I-Z

By the beginning of the 30s, the survivability of aircraft increased significantly - rifle-caliber weapons could not lead to guaranteed shooting down, even after a significant number of hits. These led to the idea of ​​installing dynamo-jet cannons (DRP) on a fighter designed by engineer Leonid Vasilievich Kurchevsky. In the summer of 1930, D.P. Grigorovich was given the task of designing a fighter under the “Z” mark (according to the plan of the Central Design Bureau - No. 7) armed with two 76.2 mm caliber AIC-4s. Design and construction was carried out in isolation from other projects.

The first copy was released in the summer of 1931. The tests were carried out by B. L. Buchholz and Yu. I. Piontkovsky . The second experimental I-Z bis was released in 1932. The engines were Jupiter VI. The wing structure is made of stainless steel ("Enerzh-6"), covered with canvas. Improvements to both the aircraft and the weapons went through as tests. A number of structural and operational defects were identified - the main one being that the design of the fighter could withstand no more than 200-300 rounds of cannons, after which it required repair. Due to the non-retractable chassis and the external suspension of the guns, the speed was only 259 km / h. The guns themselves were being refined all the time. Despite this, the fighter was launched into the series.

In 1933, a series of 21 cars was produced at Moscow factories. Armament - 2 agribusiness with wing cartridges for 6 shells (+1) in the barrel. In the series, the engine was put M-22 in 480 liters. with. After which the production was transferred to Kharkov where another 50 copies were built. Serial models differed from the experimental ones on the Townend ring on the engine and the wooden wing structure.

The aircraft layout is a strut low wing, in which the front half of the fuselage was taken unchanged from the I-5. The tail part was a duralumin monocoque of oval cross-section with a large vertical plumage and a very high located strut horizontal plumage, also duralumin. The rudder was with linen, then duralumin lining. All plumage was made particularly durable as well as the tail of the fuselage. The wing was supported by steel struts of a drop-shaped cross section with counterbows. Gottingen-436 wing profile. The ends of the wing in the form of a semicircle. Chassis - non-retractable on N-shaped struts, the front strut had rubber plate shock absorption.

During various tests, most of the serial "ZET" brought to a non-flying state. Although the speeds during firing from the DRP were minimal, pieces of planes, ailerons, and fuselage skin flew away from the planes. Aerodynamic characteristics of the fighter were also far from perfect. At the beginning of 1936 only a few instances remained in service. By that time, work on the DRP had practically been curtailed, and the use of these fighters was no longer relevant. In 1934. I-Z was used in the Link project - both in the suspended version it was docked and undocked in the air - but things did not go further than experiments. Already in 1936 he was replaced by a more advanced IP-1 .

•   the USSR

The given characteristics correspond to the I-Zet modification.

Data Source: Andersson, 1994; Shavrov, 1985

Specifications

• Crew : 1
• Length : 7.65 m
• Wing span : 11.5 m
• Height :
• Wing Area: 19.5 m²
• Wing Profile : Göttingen-436
• Empty weight: 1180 kg
• Normal take-off weight: 1648 kg
• The mass of fuel in internal tanks: 180 kg
• Power plant : 1 × air cooling M-22
• Engine power: 1 × 480 l. with. (1 × 353 kW)

Flight characteristics

• Maximum speed: 259 km / h (near the ground)
• Landing speed: 100 km / h
• Practical range: 600 km
• Practical ceiling : 7000 m
• Climb time: 5000 m in 14 min
• Flight Duration: 2.5 hours
• Bend Time: 17 s
• Wing load: 84.0 kg / m²
• Dead weight: 216 W / kg
• Takeoff run: 110 m
• Mileage: 180 m

Armament

• Rifle Cannon:
  • 1 × 7.62 mm machine gun PV-1
  • 2 × 76.2 mm APK-4 under the wing

• Maslov M. The most secret fighter (Russian) // Aviation and Time. - Kiev, 1998. - No. 5 (31) . - S. 4-13 .
• Shavrov, V. B. The history of aircraft designs in the USSR until 1938 . - 3rd. - M .: Mechanical Engineering, 1985 .-- 752 p.
• Andersson, Lennart. Soviet Aircraft and Aviation 1917-1941. - London, UK: Putnam, 1994 .-- S. 134-135. - 360 p. - ISBN 0-85177-859-3 .

• The history of the introduction of I-Z in a series at the Kharkov aircraft factory
• I-Z page on airwar.ru