[rebel-builders] vortex generators

[Mike Betti]

I remember having some conflict on my Elite. I don't remember what % cord
but I can measure it from some point on the weekend if needed.
Mike
N771ME

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Dale
Kilbey
Sent: Wednesday, April 01, 2009 9:34 AM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators


----- HI
Does anyone remember what %cord that the vg's are at? The reason I am asking

is that someone mentioned conflict with rivets on an elite wing. I laid out
the pattern for the system I am using and found no conflict with rivets.
Dale




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[Dale Kilbey]

Thanks Mike but I think I'll be OK
Dale
----- Original Message -----
From: "Mike Betti" <mbetti@hughes.net>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, April 01, 2009 7:56 PM
Subject: RE: [rebel-builders] Vortex Generators

I remember having some conflict on my Elite. I don't remember what % cord
but I can measure it from some point on the weekend if needed.
Mike
N771ME

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Dale
Kilbey
Sent: Wednesday, April 01, 2009 9:34 AM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators


----- HI
Does anyone remember what %cord that the vg's are at? The reason I am
asking

is that someone mentioned conflict with rivets on an elite wing. I laid
out
the pattern for the system I am using and found no conflict with rivets.
Dale




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[Ron Shannon]

Hmm. That "we" must be the imperial we, and for that, I have no answer. :-)

However, mere mortals are using VG's from many sources with good results,
including Harrison (http://www.landshorter.com) and Micro Aerodynamics (
http://microaero.com/) among others.

Ron
254R


On Sat, Jan 16, 2010 at 8:11 PM, craig <snowyrvr@mtaonline.net> wrote:

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig

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[Simon Smith]

Craig,
James and I are using Micro Aero VG's.
Si
----- Original Message -----
From: "craig" <snowyrvr@mtaonline.net>
To: <rebel-builders@dcsol.com>
Sent: Saturday, January 16, 2010 10:11 PM
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on
the rebel? Source? Thanks, Craig



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No virus found in this incoming message.
Checked by AVG - www.avg.com
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[craig]

The land shorter ones are 1/4 the $$. Heard anything about them?


----- Original Message -----
From: "Simon Smith" <siks@ticon.net>
To: <rebel-builders@dcsol.com>
Sent: Saturday, January 16, 2010 7:49 PM
Subject: Re: [rebel-builders] Vortex Generators

Craig,
James and I are using Micro Aero VG's.
Si
----- Original Message -----
From: "craig" <snowyrvr@mtaonline.net>
To: <rebel-builders@dcsol.com>
Sent: Saturday, January 16, 2010 10:11 PM
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on
the rebel? Source? Thanks, Craig



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No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.5.432 / Virus Database: 270.14.145/2626 - Release Date:
01/16/10
07:35:00




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[craig]

Thanks, Ron. You totally lost me on the "imperial". :)


----- Original Message -----
From: "Ron Shannon" <rshannon@cruzcom.com>
To: <rebel-builders@dcsol.com>
Sent: Saturday, January 16, 2010 7:19 PM
Subject: Re: [rebel-builders] Vortex Generators

Hmm. That "we" must be the imperial we, and for that, I have no answer.
:-)

However, mere mortals are using VG's from many sources with good results,
including Harrison (http://www.landshorter.com) and Micro Aerodynamics (
http://microaero.com/) among others.

Ron
254R


On Sat, Jan 16, 2010 at 8:11 PM, craig <snowyrvr@mtaonline.net> wrote:

Someone please refresh my memory....which brand of VG's are we using on
the
rebel? Source? Thanks, Craig

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[Ron Shannon]

Yeah well, Craig, I totally lost myself too, so everything is normal. :)

Simon, I notice that MicroAero recommends locating their VG's between the
first and second rows of rivets, which puts the front of the VG at only
roughly 1.5" aft the leading edge, or approx. 2.5% MAC -- which is pretty
far forward, compared to other recommendations that have been tossed about
here. Is that what you both did and how do you like it?

Ron


On Sat, Jan 16, 2010 at 9:12 PM, craig <snowyrvr@mtaonline.net> wrote:

Thanks, Ron. You totally lost me on the "imperial". :)

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[Ron Shannon]

Some more data points:

The Land Shorter VG's are polycarbonate instead of aluminum -- pros and cons
there perhaps. You would need more than the single $95 pack to do both wings
and stabilizers, though previous discussions have indicated VG's on the
Rebel tail may not be worth doing. As I recall, Harrison may charge a little
extra for the Loctite adhesive, at least for the amount needed for wing and
tail coverage. In any case, I think several people on the list have used
them and are very happy with them.

Micro Aero's VG's are paint-ready anodized aluminum, include enough parts
for wings and stabilizers (slightly different parts for each), include the
adhesive, are frequently discounted down to $350 at the airshows, have very
precise instructions for location specifically for the Rebel, and have what
looks like a somewhat superior installation template system.

I originally had a mega pack & extra adhesive from Land Shorter, but then
decided to get the Micro Aero's instead... though I doubt that I had a very
compelling reason for switching horses, even if I could remember what it
was. :) So I have seen both kits, but haven't actually installed or flown
either yet. Installation of the Micro's may not be far off, depending on all
the other ducks that repeatedly insist on getting out of order here.

Ron
254R


On Sat, Jan 16, 2010 at 9:19 PM, craig <snowyrvr@mtaonline.net> wrote:

The land shorter ones are 1/4 the $$. Heard anything about them?


----- Original Message -----
From: "Simon Smith" <siks@ticon.net>
To: <rebel-builders@dcsol.com>
Sent: Saturday, January 16, 2010 7:49 PM
Subject: Re: [rebel-builders] Vortex Generators

Craig,
James and I are using Micro Aero VG's.
Si

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[Eric Fogelin]

Ron mentioned the usual sources. I used the VGs from www.landshorter.com.

Their VGs are lexan instead of the more expensive aluminum angles from other
vendors. I'm leaving mine clear, but apparently you can paint lexan which
will stop UV from affecting them. Since lexan is also used for our windows
(acrylic is used for the windshield), I'm not concerned about long term UV
issues.

I experimented with adding the VGs in stages on the airplane. I really like
the VGs under the stabilizer giving more elevator authority on the Elite. I
also really like the VGs on the wing leading edge in front of the ailerons.
They seem to help keep air attached to the drooping ailerons plus give nice
authority and feel to the ailerons in slow flight.

I then added them full span so that they were ahead of the flaps. I may have
seen a few knots slower stall speed compared to just in front of the
ailerons, but lost a few knots in cruise. So, I removed them from in front
of the flaps. My plane is unpainted, so adding and removing VGs using double
sided tape is easy.

The biggest change is in how nice the stall break is with VGs only in front
of the ailerons. The break is straight and gentle. With no VGs or full span
VGs one wing would generally drop first and the break was more sudden. With
only VGs in front of the ailerons the rectangular wing nicely stalls from
the inner wing, working out to the tip. It is as if the wing had twist,
stall fences or other anti-spin devices. This makes flying slow really,
really fun.

Using the LandShorter spacing recommendations, you only need one set of 100
VGs to do tail and wing in front of the ailerons. You'll need more if you go
full span on the wing.

Eric
N645E


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of craig
Sent: Saturday, January 16, 2010 8:11 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig



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[Ron Shannon]

Thanks, Eric. As usual, great info, which I didn't see before sending my
last.

At least on other planes, I have seen some people attempting to get the
washout effect (wing root stalls first) even with full wing VG's by setting
a few of the outboard VG's further forward than the inboard ones. That
couldn't be done with Micro Aero's recommended positioning -- because it's
so far forward already -- but might be worth an experiment on yours, if you
haven't already.

Ron
254R



On Sat, Jan 16, 2010 at 9:28 PM, Eric Fogelin <elist@whidbey.com> wrote:

Ron mentioned the usual sources. I used the VGs from www.landshorter.com.

Their VGs are lexan instead of the more expensive aluminum angles from
other
vendors. I'm leaving mine clear, but apparently you can paint lexan which
will stop UV from affecting them. Since lexan is also used for our windows
(acrylic is used for the windshield), I'm not concerned about long term UV
issues.

I experimented with adding the VGs in stages on the airplane. I really like
the VGs under the stabilizer giving more elevator authority on the Elite. I
also really like the VGs on the wing leading edge in front of the ailerons.
They seem to help keep air attached to the drooping ailerons plus give nice
authority and feel to the ailerons in slow flight.

I then added them full span so that they were ahead of the flaps. I may
have
seen a few knots slower stall speed compared to just in front of the
ailerons, but lost a few knots in cruise. So, I removed them from in front
of the flaps. My plane is unpainted, so adding and removing VGs using
double
sided tape is easy.

The biggest change is in how nice the stall break is with VGs only in front
of the ailerons. The break is straight and gentle. With no VGs or full span
VGs one wing would generally drop first and the break was more sudden. With
only VGs in front of the ailerons the rectangular wing nicely stalls from
the inner wing, working out to the tip. It is as if the wing had twist,
stall fences or other anti-spin devices. This makes flying slow really,
really fun.

Using the LandShorter spacing recommendations, you only need one set of 100
VGs to do tail and wing in front of the ailerons. You'll need more if you
go
full span on the wing.

Eric
N645E

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[Walter Klatt]

I have the landshorter ones. When I did my testing back with the old 320 on
amphibs, my float take-offs were affected and my stall was lowered. I also
did full speed test runs before and after, and there was zero difference.
Later, I also noticed improved control on crosswind take-offs from my bay
during high wind conditions.

The only drawback is that I have broke a couple in front of my fuel fillers,
when filling from containers. I should never have put any there. The
aluminum ones probably would have just been flattened.

Mine are at the 10% position. Haven't tried them on the stabs, but based on
Eric's experience, might be very beneficial for the Rebel, too.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of craig
Sent: Saturday, January 16, 2010 8:11 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig



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[Darryl Conway]

Another source would be Pacific Aero Northwest. Their VG's are aluminum and have the template for exact layout for full wing, stabilizer, and vertical fin. I installed them before first flight, so I have no comparison otherwise. The cost was about $250-275, included everything needed for prep and installation. My Moose can be flown really slow, it's just too bad I can't land the thing as slow as it will fly due to the high angle of attack.


Darryl


________________________________
From: Walter Klatt <Walter.Klatt@shaw.ca>
To: rebel-builders@dcsol.com
Sent: Sun, January 17, 2010 9:25:53 AM
Subject: RE: [rebel-builders] Vortex Generators

I have the landshorter ones. When I did my testing back with the old 320 on
amphibs, my float take-offs were affected and my stall was lowered. I also
did full speed test runs before and after, and there was zero difference.
Later, I also noticed improved control on crosswind take-offs from my bay
during high wind conditions.

The only drawback is that I have broke a couple in front of my fuel fillers,
when filling from containers. I should never have put any there. The
aluminum ones probably would have just been flattened.

Mine are at the 10% position. Haven't tried them on the stabs, but based on
Eric's experience, might be very beneficial for the Rebel, too.

Walter

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of craig
Sent: Saturday, January 16, 2010 8:11 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig



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[Gary Gustafson]

I read the claims of the manufacturers of vortex generators, such as:
1. Land shorter
2. Takeoff quicker
3. Improve your flight handling, and
4. No reduction in cruise speed
I can see improved flight handling, but for performance on a Rebel,
just what are people experiencing.
How much shorter are take-offs and landings?
Did anyone experience a reduction in cruise speed at the same RPM? It
would seem to me that there is a slight increase in drag.


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Eric
Fogelin
Sent: Sunday, January 17, 2010 12:28 AM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Vortex Generators

Ron mentioned the usual sources. I used the VGs from www.landshorter.com.

Their VGs are lexan instead of the more expensive aluminum angles from other
vendors. I'm leaving mine clear, but apparently you can paint lexan which
will stop UV from affecting them. Since lexan is also used for our windows
(acrylic is used for the windshield), I'm not concerned about long term UV
issues.

I experimented with adding the VGs in stages on the airplane. I really like
the VGs under the stabilizer giving more elevator authority on the Elite. I
also really like the VGs on the wing leading edge in front of the ailerons.
They seem to help keep air attached to the drooping ailerons plus give nice
authority and feel to the ailerons in slow flight.

I then added them full span so that they were ahead of the flaps. I may have
seen a few knots slower stall speed compared to just in front of the
ailerons, but lost a few knots in cruise. So, I removed them from in front
of the flaps. My plane is unpainted, so adding and removing VGs using double
sided tape is easy.

The biggest change is in how nice the stall break is with VGs only in front
of the ailerons. The break is straight and gentle. With no VGs or full span
VGs one wing would generally drop first and the break was more sudden. With
only VGs in front of the ailerons the rectangular wing nicely stalls from
the inner wing, working out to the tip. It is as if the wing had twist,
stall fences or other anti-spin devices. This makes flying slow really,
really fun.

Using the LandShorter spacing recommendations, you only need one set of 100
VGs to do tail and wing in front of the ailerons. You'll need more if you go
full span on the wing.

Eric
N645E


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of craig
Sent: Saturday, January 16, 2010 8:11 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig



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[Walter Klatt]

On the question of drag and reduced cruise speed, here is what
landshorter.com says on their website:

"Q: It's obvious that all those little "wings" must add some drag, why
don't they slow you down?

A: Good question. Without going into too much crazy aerodynamic theory
just visualize how the little micro VG spins the air and keeps it "attached"
to the airfoil. Along the aft portion of the airfoil the air is turbulent
and causes drag to the wing. By keeping the air attached the turbulent flow
at the aft portion of the wing is thinned and offsets the drag caused by the
VG itself.

Now here's the scoop: any nasty rumors you may have heard about VG's
slowing you down a few mph was probably the result of the user placing the
VG's too far forward on the airfoil. You will see a lot of installations
where the VG's are way up front. In our experience (and a lot of others
too) you want to keep them back a little ways (usually around 10% of chord)
so you won't reduce your cruise speed.

The design of the VG is also extremely important for reducing drag- our VG's
are just the right size and shape to provide optimum performance with the
minimal amount of drag. This is based on wind tunnel testing as well as
considerable "field experience" from happy users."

Like I said, I was not able to detect any difference in cruise or top speed
on my amphib Rebel. But the changes in stall speed were dramatic (8 - 10
mph).

Walter


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Gary
Gustafson
Sent: Sunday, January 17, 2010 9:08 AM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Vortex Generators


I read the claims of the manufacturers of vortex generators, such as:
1. Land shorter
2. Takeoff quicker
3. Improve your flight handling, and
4. No reduction in cruise speed
I can see improved flight handling, but for performance on a Rebel,
just what are people experiencing.
How much shorter are take-offs and landings?
Did anyone experience a reduction in cruise speed at the same RPM? It
would seem to me that there is a slight increase in drag.


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Eric
Fogelin
Sent: Sunday, January 17, 2010 12:28 AM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Vortex Generators

Ron mentioned the usual sources. I used the VGs from www.landshorter.com.

Their VGs are lexan instead of the more expensive aluminum angles from other
vendors. I'm leaving mine clear, but apparently you can paint lexan which
will stop UV from affecting them. Since lexan is also used for our windows
(acrylic is used for the windshield), I'm not concerned about long term UV
issues.

I experimented with adding the VGs in stages on the airplane. I really like
the VGs under the stabilizer giving more elevator authority on the Elite. I
also really like the VGs on the wing leading edge in front of the ailerons.
They seem to help keep air attached to the drooping ailerons plus give nice
authority and feel to the ailerons in slow flight.

I then added them full span so that they were ahead of the flaps. I may have
seen a few knots slower stall speed compared to just in front of the
ailerons, but lost a few knots in cruise. So, I removed them from in front
of the flaps. My plane is unpainted, so adding and removing VGs using double
sided tape is easy.

The biggest change is in how nice the stall break is with VGs only in front
of the ailerons. The break is straight and gentle. With no VGs or full span
VGs one wing would generally drop first and the break was more sudden. With
only VGs in front of the ailerons the rectangular wing nicely stalls from
the inner wing, working out to the tip. It is as if the wing had twist,
stall fences or other anti-spin devices. This makes flying slow really,
really fun.

Using the LandShorter spacing recommendations, you only need one set of 100
VGs to do tail and wing in front of the ailerons. You'll need more if you go
full span on the wing.

Eric
N645E


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of craig
Sent: Saturday, January 16, 2010 8:11 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig



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[Eric Fogelin]

I went back through my notes to review the before and after VG numbers.

With no VGs power off flaps up: 50KIAS.
With no VGs power off full flaps down: 43KIAS.

With VGs power off flaps up: 46KIAS.
With VGs power off flaps up: 41KIAS.

These numbers were at or near full gross weight. These are on an 180HP Elite
with the original shorter Murphy wingtips. Airspeeds are usually less
accurate down slow and at large angle of attacks, but mine appear to be
right on.

I seemed to lose a couple of knots off cruise. My LandShorter VGs are
located at about the 10% chord.

I don't have complete landing or takeoff length data. You will land shorter
because even a couple of knots makes a difference. But, the biggest
difference is that you will land shorter because the airplane control
surface feel is better allowing you to fly a slower short final than if you
didn't have VGs.

Final I like 58-60KIAS, 55KIAS over the numbers, 3 point touch down near the
stall of 42-43KIAS. As you level out in the flare, speed drops quickly. With
VGs, takeoff ground roll less than 400ft, landing ground roll less than 700
feet (no wind).

Eric
N645E


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Gary
Gustafson
Sent: Sunday, January 17, 2010 9:08 AM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Vortex Generators


I read the claims of the manufacturers of vortex generators, such as:
1. Land shorter
2. Takeoff quicker
3. Improve your flight handling, and
4. No reduction in cruise speed
I can see improved flight handling, but for performance on a Rebel,
just what are people experiencing.
How much shorter are take-offs and landings?
Did anyone experience a reduction in cruise speed at the same RPM? It
would seem to me that there is a slight increase in drag.


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of Eric
Fogelin
Sent: Sunday, January 17, 2010 12:28 AM
To: rebel-builders@dcsol.com
Subject: RE: [rebel-builders] Vortex Generators

Ron mentioned the usual sources. I used the VGs from www.landshorter.com.

Their VGs are lexan instead of the more expensive aluminum angles from other
vendors. I'm leaving mine clear, but apparently you can paint lexan which
will stop UV from affecting them. Since lexan is also used for our windows
(acrylic is used for the windshield), I'm not concerned about long term UV
issues.

I experimented with adding the VGs in stages on the airplane. I really like
the VGs under the stabilizer giving more elevator authority on the Elite. I
also really like the VGs on the wing leading edge in front of the ailerons.
They seem to help keep air attached to the drooping ailerons plus give nice
authority and feel to the ailerons in slow flight.

I then added them full span so that they were ahead of the flaps. I may have
seen a few knots slower stall speed compared to just in front of the
ailerons, but lost a few knots in cruise. So, I removed them from in front
of the flaps. My plane is unpainted, so adding and removing VGs using double
sided tape is easy.

The biggest change is in how nice the stall break is with VGs only in front
of the ailerons. The break is straight and gentle. With no VGs or full span
VGs one wing would generally drop first and the break was more sudden. With
only VGs in front of the ailerons the rectangular wing nicely stalls from
the inner wing, working out to the tip. It is as if the wing had twist,
stall fences or other anti-spin devices. This makes flying slow really,
really fun.

Using the LandShorter spacing recommendations, you only need one set of 100
VGs to do tail and wing in front of the ailerons. You'll need more if you go
full span on the wing.

Eric
N645E


-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of craig
Sent: Saturday, January 16, 2010 8:11 PM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Vortex Generators

Someone please refresh my memory....which brand of VG's are we using on the
rebel? Source? Thanks, Craig



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