Type Two seat trainer
Engine 1 Walter Minor 4-I
Dimensions Length  7,85 m, height  ,  span 11,42 m , wing area 15,25 m2  ,
Weights Empty 480 kg, loaded  , max. take off weight 760 kg 
Performance Max.. speed  205 km/h, cruising speed  180 km/h, range 1600 km, endurance  , service ceiling 5000 m , climb
To consolidate the success Be.50 firm Benes-Mraz has developed an upgraded version of the aircraft - Be.51. The main difference between the new aircraft was closed cockpit. Light sport aircraft Be-51 was built shortly before the war (in 1937) and entered the disposal of private Air Club. In 1939, most of these aircraft was on the territory of Slovakia and was included in its Air Force. Total used 25 machines. Several Be-51 were also in the hands of the Germans and were sent to flight school, located in the former Czechoslovakia.
To consolidate the success of the Be.50, Benes-Mraz developed an upgraded version of the aircraft, the Be.51 . The main difference of the new aircraft was the closed cockpit. In addition, the Be.51 Beta Minor had a slightly reduced wing span.

The Be.51 light sports aircraft was built shortly before the start of the war (in October 1936, the first prototype flew into the air, and mass production began the following year) and was placed at the disposal of private aviation clubs. A total of 65 copies of the machine were produced.

In 1939, most of these aircraft were located on the territory of Slovakia and were included in its Air Force. A total of 25 planes were used.

The machine turned out to be successful, and after the annexation of Czechoslovakia, the German Luftwaffe used a large number of these aircraft for communication and training