Vortex Generators?
 

There's an interesting article in Model Aviation this month by Dave Scott. He advocates the use of vortex generators as a way to make control surfaces more sensitive at positions near neutral.

The reasoning is that under normal circumstances, there is a 3-4 mm layer of turbulence along the surface of the wing. At small deviations, the control surfaces are still within this turbulent layer, which reduces their ability to generate force smoothly. By adding vortex generators to the wing, the turbulence is disrupted. This reduces the stall speed of the wing and gives control surfaces more effectiveness. The price is a slight increase in drag and reduction of top speed (1%). There's a mesmerizing video about testing vortex generators in a full-sized plane here.

So my question is whether anyone has tried these on a pattern plane to see how they affect control for small stick inputs. My guess is that it would be icing on the cake, and make little difference for someone at my (modest) skill level. But I found the idea intriguing.

I have installed them on main wing of my Integral and the overall performance has been improved. My Integral is quite porky (at 5kg) and before VG installation there was a little wing rocking on horizontal lines.
After VG installation I have noticed that the wing rocking has gone and it feels more stable in the air; its penetration has been improved, too. Also, wing tip stall has almost been eliminated.
I cannot see any significant difference in the drag. However, spin entries are quite a challenge now and they require a lot more elevator

To be honest I wonder why not more F3A fliers do not use them.

Very cool, John. Can you describe your VG's? Size? Spacing? Placement? How you attached them?

They were bought from F3A unlimited and installed in accordance with the details. They come with double adhesive tape so installation/removal is easy.
Check the link for more info http://www.f3aunlimited.com/micro-vortex-generator

Interesting thing is, with the choice of airfoil on the full size in the video, it's a trailing edge initiated stall not a leading edge initiated stall..

Not sure if this thread should be in General Pattern or Electric, but anyway...

Here's a cool video about vortex generators (VGs) showing attached/separated flow with lots of nice fluid dynamics illustrations:

https://youtu.be/eP-YUDe9HF0

I have been wanting to use VGs for a long, long time, but I didn't think of an easy, reversible installation process. I bought 2 x of the F3A Unlimited kits.

I don't know if everyone knows this or not, but if not - VGs are very useful on lots of light and heavy airplanes (Boeings use them as well as bush and some cabin class aircraft such as the Aerostar). Not only that, the issue of flow separation on our little models (compared to full-size), if I'm not mistaken, is much greater - aerodynamically speaking - than it is on full size aircraft because of the relative size of a model vs a full-size which both move through the same air with the same physical properties. This is why the saying "size matters" and "bigger flies better" is true.

I think one reason they're not more widely used is that it seems 100% counter-intuitive to put sharp pointy things sticking out perpendicular to smooth shiny flight surfaces - it just totally seems wrong.

And have you heard of the "tubercles" on the pectoral fins of whales? That's right, VGs for better propulsion.

I'll give it a try and let you know how it goes.

Today I tried for the first time VG on stab. The result was not good at all. The aiplane had a weird feeling and it felt too draggy.
By the next flight, they were removed. VG only on the main wing for my Integral!