Yakovlev Yak-4

Jakowlew Jak-2 / Jak-4
Type:	light bomber and reconnaissance aircraft
Design country:	Soviet Union
Manufacturer:	OKB Yakovlev
First flight:	February 22, 1939 (AIR-22)
Production time:	1939-1940

The Jakowlew Jak-4 ( Russian Яковлев Як-4 , also: BB-22 , ББ-2) was a Soviet light bombing and reconnaissance aircraft of the Second World War .

development

Alexander Jakowlew developed the Jak-4 at the end of the 1930s as a fast photo reconnaissance aircraft AIR-22 . The first flight took place on February 22, 1939 with the pilot Julian Piontkowski. After the end of flight tests, it was decided to convert this type of aircraft into a light bomber. The changes, in particular the installation of a bomb bay and two machine guns, were carried out by the KB-70 and were completed on December 31, 1939. The prototype of the Jak-2 received two V12 engines M-103 and flew for the first time on February 22, 1940. However, the engine power turned out to be insufficient and so the Jak-2 was only built in a few copies. Instead, some changes have been made to this model; two more powerful M-105R engines were installed. This machine received the designation Jak-4 and was built from autumn 1940 to the end of 1941 in a number of about 100.

The original official designation BB-22 (Ближний бомбардировщик = Blischnij bombardirowstschik, close-bomb aircraft) was only used until the end of 1940 and applied to both the Jak-2 and the Jak-4.

When the attack on the Soviet Union began , the Yak-4 bomber squadrons suffered heavy losses, so that the remaining aircraft were only used as reconnaissance aircraft or liaison aircraft. The resulting gap was closed by the successful Petlyakov Pe-2 .

technical description

The Jak-4 was a two - seater low - wing aircraft in a mixed wood-metal construction. The fuselage frame was made of tubular steel in the rear and wood in the front. The bow of the fuselage was covered with sheet metal, the rest covered with fabric. The middle section of the fuselage contained the bomb bay for four 50 kg bombs, additional bombs could be carried on external suspensions under the wings. The structure was made entirely of wood and planked with plywood. The tail unit consisted of two rudder disks made of aluminum with fabric covering attached to the elevator. The main wheels with double tires drove backwards into the long engine nacelles; the wheels were half sunk. The tail wheel was also retractable. In winter the Jak-4 could be equipped with snow runners .

Military users

•  Soviet Union

Technical specifications

Jak-2

Three-sided view of the Jak-2

Parameter	Jak-2	Jak-4
crew	2 (pilot, observer / bombardier)
length	9.34 m	10.18 m
Wingspan	14.00 m
height	3.60 m	3.10 m
Wing area	29.40 m²
Empty mass	3,796 kg	4,000 kg
Takeoff mass	5,123 kg	maximum 6115 kg
Engines	two liquid-cooled 12-cylinder V-engines Klimow M-103	two liquid-cooled 12-cylinder V-engines Klimow M-105 R
power	706 kW (960 PS) each	809 kW (1,100 PS) each
Top speed	567 km / h at an altitude of 5,000 m	399 km / h near the ground, 533 km / h at an altitude of 5,050 m
Range	maximum 880 km	maximum 740 km
Service ceiling	10,800 m	9,700 m
Armament	a rigid 7.62 mm MG SchKAS in the front of the fuselage a movable 7.62 mm MG SchKAS firing backwards from 400 to a maximum of 800 kg bombs internally and externally

See also

• List of aircraft types

literature

• Wilfried Copenhagen : Soviet bomb planes . Transpress, Berlin 1989, ISBN 3-344-00391-7 .

Web links

Commons : Jakowlew Jak-4  - Collection of pictures, videos and audio files

Individual evidence

1. ^ Wilfried Bergholz: Russia's great aircraft manufacturer. Jakowlew, Mikojan / Gurewitsch, Suchoj . Aviatic, Oberhaching 2002, ISBN 3-925505-73-3 , p. 33 .