i was reading about the hangar 9 ultra stick 40 and it said it had quad flaps?
what are quad flaps? how do they work? do i need another servo?

Quad flaps are the name given to separate flaps that can work like ailerons and ailerons that can also work like flaps, IF you have a computer radio that will handle two flap servos and two aileron servos on separate channels and all the mixes involved. You should preferably be bored flying hot four channel airplanes before you want to tackle one of these. You could possibly build an Ultra Stick for four channels and add the flaps when and if you get the big radio with all the transmitter doo-dads. The US is a nice flying sport plane with or without the flaps, but the 40 size builds nose-heavy, not a desirable characteristic...JIM