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  #1  
Old 07-19-2013, 01:32 PM
whd721 whd721 is offline
 
Join Date: Oct 2007
Location: Beaverton, OR
Posts: 232
Default VGs

I would like to contact anyone who has actually installed Vortex Generators on a RV9.

I am specifically interested in the actual real world before and after stall speeds in the various configurations.

Thanks if you can help.
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whd721
RV9A
Sherwood, Oregon
As Bill Stout (designer of the Ford Trimotor) used to say, ?Simplicate and add Lightness?
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  #2  
Old 07-20-2013, 10:13 PM
Flinthillsjim Flinthillsjim is offline
 
Join Date: Jul 2013
Location: 8KS8, Chapman, KS
Posts: 7
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I will be installing and flight testing Micro Aero VG's on my RV-9 when I return from Oshkosh. I have used VG's on everything from my J-3 Cub to Cessna 400 series twins (no I have not put them on my antiques or aerobatic aircraft). I will be happy to share the results of the tests on the RV-9 with you after I get back from the big show. If anyone has real data and placement recommendations for the RV-9 I would welcome their input prior to our flight testing.
I will be at OSH in my '39 Waco Cabin biplane in its original black and orange CAA colors camped with the round engine crowd south of the Theater in the Woods if anyone wants to drop by and talk about all things aviation.
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  #3  
Old 07-20-2013, 10:48 PM
java's Avatar
java java is offline
 
Join Date: Nov 2006
Location: Calgary, Canada
Posts: 408
Default

I have nothing to say about VG's, but I must say that you, sir, have my envy. That Waco is beautiful.

...and I see it is your first post. Welcome to VAF!
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Calgary, Alberta, Canada
RV7 QB - Airframe largely complete, sans canopy and glass... unfortunately sold
RV6 - O-360-A1A, Hartzell CS, dual G3X VFR... purchased

Dues paid 2015

"Being defeated is only a temporary condition; giving up is what makes it permanent."
-- Marilyn vos Savant
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  #4  
Old 07-20-2013, 11:29 PM
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Mike S Mike S is offline
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,420
Default Welcome to VAF!

Jim, welcome to the good ship VAF
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Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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  #5  
Old 08-27-2013, 10:45 PM
Flinthillsjim Flinthillsjim is offline
 
Join Date: Jul 2013
Location: 8KS8, Chapman, KS
Posts: 7
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OK, here are the results:

Used Micro Aero installation instructions and the install template provided for the RV-9. Results: Absolutely no change to stall characteristics.
Moved the template aft 1.5 inches and INCREASED STALL SPEED 2 KTS.

I was shocked. Micro Aero VG's have worked great on numerous aircraft I have owned but I couldn't find a "sweet spot" to make them work on my RV9. After two time consuming attempts I tossed in the towel and decided to be happy with the 9 as built. I had installed them with the double sided tape provided so I simply removed and sent them back.

If anyone does the hard work of finding the "sweet spot" and lowers the stall speed on this airfoil please let me know where it is. All I can tell you is what doesn't work and recommend starting .75 (3/4) inches aft of the recommended install position for your first attempt.
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  #6  
Old 08-28-2013, 04:08 AM
humptybump humptybump is offline
 
Join Date: Feb 2011
Location: USA
Posts: 3,179
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Jim, you're experience may not be unusual. There may be a "sweet spot" that is not easy to find.

I say this because the builder of my RV-8 experimented with VGs and he had the same experience as you. When placed where the instructions indicated, he found not improvement in slow flight or stall speeds. He tinkered for about a month and then removed them.
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  #7  
Old 08-28-2013, 04:17 AM
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pierre smith pierre smith is offline
 
Join Date: Jan 2005
Location: Louisville, Ga
Posts: 7,840
Default Yep

....that, and they "ugly up" the airplane....and the wash cloth gets hung up on them

Besides, the slowest landing airplane Van builds doesn't need them, does it?

Best,
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Pierre Smith
RV-10, 510 TT
RV6A (Sojourner) 180 HP, Catto 3 Bl (502Hrs), gone...and already missed
Air Tractor AT 502B PT 6-15 Sold
Air Tractor 402 PT-6-20 Sold
EAA Flight Advisor/CFI/Tech Counselor
Louisville, Ga

It's never skill or craftsmanship that completes airplanes, it's the will to do so,
Patrick Kenny, EAA 275132


Dues gladly paid!
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  #8  
Old 08-28-2013, 04:34 AM
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Capflyer Capflyer is offline
 
Join Date: Feb 2005
Posts: 1,082
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Some reference on VG's by Dave Hirschman of AOPA: http://www.aopa.org/News-and-Video/A...enerators.aspx

Both Dave and I fly similar RV4's. About a month ago we did some ACM. In a turning fight I could not keep the same tight turn radius as he was without stalling, he just kept on going. It drove me crazy as he continually out turned me. I commented to him about that on the ground and he pointed to the VG's.
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JAMES AIRCRAFT.com

Flying - RV8 Hot Rod "Drone Killer"
Flying - RV8 "Look'n Good"
RV4 - FAST & FUN! Rebuilt, Flown, Sold
RV-7A Built, Flown, Sold
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  #9  
Old 08-29-2013, 09:02 AM
whd721 whd721 is offline
 
Join Date: Oct 2007
Location: Beaverton, OR
Posts: 232
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Thanks for your post Flinthillsjim.

I am surprised at the results. The article by Dave Hirschman discusses the results I hoped for.

It is surprising that in this thread there are two no votes and one yes. I would have thought there would have been some consistency.

I accept that the VGs are "Butt Ugly", grab a washing cloth and will bite a hand, but the reduced staff speed and improved control at slow speeds would be worth it.

I installed a set of VGs on my Cherokee and love them. Somewhat like a dog that chases cats, poops in your yard and sheds year round but is a great hunting dog, its worth it!
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whd721
RV9A
Sherwood, Oregon
As Bill Stout (designer of the Ford Trimotor) used to say, ?Simplicate and add Lightness?
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  #10  
Old 08-29-2013, 02:03 PM
humptybump humptybump is offline
 
Join Date: Feb 2011
Location: USA
Posts: 3,179
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I have not read a reference other than the Dave Hirschman article. I have looked for a second source to confirm his success with VG's on an RV.

I have talked with a small number of people in the other column.
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