Vortex Generator position VG

[tx_swordguy]

I am no engineer so take it for what its worth, but I don't think the a visual mark is going to be the proper place to use (highest point sitting) As Trent says too far back you will loose the boundry layer before the VGs have a chance to "stick the air to the wing" It may even disrupt the air even more and exagerate the stall but that is just me thinking here. Each airfoil is slightly different and the wing may have a different high point. I think in general the VGs are placed before the high point to ensure the air adheres to the wing to keep the lift. What ever you do I would not try to out think the VG engineers.

[efwd]

I thought we agreed that the engineers didnt get the carb synch cross tube right?

[WurlyBird]

The "engineers" also agree that somewhere between 4-12% of chord SHOULD improve flight characteristics. In this case of course, the "engineers" are any people that want to shape pieces of Lexan and be panacea salesmen. Here is a quote from the STOLspeed website,

"So, with the wing positioned at the stall angle of attack, the VGs should be slightly forward of the highest point of the airfoil."

So if my KF3 stalled in a 3 point attitude (I wish) that would mean it stalls in the same position as when taxiing or parked. I'm not trying to "out think" the engineers, just rephrase. That's also why I asked if anyone could look at their VG and confirm or deny.

And furthermore, if the "engineers" are so spot on why don't we just fly Cessnas that we could buy for less than our KF? For that matter why are all the KF so different from one another?

And if you're wondering why "engineers" is in quotes so much, it's because anyone that manufactures a solution to a problem is an engineer and level of schooling or a title is not necessarily indicative of capability. I know old school, blue collar machinists running on a GED that are far superior engineers to most Ph.D. recipients.

Now if you'll excuse me, I need to take my soap box over by my plane so I can look at the top of the wing.

[tx_swordguy]

Ok point taken. Call them basket salesmen for all I care. My vgs are ahead of the highest point of the wing when sitting 3pt. I have no idea if it stalls in that attitude or not, I believe it is much more tail down when it stalls. I followed the instructions from the site I got mine from and it worked out well for me. Your mileage my vary so do what you want

[GMKman]

You can use double sided tape to temporarily experiment with various placements ( which is what I did). I lost one or every once in a while but was worth the data. I found that the more forward/ the more effective however it came with a cost of more drag. I inevitably didn't like the look or the drag of them and didn't feel like they made much difference so off they came with no harm to the wing from the sticky tape.
I did put some on the bottom of the elevator which made a difference in authority ( I still have the small elevator with a continental engine up front).
I "glued" them on permanently now. I'm happy with them.

[redbowen]

Here is a video I put together showing a VG installation. Hopefully it is helpful.

https://www.youtube.com/watch?v=vGzHZKRZi7s

I also started a new thread for it here.

http://www.teamkitfox.com/Forums/sho...1255#post71255

[DesertFox4]

Great video Bryan.

The larger elevator would be a good mod to increase elevator authority in the flair.

[GMKman]

You can use double sided tape to temporarily experiment with various placements ( which is what I did). I lost one or every once in a while but was worth the data. I found that the more forward/ the more effective however it came with a cost of more drag. I inevitably didn't like the look or the drag of them and didn't feel like they made much difference so off they came with no harm to the wing from the sticky tape.
I did put some on the bottom of the elevator which made a difference in authority ( I still have the small elevator with a continental engine up front).
I "glued" them on permanently now. I'm happy with them.

I need to retract some of this statement. I installed Stolspeed vg's on my wing now in pretty much the same place Bryan did in his video and DEFINITELY like the improvements in lower stall speeds, low speed stability, and no real drag increase. Not sure why the other vg's I tried didn't work as well but I'm glad I have these on my wing now.

[NinerBikes]

Ed, did you end up yet with these being installed?

I don't remember looking for them on Saturday.

Or will you fly first, get some measurements, and then install at a later date, so you can note and log the stall speed difference between clean and Stohlspeed installed a few inches back?