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.

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.

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!

Welcome to VAF!
 

Jim, welcome to the good ship VAF:D

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.

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.

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,

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.

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!

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.