World Models P-51D Mustang “EP” with the Hitec HS-85BB servo for the mechanical Retracts. This servo delivers a significant increase of Torque over the initial use of the HS-81MG. As a matter of fact, 6 oz.-in. additional Torque over the HS-81MG and thereby HS-85BB delivers 42oz.-in. at the lowest Voltage setting.