Bartel BM-5
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| Bartel BM-5 | |
|---|---|
| Type | Trainer aircraft |
| Manufacturer | Samolot |
| Maiden flight | 27 July 1928 |
| Introduced | 1930 |
| Retired | 1939 |
| Primary user | Polish Air Force |
| Produced | 1929-1930 |
| Number built | 62 |
The Bartel BM-5 was a Polish biplane advanced trainer aircraft used from 1930 to 1939 by the Polish Air Force, manufactured in the Samolot factory in Poznań.
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[edit] 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 220 hp Austro-Daimler inline engine. The second prototype, flown on 15 April 1929, was designated BM-5b and was fitted with a 230 hp SPA-6A inline engine, then was refitted in August with a 320 hp 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 240 hp 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.
[edit] 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.
[edit] Operators
[edit] Specifications (BM-5d)
[edit] 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:
- BM-5a: Austro-Daimler 6-cylinder straight engine, water cooled, 220 hp nominal power
- BM-5b: SPA-6A 6-cylinder straight engine, water cooled, 230 hp take-off power, 220 hp nominal power
- BM-5c: Hispano-Suiza 8Fb 8-cylinder V-engine, water cooled, 320 hp take-off power, 300 hp nominal power
- BM-5d: Wright Whirlwind J-5 9-cylinder radial engine, 240 hp take-off power, 220 hp nominal power
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: 1× Wright Whirlwind J5 9-cylinder air-cooled radial engine, 179 kW (240 hp)
Performance
- Maximum speed: 172 km/h (93 knots, 107 mph)
- Cruise speed: 150 km/h (81 knots, 93 mph)
- Stall speed: 70 km/h (38 knots, 43 mph)
- Range: 450 km (243 nm, 280 miles)
- Service ceiling 4,000 m (13,100 ft)
- Rate of climb: 4 m/s (790 ft/s)
- Wing loading: 41.6 kg/m² (8.50 lb/ft²)
- Power/mass: 140 W/kg (0.085 hp/lb)
Armament None
[edit] References
- Andrzej Glass: "Polskie konstrukcje lotnicze 1893-1939" (Polish aviation constructions 1893-1939), WKiŁ, Warsaw 1977 (Polish language, no ISBN)
[edit] External links
- Photos and drawings at Ugolok Neba site (in Rusian)
[edit] See also
Related development Bartel BM-4
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