tsarkar wrote: what I want to understand is how much weight will we add if we stress a hard point to carry a 105 kg missile at 9 g instead of a 65 kg missile at 9g? I guess not more than 100 kg at a stretch? Same goes for the intake hardpoint for the Litening.
Before the wing redesign became public, I had speculated right here in this thread that the reason why they were not able to do the carriage and separations trials were not being done was because the IAF had given an outdated weapons requirement and that once they woke up and changed the requirements, a redesign would be required.
Siva , a former structures designer at ADA ,and had gone for his Master's in US, who used to post here (he doesn't do so anymore, maybe he has been told to shut up by the powers that be) fessed up and said, yes a redesign was done and that the wing was strengthened for torsion for the new weapons load out.
DDM picked up that bit of news from this thread here and I think it became an "issue" once it was picked up.
So I asked him how much mass was added , and he replied negligible, since all it required was a couple of layers of carbon fiber in the right places!
I guess, I have a pretty good record in speculation. I also speculated that GTRE have a working engine finally and it looks like they do . I did this when there was D&G all around about the Kaveri and there was dead silence from GTRE. This was before all the Shook Laws and In Laws of the world actually started getting into the act and doing the actual ground work and visiting places.
from the designer's mouth at AI09 --
LCA has precisely 2350kgs internal fuel
So let me speculate here as well. I might be third time lucky , who knows.
Yes that 2350 is for the "old" air frame with the targeted weight of 5500kg (Gripen has same 2250 kg internal fuel for a 6500kg airframe). I am absolutely willing to bet that the Air Force will not sacrifice range and persistence under any circumstance. Think of it , what is the point in being able to carry ordnance, if you cant reach the place where you need to drop it!.
I am willing to bet that when the MKII version rolls out, you will see the internal fuel at close to 2800 kg / 3000 kg. How can that be done ?
Let me think.. All air craft and ships and submarines and stuff are designed with some 3 % to 5% ballast (usually concrete blocks or lead weight) to allow for weight growth as equipment gets added and also to balance out the CG etc as the final version of the plane gets designed in (you cant redo the entire General Arrangement on the fly each time some equipment is changed /added/removed, you tend to add weights/remove weights as appropriate).
Now the most optimized airframe will be the one with Zero Ballast and all components at their most optimal with factors of safety that are just right. I am willing to bet that the current version has ballast and "unoptimized" components.
I doubt the current LCA is there yet in terms of optimal layout. It makes no sense to do it, because this is just an interim level with an interim engine and weapons and radar fit!. No point in doing it.
Once the final engine choice is made (EJ200 or GE 414), and the absolute final weapon fit is chosen , including the radar ,then you can have the "final" config in place , you can get the weight down to it's bare minimum..
And oh.. you will need to "fine tune" the control laws and FBW again for this final version and do the flight tests I think, since the weight , CG etc will be different and the dynamic response of the plane as well... But I guess the idea will be to "teach" the flight control system to fly with a different weight layout than the current one.