Since many people in this forum are making sweeping all knowing statements about every thing on earth,let's start with some basic understanding of what are the critical specs of a fighter aircraft and let me explain that other than RANGE the LCA is a perfectly capable air frame to do everything any non stealth aircraft can ever do.
Angle of Attack(AoA)
It is the maximum angle an aircraft makes against the air flow. Practically it means, the greater the angle of attack, the more vigoursly you can turn. This is important in close combat because the more the angel of attack, the more tighter the pilot can turn. So aircrafts having high AoA wiill have smaller turn radius.
If an aircraft exceeds its Angel of attack , then it loses its aerodynamic grip on the air. That is the pressure above the wing is no longer lower the pressure below the wing. and becomes a stone in the sky falling towards the earth.
Thrust to Weight ratoi(TWR)
TWR is obtained by dividing the Engine-thrust of a fighter by its weight. If the Thurst is more than its weight then TWR is greater than 1. If thrust is less than the weight ,then TWR is less than 1. So fighters with TWR more than 1 can zoom up into the sky like a rocket instead of gradually increasing their altitude.
Also having more thrust to weight ratio means, the fighter can use the maximum use of its angle of attack. It wont matter if your fighter has a high AoA but a poor thrust to weight, because your fighter at maximum high AoA creates more drag and slows down the fighter. The more you turn with the help of high AoA, the more you loose speed.
The only way to counteract this lose of speed, is for the engine to put out more power. More engine power(or in other words more thrust to weight ratio) means, more thrust to counteract the drag due to high AoA turn. Say both Fighter-A & Fighter-B have an angle of attack of 25 degrees, but A has TWR of 1.2 while B has a TWR of 1.1. Since A has more engine power than B, it will turn more tightly than B because the more engine thrust will counteract the slow down due to a high AoA turn.
So eventhough both B and A has 25 degrees of AoA, B won't be able to fully utilise its 25 degrees to match A's turn as it will create extra drag which cannot be counteracted by its engine thrust and will start to lose speed and become a sitting duck soon. While Fighter-A will turn tighter because the drag will be counteracted by its superior TWR(or more engine thrust).
Sustained Turn Rate(STR)
STR as the name implies is a turn which can be sustained. STR is a derived quantity from AoA and TWR. As explained above, the balance between AoA and TWR makes Fighter B to turn at 22 degrees AoA only because if it goes abve that, it will start to lose speed. At 22 degrees AoA and TWR of 1.1, lets assume Fighter B can complete a full circle 360 degree turn in 20 seconds, without losing air speed. So its sustained turn rate is, 360 degrees divided by 20 sec, which is 18 degrees per second. So the STR of Fighter B is 18 degrees per second. While Fighter A with 24 degrees AoA and TWR of 1.2, will complete a full 360 turn much faster than Fighter B. Lets assume it completes it in just 16 seconds. So its STR is 360/16 = 22.5 degrees per second.
What this means is, if both fighter A and Fighter B meet each other head-on in a turning fight and start turning(it is called a merge), (the initial difference in angle in a head on engagement is 180 degrees.), Fighter A due to its superior STR(it has a superior STR because of a superior AoA, and it got its superior AoA because of its superior TWR. Now you can see how these parameters interact with each other.), will slowly start to get behind Fighter-B. Fighter-A has an advantage of 4.5 degres per second(22.5-18), over B. So to cover 180 degrees(or get behind B's back), Fighter-A will take 40 seconds to do it(180/4.5). So after A and B meet face to face, Fighter A will be behind Fighter B in just 40 seconds and pump his asss full of lead with his cannon or missile. This is what STR is all about.
Worldover eventhough many fighter aircraft manufactures claim fantastic AOAs of 50 degrees and more practicaly it is limited to 24 degrees in general.Then what is the meaning of claim? It simply means with the aid of thrust vectoring or some passive aerodynamic design they may evade stall .Thats all
.These higher AOAs are seldom exploited in dog fight because losing speed is signing your death warrant.So any AOA higher than 24 degree cannot be used in a dogfight because of the deadly loss of speed.They camouflage this truth by saying that the fly by wire software limits its AOA to 24 degree as if turning any tighter than that is outlawed.
They hide behind the fact that if the aircraft uses higher AOA than warranted by its fly by wire software than all its pilot can do is busy counteracting the stall for the next few minutes while his enemy leisurely completes his full circle within his fly by wire mandated STR and deliver the killing blow simply by his cannon.
Here let me state that LCA too has as good as any modern fighters with its fly by wire software limited AOA of 24 degrees.It has TWR of 1.07 with 85 KN engine in its debut.Wit MLUs of higher power engine they wont be obsolete as many people claim in this forum.It can increase its STR and even turn tighter.
But the basic point to note is that while F-16 like fighters try to draw deltas into turning fight The deltas will avoid that by using their inherently higher ITRs(explained below) and try to draw the F-16s into climbing fight,where the F-16s cannot match them.Because to climb you have to have lower wing loading(higher wing area per weight).The LCA(deltas) have obviosly more wing area than F-16s and grippens(delta with lower wing area than LCA).
This is the basic physics of flying.Nomamount of arguing will ever change this.Lcaa is a smaller aircraft while F-16 is a bigger aircraft.the engine thrust per weight of the fighter is limited only by the critical single crystal blade technologyThe122 kn thrust of UAE bought F-16 may look bigger compared to LCA's 95 KN. But the truth is LCA is significantly lighter than F-16.So per ton thrust of any fighter is limited only by the engine blade technology which determines the maximum stress handled by a single blade.
Thrust vectoring changes the game here altogether ,thats why SUKHOIS rule.They help the aircraft in dog fight.But nothing forbids LCA from also having Thrust vectoring.It is an engine feature that can be added on in later mid life up grades.Thats what si mentioned by ADA scientists when they say the IAf is asking for SUKHOI like parameters for LCA and it can be done.
Instantaneous Turn Rate(ITR)
ITR , is a turn which is performed instantaneously. Here the full 25 degrees AoA is used by both fighters A and B. As a result, both A and B whose STR limits them to 24 and 22 degrees respectively, doesn't matter here. Ofcourse turning at 25 degrees AoA creates massive drag, which slows down both the fighters, with B slowing down much more than A.
So you can ask, why on earth would a fighter turn like that, lose speed and become a sitting duck? A few years ago that would have been true, but with the new short range high off boresight missiles, all u have to do now is to turn using your full AoA advantage and quickly point your nose to the direction of the enemy fighter, get a lock on, with your missile, and then fire!
So you can turn instantly, move your nose in the general direction of the enemy, get a lock on your HMS, get a good tone on your Short range off-bore sight missile, and launch it.
With off bore-sight missiles, this becomes even more easier since you don't have to fully turn and only come into the off bore of the missile in order to launch. So when on a headon engagement(180 degrees difference), Fighter-A with 90 degrees high off boresight missiles and HMS, coupled with thrust vectoring, will perform a much higher ITR, and as a result will turn faster and will be able to get a lock-on much faster than Fighter-B (with its own 90 degrees high off boresight missile and HMS).
This is the standard tactics employed by deltas against F-16 like composite wing fighters.If challenged by a F-16 for turning fight the deltas use their ITR advantage(which is the result of higher wing area) over F-16 like composite wings and try to get out of the tighter turning F-16 with their higer ITR for off bore missile shot.
An aircraft with thrust vectoring can be an even bigger winner here because its ITRs are league ahead of others. and they dont have to worry about loss of speed and staling .But as I said earlier Thrust vectoring is just rotating nozzles and it does not pertain to aerodynamic layout of the aircraft.The LCAa can have as good a performer as SUkhoi with thrust vectoring in future upgrades.
An even better tactics is to climb and shake off the F_16 (composite wing) ,because even though the F_16 advertises its high verical climb rate it can not move from hhorizantal to vertical in small enough time to win over the deltas
