Sukhoi Su-37 what would result in the Su-30MKI, which is a two-seat fighter design that incorporated the canards, N011M radar and thrust-vectoring technology that were present and evaluated on the Su-37. In addition, through tests of the Su-27M and the Su-37, engineers had determined that thrust vectoring could compensate for the loss of manoeuvrability brought about by the removal of canards, the design of which imposed a weight penalty on the airframe. The modernized Su-35, without canards, made its first flight in February 2008. Sukhoi Su-37 The Sukhoi Su-37 (-37; NATO reporting name: "Flanker-F") is a single-seat twin-engine aircraft designed by the
Sukhoi Su-15 the Su-15 was abruptly retired from the new Russian Air Force in 1993 to comply with the Treaty on Conventional Armed Forces in Europe. Most were hastily scrapped in favour of more advanced interceptors, including the Su-27 and MiG-31, but some are in reserve storage for emergency use. In Ukraine, the last Su-15s (at Kramatorsk and Belbek) were withdrawn from use in 1996. Some Western reports indicate that the Su-15TM was also designated Su-21 and the Su-15UM Su-21U. These reports are apparently incorrect. Designation Su-21 was reserved for Su-17M4 but never used. Sukhoi Su-15 The Sukhoi Su-15 (NATO reporting name: