BillS

Kadet Senior ARF– aileron differential

I am flying a Kadet Senior ARF wing on a kit fuselage and the airplane has a remarkable amount of adverse yaw. The original wing behaved much better. Maybe some aspect of the aerodynamics has been overlooked.

Are you finding adverse yaw with the Kadet Senior ARF? Are you finding aileron differential to be necessary?

Fubar-One

My Feedback: (1)

I have a Kadet Senior ARF and I have no aileron differential set up. Flies great even with an added payload.

cwrr5

My Feedback: (32)

Ditto. Haven't noticed any, but then again I use rudder a lot. (ya know, the LEFT stick????)

Is the fuse any different between the two? I know the wings have a slight difference in span, not sure that it would affect much though. How much dihedral in each wing?
Interesting.... I hadn't heard of anything similar with the KSRs until now. Differential would probably sort it out, but wouldn't tell you why you're getting the yaw.

hookedonrc

This is only a guess, but a buddy of mine has a cadet senior and the wing incidence was not equal on both sides. I would check to see if there is a twist or warp in the wing. His wouldn't fly at all till he reheated the covering and straightened the wing.

4 stroken ron

My Feedback: (29)

I had a Kadet Senior built from a kit a few years ago (RIP). I used 2 aileron servos and a computer radio. I had "down" movement set at 0% and "up" set at 140%. Worked perfect. no adverse yaw at all. I do the same thing with my Cub. I guess you could say that is 100% differential.
cwrr5's method (rudder) will also work well.
Ron

BillS

Kit wing – 2 1/4” dihedral – 78 1/4” long
ARF wing – 2 5/8” dihedral – 80” long

The span is less than 2” different with the ARF wing being longer and the dihedral is close considering the span. The ARF wing has barn door ailerons and the kit wing has strip ailerons.

The question was asked to gain a better understanding of the adverse yaw of a standard ARF and not as a complaint. No adverse yaw was noticed with the kit wing but the yaw on the bashed ARF wing is quite bad. If others are not experiencing adverse yaw then bashing has introduced a design error that is being overlooked. In addition the aileron authority is not very good.

Thanks.

Bill

cwrr5

My Feedback: (32)

It's an intresting question, and I had really never thought about it previously... It didn't sound like a negative towards the KSR to me, they're great flying planes, even with very "tame" ailerons and such. I have a KSR kit that I will eventually get around to(again), flying an ARF at the moment as a glider launch/aerial camera platform, but usually it flies without the "toys". I really haven't noticed any yaw tendency, but my flying style originated with elevator/rudder only planes, and I carried that on through the years(mostly ) Plus - I'm a taildragger enthusist(sp?), so I use a lot of rudder anyway, and would not necessarily notice as much.

So the question is :
What factor or combination of factors will cause adverse yaw in a high wing airplane? The Kadet is used as an illustration/example.

right?

Edit: I would think the barn-door vs. strip ailerons would be the culprit in this case, you have more control surface deflection over a larger portion of the wing, including the area next to the fuselage where the prop blast is. So, if the airflow from the prop is hitting the upper wing in a bank(roll), with the surface deflected, you have more drag on that side.
Sorry, that's a pretty crude way for me to say what's rolling around in my mind, best I could do. I don't know if thats right, or if that even makes sense to anyone besides me??? [sm=confused.gif]

Edit#2: See below, more better explanation of what I was trying to say!

ICE_MAN

Could it be that the 2" longer is pushing it over the "limit"? The fuse Is to short for how long the wing is soooo the "top" half of the wing in a turn is making enough drag to push the tail down and cause the adverse yaw? Sort of like a Piper Cub, Anyone whose ever flown one knows that they have to have rudder in the turns (in most if not all cases).. Also the plane in question is trike gear right? I'm not sure if a trike can ever really get "squirelly" on the ground but is it? I know that taidraggers with LONG wings And SHORT fuselages tend to bevery touchy on the ground.. Again think of a J-3 Cub..

That's my theory.. If it proves correct just coordinate your turns with some rudder.. My.02, Regards, Cody.

cwrr5

My Feedback: (32)

My ARF isn't "squirrely" on the ground, but does float forever. (going to add drag flaps soon). Dang, now I'm curious. I'm gonna have to build a wing to "experiment" on this one!

BillS

Nothing I have floats. Usually it is epoxy related but not this time. More later since it is time to perform some more tests.

BillS

Aileron authority and adverse yaw seems to have been solved with differential (one spline on the servo) and sealing the hinge line with a 1” wide plastic strip. Authority is good and adverse yaw is virtually nonexistent.

britbrat

The problem is most likely caused by the barn-door ailerons. They are considerably less efficient than strip ailerons, but are every bit as draggy --- and all of that drag is at the outboard end of the wing.