The aircraft was designed by Ryszard Bartel in the Samolot factory in Poznań, as a trainer-fighter plane. A mixed construction biplane. Steel framed fuselage, rectangular in cross-section, canvas covered (engine and upper sections - aluminum covered). Rectangular two-spar wings with rounded ends, plywood and canvas covered. Upper wing span: 7.36 m, lower wing span: 8.10 m. Lower and upper wing halves were interchangeable. Single pilot, sitting in open cockpit, with a windshield. The V8 engine Hispano-Suiza 8Be was modified to lower power output (from 220 hp to 180 hp). Radiator below the fuselage. Fixed landing gear, with a rear skid.
The BM-6 prototype, designated BM-6a, was flown on 8 April 1930 in Poznań. Its advantage was an easy construction and maintenance, according to Bartel's design philosophy. A distinguishing feature of all Bartels was an upper wing of a shorter span, because lower and upper wing halves were interchangeable (i.e. the lower wingspan included the fuselage width). It first introduced a mixed construction to Bartel's designs.
After trials, the prototype was modified in July 1930. The prototype was later redesignated BM.6a/II after it was substantially modified. It offered quite good flight characteristics and was capable of aerobatic flight. It was demonstrated in a fighter-plane competition in Bucharest in 1930, along with the similar PZL P.1.
The second prototype BM-6b, with a Wright Whirlwind 220 hp radial engine, was ordered, but work upon it ceased with closure of the Samolot factory in mid-1930. The PWS works, which inherited many of Samolot's projects, did not continue the project, for it had its own similar design, the PWS-11.
After state trials in 1931, the prototype was used in an advanced training school in Grudziądz, then in an aviation training center in Dęblin.
Engine: 1 × Hispano-Suiza 8Be (modified), 180 hp
Propeller: Two-blade wooden fixed pitch
Wingspan: 8.10 m
Wing area: 17.6 m²
Length: 6.30 m
Height: 2.76 m
Empty weight: 697 kg
Loaded weight: 985 kg
Fuel capacity (fuselage): 168 lt
Useful load: 288 kg
Wing loading: 56 kg/m²
Maximum speed: 192 km/h
Cruise speed: 165 km/h
Stall speed: 85 km/h
Range: 550 km
Service ceiling: 3,800 m
Rate of climb: 4 m/s
Armament: One synchronised 7.7 mm Vickers machine gun in fuselage