what I found with my NEXTAR was that it needed a long T.O. run to get up to speed and airborne.
getting in the air without any airspeed will end up being trouble,the NEXTAR is a pretty forgiving plane but even it will tip stall if its going too slow under power.
the 46 is not a over powering engine for the size of plane the NEXTAR is.
larger wheels is a good idea trying to force this plane in the air will just lead to a crash because of lack of flying speed.