Help with skinning!!!

[The Ones]

i've a problem with skinning, because i'm a noob-skinner! when i want to skin a plane or something. first i apply the unwrap uvw modifier, like in the tutorial, and then i select the polygons from the wing i want to skin, than when i click on edit you see a streched wing (not the right sizes). so when i want to make a round in the skin, the round is streched on the wing. how do i get it just round?
i think it's somethiing with uv mapping. but like i said: i'm a noob skinner can someone help me plz thx