Yakovlev AIR-3

Yakovlev AIR-3

Company type	Aircraft
Industry	Aviation
Founded	1920s
Founder	Aleksandr Sergeyevich Yakovlev
Products	General aviation monoplanes
Parent	Yakovlev Design Bureau

The Yakovlev AIR-3 was a two-seat general aviation monoplane from the 1920s, developed and constructed in the Soviet Union under the guidance of Aleksandr Sergeyevich Yakovlev.

Development

After creating the earlier models Yakovlev AIR-1 and AIR-2, Yakovlev enrolled at the Zhukovsky Air Force Engineering Academy, also known as the Nikolai Zhukovsky Air Force Engineering Academy, where he designed the AIR-3. This aircraft featured a strut-supported high parasol wing, bearing resemblance to the preceding AIR-2 biplane. It was powered by a 60 horsepower (45 kW) Walter NZ-60 radial engine, and gained the nickname Pionerskaya Pravda, named after the young communist publication that funded its construction through reader contributions. On 6 September 1929, the AIR-3 completed a nonstop flight covering 1835 km from Mineralnye Vody to Moscow, setting two world records for light aircraft.

In 1930, improvements led to the Yakovlev AIR-4, which incorporated a redesigned split-axle landing gear, expanded cockpits equipped with access doors, and increased fuel capacity.

One of these AIR-4 units was adapted in 1933 into the Yakovlev AIR-4MK to evaluate nearly full-span split flaps. To maximize trailing edge flap area, floating wingtips were installed to manage roll control.

A military liaison version known as the Yakovlev AIR-8 emerged in 1934, featuring an 85 horsepower (63 kW) Siemens engine and wings with constant chord and larger surface area.

Kozlov PS

File:Kozlov PS.jpg

The Kozlov PS (transparent aircraft)

In 1935, following initial trials with a Polikarpov U-2, Professor Sergei Grigorevich Kozlov from the Nikolai Zhukovsky Air Force Engineering Academy adapted a Yakovlev AIR-4 to create the Kozlov PS (Prozrachnyy Samolyot — transparent airplane). The traditional fabric covering on the wings and fuselage was replaced by a clear plastic material known as ''Cellon'' or ''Rhodoid''. Additionally, the solid structural elements were coated with a white paint mixed with aluminum powder. Both ground and aerial evaluations validated Kozlov's concept, also providing exceptional visibility for the crew. However, despite early promising results, the transparency diminished over time due to dirt accumulation and sun exposure, which caused the plastic film to become opaque, reducing the aircraft's camouflage effectiveness.

Kozlov envisioned a single-seat reconnaissance plane constructed entirely with this transparent plastic material. Nonetheless, concerns regarding the material’s structural integrity prevented further development. Subsequent investigations into transparent aircraft were conducted by the experimental institute led by Pyotr I. Grokhovskii, but no additional aircraft employing Kozlov’s transparency techniques were produced.

AIR-3

A two-seat monoplane powered by a 60 hp (45 kW) Walter NZ-60 radial piston engine, developed as an evolution of the Yakovlev AIR-2. Only a single AIR-3 unit was manufactured.

AIR-4

An enhanced model featuring increased fuel capacity and redesigned landing gear. Production included at least five AIR-4 aircraft.

AIR-4MK

(MK – Mekhanizeerovannoye Krylo, meaning mechanized wings). One AIR-4 (registration CCCP-E-31) was modified for research on high-lift devices used in approach control. It incorporated full-span split flaps and floating wingtips that rotated around transverse axes to manage roll.

E-31

This designation corresponds to the AIR-4MK variant, derived from its registration number.

Kozlov PS

Sergei G. Kozlov converted a single AIR-4 to test his concept of low-visibility aviation, effectively creating an early form of stealth aircraft. The aircraft was covered with transparent plastic sheeting, while internal structures and opaque sections were painted silver. Initially, the plane was very difficult to detect; however, the effect rapidly declined as dirt accumulated and the plastic covering lost its transparency.

AIR-8

A military liaison version equipped with an 85 hp (63 kW) Siemens engine and featuring a constant chord wing with increased surface area. Only one AIR-8 was built.

External links

• Yakovlev AIR-3