I'm building the GP Stuka but it's my first plane with flaps. Should I use them with a switch or on a knob? (I have a Futaba FF9)
I heard I probably won't have to use the flaps because the plane looses speed quite fast?

I have at home an OS61FX and an OS91FX and would like to know which to use on the Stuka. According to GP instructions, I should mount the OS61 but I think the extra power of the 91 is always useful.