??The su-57 fighter (design code: i-21 / t-50) is a single, double stealth, multi-function heavy combat aircraft of the Russian air force. It is the fifth generation Russian fighter (known as the fourth generation fighter in western countries). Su-57 fighter [1] has a maximum takeoff weight of 35,000 kg, a supersonic cruise speed of 1450 km/h, a maximum speed of 2140-2600 km/h, a combat radius of 1200 km, a combat load of up to 6 tons, and four weapon pods built in. It has the characteristics of good stealth, short takeoff and landing distance, super maneuverability and supersonic cruise. The su-57 was developed by the Russian "PAK FA" program, formerly known as the t-50 fighter, and first flew on 29 January 2010. From 2010 to the fall of 2015, the t-50's five prototypes completed 700 test flights, many of which underwent long maintenance. It was officially named su-57 on August 11, 2017. Russia plans to replace the su-27 with this type of fighter to compete with the American f-22.completed