S7 STi Wing

[Owyhee Fox]

I attended the factory Fly-in Friday (nice to live 3 miles from the factory) and noticed several STi's without the mid wing fences installed. Why do some elect to not install them and how would the deletion affect the flight characteristics? I'm asking because I will be building a STi as soon as kitfox builds my kit. BTW, had a great time and thank you to kitfox for putting on the nice event, I learned a lot and met some great folks!

John Levanger
Homedale, ID (S66)

[Shadowrider]

The mid fence doesn't help with stall speed and adds drag. I love the looks of the fence, but don't want the added drag so we left them off on ours.

[SNOW JW]

Would it aid slowing you down in a slip?

Sent from my SM-G960U using Tapatalk

[Owyhee Fox]

Has anyone done a comparison of the stall characteristics with and without the fences on the same aircraft? My only experience with wing fences are on an aircraft that has no design similarities to a Kitfox, (turbojet engine, swept wing, fowler flaps, traditional ailerons, speed brakes, etc). The wing fences were added after the initial design to "soften" the stall characteristics (abrupt stall, wing drop). The added drag was found to be negligible.They also found that the fences increased the aileron authority in slow flight regimes. With the kitfox's flaperon design this attribute may be negated since they (flaperons) almost "fly" separate from the wing. I'd really like to see some data if anyone has done a comparison.

John Levanger
Homedale, ID (S66)

[Shadowrider]

Stall fences work on tapered wings and I am not disputing that but with the kitfox being a rectangular wing I don’t think there is much aerodynamically being offered but more cosmetically. I don’t think the stall moves on the wing so stall fences don’t seem like they would offer much. I do love the way they look, but with this aircraft being tricky to always fly perfectly ball centered, just seems like more drag.

They would offer more drag in a slip, but with 29”, and bush gear they are plenty draggy. Do a before and after for us and let us know if we should install them?

[Denalifox]

I kept the fences and VG's off my wing because it lives outside in Alaska. They get in the way of wing covers and clearing snow. I believe the fences are help with the "short coupledness" of the KF design. That being said, I stall in the high 30's and never had a single adverse issue with a clean wing.