How does fighter design starts?
A hypothetical scenario,
ASR specifies,
Range, weapon load, close combat specs like ITR, AOA, TWR of entire fighter,Max G,STR, roll rate, climb rate etc,
Designers decide,
With the available engine tech, & engine TWR,
Whether it is possible,
Or,
Not.
Give feedback , arrive at a mutually agreed design goals,
Then, engine thrust, empty weight of the fighter needed to support the fuel, weapon load
Wing area needed to lift that mass & achieve those close Combat specs are arrived at,
This will be an iterative process, which will result in final empty weight of the fighter needed to support the wing area, and other parts get finalized,
Weight distribution of all LRUs, CG,drag calculations, CL, margin of stability or instability all play an important role in it.
Then design & prototyping progresses , ends up in a fighter type after decades of hard work, 1000s of test flights,
After that adding 300 kg to engine( for 20 % extra thrust of 16 KN,), at the tail, adding another balancing 300 kg of avionics at the nose,
Adding some more weight in fuselage to support these 600 kg at 9G, ,
Then wing size too needs increase, to generate better lift to support the weighter,
will get teja mk1 weigh up by say 700 KGS,
Then to support these 700 kgs , through out the combat range of the plane, we need more fuel , (some more weight gets added up, )
&
More importantly fuselage volume , to house that fuel & extra avionics weighing 300 kg.
This is called weight spiral.
Then we get a 7.5 ton empty weight tejas, with 96 KN engine thrust. 13.5 ton MTOW,
That means it is the same fighter like 6.5 ton tejas mk1, with 12.5 ton MTOW,
All specs will be same
, MTOW increases, but empty weight too increased, so no gain.
Engine thrust increases but fighter's TWR stays the same.No gain
But all calculations for CG, CL, margin of safety, drag need to be redone,
need to be revalidated, taking countless test flights & number if years.
It's like a guy strapping a 20 kg kerosene can on Ussain bolt's back,
Setting it on fire , in the hope of him completing 100 meters run in 5 seconds,
That's why ADA didn't choose that ruinously disastrous path advocated by Air Marshal Matheshwaran,by increasing stages & engine weight,
instead going for a better engine TWR GE 414 for mk2,
But our folks are getting their knickers in knots over stuffing 300 kg extra weight on Teja tail,
&
May be fly it in martian atmosphere with Maheswaran Sir in cockpit, to get a better tejas,
ROFL.
If canards were added to support super heavy radar in su 30 MKI, as alleged by some members,
It gives su 30 mki a cutting edge powerful radar, so worth it. & It was done along with many other IAF specific enhancements in a useful redesign.
Point to note is additional lift & control surface like canards,
& an extensive redesign
was needed to support this extra 500 kg in a massive 30 mki , twin engine, beast of a plane , with truck loads of thrust, if the statement, "that canards were added to support radar weight" is true.
In case of Tejas , it is zero gain for a decade & thousands of correa invested in such a re engineering.
I don't know how long are these guys are going to hang on for this extra engine weight, thrust, tejas.
This will be my last post on this subject,
