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  #21  
Old 07-11-2017, 08:28 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
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Quote:
Originally Posted by moosepileit View Post
I bet a few VGs in the right spot would remove the buffet. Do all series of wingtips act the same?
The buffeting has been attributed to the nose on the "up" aileron sticking down below the bottom surface of the wing and tripping the airflow as it passes under the aileron. 20 years ago (or thereabouts) Van tried VG's on the leading edge of the ailerons to address this issue. I never saw the results from that trial.

Personally, I might try the VG tape the sailplane guys use. Properly positioned on the LE of the aileron, it might keep the airflow attached and prevent the buffeting. Or it might not. ;-)
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  #22  
Old 07-11-2017, 08:40 PM
rv7charlie rv7charlie is offline
 
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Location: Pocahontas MS
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If memory serves, when I 1st experienced it over 20 years ago in my 1st -4, I called Van's and they told me it was aileron *stall*. Empirical evidence supports this; higher airspeeds reduce the bumping.
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  #23  
Old 07-12-2017, 11:06 PM
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nigelspeedy nigelspeedy is offline
 
Join Date: Dec 2008
Location: Tehachapi, CA
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Default VGs probably won't help

I tried VGs on my RV-8 on the outboard wing leading edge i.e. in front of the ailerons. They made no difference to the stick buffeting that you are talking about or the roll rate under any configuration.
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Nige
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  #24  
Old 07-13-2017, 08:33 PM
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RV8JD RV8JD is offline
 
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Quote:
Originally Posted by nigelspeedy View Post
I tried VGs on my RV-8 on the outboard wing leading edge i.e. in front of the ailerons. They made no difference to the stick buffeting that you are talking about or the roll rate under any configuration.
Cheers
Nige
What about VGs on the wing, but located just forward of the aileron hingeline (instead of the wing leading edge)? But since the buffet we are talking about occurs at large aileron deflections, that may not work either.

There are some large airplanes I'm familiar with that have VGs just ahead of the aileron hingeline to preclude buffet due to flow separation over the aileron under certain conditions. But those conditions usually don't involve large aileron deflections.

I should add that I don't think this aileron buffet is an issue that needs a fix on the RVs.
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Last edited by RV8JD : 07-13-2017 at 10:04 PM.
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