Countdown to India's big Agni leap begins

[Screambowl]

If I add extra stage that extra stage allows me to increase the range. Say by X kms.

But if I increase my range by only Y kms (where Y<K) it means I can increase payload of missile. (motor may be required to be changed or may not be but it is not a 100% necessity as it depends upon the whether the added stage is too big or manageable with the existing motor).

but for agni V they have not reduced the payload to increse range. They hava used same/more payload by using extra stage with new or improved motors as reducing payload to increase range makes little meaning.

I agree with the bold part.

But the second stage is Modified because the 3rd stage weighs around 2 tons it is an official report. One thing I cannot digest is that the officially disclosed max Payload weight is only 1.2 tons. Where as Agni 3 could carry 2 - 2.5 tons. Then why are they testing with only 1.2 tons.

so that means to carry 2.5 ton payload they have to change their trajectory. Make it more steeper like Agni 4, to reach early in space and use rest 2 stages(3rd and 4th) for covering further distance.

 

[Dharmachakra]

^^^

For a brief comparision let me bring up the A-II and A-IIP(aka A-IV)
A-II weighs 16 tons(including the payload of 1000-1500kg)being 21mts in lenght while A-IV with a modified upper stage( which got an all new composite motor casing with HEP) weighs 17tonns but measures ~20m while the throw weight is retained for an increased range from 2500km to 3500km.
And let me also mention that the flight ceiling has increased from a mere 450km to 900km. This can be attributed to the flight path hence the increase in range and performance.

Similarly A-III weighs 48 tons(including the 2500kg payload) and throws to a distance of 3500km with full load and reaches a ceiling of 450km.While modified A-III which is an A-V with an extra composite stage measures almost the same length and weighs little more ~50 tons(including the same payload of A-III which is 2500kg) pushes the range to 6500km with max load out and reaches the ceiling of almost 800km.Again the flight path has been changed.
How A-IV compensates the extra add-up weight while retaining the performance driven by the extra composite stage filled up with high energy propellant is really interesting.The first 2 stages burn-up remained the same like in A-III while the 3rd stage burn-up is considered important,cos it helps in reaching the max altitude and then lets the RV take its own course.THe final stage( common for all RV in A series) further steers the RV in a designated trajectory until the t-100 sec before the MIRV bus separates the petals. This is albit different to MaRV which A-III and others adopted.

Hence the increase in range can also be attributed to the change in payload structure(from MaRV to MIRV).

This is one reason why western ICBM`s with MIRV`s boast of longer ranges than the ones with MaRV with same specs.

 

[Screambowl]

^^^

For a brief comparision let me bring up the A-II and A-IIP(aka A-IV)
A-II weighs 16 tons(including the payload of 1000-1500kg)being 21mts in lenght while A-IV with a modified upper stage( which got an all new composite motor casing with HEP) weighs 17tonns but measures ~20m while the throw weight is retained for an increased range from 2500km to 3500km.
And let me also mention that the flight ceiling has increased from a mere 450km to 900km. This can be attributed to the flight path hence the increase in range and performance.

that is what I was telling. retaining the actual payload is only possible if you change the trajectory, modify the motors. Just adding an extra stage of the same potential won't help in increase in range. One of the stages must be modified to over come the load.
But my Only point was. they could have tested direct 2.5 ton Actual Payload on A5 be it Mirv or Marv or any design. with current parameters unchanged which aim for 5000kms range and accuracy. To test the Load carrying capacity.

Similarly A-III weighs 48 tons(including the 2500kg payload) and throws to a distance of 3500km with full load and reaches a ceiling of 450km.While modified A-III which is an A-V with an extra composite stage measures almost the same length and weighs little more ~50 tons(including the same payload of A-III which is 2500kg) pushes the range to 6500km with max load out and reaches the ceiling of almost 800km.Again the flight path has been changed.
How A-IV compensates the extra add-up weight while retaining the performance driven by the extra composite stage filled up with high energy propellant is really interesting.The first 2 stages burn-up remained the same like in A-III while the 3rd stage burn-up is considered important,cos it helps in reaching the max altitude and then lets the RV take its own course.THe final stage( common for all RV in A series) further steers the RV in a designated trajectory until the t-100 sec before the MIRV bus separates the petals. This is albit different to MaRV which A-III and others adopted.

Hence the increase in range can also be attributed to the change in payload structure(from MaRV to MIRV). [/B]

But the official data indicates ,A5 it will carry only 1.2 tons. So is it due to RV design, that the missile will only have space to accommodate MIRV of 1.2 tons ?

This is one reason why western ICBM`s with MIRV`s boast of longer ranges than the ones with MaRV with same specs.

well their weapon design is simply too advance and the weapon itself weighs not more than 100 kgs

 

[Dharmachakra]

that is what I was telling. retaining the actual payload is only possible if you change the trajectory, modify the motors. Just adding an extra stage of the same potential won't help in increase in range. One of the stages must be modified to over come the load.
But my Only point was. they could have tested direct 2.5 ton Actual Payload on A5 be it Mirv or Marv or any design. with current parameters unchanged which aim for 5000kms range and accuracy. To test the Load carrying capacity.

But the official data indicates ,A5 it will carry only 1.2 tons. So is it due to RV design, that the missile will only have space to accommodate MIRV of 1.2 tons ?

well their weapon design is simply too advance and the weapon itself weighs not more than 100 kgs

There need no modification to the existing base(1,2) stages of A-III.They are driving the commonality.The major modification will be removal of ventilated stage and then the added 3rd stage.
And when it comes to flight control system, it needs a huge change.Considering the trajectory and altitude required to push those MIRV`s 1000`s of kms.

It does help significantly in enhancing the range by the addition of extra stage. Its only that the physics your are considering goes advanced while considering the each stage burn-out time and their specific impulses at both sea level and vaccum. What happens when the missile reaches an altitude of 200+ km is totally different to its behavior at sea level.

Even 200+ is too much when we consider Karman Line at 100km above sea level.So, all it comes to the thrust required to push that 50 tonne to above 100+ and then taking it to 800+km or so depending upon the flight path.

Historically DRDO never tried full payload on a first flight. so that testing of 2500kg is out of equation atleast for the first 2 or 3 flights.

When anyone says the throw weight is X kg, it includes the warhead and other countermeasures and everything that goes into RV. Since the RV is configured for MIRV, I assume the whole 2500kg will include the bus structure with payload(3-5 warheads) and dummies+ECM to protect the warhead reach the target safe.

So, I can discount the other 1.3 tonne for all the necessary countermeasures and include a full 1.2 ton read warheads.

So far simulations has been done and warheads design was frozen only upto 750kt.So 3 of those can be fit with counter-measures.But if they decide to go for either 250kt or 500kt,they can go for either 5 or 7 or wot-ever the bus structure limits to.

So they play a balance between the counter-measures and actual warheads.