History Construction Tally

Bartel BM-4. 1927.

Kraków 2020-02-22

00127a Rozdział 1927-12-20

WWS „Samolot” Bartel BM-4


Bartel BM-4 is a school and sports plane, two-seater, biplane, wooden structure.

Bartel BM-4c. Photo of LAC
Bartel BM-4c. Photo of LAC

Bartel BM-4a with a La Rhone rotary engine. Photo of LAC
Bartel BM-4a with a La Rhone rotary engine. Photo of LAC

Wings with wooden structure, interchangeable between position at the top or bottom. The upper lobes are extended in relation to the lower ones. Between the wings there are N-shaped posts made of steel pipes that have been profiled. The crucifixion was made with steel wires. The wing fittings are metal. The wings have a Bartel 37 II a profile, with a profile thickness of 15.8%. The wings cover in the front is plywood, the rest is covered with canvas. The shuttlecocks are on all wings.

The BM-4 fuselage has a rectangular cross-section and slightly rounded from above. The front part of the fuselage is of circular cross-section, made of sheets that cover the engine. The engine bed is made of steel pipes and is attached to wooden stringers with the help of fittings. Behind the engine there is a fuel tank with a capacity of 82 liters and an oil tank with a capacity of 7.5 liters. The engine space from the hull is separated by a firewall made of aluminum sheet. Two-seater cabin. The controls are in both cabins. The onboard instruments are only in the first cabin. Some of them are on the pillars to be visible from the other cabin. The seats are adjustable and adapted for sitting and back parachutes.

Classic fitting made of steel pipes connected by welding. The cover was made of canvas.

Classic chassis. Main landing gear wheels 0.70 m in diameter, mounted on a common axle. Shock absorbers made of rubber rings.

Engines on Bartel BM-4 planes.

Version BM-4a - "Le Rhone" rotary motor, 80 HP, 120 revolutions per minute. The engine weight is 115 kg. Fixed propeller, two blades, Szymański HT-2, made of wood, gluing method. The propeller diameter is 2.55 m.

Version BM-4b received a star engine, 7-cylinder, "Walter" with 85 hp.

Version BM-4c with engine engineer W. Zalewski "Avia WZ-7", 80 HP.

Version BM-4e also with the Polish engine of engineer F. Peter "Peterlot", with 85 HP.

Version BM-4f also with the Polish engine of Nowkuński engineer "G-594 Czarny Piotruś", with 100 HP. The aircraft was built in 1930 in PZL Warsaw.

Version BM-4g with Gipsy engine, 105 HP. The aircraft was built in 1931 in the LOT Polish Airlines workshop.

Version BM-4h with Walter-Junior engine, 100 HP. The aircraft was built in 1931, and produced serially at the PWS plant in Biała Podlaska.

Data T-T Bartel BM-4a

Span 10.17 m

Length 7.22 m

Height 2.89 m

Bearing area 25 m2

Curb weight 538 kg

Total weight 791 kg

Fuel weight 65 kg

Maximum ceiling of 3,750 m

Top speed 125 km / h

Landing speed 55 km / h

Climbing time 9 minutes 40 seconds on 1,000 m

Climbing time 23 minutes 20 seconds on 2,000 m

Written by Karol Placha Hetman