In my schoolyard scale electric J-3 Cub plans it states "Contour sand the leading edge using the contour gauge provided. If left with sharp edge wing will stall."

A] I have a simple, if not ignorant, question: What is 'wing stall'?

B] Also I made the mistake of gluing the left panel wing tip flush with the tip rib bottom (flat on the building board) instead of off-center with the rib and centered with the leading edge. I filled the gaps nicely at the leading and trailing edge with scrap balsa but would like to know: I know I will have to do the same with the right wing panel but . . . will the slight displacement of the tips cause any significant difference in the flight or the tip's airfoil characteristics?

From Wikipedia

As the quote says, as stall is when the wing quits producing lift.

Ken

Wing stall simply means that the air flow over/under the wing is no longer providing the neccisary lift to keep the plane flying. For some reason (ask the aero dynamics guys) a sharp leading edge stalls at a higher speed than a more blunt LE. As far as your wing tips go. I'm not exactly sure what you mean but it would be hard to make it unflyable. Can you upload a picture?

Working on pics now.

Here they are. Photos 1, 2 & 3 is how I glued'em on. Photos 4 & 5 are how it was supposed to be done. The plans did not show it very closely and by the time I looked more closely at it they were already glued (medium CA)

Yes it will still fly just fine... My guess is that it's a little scale detail they added to the kit that only has a semi-scale wing anyway. The only reason anyone would know you goofed it would be because you told them

Ditto, but let me just take this opportunity to say, "READ before doing"

It's way too easy to look at a picture and glance at the instructions and THINK you know what to do next. This was a mistake that won't hurt anything, but the next mistake could mean ripping everything apart and re-doing it

What is wing stall- hmmmmmmmmmm - expensive?

You can see what wing stall is all about if you go over to Van's Aircraft web and click on the RV-12 stall/spin testing video's half way down the page. They have the wing and fuselage tuffed so that you can see how a stall develops. Notice the angle of the horizon in the background as the pilot slows down the aircraft for an unaccelerated stall.

http://www.vansaircraft.com/

But can be cheeper if high enough!!!!

Those are really cool videos. The sails of sailboats usually have tufts on them to warn the skipper that his sail is in a stall. (slow sailing) These tufts are usually called "tell tails" and if they are not streaming straight back, the sail is over trimmed.