HOW does a cub take off in 10 feet ?

With about a 35kt headwind.

so they just hit full up elevator and go into a strong wind? whats the weight factor , they obviously cant do this loaded down.?

You're probably looking at the Valdez competition. Extremely lightweight, high horsepower and usually 20kts of wind down the runway. I can get mine off in around 50-60ft lightly loaded in a good wind. I have an O-320 putting out about 185hp. Don