Aleksandr Sergeyevich Yakovlev designed and constructed the Yakovlev AIR-3, a Soviet general aviation monoplane with seating for two individuals, during the 1920s.
Yakovlev, after successfully designing the AIR-1 and AIR-2, was admitted as a student at the Nikolai Zhukovsky Air Force Engineering Academy.
During his time there, he created the AIR-3, which shared similarities with the previous AIR-2 biplane but featured a strut-braced high parasol wing.
The AIR-3 was equipped with a 60 hp (45 kW) Walter NZ-60 radial piston engine.
It was also referred to as Pionerskaya Pravda, named after a young-communist newspaper that had gathered funds from its readership to support the aircraft’s construction.
Notably, on 6 September 1929, the AIR-3 accomplished two light aircraft world records by completing a non-stop flight of 1835 km between Mineralnye Vody and Moscow.
In 1930, the Yakovlev AIR-4 underwent a refinement process that resulted in several improvements.
These enhancements included the introduction of a new split-axle landing gear, wider cockpits with entrance doors, and additional fuel capacity.
Furthermore, one of the AIR-4 aircraft was modified in 1933 to become the Yakovlev AIR-4MK, which served as a testbed for nearly full-span split flaps.
To maximize the effectiveness of the flaps, floating wingtips were incorporated to provide roll control and allow for the release of as much trailing edge as possible.
Additionally, a military liaison variant known as the Yakovlev AIR-8 was manufactured in 1934.
This variant featured an 85 hp (63 kW) Siemens engine and constant chord wings with a larger surface area.
In 1935, Professor Sergei Grigorevich Kozlov, from the Nikolai Zhukovsky Air Force Engineering Academy, conducted a preliminary experiment utilizing a Polikarpov U-2 aircraft.
Following this, he proceeded to modify a Yakovlev AIR-4 aircraft, resulting in the creation of the Kozlov PS, also known as the Transparent aircraft.
The conventional fabric covering both the fuselage and wings was substituted with a transparent plastic material referred to as “Cellon” or “Rhodoid”.
Additionally, the previously opaque structure was coated with a white paint infused with aluminum powder.
Subsequent ground and airborne trials confirmed the validity of Kozlov’s theories while also providing the crew with exceptional visibility.
However, the film used to achieve transparency was found to lose its effectiveness due to the accumulation of dirt and the deteriorating effects of sunlight, thereby diminishing the desired “invisibility effect”.
Kozlov proposed the development of an invisible single-seat reconnaissance aircraft utilizing transparent plastic material.
However, concerns regarding the structural integrity of the material hindered further progress in this direction.
Consequently, additional research into transparent aircraft was commissioned from the experimental institute under the leadership of Pyotr I. Grokhovskii.
Nevertheless, no further aircraft employing Kozlov’s methods were constructed. Variants AIR-3 Two-seat monoplane with a 60 hp (45 kW) Walter NZ-60 radial piston engine developed from the Yakovlev AIR-2. Only one AIR-3 was built. AIR-4 The improved variant fitted with increased fuel capacity and modified landing gear. At least five AIR-4 aircraft were built. AIR-4MK (Mechanised wings) For research into high lift systems for approach control, a single AIR-4 was modified with full-span split flaps, with floating wingtips rotating around transverse axles for roll control. E-31 An alternative designation for the AIR-4MK taken from the registration. Kozlov PS Sergei G. Kozlov modified a lone AIR-4 aircraft to showcase his hypothesis on low-observable planes, effectively creating an early version of a stealth aircraft. The aircraft was coated with a transparent plastic sheeting and painted silver on the interior structure and opaque parts.
Initially, the PS was challenging to spot due to its low visibility, but the accumulation of dirt and the sheeting becoming opaque reduced the effect quickly. AIR-8 Military liaison variant with an 85 hp (63 kW) Siemens engine, fitted with a constant chord wing with greater area. One AIR-8 was built. Specifications AIR-3 Crew Two Length 11 m (36 ft 1 in) Wingspan 7.1 m (23 ft 3 in) Wing area 16.5 m2 (178 sq ft) Empty weight 392 kg (864 lb) Gross weight 587 kg (1,294 lb) Powerplant 1 × Walter NZ-60 radial piston engine, 45 kW (60 hp) Performance Maximum speed 146 km/h (91 mph, 79 kn) Range 1,835 km (1,144 mi, 994 nmi) Service ceiling 4,200 m (13,776 ft) 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. The History of Soviet Aircraft from 1918-Vaclav Nemecek. Soviet AF Fighter Colours 1941-45-Erik Pilaeskii. Soviet Combat Aircraft of the Second World War, Vol 1, Single Engined Fighters-Yefim Gordon and Dmitri Khazanov. Early Soviet Jet Fighters, The1940s and early 50s-Yefim Gordon. Soviet Secret Projects, Fighters Since 1945-Tony Buttler & Yefim Gordon. Soviet Secret Projects, Bombers Since 1945-Tony Buttler & Yefim Gordon. Soviet Aircraft of Today-Nico Sgariato. Modern Soviet Fighters-Mike Spick.
