The German V-2 was the world's first ballistic missile In order to control the roll on the vehicle, special trim motors such as this one were attached to the air vanes on fins I and III, whereas the air vanes on fins II and IV were mechanically linked by a sprocket drive to the servomotors for the jet vanes on those fins. When the yaw and roll commands on the jet and air vanes for fins II and IV were out of synchronization, the missile's control system adjusted the roll trim on the other two air vanes to remove any unwanted rolling of the missile.
This motor was a gift of Dr. Helmut Hoelzer, a guidance specialist at Peenemuende who was also a pioneer in computing there. He came to the United States as a member of Wernher von Braun's group of rocket engineers.
Gift of Dr. Helmut Hoelzer