Stolspeed VG's

[Nev]

Yesterday I installed Stolspeed VG's on my 4-place B model and spent an hour or so repeating stalls both power on and power off.

In a nutshell (and at first glimpse) at 2200 lbs the power off stall speed has dropped about 5 kts for all flap settings. Power on stalls didn't show much change in the stall speed, but at this early stage I didn't see any wing drops. I was able to fly at around 45kts in level flight at 3000ft in full control. When the wing stalled with F3 or F4 the descent rate increased but the wings remained level.

I've got alot more to do in this area, this was just a first look.

[Gerd Mannsperger]

Same spacing between VG's but More forward on the outboard section a little may go a long way. Some wings do not need a set back at all.

You can just use double sided carpet tape to try out the swept or set forward designs base on what you prefer or try different settings..

I prefer the paired spacing much like the Mircro VG set up on cubs.

[zkelley2]

Did you have the spacing of the VG's reduced at the tips before you moved them back? Stolspeed has you do 60mm spacing at the ailerons and 90mm for the rest of the wing.

[svyolo]

Good info, and easier than wing twist/washout.

[Gerd Mannsperger]

For anyone who worries about the wing stalling all at once with VGs I did have that in a few application where the stall speed dropped noticeably but the stall became more abrupt.

The fix is to either move the VGs inboard of the Aileron back 1-2 inches in comparison to the outboard VGs Or a nice very smooth stall is generated by having the outboard section swoop forward.

I found 1" sweep forward from mid wing to the tip to be sufficient in most cases to give a very smooth approach into the stall with the tips flying well into the stall with very good feel to the aileron

throughout slow flight and right to the end. Properly set up VGs are a great enhancement to control and safety right in the most critical phase of flight ,

never mind the slower landing and take off speeds that is just a side benefit. I wish more people would recognize and see them for that instead of a stol mod.

[huntaero]

I was looking at these a while ago at Aircraft spruce https://www.aircraftspruce.com/catal...ickkey=3018758

[Ray Strickland]

I recently installed Stolspeed VG's on my A model 4-place wing only, w/ profiled hor stab & gap seals. Preliminary tests show 3 mph reduction in stall with clean, but gentle break w/o buffet. No reduction in cruise speed @ 50 percent power. Installed with highest part of VG in line with 4th row of rivets. Will keep them.

[kestrel]

With the profiled tail fitted on a 4-place, flying near empty weight, you should still run out of control authority at the flare with the throttle closed.
Otherwise you are landing too fast

I prefer effective controls that let me fly the airplane where I want it. ...only an issue at the lightest loads.

[Battson]

Maybe not if you don’t have a heavy 540 on the front😜

Good point - could be worse I guess, I hear those TCM engines are even heavier - you can't trust those "book values".

[whee]

With the profiled tail fitted on a 4-place, flying near empty weight, you should still run out of control authority at the flare with the throttle closed.
Otherwise you are landing too fast

Maybe not if you don’t have a heavy 540 on the front😜

[Battson]

With the profiled tail fitted on a 4-place, flying near empty weight, you should still run out of control authority at the flare with the throttle closed.
Otherwise you are landing too fast

[Isilverone]

Whee, don’t put VG’s on the profiles tail. They suck. At least they do on the patrol. On my slab tailed 4-place, they added control authority in both pitch and yaw stability on low speed approach and in ground effect. Just my experience speaking so maybe not the same for others

[jaredyates]

Question for those with 4-place BHs: What are you feeling that makes you like VGs and/or gas seals on the tail?

I put a profiled tail on my BH and can’t think a reason to change anything. I’ve very curious what I’m missing.

I think you fixed it with the profiled tail. With the flat tail at forward cg, we can run out of elevator before the wing stalls.

[whee]

Question for those with 4-place BHs: What are you feeling that makes you like VGs and/or gas seals on the tail?

I put a profiled tail on my BH and can’t think a reason to change anything. I’ve very curious what I’m missing.

[kestrel]

Kestrel, Isilverone - which gap seal are you using?

I'm using gaffers tape. A single layer applied across the top and laid down into the middle of the hinge. I find I need to replace it about once per year. Simple, cheap, works well. ...but I would consider a more permanent solution if I found a good one.