So, getting ready to finish the trailing edge of the pathfinder wing. Flaps not full span, so there's an extension to the tip. Is making the outboard ext. adjustable that big of a trim aid? Thanks Jack

Thanks Geoff, and I like the idea of the leadout in the tube. That was a concern with the tubing I had. The rudder has hinges and a little rod with a ball link. Hope that works ok. Jack

So, getting ready to finish the trailing edge of the pathfinder wing. Flaps not full span, so there's an extension to the tip. Is making the outboard ext. adjustable that big of a trim aid? Thanks Jack

   I think it's generally a mistake to count on it. It is useful for quickie field fixes but if you have a significant warp you definitely want to fix it and not rely on the tab for any more than the tiniest adjustments.

    Brett

The January 2011 Flying Models shows an adjustable flap extension using a short RC pushrod anchored in the wing, with a nylon control horn on the extension.

Listen to Brett, he's a smart guy. If the wing is warped, fix it. Don't rely on a tab to fix it. Easier to tweak the flaps a very small amount to make small adjustments. Just my thought.

Jack...FWIW, I would never ever hang a tab or rudder on pieces of tubing, bending the tubes to make an adjustment. One little bump, and your adjustment is gone. I'd suggest using some sort of hinges and adjuster scheme on any tabs or the rudder. Pretty much your choice as to what sort, but the Robart "hinge points" and "horney hinge points" seem particularly useful for this.

Based on what Brett and Howard are preaching (i.e., do what you have to, to make it straight), one thing you can do on the field to do a "quick and dirty" is to tape some trailing edge stock onto the bottom of the TE. Thick edge aft, inboard wing if it's low, outboard wing if it's low. This you can do on the first flying session, to allow you to get more than one flight in, and get your engine/tank/prop sorted out to some extent. It's an old free flight trick, but works fine on CL models.   Steve

   I think it's generally a mistake to count on it. It is useful for quickie field fixes but if you have a significant warp you definitely want to fix it and not rely on the tab for any more than the tiniest adjustments.

    Brett

Absolutely right on. From R/C and C/L consensus on many good pilots, adding a tab to any wing only corrects the aircraft in that specific attitude or maneuver. There are corrections for knife edge that are generated by programming to add elevator/flaps/ail depending on the aircraft's tendencies. But those are released back to neutral after completion. I have added tabs at the wing tip (right wing!), perpendicular to the airflow, to increase line tension. It works great. There is no effect from up or down elevator (Rudder causes a tendency to roll with up/down elevator)and the influence is much greater with less area. A warped wing on a combat ship can somewhat be fixed with a tab but it affects the overall performance of loops and line tension. But then, in combat we are not worried about perfect loops... I used to know a guy that said:
 " Build the wing and if it is not straight, throw it away and start over"

Raf