The FLUGWAG Bremen ESS 641 was a 1970s German glider-towing monoplane designed and built by the Flugwissenschaftliche Arbeitsgemeinschaft Bremen research organisation.
[1] The ESS 641 is a low-wing cantilever monoplane with a fixed tail-wheel landing gear.
[1] Powered by a 180 hp (134 kW) Avco Lycoming O-360 flat-four piston engine.
[1] The pilot had an enclosed cockpit with a transparent canopy.
[1] Data from The Illustrated Encyclopedia of Aircraft[1]General characteristics Performance