those planes run tale heavy from the get go.i moved my engine way out onto the rail to get it to balance and keep from adding any more weight.i don't know why the prop was hitting the ground unless you had small wheels on it i had 2 1/2 wheels.i run a 12/8 to 13/8 prop on mine and don't have any problems with prop hitting the ground.i cut lightning holes in my rudder and horizontal stabilizer to lighten up the tale some that worked pretty well.