@Deino
What does the engine have to do with the aircraft---it starts---it makes the aircraft fly with the needed load---its spool up time is very fast---its maintenance is very low---it is very cost effective for pakistan---.
If You really have no clue, what an "engine does have to do with the aircraft" I cannot help you, go and ask someone who you do more trust than me.
Is the issue that the J31 is a copy of F35---????
I really have no idea why you are constantly repeating this nonsense and seemingly boasting about being right ... the only one who continues to undermine his reliability and make himself ridiculous is you, but you either do not seem to see it or to actually believe this nonsense.
Again, an aircraft may well be based on another types external configuration, it may even take over another's design features, but if there were no blueprints available, or as here the FC-31 looks vastly different to the F-35, then it cannot be a clone or a copy; period. How should a twin-engine aircraft be a copy of what you call a single-beam type?
So if you are not willing to accept my explanation, that we both have different definitions of "copy or clone", but instead continue to insist on your version the FC-31 = a copy of the F-35, then please do not be surprised that some serious ones take with a huge grain of salt.
I'm sorry, but regardless how many hommies here or anywhere cheer you, that still does not make this nonsense a fact.