Simple Champ Landing

Earl Turner

Member
Champ.jpeg

Here is my Champ after rebuilding the wing (a tree jumped in front of it) Notice the smooth upper surface. Instead of just making 2 score lines as per the Simple Cub plans, I score every 1/2 inch from the leading edge to the back of the spar.
 
Dang. If you hadn't said anything I wouldn't have thought the wing was made out of regular foam board. I'll have to use that technique on my next wing!
 
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d8veh

Elite member

Here is my Champ after rebuilding the wing (a tree jumped in front of it) Notice the smooth upper surface. Instead of just making 2 score lines as per the Simple Cub plans, I score every 1/2 inch from the leading edge to the back of the spar.

That's interesting. There's a theory floating round that the angles on the normal wings has a turbulator effect to reduce the stalling. I can see some merit in that theory. It would be interesting to do a side-by-side comparison. can you detect any difference from memory?
 

Earl Turner

Member
That's interesting. There's a theory floating round that the angles on the normal wings has a turbulator effect to reduce the stalling. I can see some merit in that theory. It would be interesting to do a side-by-side comparison. can you detect any difference from memory?
I dont see any diference in the way the airplane flies, between the old wing & the new wing. It flies better on every flight as my piloting skills improve. Moving the motor forward 1/2 in and giving a bit of down & right thrust made a big difference however.
 

Merv

Site Moderator
Staff member
I dont see any diference in the way the airplane flies, between the old wing & the new wing.

I agree, I did not see any noticeable difference between a smoothly curved wing and a FT wing (faceted wing) but I have not made a smooth wing in a long time. I should retest. I am seeing a better glide slope with a smoother training edge. similar to this.

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The FT wing have more of a stepped TE. I make my wings with a faceted upper surface and a smoother TE (not stepped). I sand one layer of foam down to a sharp edge before I fold the wing. The TE is just 1 layer of foam thick, the aileron will also be tapered in an effort to reduce turbulence/drag.
 

Hai-Lee

Old and Bold RC PILOT
Just a note of caution. A sharp trailing edge is ideal aerodynamically but it is a disaster structurally. If too sharp there is too little material for the trailing edge to hold its shape at times of high aerodynamic forces, as in landing, turbulence, and high speed flight or when handling on the ground..

In the extreme you can get the trailing edge flexing in flight giving poor stability and even a form of control reversal at high speed. In addition there is a possibly of permanent warping or even surface failure long term.

Tapering the Wing trailing edge is fine but DO NOT WEAKEN the structural strength too much or problems will definitely ensue!

Just a cautionary note!

have fun!