Long before the Russian concern of Tupolev OKB was developing famous Soviet Cold War bombers, it tried its hand at fighter design in the I-4 (ANT-5) biplane fighter of 1928. The type became the first Soviet all-metal fighter and was produced in the hundreds during the inter-war period. A handful of variants greeted the service career of this oft-forgotten warplane. Design of the fighter is attributed to Pavel Sukhoi.
Apart from its all-metal design, the I-4 exhibited traditional physical qualities consistent with the inter-period. The single pilot sat in an open-air cockpit behind the upper wing assembly. The upper and lower components were joined to one another by V-type struts. The lower assembly was also shorter in span making the biplane wing arrangement "sesquiplane". The undercarriage, wheeled at the two main legs under center mass, with a skid added under the tail for ground running. The tail unit was conventional with a single fin and low-set horizontal planes.
Engineers elected for the French Gnome-Rhone "Jupiter" 9-cylinder air-cooled radial piston engine of 420 horsepower and this was installed in the nose section. The engine drove a two-bladed propeller which held a large-diameter spinner at its center for aerodynamic efficiency.
Proposed armament had become 2 x 7.62mm machine guns synchronized to fire through the spinning propeller blades. Provision was added later during testing for rockets to be carried along the upper wing - increasing the fighter's attack value.
A first-flight (in prototype form as the "ANT-5") was recorded during August of 1927. This led to some revisions in the design including a new cowling and reworked tail unit. The ANT-5 then entered service as the "I-4".
Performance-wise, the I-4 netted a maximum speed of 160 miles per hour, a range out to 525 miles and a service ceiling up to 25,100 feet. Rate-of-climb was 1,820 feet-per-minute. Empty weight was 2,155lb with a Maximum Take-Off Weight (MTOW) of 3,155lb.
A revised first-series model appeared with the Mikulin M-22 engine (a license-built copy of the Gnome-Rhone "Jupiter" 9ASB) of 460-480 horsepower. The "I-4Z" then followed and this version introduced smaller lower wings. Having the lower wings completely removed - therefore becoming a true monoplane - the aircraft was revised in the "I-4bis" developmental form. The "I-4P" became a converted floatplane derivative.
A total of 369 I-4 fighters were completed into 1934 and the last of the lot was retired from frontline commitments back in 1933 - though the I-4 went on to serve for a time longer as an instructional vehicle. The I-4 series was also briefly trialed as a "parasite fighter" in experiments of the 1930s (that also included the firing of the 76mm Kurchevski recoilless gun from the aircraft), coupled to the new Tupolev TB-1/TB-3 bomber series mothership (detailed elsewhere on this site).
Production 369 Units
Tupolev OKB - Soviet Union
23.79 ft (7.25 m)
37.47 ft (11.42 m)
9.25 ft (2.82 m)
2,161 lb (980 kg)
3,153 lb (1,430 kg)
(Showcased weight values pertain to the Tupolev I-4 production model)
1 x Mikulin M-22 (Bristol Jupiter) air-cooled radial piston engine developing 460 horsepower and driving a two-bladed propeller at the nose.
160 mph (257 kph; 139 kts)
25,115 feet (7,655 m; 4.76 miles)
522 miles (840 km; 454 nm)
1,820 ft/min (555 m/min)
(Showcased performance values pertain to the Tupolev I-4 production model; Compare this aircraft entry against any other in our database)
2 x 7.62mm machine guns fitted over the nose and synchronized to fire through the spinning propeller blades.
Rockets fitted on rails at the upper wing assembly.
(Showcased armament details pertain to the Tupolev I-4 production model)
I-4 - Base Series Designation; initial production model.
ANT 5 - Developmental designation.
I-4Z - Reduced span lower wing element.
I-4bis - Monoplane-winged form (sans lower wing span).
I-4P - Floatplane/seaplane derivative.
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
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