I've been looking through the information of the use of vg's on full scale aircraft. It seems like it would be a highly interesting project/experiment to construct some of them and put then on my 4Star 40. Any comments on this or ideas?

What do you have in mind? This airplane is a fairly basic design and, with a rectangular wing plan, is not particularly likely to suffer tip-stalling. Are you thinking of linear turbulator strips or little stand-up thingies or what. Also, what is your goal, performance wise?
Allan

Might be interesting.... Just keep in mind that they are going to be really tiny to match full-scale for the same effect. Keep us posted how it werks.

I have in mind the little tabs that oppose eachother at something like 45 degrees near the LE of the wing. I know it wouldn't do much since this plane is already pretty good at STOL performance. I am just curious to see what happens. I am just in the idea stage right now. I am thinking of using something like posterboard (not the foamcore stuff) or 1/32" ply to make the fins. Will keep updated.

Something along the lines of this:

I wonder if some CA hinge material (suitably sized&cut) would work?

Vortex generators could be helpful in delaying tip stall, and thus keeping your ailerons in business, if they were attached to the outer one-third of the wing. Remember, in aerodynamics, as everywhere else, there is no free lunch. Carefully designed full-span vortex generators, attached at somewhere around the 15% chord point, will produce a higher maximum lift coefficient, but the stall will be more abrupt, as with virtually all high lift coefficient airfoils.

I recently recommended vortex generators on the too-short final diffuser of a poorly performing 250 HP wind tunnel. Static pressure recovery was higher than would be expected from the alternative, a rather costly retrofitted screen, and a second row if planned, since airflow is still separating from the wall, although farther downstream.

Aja,
Maybe you should consider some kind of flaps too. The vortex generators would make them more effective.
Allan

I like the CA hinge idea and will consider it. Also, i can now be aware of a speedier stall if i do in fact put them on. The flap idea is an interesting one, but I'm not sure there is a way to do this without major structural modification. One question is how do I find the perfect location for the vg's. Rotaryphile said the 15% point. I'm not sure how to find that location.

The 4*40 wing is straight.
Measure the chord.. find 15% of that.
(1-1/2" on 10", for example)

Sounds simple enough. However, one question. Do I measure to the end of the wing or the end of the aileron (if so the widest or narrowest part).

You need to include the ailerons. They are always part of the wing and must be included in any calculations.

VG's are merely another form of turbulator. All the turbulators are intended to cure an early airflow separation problem or to tailor the stall charactaristics of a wing. As such using them on your 4Star is only going to help the handling down near the stall and may delay the final stall by a few mph. The extra drag will also cut down the top speed slightly. The only other spot where they may come in handy is during high speed sharp pullups or very tight high speed turns where the model may have stalling issues due to the heavy loading from the G forces. For general flying you probably won't notice a thing. The final effect is mostly related to how the air flows over your wing section.

I've had great results from using turbulator strips (long line of double layered auto trim striping tape) on two gliders that had lousy slow speed manners. Two other models I tried them on gained nothing at the slow speed end and suffered a slight loss in top speed so they were removed.

It'll be a very interesting experiment but just be prepared to not see much if any difference.