Bartel BM 6

The Bartel BM 6 was a Polish biplane trainer fighter aircraft of 1930. It did not advance beyond the prototype stage.

Bartel BM 6
Role Trainer aircraft
Manufacturer Samolot
First flight 8 April 1930
Status Prototype
Primary user Polish Air Force
Number built 1

Design and development

The aircraft was designed by Ryszard Bartel in the Samolot factory in Poznań, as a trainer-fighter plane. 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.

Operational history

After state trials in 1931, the prototype was used in an advanced training school in Grudziądz, then in an aviation training center in Dęblin.

Operators
 Poland

Description

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. Two-blade wooden propeller of fixed pitch. Fuel tank in fuselage: 168 l capacity.


Specifications (BM 6a)

Data from Polish Aircraft 1893–1939[1]

General characteristics

  • Crew: 1
  • Length: 6.35 m (20 ft 10 in)
  • Wingspan: 8.09 m (26 ft 7 in)
  • Height: 2.8 m (9 ft 2 in)
  • Wing area: 17.6 m2 (189 sq ft)
  • Empty weight: 697 kg (1,537 lb)
  • Gross weight: 985 kg (2,172 lb)
  • Fuel capacity: 170 l (45 US gal; 37 imp gal)
  • Powerplant: 1 × Hispano-Suiza 8Be V-8 water-cooled piston engine, 130 kW (180 hp)
  • Propellers: 2-bladed Heine fixed pitch propeller

Performance

  • Maximum speed: 194 km/h (121 mph, 105 kn) atsea level
  • Never exceed speed: 420 km/h (260 mph, 230 kn)
  • Service ceiling: 3,800 m (12,500 ft)
  • Time to altitude: 4 minutes 24 seconds to 1,000 m (3,300 ft); 18 minutes 57 seconds to 3,000 m (9,800 ft)
  • Wing loading: 56 kg/m2 (11 lb/sq ft)
  • Power/mass: 0.138 kW/kg (0.084 hp/lb)

Armament

See also

Aircraft of comparable role, configuration and era

References
  1. Cynk, Jerzy B. (1971). Polish Aircraft 1893–1939. London: Putnam. pp. 368-371. ISBN 978-0-370-00085-5.

Further reading
  • Glass, Andrzej (1977). Polskie konstrukcje lotnicze 1893–1939 (in Polish). Warsaw: WKiŁ.
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