Who is using VGs?

[Maverick]

Our vg's are 8 1/2 in. from the front of the wing to the REAR of the vg. Measured using a square, not along the contour of the wing. I made several marks then chalk lined the wing. Then just taped the template up and started gluing. Ther are 57 per wing.

[Battson]

Our vg's are 8 1/2 in. from the front of the wing to the REAR of the vg. Measured using a square, not along the contour of the wing. I made several marks then chalk lined the wing. Then just taped the template up and started gluing. Ther are 57 per wing.

Awesome - thanks Maverick!

Did you get any interesting results in terms of performance changes after the VGs were installed?

[Maverick]

Nothing more than Mike added. I liked the slow flight and mostly the latter part of the landing evolution. Since I installed them in the middle of my tailwheel endorsement I really noticed that they kept me from plopping on as easily. With full flaps it seems to float a little unless you are slow enough. Nothing alarming and all improvement other than cruise, in my opinion.

[alaskabearhawk]

Interesting it has been labeled a "bearhawk bounce". I fly a DHC-2 Beaver on wheels and unless you are proficient it does this as well. Not a bounce, but a skip.

[Maverick]

Until I had about 9-10 hours, I just thought I was a retard. Interesting about the Beaver. I have always liked them and wondered about their characteristics. Do any of them have VG's?

[alaskabearhawk]

No vg's but there have been companies that make all sorts of mods. I'm only aware of flow fences for the wings as far as aerodynamics go. I think some may have the VGs available, but I've never sen them. It would be really tough to improve on that aerodynamic design. They really got it right the first time.

No retard that I can see! As far as I know, you only go back in the air for a few reasons. One is mechanical, i.e. if the gear puts you back up, like spring gear. The other reason is the aircraft is not done flying. This may be due to gusty wind or the touchdown was made before the airplane quit flying.

[Mark Moyle]

Dave Roberts may chime in on this one. He said he didn't care for his Bearhawks handling until he installed the VG's. After installation of the VG's he fell in love his Bearhawk. Mark M. Sent from my iPad using Tapatalk

[alaskabearhawk]

Do you know if he made his VG's or got a kit from someone?

[Mark Moyle]

I don't recall. They look factory made....then again Dave fabs quality stuff! Sent from my iPad using Tapatalk

[oismith]

Installed VGs on the HS today and did one flight. It certainly solved the problem I was having with lack of elevator authority at low speeds and forward CGs. Landing characteristics are now much more conventional, even with full flaps. No need to add a little power in the flare, or alternatively run a little higher approach speed and time the flare just right. I used STOLspeed VGs and installed them at the recommended 100 mm forward of the elevator.

Owen Smith

[kestrel]

I installed STOLspeed under the horizontal stab. Made a significant improvement in my ability to get to a 3 point landing at full flaps and no power. I later added them to the wing and got zero improvement in stall speed or handling. Mine are reasonably far forward (don't recall the distance). My understanding is that forward could hurt cruise, but should only ensure good low speed performance. I've been getting around to trying some variations before removing them. My pairs aren't as close as typical, though were placed using the STOLspeed wing template. Ty -- Bearhawk

[Battson]

My STOLspeed VGs arrived this week, and I might get a chance to trial them this weekend. Depends if we get weather taking the plane hunting or not.

First impressions are they are a lot harder and stiffer than the advertising might make you think, flexible but very stiff, it's definitely Polycarbonate not PVC/ Nylon. They are good to look at compared to the usual STCd designs, for sure, and the packs are well presented. I can tell they are going to be a subtle addition to the aircraft, and the laser-cut adhesive pads and cambered base make them look a natural fit on the wing. There is certainly a lot less instructional materials than you get with an STCd set, but hey - that's home-building. There's also a big warning that fuel degrades Polycarbonate, haha... But they include (at least) 8 spares in case you have an "oops", and they would be dead-easy to change given the adhesive pads - compared to a glued on version anyway.

[Battson]

Our vg's are 8 1/2 in. from the front of the wing to the REAR of the vg. Measured using a square, not along the contour of the wing.

I finally found time to read the installation literature that came with the brand I bought.

They recommended 8-12% of chord, to the back/top of the VG ​(that is 5.2" to 7.9" on the Bearhawk) but the main thing is they are meant to be at the highest point on the upper surface when the wing is in stall attitude - to catch maximum airflow; otherwise they can be buried in the separating boundary layer and have no effect right when you need them. I figure about 6" to the back in that case, but I need to fly some tests.

Tyson - I would love to know roughly where you put yours if you have a measure nearby one day? Sounds like Mavrick's are a little further towards the back of the envelope.

[kestrel]

I'll take some pics and measurements when I can. Cheers! -- Bearhawk

[Battson]

Thanks heaps mate!

[kestrel]

I hope I have done this correctly. I have attached? 5 photos of my VG's. Sorry, I don't have measurements as I didn't have measuring tools with me.

The VG's under the stab were installed per STOLspeed's instructions for closely spaced VG's under a stab. I found them to make a very real difference in ability to 3-point/flare and get closer to a power off stall with a forward CG.

The wing VG's made little to no difference. The first thing I'm getting around to trying is making it so that each pair is close to each other. I installed them using STOLspeed's wing template which spaced them all evenly, instead of close pairs. If you look closely at the close-ups, you should be able to see the most forward rib rivet under the front end of one of the VG's. ...is that a good enough indication of how far back they are? You can also get an idea of it from the picture showing the span of the wing.

As I said before, my understanding is that for STOL/stall performance, unless you are getting so that they are under the leading edge, they can't be too far forward, only too far aft. Placing them further forward than needed may increase cruise drag, but shouldn't hurt STOL performance. Also, different airfoils are going to behave differently. Just because they help a Cub or Rebel, doesn't mean that they will do the same for the airfoil on a Bearhawk.

...but I'm going to keep trying when time and temperatures allow!

Please ignore the oil/cruft streaming back from my elevator hinges. ;-)

Cheers!
Ty