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Bartel BM-5

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The Bartel BM-5 was a Polish biplane advanced trainer used from 1930 to 1939 by the Polish Air Force, manufactured in the Samolot factory in Poznań.

Design and development

The aircraft was designed by Ryszard Bartel in Samolot factory in Poznań, as an advanced trainer, transitory between primary trainers and bomber or reconnaissance aircraft. Bartel had worked since 1926 on his BM-3 advanced trainer design, the preliminary design for which won a military contest, but in the meantime he developed a quite successful primary trainer Bartel BM-4 and then decided to model the advanced trainer upon that plane, to obtain better durability. The result was the BM-5 design. The BM-5 prototype was built in 1928 and flown on 27 July that year in Poznań. It had good handling, high stability and spin resistance, which made it a suitable trainer for larger aircraft. 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 width of the fuselage).

The first prototype was designated BM-5a and was fitted with a Template:Convert Austro-Daimler inline engine. The second prototype, flown on 15 April 1929, was designated BM-5b and was fitted with a Template:Convert SPA-6A inline engine, then was refitted in August with a Template:Convert Hispano-Suiza 8Fb V-engine and redesignated BM-5c (it was meant to utilize engine stores from the Bristol F.2 Fighter). There were next built 20 aircraft of each type: BM-5a, BM-5b and BM-5c.

A disadvantage of most BM-5s were old and faulty engines. Apart from it, the BM-5a variant was heaviest and had worst performance. That is why one BM-5 was fitted in 1935 at the PZL works with a Template:Convert Wright Whirlwind J-5 radial engine, produced in Poland (in Polish Skoda Works, then Avia). This variant was designated the BM-5d and 20 of BM-5a and BM-5b were next converted to BM-5d.

Operational history

BM-5s were used in the Polish Air Force for training from 1930, in a central pilots' school in Dęblin. 5 BM-5c's were used in Naval Air Unit (MDLot) in Puck. Most were written off in the second half of 1930s and replaced with the PWS-26. Some survived until the German invasion of Poland in September 1939. None survived the war.

Operators

Template:POL

Specifications (BM-5d)

Description

Wooden construction biplane. Fuselage rectangular in cross-section, plywood covered (engine section - aluminum covered). Rectangular two-spar wings, plywood and canvas covered. Crew of two, sitting in tandem in open cockpits, with individual windshields and twin controls, instructor in rear cockpit. Fixed landing gear, with a rear skid. Engine in front, with a water radiator below fuselage nose (BM-4a,b,c). Two-blade wooden propeller. Fuel tanks in upper wings and fuselage, capacity: 235-270 l.

Engines used:


General characteristics

  • Crew: 2, student and instructor
  • Length: 7.6 m (24 ft 11 in)
  • Wingspan: 11.2 m (36 ft 9 in)
  • Height: 3.18 m (10 ft 5 in)
  • Wing area: 31 m² (334 ft²)
  • Empty weight: 900 kg (1,980 lb)
  • Loaded weight: 1,290 kg (2,838 lb)
  • Useful load: 390 kg (858 lb)
  • Powerplant:Wright Whirlwind J-5 9-cylinder air-cooled radial engine, 179 kW (240 hp)

Performance

Armament

None


References

  • Andrzej Glass: "Polskie konstrukcje lotnicze 1893-1939" (Polish aviation constructions 1893-1939), WKiŁ, Warsaw 1977 (Polish language, no ISBN)

External links


Template:Bartel aircraft

pl:Bartel BM-5

This article is licensed under the GNU Free Documentation License.
It uses material from the Wikipedia article "Bartel BM-5".