Use of lightly armed I-16 Type 5,
6 and 10 against ground targets during
the Spanish Civil War clearly shown ineffectiveness of 7.62mm guns. More powerful weapon was needed to destroy armored
vehicles and protected targets.
At the same time experiments with I-16P and
TsKB-12P provided necessary experience in use of high-rate cannons on light fighters.
It did not took long time for N.N.Polikarpov to put new attack aircraft into mass
Two 20mm ShVAK cannons with 150 rounds each replaced the wing-mounted
pair of 7.62mm ShKAS. Ammo for the
ShVAK could consist of explosive or armour piercing shells - or mixture of both,
depending on mission objectives. Long barrels of new cannons with gas pressure cylinders were a distinctive feature of new I-16
Type 17 attacker.
To accommodate increased weight of the weapons, number of internal changes were introduced. Gross weight of the aircraft
compared with original I-16 Type 10 was increased by 84-90kg. This
did not affect the horizontal speed that much, but rate of climb turned to be much worser.
Type 17 was never exported. It was used in 1939 clashes with Japanese on
Mongolia-Manchuria border. When the Great Patriotic War broke out, I-16 Type 17 (and its cannon-armed successor
Type 27) performed well in the ground support role, strifing concentrations of
advancing troops and armored vehicles on many battle fronts, until much more effective
Il-2 became available in quantity. Then I-16 attackers were reassigned to minor
theaters of operation such as the Baltic and the Black Sea district.