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Vortex Generators

PostPosted: Tue Aug 15, 2017 12:10 pm
by Tralika
Has anyone found a special mounting location for the Harrison Designs Vortex Generators that works better than the factory instructions?

Re: Vortex Generators

PostPosted: Wed Aug 16, 2017 10:53 am
by gkremers
When I built my Highlander the factory suggested a placement location but said to follow the instructions. The instructions were easy to follow. The only thing I didn't like was the template wasn't very big so I redrew them in a CAD program and had a couple of 48" templates made. Much easier to tape them down on the entire wing. I also used the factory suggestion of applying with a clear silicon. If you use the glue recommended in the instructions it will pull the paint off when you catch one over time.

3+ years and 300 hours, still holding up fine.

I also installed them under the horizontal stabilizer.

Re: Vortex Generators

PostPosted: Fri Aug 18, 2017 10:11 pm
by Tralika
Thanks for the reply Gary. I have a piece of painted fabric I cut out of my rear window so I've been testing different adhesives to attach the VG's. The Locktite 401 (very expensive) worked well but when I pulled off the VG it took the paint right off. I tried clear silicone adhesive and it didn't work well. I tugged lightly on the VG and it came right off. I tried Seal-All It worked well, I was able to pull the VG off but it didn't take off the paint. I also tired two sided tape. It holds the VG on really well but the folks at Harrison Designs do not recommend it. They say the VG's will eventually come off with two sided tape. Could be that tape breaks down over time due to sunlight coming through the clear VG's. So I'm not sure what to use.

I was talking to an IA friend a couple of days ago. When rebuilding wings he glues the VG's directly to the bare fabric before painting. He then covers the VG's with a continuous strip of fabric tape the length of the wing, cutting slits for the vertical section of the VG's to poke through. After gluing down the tape he paints everything. He claims he has NEVER had a single VG come off using this method. Of course I finished painting my wings last year. Now he tells me!

I'll have to get this figured out in the next few days. I'm just about ready to put my wings on. Hopefully I'll have my visit with the DAR in a couple of weeks.

Re: Vortex Generators

PostPosted: Fri Aug 18, 2017 11:01 pm
by FlyerChief
I have had my VG's on for over 3 years now and the only ones I have "lost" are the ones I accidentally spilled a bit of fuel on or broken off by setting the 5 gallon fuel can on them. The double sided tape works very well and doesn't remove paint when you take them off. I always carry a few spares just in case, but I have only ever had to replace ones that were subjected to the abuse mentioned above. I'm not sure if they are Harrison Designs VG's... they are whatever Just Aircraft supplied when I ordered that option. Just make sure you press them down well when installing them to keep dirt and moisture from getting under the edges and loosening the tape. I found the spacing specified by the manufacturer works well. I made up a template from a piece of 1/4" plywood that allowed me to precisely position the VG's along the wing and across the Lexan on the top of the plane since it's also part of the lifting surface. I also placed them on the bottom of the horizontal stab, but am questioning the wisdom of that. I often wonder if it would have been better to seal the elevator gap with tape. Has anyone got any info to offer in that regard?


Re: Vortex Generators

PostPosted: Sat Aug 19, 2017 10:08 am
by danerazz
My understanding is the tape helps in general by keeping the low pressure under the stab, and it will help the efficiency of the VGs if used in conjunction with them. Kind of like the discussion of flap gap and VG elsewhere on the forum.