Hi dear
@Quwa
I must confess that your article is well written and very balanced-very rare to find such piece written by pakistani authors. But I would like to add couple of things that i felt you missed in your article.Kindly bear with me,as i will be a little rigorous mathematically.
Firstly,keeping everything aside,Tejas as a platform is superior to JF-17 thanks to two factors that I will explain mathematically-
1)Wing Loading:
Wing Loading is a very important factor in a lot of aircraft performance parameters. This is nothing but mass of the aircraft divided by itz wing surface area.A lower wing loading is prefered over higher wing loading as it vastly improves a lot of things ranging from min stall velocity,turning radius,take off distance to name a few.And i will prove all my points based on hard mathematics,i will try to not use advanced mathematics so that most can follow-pre requisite: Free body diagram analysis
View attachment 315602
(a) Effect of wing loading on turning radius: (kindly refer to my page above right side)
A lower wing loading(represented by Wl) will have lower turning radius vis-a-vis an aircraft higher wing loading- keeping everything constant
(b)Effect of wing loading on velocity required for take off: (on the left hand side of my page above)
Velocity is directly proportional to the square root of the wing loading,hence a lower wing loading will result into lower velocity with which an aircraft can take off- or land.This is specifically evident if we compare the take off and landing runs of both LCA and thunder-former's take off run is shorter by at least 200m!
I would like to point out that I have taken Thrust to be along V and L to be perpendicular to it,where "gamma" as usual denote flight path angle .Dotted line indicated local horizontal and vertical.
2)Second factor that makes LCA superior to JF-17 is "RELAXED STATIC STABILITY" in pitch plane. This helps LCA achieve higher pitch rates as compared to JF-17. Just for the benefit of readers I want to point out that a conventional flight must be simultaneously "balanced or trimmed at a particular alpha" and "stable".However due to requirement of higher maneuverability,modern fighter jets have inbuilt instability and that i achieved by placing CG aft of aerodynamic centre. This has a lot of advantages apart from providing excellent pitch rates and i will list them here-
(a) An unstable aircraft requires lesser hinge torque to displace the control surfaces.This in turns results in smaller actuators that can do our job.
(b)An unstable aircraft requires smaller net control surface area for producing moments.This in turns translates into smaller drag produced by control surfaces.
But this makes the design of control appreciably much more complex vis-a-vis an aircraft with stable design.Because now the aircraft wont return to itz equilibrium trim state when disturbed,so control surfaces must be "actively" used to constantly keep the aircraft in trim state. Thankfully RSS is almost always used by FBW system,because it is almost impossible to fly an unstable aircraft manually- which entails- balancing or trimming at a particular angle and stability.The pilot will just go mad! Hence a computer actively controls the stabilators to constantly trim the aircraft at a particular alpha as commanded by the pilot.This is also known as "artificial stability" in american literature because although the aircraft isnt stable,it "appears" stable thanks to behind the scene action of a computer- that makes it stable to fly for pilots!
The only area where JF-17 is ahead is operational deployment in force structure of PAF.This would have enabled them to frame their combat policies and deployment including thunder.This will take couple of years in IAF with LCA.We must also accept the fact that when thunder was inducted into forces,it could hardly fire BVR,a2a refueling,carry a designator pod,EW suite etc,However the IAF didnt give the IOC unless it could do all of it. SO,I tend to think that PAF inducted a fighter that couldnt perform any of these whereas IAF chose otherwise.
I would like
@Oscar and
@JamD to add their points to expand this discussion- ofcourse based on rigorous mathematics.