ORIGINAL: broke_n_bummin

On 3D and pattern planes and some sport planes, the engine has no downthrust and no latteral thrust. Those angles are built in on scale models and trainers to offset wing incidence and P factor. You add side thrust, and you'll fight with it to do a knife edge or flat spin. You add downthrust, and it won't hover easilly, and you'll have to keep up elevator to fly inverted.