get a strong wing tip
vortex at the outer elevator edge. The flow on the top would be
inboard. Seal the outer (and inner?) edges of the elevator and you
eliminate this vortex flow, the tufts should not flow inboard as
readily.
This is why they add droopy wing tips to stol aircraft, to make it
harder for the vortex to roll back onto the trailing edge of the wing
and disrupting the normal airflow over the wing.

As always, I could be wrong.

Ed m



> Ed
>
> I don't read the tufts moving inboard together as a sign that air
is
leaking
> through the outboard elevator/ canard gap. I don't know why they do
this
> just yet.
> Larry
>
> > Hi Larry,
> >
> > It sound like the inboard leak phenomenon is occurring at the
> > outboard end of the elevator. Does this agree with your
observations?
> > Perhaps the prop is blasting away the air leaking in at the root
and
> > the outboard leak becomes more significant.
> >
> > Ed m
>




To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html
Don Stewart <siinc@...>
 

Is that what those ridges are, on the Eagle 150B wing?
Don

Ted VanMeter wrote:



One would probably only need an upper and lower fence on both the outboard
and inboard of the elevator. The vertical dimensions would be dictated by
elevator travel. The gap could then be "sealed" by the little fuzzy strips.
This setup could still utilize a canard to fuselage fairing or fillet. Ted
-----Original Message-----
From: Jon Finley <finley@...>
To: Q-LIST@... <Q-LIST@...>
Date: Thursday, September 14, 2000 6:13 AM
Subject: RE: [Q-LIST] Re: Airflow over the canard


Guys,

I've been reading your thoughts and pondering my experiences. I really do
not know what is happening so any ideas that I may offer are only GUESSES!!

I do not recall if my tuft "bank" moves one way or the other when airflow
is
gone/degraded/disturbed/etc BUT I do know that I have one tuft that likes
to
spin in circles almost all the time. It attached in the middle (both
horizontally and vertically) of the left (pilot side) elevator, is about
three inches long, and spins clockwise about the end that is attached to
the
elevator (with a really small piece of fine tape). Next time I fly I will
pay attention to see if there is a direction that all tufts move.

Keep up the discussion - fun stuff!! For all those that are flying - put a
few tufts on your canard and tell us what they are doing!! It takes about
five minutes, is free (unless you don't have tape and
yarn/string/whatever),
and you may learn something about your airplane!
Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html



-----Original Message-----
From: Ed MacLeod [mailto:ed@...]
Sent: Thursday, September 14, 2000 7:49 AM
To: Q-LIST@...
Subject: [Q-LIST] Re: Airflow over the canard



My Groups | Q-LIST Main Page | Start a new group!


--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Hi Larry,

I have a hard time dreaming up another expaination for the inboard
flowing tufts. With the elevators down, you get a strong wing tip
vortex at the outer elevator edge. The flow on the top would be
inboard. Seal the outer (and inner?) edges of the elevator and you
eliminate this vortex flow, the tufts should not flow inboard as
readily.
This is why they add droopy wing tips to stol aircraft, to make it
harder for the vortex to roll back onto the trailing edge of the wing
and disrupting the normal airflow over the wing.

As always, I could be wrong.

Ed m



> Ed
>
> I don't read the tufts moving inboard together as a sign that air
is
leaking
> through the outboard elevator/ canard gap. I don't know why they do
this
> just yet.
> Larry
>
> > Hi Larry,
> >
> > It sound like the inboard leak phenomenon is occurring at the
> > outboard end of the elevator. Does this agree with your
observations?
> > Perhaps the prop is blasting away the air leaking in at the root
and
> > the outboard leak becomes more significant.
> >
> > Ed m
>




To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html










To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html



To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html
Ted VanMeter <tvanmeter@...>
 

One would probably only need an upper and lower fence on both the outboard
and inboard of the elevator. The vertical dimensions would be dictated by
elevator travel. The gap could then be "sealed" by the little fuzzy strips.
This setup could still utilize a canard to fuselage fairing or fillet. Ted

-----Original Message-----
From: Jon Finley <finley@...>
To: Q-LIST@... <Q-LIST@...>
Date: Thursday, September 14, 2000 6:13 AM
Subject: RE: [Q-LIST] Re: Airflow over the canard



Guys,

I've been reading your thoughts and pondering my experiences. I really do
not know what is happening so any ideas that I may offer are only GUESSES!!

I do not recall if my tuft "bank" moves one way or the other when airflow
is
gone/degraded/disturbed/etc BUT I do know that I have one tuft that likes
to
spin in circles almost all the time. It attached in the middle (both
horizontally and vertically) of the left (pilot side) elevator, is about
three inches long, and spins clockwise about the end that is attached to
the
elevator (with a really small piece of fine tape). Next time I fly I will
pay attention to see if there is a direction that all tufts move.

Keep up the discussion - fun stuff!! For all those that are flying - put a
few tufts on your canard and tell us what they are doing!! It takes about
five minutes, is free (unless you don't have tape and
yarn/string/whatever),
and you may learn something about your airplane!
Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html



-----Original Message-----
From: Ed MacLeod [mailto:ed@...]
Sent: Thursday, September 14, 2000 7:49 AM
To: Q-LIST@...
Subject: [Q-LIST] Re: Airflow over the canard



My Groups | Q-LIST Main Page | Start a new group!


--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Hi Larry,

I have a hard time dreaming up another expaination for the inboard
flowing tufts. With the elevators down, you get a strong wing tip
vortex at the outer elevator edge. The flow on the top would be
inboard. Seal the outer (and inner?) edges of the elevator and you
eliminate this vortex flow, the tufts should not flow inboard as
readily.
This is why they add droopy wing tips to stol aircraft, to make it
harder for the vortex to roll back onto the trailing edge of the wing
and disrupting the normal airflow over the wing.

As always, I could be wrong.

Ed m



> Ed
>
> I don't read the tufts moving inboard together as a sign that air
is
leaking
> through the outboard elevator/ canard gap. I don't know why they do
this
> just yet.
> Larry
>
> > Hi Larry,
> >
> > It sound like the inboard leak phenomenon is occurring at the
> > outboard end of the elevator. Does this agree with your
observations?
> > Perhaps the prop is blasting away the air leaking in at the root
and
> > the outboard leak becomes more significant.
> >
> > Ed m
>




To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html










To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html
L Koutz <koutzl@...>
 

Jon
My tufts (3 of them) mid elevator did the same thing, spin around, that is.
I don't remember which direction. What do you think of that!?!
Larry

----- Original Message -----
From: "Jon Finley" <finley@...>
To: <Q-LIST@...>
Sent: Thursday, September 14, 2000 9:10 AM
Subject: RE: [Q-LIST] Re: Airflow over the canard



Guys,

I've been reading your thoughts and pondering my experiences. I really do
not know what is happening so any ideas that I may offer are only
GUESSES!!

I do not recall if my tuft "bank" moves one way or the other when airflow
is
gone/degraded/disturbed/etc BUT I do know that I have one tuft that likes
to
spin in circles almost all the time. It attached in the middle (both
horizontally and vertically) of the left (pilot side) elevator, is about
three inches long, and spins clockwise about the end that is attached to
the
elevator (with a really small piece of fine tape). Next time I fly I will
pay attention to see if there is a direction that all tufts move.

Keep up the discussion - fun stuff!! For all those that are flying - put
a
few tufts on your canard and tell us what they are doing!! It takes about
five minutes, is free (unless you don't have tape and
yarn/string/whatever),
and you may learn something about your airplane!
Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html



-----Original Message-----
From: Ed MacLeod [mailto:ed@...]
Sent: Thursday, September 14, 2000 7:49 AM
To: Q-LIST@...
Subject: [Q-LIST] Re: Airflow over the canard



My Groups | Q-LIST Main Page | Start a new group!


--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Hi Larry,

I have a hard time dreaming up another expaination for the inboard
flowing tufts. With the elevators down, you get a strong wing tip
vortex at the outer elevator edge. The flow on the top would be
inboard. Seal the outer (and inner?) edges of the elevator and you
eliminate this vortex flow, the tufts should not flow inboard as
readily.
This is why they add droopy wing tips to stol aircraft, to make it
harder for the vortex to roll back onto the trailing edge of the wing
and disrupting the normal airflow over the wing.

As always, I could be wrong.

Ed m



> Ed
>
> I don't read the tufts moving inboard together as a sign that air
is
leaking
> through the outboard elevator/ canard gap. I don't know why they do
this
> just yet.
> Larry
>
> > Hi Larry,
> >
> > It sound like the inboard leak phenomenon is occurring at the
> > outboard end of the elevator. Does this agree with your
observations?
> > Perhaps the prop is blasting away the air leaking in at the root
and
> > the outboard leak becomes more significant.
> >
> > Ed m
>




To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html










To unsubscribe from this group, send an email to:
Q-LIST-unsubscribe@...

Quickie Builders Association WEB site
http://web2.airmail.net/qba321tm/q-page1.html
mbrowner1@...
 

I was planning on putting fences on the otbd elevators....originally not for
aerodynamics, but to index with control deflection angle marks for my test
phase.

Mike

In a message dated 09/14/2000 6:05:34 PM Central Daylight Time,
tvanmeter@... writes:

<< One would probably only need an upper and lower fence on both the outboard
and inboard of the elevator. The vertical dimensions would be dictated by
elevator travel. The gap could then be "sealed" by the little fuzzy strips.
This setup could still utilize a canard to fuselage fairing or fillet. Ted
- >>
David J. Gall
 

Larry,

Those spinning yarns at midspan are probably plus or minus about 20 degrees
in line aft from the mid-span elevator hinge, no?

David J. Gall

----- Original Message -----
From: "L Koutz" <koutzl@...>
To: <Q-LIST@...>
Sent: Thursday, September 14, 2000 8:10 PM
Subject: Re: [Q-LIST] Re: Airflow over the canard



Jon
My tufts (3 of them) mid elevator did the same thing, spin around, that
is.
I don't remember which direction. What do you think of that!?!
Larry


----- Original Message -----
From: "Jon Finley" <finley@...>
To: <Q-LIST@...>
Sent: Thursday, September 14, 2000 9:10 AM
Subject: RE: [Q-LIST] Re: Airflow over the canard



Guys,

I've been reading your thoughts and pondering my experiences. I really
do
not know what is happening so any ideas that I may offer are only
GUESSES!!

I do not recall if my tuft "bank" moves one way or the other when
airflow
is
gone/degraded/disturbed/etc BUT I do know that I have one tuft that
likes
to
spin in circles almost all the time. It attached in the middle (both
horizontally and vertically) of the left (pilot side) elevator, is about
three inches long, and spins clockwise about the end that is attached to
the
elevator (with a really small piece of fine tape). Next time I fly I
will
pay attention to see if there is a direction that all tufts move.

Keep up the discussion - fun stuff!! For all those that are flying -
put
a
few tufts on your canard and tell us what they are doing!! It takes
about
five minutes, is free (unless you don't have tape and
yarn/string/whatever),
and you may learn something about your airplane!
Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html



-----Original Message-----
From: Ed MacLeod [mailto:ed@...]
Sent: Thursday, September 14, 2000 7:49 AM
To: Q-LIST@...
Subject: [Q-LIST] Re: Airflow over the canard



My Groups | Q-LIST Main Page | Start a new group!


--- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
Hi Larry,

I have a hard time dreaming up another expaination for the inboard
flowing tufts. With the elevators down, you get a strong wing tip
vortex at the outer elevator edge. The flow on the top would be
inboard. Seal the outer (and inner?) edges of the elevator and you
eliminate this vortex flow, the tufts should not flow inboard as
readily.
This is why they add droopy wing tips to stol aircraft, to make it
harder for the vortex to roll back onto the trailing edge of the wing
and disrupting the normal airflow over the wing.

As always, I could be wrong.

Ed m



> Ed
>
> I don't read the tufts moving inboard together as a sign that air
is
leaking
> through the outboard elevator/ canard gap. I don't know why they do
this
> just yet.
> Larry
>
> > Hi Larry,
> >
> > It sound like the inboard leak phenomenon is occurring at the
> > outboard end of the elevator. Does this agree with your
observations?
> > Perhaps the prop is blasting away the air leaking in at the root
and
> > the outboard leak becomes more significant.
> >
> > Ed m
>




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Jon Finley <finley@...>
 

David,

I'd have to look to be positive but am pretty sure that is where my spinning
tuft is located. What does this mean/imply???

Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html

-----Original Message-----
From: David J. Gall [mailto:David@...]
Sent: Thursday, September 14, 2000 10:33 PM
To: Q-LIST@...
Subject: Re: [Q-LIST] Re: Airflow over the canard




My Groups | Q-LIST Main Page | Start a new group!


Larry,

Those spinning yarns at midspan are probably plus or minus about 20
degrees
in line aft from the mid-span elevator hinge, no?

David J. Gall

----- Original Message -----
From: "L Koutz" <koutzl@...>
To: <Q-LIST@...>
Sent: Thursday, September 14, 2000 8:10 PM
Subject: Re: [Q-LIST] Re: Airflow over the canard


>
> Jon
> My tufts (3 of them) mid elevator did the same thing, spin around, that
is.
> I don't remember which direction. What do you think of that!?!
> Larry
>
>
> ----- Original Message -----
> From: "Jon Finley" <finley@...>
> To: <Q-LIST@...>
> Sent: Thursday, September 14, 2000 9:10 AM
> Subject: RE: [Q-LIST] Re: Airflow over the canard
>
>
> >
> > Guys,
> >
> > I've been reading your thoughts and pondering my experiences. I
really
do
> > not know what is happening so any ideas that I may offer are only
> GUESSES!!
> >
> > I do not recall if my tuft "bank" moves one way or the other when
airflow
> is
> > gone/degraded/disturbed/etc BUT I do know that I have one tuft that
likes
> to
> > spin in circles almost all the time. It attached in the middle (both
> > horizontally and vertically) of the left (pilot side) elevator, is
about
> > three inches long, and spins clockwise about the end that is attached
to
> the
> > elevator (with a really small piece of fine tape). Next time I fly I
will
> > pay attention to see if there is a direction that all tufts move.
> >
> > Keep up the discussion - fun stuff!! For all those that are flying -
put
> a
> > few tufts on your canard and tell us what they are doing!! It takes
about
> > five minutes, is free (unless you don't have tape and
> yarn/string/whatever),
> > and you may learn something about your airplane!
> > Jon Finley
> > Q1 N54JF - 1835cc VW
> > Q2 N90MG - Subaru EA-81 DD Turbo
> > Apple Valley, Minnesota
> > http://63.90.191.136/Finley/finley-subaru.html
> >
> >
> >
> > -----Original Message-----
> > From: Ed MacLeod [mailto:ed@...]
> > Sent: Thursday, September 14, 2000 7:49 AM
> > To: Q-LIST@...
> > Subject: [Q-LIST] Re: Airflow over the canard
> >
> >
> >
> > My Groups | Q-LIST Main Page | Start a new group!
> >
> >
> > --- In Q-LIST@..., "L Koutz" <koutzl@S...> wrote:
> > Hi Larry,
> >
> > I have a hard time dreaming up another expaination for the inboard
> > flowing tufts. With the elevators down, you get a strong wing tip
> > vortex at the outer elevator edge. The flow on the top would be
> > inboard. Seal the outer (and inner?) edges of the elevator and you
> > eliminate this vortex flow, the tufts should not flow inboard as
> > readily.
> > This is why they add droopy wing tips to stol aircraft, to make it
> > harder for the vortex to roll back onto the trailing edge of the
wing
> > and disrupting the normal airflow over the wing.
> >
> > As always, I could be wrong.
> >
> > Ed m
> >
> >
> >
> > > Ed
> > >
> > > I don't read the tufts moving inboard together as a sign that air
> > is
> > leaking
> > > through the outboard elevator/ canard gap. I don't know why they
do
> > this
> > > just yet.
> > > Larry
> > >
> > > > Hi Larry,
> > > >
> > > > It sound like the inboard leak phenomenon is occurring at the
> > > > outboard end of the elevator. Does this agree with your
> > observations?
> > > > Perhaps the prop is blasting away the air leaking in at the root
> > and
> > > > the outboard leak becomes more significant.
> > > >
> > > > Ed m
> > >
> >
> >
> >
> >
> > To unsubscribe from this group, send an email to:
> > Q-LIST-unsubscribe@...
> >
> > Quickie Builders Association WEB site
> > http://web2.airmail.net/qba321tm/q-page1.html
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > To unsubscribe from this group, send an email to:
> > Q-LIST-unsubscribe@...
> >
> > Quickie Builders Association WEB site
> > http://web2.airmail.net/qba321tm/q-page1.html
> >
> >
> >
> >
>
>
>
> To unsubscribe from this group, send an email to:
> Q-LIST-unsubscribe@...
>
> Quickie Builders Association WEB site
> http://web2.airmail.net/qba321tm/q-page1.html
>
>
>
>



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David J. Gall
 

Jon,

I think it means that you have some air leakage around the hinge. The
higher-pressure air along the lower surface finds its way through the hinge
slot and makes a little jet or invisible geyser of air that sets up two
little counter-rotating vortices in its wake. No big deal unless you're Jon
Sharp....


David J. Gall

----- Original Message -----
From: "Jon Finley" <finley@...>
To: <Q-LIST@...>
Sent: Friday, September 15, 2000 7:13 AM
Subject: RE: [Q-LIST] Re: Airflow over the canard



David,

I'd have to look to be positive but am pretty sure that is where my
spinning
tuft is located. What does this mean/imply???

Jon Finley
Q1 N54JF - 1835cc VW
Q2 N90MG - Subaru EA-81 DD Turbo
Apple Valley, Minnesota
http://63.90.191.136/Finley/finley-subaru.html



-----Original Message-----
From: David J. Gall [mailto:David@...]
Sent: Thursday, September 14, 2000 10:33 PM
To: Q-LIST@...
Subject: Re: [Q-LIST] Re: Airflow over the canard




My Groups | Q-LIST Main Page | Start a new group!


Larry,

Those spinning yarns at midspan are probably plus or minus about 20
degrees
in line aft from the mid-span elevator hinge, no?

David J. Gall
1 - 12 of 12