This engine was a design from the Righter Aircraft Company to power a small, radio operated target drone used by both the US Navy and US Army for target practice by ship, airborne and ground based anti-aircraft gunners.
Righter’s original engine was a single prop engine at 6 HP but the torque threw the small plane “off balance”. Later engines had two counter rotating props to offset the torque of the single propeller and added 2 more horsepower. The counter rotating gearbox came from an earlier design and was adopted without compensation on all later 2-GS-17’s. The small airplane was launched from an inclined rail into the air and then radio controlled until it was shot down or ran out of gas. A parachute was added to the aircraft for recovery.
By the time the contracts were awarded to produce the aircraft, real airplanes (full-sized fighters and bombers) went much faster than these drones. At the end of the war, most of these plane and engine combinations were found in warehouses to be sold as surplus to radio control enthusiasts.
When Righter could not produce enough engines for the military, other companies were also given contracts using the same design. The engine on display was manufactured by the Herkimer Tool and Manufacturing Corp, in Herkimer, NY.