That’s not a short story.
If you calculate the proper dimensions of vortex generators for a wing of 22 cm chord at 14 m/s with the corresponding reynolds number, you find that most of the historical tests were performed wit generators that were far too large.
I found a product that bills itself as a turbulator that actually was a vortex generator tape in self-adhesive form and was pretty close to the proper size and spacing- 0.6 mm high instead of the 1mm that would have been ideal, so I used that for the generators. We all know the nasty tip stalls that some otherwise great aircraft have, and I was trying to find out if that problem could be reduced with devices to delay the stall at the tip.
In short, it worked partially on my much-abused but still true X-8, with the placement in the most effective position of 27% chord aft and a length of around 25 cm, with no detectable reduction of the L/D. The tip stall was reduced to the point where my fairly heavy X-8 would stall at around 7 M/sec. and a pitch angle held to around 5 degrees, with only a slight rolling tendency. I balanced the roll by varying the length of the generator strips until I got it as close to a straight-ahead stall as possible, but it never got to the point where you could say the problem was cured- only to the point where an alert pilot could dump the stick for less than a second to break the stall, still in stabilized mode, and it would fly right out of it—far better than the original condition. Here’s the link to the product.
https://www.topmodel.fr/en/product-detail-21380-turbulator-tape-white-5m-roll
Was this product truly making vortexes that would draw the free-stream air flow to the surface and keep it attached? Can’t really say, but it definitely worked to retard the stall.