In 1924, a program was initiated to construct experimental aircraft, which involved the development of five new aircraft with different purposes.
This program was officially approved on January 24, 1925, and one of the aircraft included in the program was equipped with a 185-hp BMW III engine.
This particular aircraft was designed to serve as a training aircraft, commonly referred to as the school aircraft, while also being suitable for initial training purposes.
The project was led by N.N. Polikarpov, and the aircraft was designated as 2UB III, indicating its two-seater configuration, training role, and the BMW III engine.
The design and construction of the 2UB III began in the spring of 1925, and it was brought to the airfield for testing on February 20, 1926.
The first flight of the aircraft took place on March 14, 1926, with V.N. Filippov as the pilot, who reported satisfactory flight quality of the aircraft.
The 2UB III was a conventional biplane with a seating capacity for two individuals.
It was constructed using wood and had canvas covering on its wings and tail surfaces.
To meet the requirements of UVVS (the Main Directorate of the Air Fleet), the aircraft featured a rigid strut made of profiled steel pipe to support the fender box.
The steel chassis pipes were equipped with rubber harness shock absorption.
The engine, which had a windshield radiator, was fully enclosed by a duralumin hood.
The surface of the hood had a longitudinal corrugation to provide additional rigidity.
The air propeller was covered by a fairing.
In September 1926, the 2UB III was transferred to the NLA (Scientific Experimental Aerodrome) of the Air Force, which served as the prototype for the Air Force Research Institute.
The aircraft underwent further testing until February 1927, during which it demonstrated good flight qualities.
As a result, an order was placed for the construction of ten additional aircraft, designated as P-1 (transitional) in the Air Force.
These aircraft were intended to be used not for initial training, but as transitional aircraft for pilots transitioning to more complex military aircraft.
Even before the completion of the tests in November 1926, an order was issued to arm the P-1 aircraft with a forward synchronous machine gun “Vickers” and a rearward “Lewis” machine gun on a turret. Sources King of Fighters – Nikolay Polikarpov and his Aircraft Designs – Vol 1 & 2. The History of Soviet Aircraft from 1918-Vaclav Nemecek. The Osprey Encyclopedia of Russian Aircraft 1875–1995-B Gunston. Polikarpovs Biplane Fighters-Yefim Gordon & Keith Dexter.
