Superb performance and
huge development potential of the Su-27 fighter gave birth to the family of successful aircraft - the Su-27UB, Su-30, Su-33, Su-35 and Su-37. The family was conceived by the three forces - Pavel
Sukhoi's idea of an integral, statically-unstable design, Mikhail Simonov's creative will, intuition and perception, and SibNIA's large experience of wind-testing. At first, the Su-27 project did
not go well. The first series of wind tests conducted in 1975 on a preliminary model highlighted a lot of shortcomings. The shape of the wing, location and geometry of the empennage and other
elements were met with a storm of criticism. Almost all components in the initial aerodynamic layout needed changing. SibNIA continued wind tests, trying various configurations of fuselage
extensions to the wing. Basing on the rich experience of the wind tests, Mikhail Simonov formed a new layout in 1976, introducing a principally new element, the adaptive deflection of the wing's
leading and rear edges. From its side, SibNIA looked carefully at the plane's aerodynamics performance in unstable, non-sustained flight regimes. Also conducted were numerous experiments and studies
on aerodynamic damping and finding areas of cinematic parameters where "anti-damping" occurred. A few "exotic" configurations were also tried, including ones with canards. As a
result the initial Su-27 turned into a radically-new highly-successful fighter. |