babbupandey wrote:A question to the gurus, while we are talking of TVC
When TVC is added to an aircraft, while it does add to maneuverability of the aircraft, however, do those maneuvers put some exert some extra stress on the airframe while executing tight turns?
If yes, then is Tejas designed address that?
Please bear with me through this long post. I hope it will be an interesting read.
I will try to find out the thrust vectoring articles again. I read them some years back, so please give me some time to locate them. Actually they are lengthy reads. There was a period of time (almost a decade) where everybody wanted to know whether thrust vectoring will be a game changer. So there were lots of to-and-fro discussions.
But for the crux of the discussion was somewhat captured by a German professor/scientist who proved through simulations that thrust vectoring doesn't add to the maneuverability of a aircraft. But it really lowers the stall speeds for quite a few maneuvers. This is critical for a heavy plane (notice that till now only heavy planes employ TVC). Remember what are the signature moves of the Su-30, Su-35, F-22, all are low speed!
Let me paint you a picture. And this picture is not hypothetical. If you are a reader of DACT exercises, you will find many examples of the same. Suppose you are in a dogfight with a light fighter (say the F-16) and you are ahead. What will you try to do? You would like to turn in any axis where you think you can out turn your opponent who is on a heavier plane behind you. You would like to slow the arena down as much as you can so that the opponent shoots forward and then you can turn in on his tail! On the other hand your opponent with a heavier plane is trying desperately to point his nose inside your turn and ahead of you so that he can have a shot at you. Unfortunately his plane is heavier (assuming slightly asymmetric TWR) . At this slow speed, he can barely maintain this turn rate.
What would he wish for, something which can help him make this slow turn or make his nose point ahead of you or both. And here comes the TVC! It has been proven that just because of this, a heavy plane with TVC might have a flight envelope of a light agile fighter. This is a game changer, something which is enjoyed by the Su-30MKI. Inspite of being a heavy dominance fighter, it is a supreme dog fighter!
But bear in mind, with TVC you can't suddenly turn faster. A plane at such speeds has too much of momentum for the TVC to change the direction of flight. For example none of the thrust vectored planes advertise a faster turning rate because of the vectoring. So you wouldn't suddenly start pulling 10G turns instead of 9Gs! So the airframe doesn't need to change. But what about the engine mount? It has to be made stronger, because when the nozzles are deflected, the engine itself is creating a moment about it's CG. So the mountings will have to be strengthened to bear this load. Hence you would read about the weight gain for TVC engines. It is not just from the mechanism to deflect the nozzles.
I am sorry to have written such a long reply, but I hope I have answered your question satisfactorily. At the same time I would love to learn more or be corrected.