The Yakovlev Yak-6 was a twin-engined utility aircraft developed and constructed by the Yakovlev design bureau during World War II.
The aircraft was designed to serve as a short-range light night bomber and a light transport, supplementing smaller single-engined aircraft such as the Polikarpov U-2.
The design brief called for a simple-to-build and operate aircraft, and the design and construction process was expedited, resulting in the first prototype Yak-6 taking flight in June 1942.
The aircraft passed its state acceptance tests in September of the same year and was swiftly approved for production.
The Yak-6 was a cantilever low-wing monoplane constructed entirely of wood with fabric covering.
It featured a retractable tailwheel undercarriage, with the main wheels retracting rearwards into the engine nacelles.
The horizontal tail was braced, and the aircraft was powered by two 140 hp Shvetsov M-11F radial engines driving two-bladed wooden propellers.
The engine installation was based on Yakovlev’s UT-2 primary training aircraft.
To conserve scarce resources, the aircraft’s fuel tanks were constructed of chemical-impregnated plywood rather than metal or rubber.
Many Yak-6s were equipped with fixed landing gear.
The Yak-6 was produced in two versions.
The first version served as a transport and utility aircraft for the supply of partisans, transport of the wounded, and for liaison and courier services.
It could accommodate two crew members side-by-side in an enclosed cockpit and had the capacity to carry four passengers or 500 kg (1,100 lb) of cargo.
The second version was a light night bomber, capable of carrying up to 500 kg of bombs on racks under the wing centre sections and equipped with a single ShKAS machine gun in a dorsal mounting for defensive purposes.
A total of 381 Yak-6s were produced, with production ending in 1943.
A few examples of an improved version of the Yak-6 with swept outer wings were flown, and the modified version was sometimes referred to as the Yak-6M.
The Yak-6M ultimately led to the development of the larger Yak-8, which took flight in early 1944.
Military History
The Yak-6 aircraft played a significant role in the Great Patriotic War, serving as both a transport and a bomber on the front lines.
Despite its popularity among crews, the aircraft’s susceptibility to entering a spin if overloaded or mishandled led to its production being discontinued in 1943 in favor of the Shcherbakov Shche-2, which shared a similar power source.
By 1944, the majority of operational units within the VVS had incorporated the Yak-6 as a utility aircraft.
During the Battle for Berlin, the Yak-6 was equipped with rocket launchers beneath its wings, capable of carrying ten 82-mm RS-82 missiles for ground target engagement.
Following the conclusion of the Second World War, some Yak-6s were provided to allied forces, while the Soviet military continued to utilize the aircraft on a large scale until 1950.
Variants
Yak-6
Twin-engined light utility transport aircraft.
NBB
Short-range night bomber aircraft.
Yak-6M
Improved version of the Yak-6.
Yak-8
The Yak-8 was an enhanced iteration of the Yakovlev Yak-6, featuring a slightly enlarged size while retaining the mixed construction and general layout of its predecessor.
The forward and central fuselage sections of the aircraft were constructed using a wooden semi-monocoque design, which was covered with a 2 mm (0.079 in) layer of plywood both inside and outside.
In contrast, the rear fuselage was made from a tubular steel framework that was covered with fabric.
The aircraft’s two-spar wooden wing was produced in a single piece and featured fabric-covered ailerons.
The Yak-8’s main undercarriage was retractable and retracted rearwards into the rear of the engine nacelles, while the castoring tailwheel was non-retractable.
The aircraft was originally intended to be powered by two 190-horsepower (140 kW) Kossov M-12 engines, but due to their unavailability, the 145-horsepower (108 kW) Shvetsov M-11FM was used instead.
As a dedicated transport, the Yak-8’s fuselage was deeper than that of the Yak-6, providing more headroom for passengers.
As a result, the Yak-8 could accommodate six passengers, compared to the four of its predecessor.
The Yak-8 underwent two prototype iterations, with the first taking flight in early 1944.
The second prototype was approximately 250 kg (550 lb) lighter than the first and successfully passed its State acceptance tests.
Despite being recommended for production, the Yak-8 was never ordered, likely due to the Soviet Union’s shift towards all-metal aircraft.
Yak 16-II
The Yak-16-II military transport variant was distinct from the passenger version due to several modifications.
It was equipped with a UTK-1 ball turret that housed a 12.7 mm (0.50 in) Berezin UBT machine gun, positioned directly behind the flight deck.
Additionally, the cargo cabin floor was reinforced, the vertical tail was slightly larger, and the fuselage was slightly longer.
The aircraft utilized three-bladed V-511 feathering propellers with scimitar-shaped blades.
It had the capacity to transport seven paratroopers, ten fully equipped troops, or six stretcher cases and a medical attendant.
The aircraft also featured a large clamshell door on the left side of the fuselage to facilitate cargo loading, which included a smaller, inward-opening door set into its forward half.
Furthermore, it could accommodate up to three TsDMMM-120 supply containers on racks underneath the wing centre section and was equipped with a glider tow hook.
The Yak-16-II successfully completed its manufacturer’s trials in April 1948 and subsequently underwent State acceptance trials.
These trials revealed several deficiencies, prompting the need for an increase in the horizontal tail area and the installation of de-icing equipment on the leading edges of the wings and tail.
Following these modifications, the aircraft was resubmitted for another round of State acceptance trials, which ultimately approved it for production.
However, despite this approval, the Yak-16-II was not chosen for production due to the belief that the Antonov An-2 was more versatile in both roles.
In an attempt to generate export sales in Eastern Europe, some efforts were made, but no interest was shown as the aircraft was not in service with Aeroflot.
The prototypes of the Yak-16-II were utilized for a period of time by the Yakovlev OKB and Factory No. 464, the entities responsible for their construction.
Specifications
Crew
Two
Capacity
Four passengers
Length
10.35 m (33 ft 11 in)
Wingspan
14.0 m (45 ft 11 in)
Wing area
29.6 m2 (319 sq ft)
Airfoil
Clark-YH
Empty weight
1,415 kg (3,120 lb)
Gross weight
2,300 kg (5,071 lb)
Powerplant
2 × Shvetsov M-11F 5-cylinder radial engines,
100 kW (140 hp) each
Performance
Maximum speed
187 km/h (116 mph, 101 kn)
Range
900 km (560 mi, 490 nmi)
Service ceiling
3,380 m (11,090 ft)
Time to altitude
5.4 min to 1,000 m (3,300 ft)
Armament
Guns
1 × ShKAS machine gun in dorsal position
Rockets
provision for 10 × RS 82 rockets
Bombs
Up to 500 kg (1,102 lb) bombs.
Sources
Yakovlev Aircraft Since 1924 – Bill Gunston & Yefim Gordon. OKB Yakovlev, A History of The Design Bureau and Its Aircraft-Yefim Gordon, Dmitriy Komissarov & Sergey Komissarov. Soviet Aircrafts Illustrated-A.S.Yakovlev.
