The first pictures of the Sukhoi S-37 Berkut combat aircraft reveal a twin-engined aircraft of similar size to the Su-27 Flanker, but with an aerodynamic design optimised for agility at extremely high angles of attack.
Russian press reports say that the twin-engined aircraft is 22.6m long, with a 16.7m wingspan. Take-off weight is given as 24t.
It remains unclear whether the aircraft is powered by the Lyulka/ Saturn AL-31F used on the Su-27, or the Aviadvigatel D-30F6, which powers the Mikoyan MiG-31 Foxhound A. The S-37 will be fitted with thrust-vectoring nozzles later in the test programme.
The aircraft has large canards mounted on the intake sides just forward of the forward-swept wing. Unlike those on a model mistakenly revealed earlier , the S-37's vertical stabilisers are canted slightly out, not inward. The model aircraft also had an arrestor hook.
Also visible on the centre fuselage section appear to be two large auxiliary intake doors, the purpose of which is not known. The aircraft's starboard tail sting, slightly longer than the port one, may house a spin-recovery chute.
The horizontal stabilators are much smaller than those of the Su-27, and appear to have an angle of sweep of around 70¹. With the canards providing pitch control, the stabilators are almost certainly used only to provide trim, and for pitching the nose forward to recover from extremely high-angle-of-attack manoeuvres. The S-37 is thought to be the first Russian aircraft to have an all-composite wing.
Sukhoi showed the aircraft to senior officers from Russia's air- defence forces and naval aviation officers at the Zhukovski flight-test research centre outside Moscow in late October. No senior air force officials were present, which casts doubts on whether there is support for the S-37 from the air force. Sukhoi is pushing the aircraft as a candidate for the air force's fifth-generation fighter requirement, replacing MIG MAPO's moribund Article1.42. The forward-swept-wing design, however, may have had its origins as a technical-demonstrator project.
The nose and intake section appear similar to a previous design, also designated the S-37. This project was for a supersonic multi-role strike fighter to replace the Su-22 and Su-25.
The S-37 in flight and on rotation - beside the hallmark forward-swept wing, the leading-edge chines and large intakes are readily apparent
Clearly visible viewed from above are what appear to be centre-fuselage auxiliary air intakes, as well as the aircraft's sharply swept stabilators
Source: Flight International
