If you are installing rudders on The F15 you dont need a great deal of power . Mine has been flying wit a JetCat 120 with JR 9021s driving the rudders. The servos are installed at the rear outboard of the engine bay and connect to the rudder arms with Sullivan cables. Results are perfect, and linkages are totally concealed. . Volz wing Maxx servos would also be perfect. My F15 wont do 175 even with a JetCat 120 installed, too much intake drag. JR 8411s great for stabs.