The Polikarpov I-1 was the first indigenous
Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
monoplane
A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
fighter. It had to be redesigned after the crash of the first prototype, and was eventually ordered into production in small numbers, but it was never accepted for service with the
Soviet Air Forces
The Soviet Air Forces ( rus, Военно-воздушные силы, r=Voyenno-vozdushnyye sily, VVS; literally "Military Air Forces") were one of the air forces of the Soviet Union. The other was the Soviet Air Defence Forces. The Air Forces ...
.
Development
The I-1 (I = ''Istrebitel'' or fighter) was a single-seat, low-wing, wooden aircraft. The first prototype, known as the IL-400, was designed around the
Liberty L-12
The Liberty L-12 is an American water-cooled 45° V-12 aircraft engine displacing and making designed for a high power-to-weight ratio and ease of mass production. It saw wide use in aero applications, and, once marinized Marinisation (also m ...
piston engine. It used the
radiator
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics.
A radiator is always a ...
and
propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...
of the
Airco DH.9A
The Airco DH.9A was a British single-engined light bomber designed and first used shortly before the end of the First World War. It was a development of the unsuccessful Airco DH.9 bomber, featuring a strengthened structure and, crucially, repla ...
. The fuselage and wings were covered with a mix of plywood and fabric. The landing gear was braced by wires and the wingtips were protected by tubular curved skids. On the IL-400's
maiden flight
The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets.
The maiden flight of a new aircraft type is alwa ...
on 15 August 1923, the aircraft
stalled and crashed because its
center of gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weight function, weighted relative position (vector), position of the distributed mass sums to zero. Thi ...
was too far aft.
[Gunston, p. 286]
A second prototype, designated as the IL-400bis or IL-400B, was built, but it had to be redesigned to cure the center of gravity problem. A new, thinner, aluminum wing was designed and the
tailplane
A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplane ...
and
vertical stabilizer
A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...
were enlarged. The cockpit and engine were moved forward and the radiator was replaced by a Lamblin type. It made its first flight on 18 July 1924 and was cleared for production on 15 October as the I-1.
[Gunston, pp. 286–87]
Thirty-three aircraft were ordered, but the first production aircraft was still a prototype. The aluminum skin was replaced by plywood, the radiator was switched for a honeycomb type, and two synchronised 7.62 mm (0.3 in)
PV-1 machine gun
PV-1 (''Pulemet Vozdushny'', airborne machine gun) is a Soviet air-cooled version of the Russian M1910 Maxim for mounting on aircraft. It was designed between 1926 and 1927. The first prototypes were produced and accepted into service in 1928.Ш� ...
s were fitted. The production aircraft differed from one another and all were used for testing. This showed that the I-1 did not easily recover from a
spin
Spin or spinning most often refers to:
* Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning
* Spin, the rotation of an object around a central axis
* Spin (propaganda), an intentionally b ...
and
Mikhail Mikhaylovich Gromov was forced to make the first Soviet
parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...
jump during one such incident on 23 June 1927. The aircraft never entered operational service.
[
]
Operators
;
*Soviet Air Force
The Soviet Air Forces ( rus, Военно-воздушные силы, r=Voyenno-vozdushnyye sily, VVS; literally "Military Air Forces") were one of the air forces of the Soviet Union. The other was the Soviet Air Defence Forces. The Air Forces ...
Specifications
See also
Notes
References
*
*
{{Soviet fighter designations
1920s Soviet and Russian fighter aircraft
I-001
Aircraft first flown in 1923