Which would be a good starting point to install them relative to the high point of the airfoil?
Hi Claudio,
I guess you must of missed this post..
http://stunthanger.com/smf/index.php?topic=23110.0;all (http://stunthanger.com/smf/index.php?topic=23110.0;all)
Here's what the ones I make look like. They are about 4.6 mm high, but may be way too big. I'm still experimenting with location and spacing, but here are a couple of examples. The ones on PW's wing are PJ's, in his recommended location. There is nothing special about the "high point".
Assuming that VGs have an effect on stunt planes, it matters where the VGs go. The best chordwise position is probably a function of VG spacing and wing design. I started by picking a chordwise position that worked on other people's airplanes.
There is no aerodynamic significance to the "high point". The air doesn't know when it passes it.
A quick google image search will show you that slower flying planes, Alaskan bush types, and many private single engine planes will have the VGs placed ahead of the highpoint of the wing.
I tend to think our models are more along those lines as we slow our down considerably when we maneuver through certain points in the pattern. We are already at low speeds 55 mph or so. When I tested them I placed them just in front of the high point. I had seen the illustration below and noted the placement on slower flying aircraft and thought it made sense. Then PJ's extensive work in the area only proved the forward area to be a good starting point.
I also saw the test pic as well and the split off happens pretty far aft the high point. But they placed them forward for the best results.
Personally, I would put them just ahead of the high point.
We fly at an airport. A Cessna 182 was parked next to our circle last week. It had a plethora of VGs on the wing at 10% chord and some corotating ones on the vertical stabilizer. The pilot said they work a treat. They come from a company north of town. I'll have to stop by sometime and see what those guys are up to.