Su-T50 PAKFA aerodynamics analysis:
T-50’s airframe fuselage has nothing to do with Su-27’s design. Although people tend to confuse that it’s derived from T-10M’s airframe, but It’s completely a new design with smoother edge and parallel edge surface leadins to very low observable design and reduced radar cross-section. Although the ”official” RCS of T-50 is yet to be disclosed, but it can’t be more than 0.01sq.m even in ”worst case-scenario.”
2- LEADING EDGE ROOT EXTENSION (LERX):
The articulated LERX of the PAKFA generates high speed vortex during high AoA which is a must for any modern 5th gen fighter assigned to air superiority role.
3-TRAPEZOIDAL WING PLANFORM:
PAKFA is the first Sukhoi design to have trapezoidal wing planform instead of traditional swept-back wing. The ~840 sq.ft wing area provide max lift during take off. The main wing leading edge has a sweep angle of 47degree. The wings are smoothly jointed with the flat shaped fuselage via a wide chord created by the negative sweep angle of the trailing edge of the wing. This allows for large values of absolute height especially at the root but small values of relative thickness combining good structural integrity with lower drag forces in the trans and supersonic flight.
The all moving stabilizers add more control surface to the aircraft. It provides pitch control in all flight regimes by moving in-phase. At supersonic speed it also provides roll control by differential movement.
The vertical tails are also all- moving, a rather unusual approach. They are widely spaced in order to provide the necessary momentum but with a smaller surface. They move in-phase to provide yaw control operating as rudders and differentialy to increase drag, acting as an air brake. They are also inclined outwards to reduce the radar visibility in the lateral hemisphere.
6-AL-41F TVC ENGINE:
The AL-41 bypass turbofan engines are widely placed to create space between them for internal payloads. The 2x AL-41F engine produces a max of 170KN Thrust with supercruising capability. The TWR with full tank fuel and max combat load is predicted to be around 1.3
7-AIR INTAKES:(not shown in the top-view figure)
The air intakes are located similarly on each side of the fuselage and they are beveled in two planes in order to keep the flow attached even at high angles of attack. The air intakes are further apart in respect to the vertical and horizontal planes than the engines thus the ducts are curved. This curvature hides the compressor and reduces the radar signature of the engine in the forward hemisphere.(so please don’t say the fan-blades of PAKFA are visible and vulnerable to IRST detection)
8-NEW DESIGN CANARDS:
PAKFA has a new design canards which can’t be actually said to be canards. Actually these are mixed between canard and airfoil. These are full moving and provides additional lift during take off and help achieving better AoA.
The leading edge slats starting from the wing root to wing tip is full moving and provides additional lift at higher AoA.
The ailerons provided at the trailing edge of the wings have almost 30% of span of the outboard section of the wing and thus providing max yaw control.
The large trailing edge flaperons spanning about 60% of outboard wing section and truncated and blended with the leading edge of horizontal stabilizers.
12 & 13- ???
Can’t identify the component what the pic intended to.
14- 3D TVC NOZZLE:
The nozzles are faced slightly outwards and placed at a significant distance from each other. This feature with 3D thrust vectoring capability provide better control of the aircraft. The 2 nozzle can deflect the thrust vector by rotating around two axes either in synchronism or differentially. The angle between their axis and the vertical plane can create rotating moments when different thrust is produced by each engine and also counter-acts the asymmetrical moment each engine creates because of its lateral distance from the longitudinal symmetry axis.
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