Here it's;
Another fighter, included in the pilot construction plan for 1930-1933, received the designation
I-9. Polikarpov carried out his sketches and initial calculations in the summer of 1929. The aircraft was defined as high-speed, therefore it was made according to the monoplane scheme.
The project was discussed from November 1929, so work on the I-9 was continued by S.A. Kocherigin. Spring 1930
The Air Force Directorate has prepared tactical and technical requirements for a single-seat fighter I-9 with an engine
M-32 with 600 hp The following characteristics were required:
Speed max. at an altitude of 5000 m 330-350 km/h
Climb time 5000 m 5-7 min
Practical ceiling 8000-10 000 m
Landing speed 95 km/h
Armament - two machine guns PV-1 plus two more PV-1 in overload or a gun of 20-30 mm caliber. Bomb load - 80-100 kg. Additional requirements were: the installation of a Stroganov photo-machine gun and the possibility of a straight flight with an abandoned control stick. "An aircraft with a payload of 221 kg with a full supply of fuel must provide a flight range of 700-800 km at a combat altitude of 5000 m."
The possibility of obtaining the M-32 engine at the right time was regarded as unlikely, therefore, on March 16, 1930, the Scientific Committee of the Air Force Directorate sent to the plant
No. 25 technical requirements for the Curtiss "Conqueror" engine. Next, an approximate aerodynamic calculation of the I-9 was prepared, according to which the following flight data were assumed:
Maximum ground speed 275.4 km/h
Maximum speed at an altitude of 3000 m 264.7 km / h
Maximum speed at an altitude of 5000 m 261 km / h
Climb time 3000 m 6.4 min
Climb time 5000 m 14.3 min
Flight range 1030 km
Practical ceiling 7580 m
The document was signed by the director of plant No. 25 Gorshkov, assistant director for the technical part of Zonshine, head of the settlement part Yarovitsky. Judging by subsequent events, the layout of the aircraft and the possible power plant continued to be uncertain. On July 1, 1930, a meeting of the mock-up commission for the I-9 in the biplane version with the M-19 engine was held. Design work
continued until the middle of summer 1930. During this period, Kocherigin was the chief designer of aircraft plant No. 25, Sutugin and
Yatsenko. On the appointment of the I-9 fighter, it was said: “Offensive air combat with all types of aircraft and aeronautic vehicles both at the front and in their own air defense rear ... In exceptional cases -
ground assault and air reconnaissance. In the fall of 1930, the I-9 fighter project was excluded
from the pilot plan. This is the story of fighters designed by N.N. Polikarpov period of the 1920s
years has ended.