Kh-31A Missile on a Sukhoi-30MKI

A Kh-31 missile being loaded on a Sukhoi-30 MKI of No.20 Squadron. The most interesting component of the Kh-31P is its dual propulsion system designed by the "Soyuz" Design Bureau in Turayevo near Moscow (note: there are several "Soyuz" engineering groups in Russia). First the missile is accelerated by its solid-fuel rocket engine to a speed of Mach 1.8, then the engine is discarded and the interior of the missile is converted into the combustion chamber of the missile's jet engine. The latter accelerates the missile to a speed of almost Mach 4.5, while four air intake holes on the sides of the missile body open up. (FAS.org)