Hello.
Following the recent update, the SD-10A (export version) reaches Mach 5 with a 80km range, while the PL-12A (domestic advanced version) is limited to Mach 4 but reaches 120km.
Both missiles use the same airframe. The PL-12A is documented as an evolution of the PL-12/SD-10A with an improved dual-pulse motor. It is physically inconsistent for the older export model to achieve a higher top speed (Mach 5) than the advanced domestic model (Mach 4).
A missile reaching Mach 5 has a significantly higher energy state. Unless the SD-10A has a much higher drag coefficient (which it doesn’t, airframes are identical), its range should naturally extend further or the PL-12A’s speed should be corrected upwards to match its superior motor technology.
According to AVIC/LETRI (607 Institute) specifications, the PL-12 series top speed is consistently rated at Mach 4. The Mach 5 value for the SD-10A appears to be an over-performance (over-buff) not supported by technical data of the 203mm diameter motor.
While early Chinese BVR (Beyond Visual Range) projects like the PL-11 were based on Italian or Russian tech, the SD-10/PL-12 series is a domestic development. The seeker head of the SD-10A is the AMR-1, developed by the Leihua Electronic Technology Research Institute (LETRI).
Even if one argues that the seeker has Russian heritage (R-77), the seeker only controls guidance, not kinematics. A “Russian-style” seeker does not grant a Mach 5 top speed if the rocket motor and airframe are Chinese-designed and rated for different parameters. The seeker seems to be the inly difference between these missiles.
Since the SD-10A does not share the airframe or the high-drag grid fins of the R-77, using Russian performance data to “buff” the SD-10A to Mach 5 is a technical error. The SD-10A is more aerodynamically similar to an AIM-120 than an R-77.
If the SD-10A reaches Mach 5, its peak kinetic energy is significantly higher than a Mach 4 PL-12A. In the vacuum of high altitude, a Mach 5 missile with the same airframe as a Mach 4 missile cannot have a shorter range (80km vs 120km) unless the drag coefficient is bugged or the motor burn time is artificially truncated.
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