Stolspeed VG's

[500AGL]

IMG_0158.jpg If you zoom in on these photos, you can see the VG’s on the slope of the leading edge. We can ask Virgil to put a straight edge up and measure back, but as I recall and looking at the photos I’m thinking it was 2-2.5” back from the LE, horizontally.

That would equate to 3.5-4% of the 60” chord.


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[AKKen07]

Right on, thanks for the intel. It’s encouraging that so much variation seems to yield good results.

Gosh that Patrol is a good looking airplane. But I definitely don’t want to build another plane… definitely…

[rodsmith]

Completed installing Stolspeed VGs on the wings yesterday at 7% chord and had my first flight today with them. You have to experience the difference with them. I normally take off with flaps 2, lift the tail at around 30k and lift off at 50k. I didn't get the tail up to level before leaving the ground, according to Flysto.net that was at 37k. My Vso has been a very repeatable 46k. I did four flaps up stalls and they all occurred halfway between the 41 and 42 on the airspeed tape. With flaps 2 the stall was occurring at 39k. Flaps 3 and 4 I could only get to 38k with full elevator and it wouldn't stall, just developed a very high sink rate. I thought I had ordered Vgs for the stabs at the same time but turned out I didn't, so I had to place another order. They are supposed tp arrive tomorrow, can't wait to see what they do. Hopefully with them in place I can get the plane to stall at flaps 3 and 4. Lots of testing to do now. I did not check my cruise speed or top speed. With what they have done for the stall speed and the overall solid feel of the airplane in slow flight, I don't mind sacrificing a couple knots on the top end.

[Battson]

Glad to hear you like them Rod, this is much the same as my memory of first flying with them. They transform the aircraft. I would never want to own a Bearhawk without Stolspeed VGs installed.

[Nev]

Completed installing Stolspeed VGs on the wings yesterday.....

Excellent results Rod.

A interesting exercise is to perform a number of stalls with power ON to keep the elevator authority going into the stall. It can change the outcome markedly with a much higher pitch attitude (28° in my case) before dropping wing. Having an aft CG on mine also keeps the elevators active at low speed and changes the stall characteristics. My lowest stall speed (F3 or F4) at 2200 lbs is also around 37-38 KIAS.

Good work !

[BarrysLSA]

With my LSA, I am easily getting in and out of a grass strip in 400 feet or less at 80 degrees with a stock o200A, Catto prop and Vetterman exhaust. Not too shabby. It handles very well at low speed with no complaints. The stall is a non event and very docile but it does stall pretty much across the wing as it does not have washout. I flew other small planes with VG's and was impressed. I bought a set of Stolspeed's and was wondering if anyone has used them on the LSA. If I can make it land a few kts slower and not lose any cruise speed for less than $200, I am all in. If I place them at 5 percent as Stolspeed suggests, this will be 3 inches back from the LE. I think 4 percent would be be better for this Riblett airfoil. This would be 2 1/2 back. I wonder if placing them that far forward will affect cruise speed.

[Sierra Skydog]

I’m interested in hearing about your results with vg’s, am also thinking about adding them to my LSA. I also have O-200, Catto prop, vetterman exhaust.

[rodsmith]

Completed testing the VG installation. They were installed at 7% chord. I considered 5% but Jon Battson had very good results with 7% on his A model wing. I installed them according to directions with one exception. You are supposed to use 60mm spacing for the first 15 vgs inboard from the wingtip, about 36" and 90mm spacing inboard. I calculated that I had enough to cover from wingtip to the inboard end of the ailerons at 60mm spacing. I asked G J his opinion, he said can't hurt, might help. I am thoroughly impressed with them. Verified they decreased the stall speed a solid 5 kts from no flaps to full flaps. Adding VGs under the horiz stab increased the elevator authority at slow speeds. With just the wing VGs, I couldn't get a stall break at F2, F3. That changed with the stab VGs. Also I was not able to make a full stall landing before installing the stab VGs. Now I can make a full stall landing tailwheel touching just before the mains, touch down speed high 30 kts. I have verified that cruise speed dropped 2 knots which is an okay tradeoff. Strangely, full power speed seems to be the same as before. The one change I don't like is that the glide ratio decreased from 9.2 to 8.4. I will be retesting that as the air wasn't as stable as my first test, and OAT was 18F warmer.

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[BarrysLSA]

I installed the Stolspeed's on my LSA and flew it this morning. I know that the bigger Bearhawks have had good success at 7 percent of chord. I couldn't decide between 6, 6 1/2 or 7 so I decided on 6.665 which is an even 4 inches of chord. This morning I flew it at 85 degrees on a grass strip solo with 1/2 fuel. Previously when I took off, if I eased it off when it started flying, it would skip on the ground once or twice. Now when it started flying, it flew right off in less than 350 feet. I lost about 1 mph in cruise but lowered my power off stall 3-4 mph. Power on is even better. I have always had good aileron control in the stall and still do. I put about 1/4 inch reflex on the ailerons when I built it. I did have to relearn how to approach and land though. Before, i would be downwind in cruise, apply carb heat and reduce power to 1500 abeam the numbers and slow to 60 mph and turn base. I would let it slow to 50 mph while reducing more power on base and turn final then slip it to a landing while reducing speed some more. It would land 3 point after floating a short distance. Now, I turned base at 60 and it would not slow down while descending on base at idle. Turning final at 60, it was hard to get it to slow down so I slipped it down and floated halfway down the runway. Interesting. Tried again but reduced power earlier in the pattern and got 50 before turning base. This time I slowed to to 45 and slipped it to a decent landing but still floated. In both of these landings, in my "hurry" to land the mains touched first. I did a couple of more like this and realized that it wheel lands much better. It had always been a struggle to wheel land it on grass. On my last landing, I turned base at 50 and got it to slow to 45 on base, slipped it a little and was short final at around 40. It landed 3 point in less than 300 ft in wet grass. The wheels locked up the wet grass so I didn't get a lot of braking. I always had aileron and elevator control. So far, I really like them. The airplane certainly wants to fly at lower speeds. Later, I will report how it does with a passenger and on pavement.

[500AGL]

If you are ambitious enough to move them you’ll find they work even better at a shorter chord percentage. Less than 4% chord is my recommendation.

[BarrysLSA]

Hey 500 AGL. What percentage did you use on your LSA and did it affect cruise speed?

[BarrysLSA]

Hey 500 AGL. I now see that you have a Patrol. As you know, the LSA doe not have flaps. Also the LSA wing is a 60 inch chord instead of 66. As I understand it the LSA has a different airfoil because of this. I am perfectly willing to move the VG's anywhere to get the optimum performance. I do travel around with it and don't want to lose much cruise speed. I put them at .665 to just to get started. I would like to hear from anyone else that use the VG's on an LSA. I am happy where they are but am certainly willing to change them. Hope to see you at Oshkosh.

[Bcone1381]

Hey 500 AGL. I am perfectly willing to move the VG's anywhere to get the optimum performance. I do travel around with it and don't want to lose much cruise speed. I put them at .665 to just to get started. .

I am curious and want to know how difficult it is to move your VG's once you install them.

[BarrysLSA]

The Stolspeed's attach with their double sided tape which is included with the kit. The tape is laser cut to fit each VG. They appear to be fairly easy to remove without scratching the paint. I haven't tried it yet. I guess the easiest thing to do would be to contact them to order some more laser cut tape and just reattach them all. I won't move mine until someone else with an LSA tries something different and convinces me. It appears that I might be the first one to try it on the LSA. I will give more info as I fly it more.

[rodsmith]

I am curious and want to know how difficult it is to move your VG's once you install them.

I found if you twist them they pop right off. I bought a sheet of the 3M adhesive that JG provides laser cut, pushed the VGs into it and cut it out with an exacto knife to replace the adhesive. I had initially misunderstood the instructions for under the stabs and had to redo half of one side.

[BarrysLSA]

I just removed the VG's from my LSA. Last year while flying to Lakeland, I landed at an airport with a serious gusty crosswind - at least 15 gusting to 25- and managed to land on pavement with no issues. Yesterday I encountered a lesser gusty crosswind and it was a chore to keep the airplane planted on the ground. With every gust it wanted to fly when I wanted it to stay on the ground. Another problem I had was it was almost impossible to do a 3 point landing. I would run out of elevator when flying solo. Of course, I could put VG's on the tail to help that but the crosswind episode helped me decide.