The Polikarpov I-1, the inaugural domestically produced monoplane fighter of the Soviet Union, underwent a series of modifications subsequent to the unfortunate crash of its initial prototype.
Despite being authorised for production in limited quantities, it regrettably failed to secure approval for active duty within the Soviet Air Forces.
The I-1, an aircraft with a single seat and low-wing configuration, was primarily constructed using wood.
Its initial model, referred to as the IL-400, was specifically designed to accommodate the 400-horsepower (300 kW) Liberty L-12 piston engine.
The IL-400 incorporated the radiator and propeller from the Airco DH.9A.
To ensure structural integrity, the fuselage and wings were covered with a combination of plywood and fabric.
The landing gear was reinforced with wires, while tubular, curved skids provided protection to the wingtips.
Unfortunately, during the inaugural flight of the IL-400 on the 15th of August 1923, the aircraft experienced a stall and subsequent crash due to an excessively rearward centre of gravity.
The IL-400bis or IL-400B, which served as the second prototype, underwent significant modifications to address the centre of gravity issue.
To rectify this problem, a new wing made of thinner aluminium was designed, and the tailplane and vertical stabiliser were enlarged.
Additionally, adjustments were made to the cockpit and engine placement, while the radiator was substituted with a Lamblin type.
On 18 July 1924, the modified prototype successfully completed its inaugural flight, and it received clearance for production on the 15th of October under the designation I-1.
Although an order was placed for thirty-three aircraft, the initial production model remained in the prototype stage.
Notable changes were made to the production aircraft, including the replacement of the aluminium skin with plywood and the substitution of the radiator with a honeycomb type.
Furthermore, two synchronised 7.62 mm (0.3 in) PV-1 machine guns were installed.
Each production aircraft exhibited variations from one another, and all were utilised for testing purposes.
These tests revealed that the I-1 had difficulty recovering from a spin, leading to an incident on 23rd of June 1927 where Mikhail Mikhaylovich Gromov was compelled to execute the first Soviet parachute jump.
Consequently, the aircraft never saw operational service. Specifications Crew 1 Length 8.3 m (27 ft 3.75 in) Wingspan 10.80 m (35 ft 5.25 in) Wing area 20 m2 (215 sq ft) Gross weight 1,510 kg (3,329 lb) Powerplant 1 × Liberty L-12 piston engine, 298 kW (400 hp) Performance Maximum speed 264 km/h (164 mph, 143 kn) Range 650 km (404 mi, 351 nmi) Service ceiling 6,750 m (22,150 ft) Armament 2 × synchronised 7.62 mm (0.3 in) PV-1 machine guns. Sources King of Fighters: Nikolay Polikarpov and His Aircraft Designs, Vol 1 & 2. The Osprey Encyclopaedia of Russian Aircraft 1875–1995-B Gunston. The History of Soviet Aircraft from 1918-Vaclav Nemecek.
