Abstract: An aircraft starter motor assembly for starting an aircraft engine is provided, and includes a DC motor, a planetary gearset, a ring gear clutch, and a starter adapter. The sun gear from the gearset is mounted to the motor output shaft. The ring gear clutch is used to rotationally fix the ring gear or to permit the ring gear to freewheel. The starter adapter including a worm, a spring, a worm gear, a wrap spring clutch and an output shaft. The worm drives the worm gear, which drives the output shaft via the wrap spring clutch. By using the ring gear clutch to let the ring gear freewheel, the wrap spring clutch can more easily unwind and disengage from the output shaft after the engine has been started.