Indian Missiles News & Discussions - May 2017

[JayS]

Tender for Rudra MII testing assembly mentions 200kg Warhead.

[Indranil]

No sir, there is no motor ahead of that part.

well those things are ram air plumbing in to the chamber, at 90 degrees x4, intake nested between front fins.

Correct.

Could not follow this part. Akash uses an integral ramjet. After the solid-fueled booster grains have burnt out, the cavity left behind forms the combustion chamber for the ramjet engine. In front of the "joint" is the sustainer fuel, control system, warhead and guidance mechanism.

Yaakwaala can confirm but I believe that section has the solid fuel for ram jet. I am told a marvellous design, where controlled amount of partially oxidixed fuel is burnt and fed into jet engine chamber.

Yes. It is a very beautiful and elegant design. That is how they can achieve limited throttle-ability while using solid propellants. I have been following the LFRJ tenders closely. As far as I can tell, their first test bench uses near identical setup as the Akash : same diameter motor and same intake set up. But that could be to understand the LFRJ engine characteristics. The final intakes/shapes may be completely different.

[JayS]

[Yaakwaala can confirm but I believe that section has the solid fuel for ram jet. I am told a marvellous design, where controlled amount of partially oxidixed fuel is burnt and fed into jet engine chamber.

That would make it a ducted rocket design wouldn't it..? Or what am I missing..?

[Karan M]

Tender for Rudra MII testing assembly mentions 200kg Warhead.

Do we know what is Rudra - SSM?

[Karan M]

I am assuming SSM as name certainly has the same kind of gravitas as Pralay and 200 kg warhead.

[JayS]

Tender for Rudra MII testing assembly mentions 200kg Warhead.

Do we know what is Rudra - SSM?

All we know it Rudra MII and MIII are sanctioned projects.

And we know that it will be flown on Su-30MKI. At least to start with. I had posted about the tender regarding this previously.

viewtopic.php?f=3&t=7342&p=2225999&hili ... r#p2225999

[Indranil]

Haridas ji,

1. I agree with you that the Isps of the upper stage of Agni III/V is unlikely to be better than the upper stages used by ISRO. But I don't think that DRDO is using kevlar for the upper stage. I think they are using some glass composite which does not have the same strength but is much lighter. I forgot where I read it. It was a book written by two ISRO scientist. They had studied glass composites which where 67% lighter than Kevlar (obviously with commiserate loss of strength).

Indranil ji, you think the DRDO scientists assertions were credible? To lay reader it will sound like walking on water, but in reality misleading.

OTOH IIRC in my post i didnt claim or asserted the use of kevlar. So i will like to know more about agni composite stages.

I have one request. Please drop the "ji". I am a casual observer and student. I feel very uncomfortable with salutations.

I don't know what kind of composites are used for the Agni V. But it is very unlikely to be kevlar based. When ASL developed the casings for the first time around 2007, Avinash Chander, the then director of ASL said that it was made out of wound carbon-fiber composites and that the weight savings were 40% vis-a-vis maraging steel.

2. I have never seen any pictures of the modified Agni 3. For example, here's the website of the company that makes the TELs for Agni and other missiles: Gallery defence and Products Defence. Note the only trailer missing: Agni 3. I lost an important document: ANS had floated a tender for the transporter of K4. I don't think I can trace it again. It had the details of weights/diameter and length of each stage. That was revealing. AFAIK, the total weigth was indeed in that 20-25 Ton range. Note that Deftec also has a 25 ton trailer for which it did not produce any pictures.

A) I too recall that tender. But the size and wt, is so different from A3 that it would be unwise/unreasonable to call it a modified A3.
B ) Your assertion of 'composite case booster resulting in payload increase from 1 ton to 3 ton' can't be justified on the basis of expected mass fraction improvent and mirginal ISP increase.

I think we have spoken so much that we are starting to speak past each other. These were not my assertions. I contend that:
A) That tender was for K4. Agni 3 and K4 have identical throw weight and range. They are designed and built by the same folks. So it is unlikely that a modified Aagni3 is going to look much different than the K4, except for the nose cone.
With improvements in precision, they have decreased the payloads across the board: in Agni 2P, Agni 5. So, a modified Agni 3 would also have lower payload. If that is the case, a modified Agni 3 can be made much lighter.

3. One hint that Avinash Chander dropped was that weight savings from the composite upper casing, lighter payload and systems etc. is equivalent to the weight of the third stage.

But iirc your argument was the throw weight (payload) increased for the given datum range.

I must not be communicating clearly. That is not my assertion at all. Please read the above clarification.

Nevertheless adding an additional stage is a major reconfiguration of the rocket, not a progressive evolution of a baseline where efficacy of a design change can be evaluted on resulting system performance measure (as a partial differential coefficient).

We can start from there. What is the propellant mass required for the second stage of Agni 2 Agni 3 if the payload + inert weight is dropped by the weight of the third stage of Agni V. We can ignore the higher Isp and more efficient stage separation for now.

I presume this is a new discussion topic. Or could you clarify it by elaborating it?

Absolutely, no questions about staging and efficiency. I also made a typo, which I have striked through and corrected above.

I am saying something simple. Imagine a modified 2-stage Agni 3. If we decrease the payload to 1.2 tonnes and the inert weight of the second stage using composite casings and lighter subsystems, then the weight savings would be almost the same as the overall weight of the Agni-Vs third stage (2.5 tonnes). Avinash Chander said so in an interview reported above. So now, what would be the propellant mass required for the second stage of Agni 3 to eject the 1.2 Ton payload at 4.2 km/s? Working backwards what would be the propellant mass required for the first stage given the significantly lighter second stage.

I think the only difference between Agni 2P (4) and Agni 3 modified is form factor. Instead of having a slim slender profile of the Agni 4 (1.2 mtrs wide and 20 mtrs long), the modified Agni 3 is 2 mtrs wide and about 12 mtrs long. It is slightly heavier because it can throw slightly heavier payload (1.2 tons instead of 0.8-1.0 tonne) than Agni 4. Therefore, its reported weight of 22 tons just over 17 tons of Agni IV is completely believable!

[Katare]

Weight savings from composite motor casing are significant but it’s not the only major factor in choosing it over maraging steel.

1 cubic meter of maraging steel weighs > 8000kg
Kevlar would weight 1400kg
Graphite/carbon would weigh 2200 kg.

So weight savings are huge but once you move to composite casing it allows several other optimizations that are not possible with steel. Higher pressure and faster burn both can be achived.

Probably the most important factor is the pressure on propellant grains which is much higher in maraging casing because it’s a lot more stiff material. Composits expand which lowers pressure experienced by grains, this allows better energy density grain arrangement and chemicals. The thickness and fiber orientation can be changed both axislly ir radially to the most stressed area allowing more loading/faster burn.

So in a-nut shell once you have the composites casing technology it opens up many more gates for you to optimize the missile

[Mihir]

Yes it is large. But it is not inefficient . It is powered all throughout unlike solid rocket based missiles which coast for very long periods of flights. You don't want to be painted by this thing.

I don't think this is correct. The sustainer motor on the SA-6 has a burn time of about 20 seconds. The Akash's shouldn't be all that different, given that their range is similar. The advantage of ramjet propulsion lies in the fact that the missile doesn't need to lug around an oxidiser.

[Rakesh]

IR, I moved my post below yours...so there is continuity in discussion above.

https://twitter.com/SJha1618/status/963678793071300609 ---> Couple of images of the launcher for the Nirbhay ground launched cruise missile. Source: DRDO. However, I think this launcher has been developed for the test-regime. The deployed system will probably be different.

[Indranil]

Yes it is large. But it is not inefficient . It is powered all throughout unlike solid rocket based missiles which coast for very long periods of flights. You don't want to be painted by this thing.

I don't think this is correct. The sustainer motor on the SA-6 has a burn time of about 20 seconds. The Akash's shouldn't be all that different, given that their range is similar. The advantage of ramjet propulsion lies in the fact that the missile doesn't need to lug around an oxidiser.

While that is correct, 20 seconds at an average sped of 2.5 Mach is over 17 kms of powered flight.

[John]

Yes it is large. But it is not inefficient . It is powered all throughout unlike solid rocket based missiles which coast for very long periods of flights. You don't want to be painted by this thing.

I don't think this is correct. The sustainer motor on the SA-6 has a burn time of about 20 seconds. The Akash's shouldn't be all that different, given that their range is similar. The advantage of ramjet propulsion lies in the fact that the missile doesn't need to lug around an oxidiser.

Ramjet design used by Akash it based on SA6 which is bit dated the burn time for Brahmos liquid fueled Ramjet is far greater. Another advantage of liquid fueled Ramjet is that it can be throttled.

For Nirbhay i do wish we had gone for canisterized launch platform would have made it easier to adapt this for ship and sub launch.

[Indranil]

They will be canisterized. This is just a test set up. Just like the Prahaar/Pragati.

[John]

Any sources for that? All of Prahaar mock ups displayed it in a launcher so far but I haven’t seen any Nirbhay mockups showing it in a canisterized launcher and Universal launcher CGI images strangely didn’t have Nirbhay as well.

[RoyG]

AGONIZING OVER THE AGNI
https://www.armscontrolwonk.com/archive ... -the-agni/

[prasannasimha]

^ the entire podcast had nothing in it worthwhile. I wish there was a transcript that could have been glossed over.

[Indranil]

Any sources for that? All of Prahaar mock ups displayed it in a launcher so far but I haven’t seen any Nirbhay mockups showing it in a canisterized launcher and Universal launcher CGI images strangely didn’t have Nirbhay as well.

No source. My memory may be failing me but I think Tata 12X12 was pitched for Nirbhay carrier.

Although the mock ups and recent tests have shown AAD/Prahaar in canisters, for the first few years of testing, it was always a grid to hold the guide rails, just like Nirbhay.

[Haridas]

I have one request. Please drop the "ji". I am a casual observer and student. I feel very uncomfortable with salutations.

Parents , rural culture and my Guru dev have instilled in my personality to offer respect and humbleness in interacting with "sajjan purush", vidvaan, soilder, teacher and servitor of a higher cause. I couldn't deviate from the dharma taught by elders, so I insist on following it. Kindly forgive my indulgence and tolerate my adressing, just like you tolerate a affectionate person.

[Indranil]

Ramjet design used by Akash it based on SA6 which is bit dated the burn time for Brahmos liquid fueled Ramjet is far greater. Another advantage of liquid fueled Ramjet is that it can be throttled.

Whether the solid fueled Akash/SA6 can be throttled or not is matter of great debate. In theory, there is a primary combustion wherein the oxidized solid grains are changed into gas which are even more combustible. These gases are then introduced into the secondary combustion chamber through a valve wherein they burn with the air injected through the ram ducts. In theory, the amount of gas injected into the secondary chamber can be throttled using the valve. But there are limits to this. Once the primary combustion has started, it cannot to stopped and reignited like in a liquid ramjet. There are limits on pressure etc.

None-the-less, the Isp of this kind of solid ramjet has been found to be as high as liquid ramjets. In literature, you can find it to vary between 400 to 1000. That's much higher solid rocket motors.

[Haridas]

A) That tender was for K4. Agni 3 and K4 have identical throw weight and range. They are designed and built by the same folks. So it is unlikely that a modified Aagni3 is going to look much different than the K4, except for the nose cone.

Indranil ji,
1. Could you tell me the A3 range - payload spec that you believe is true and it's web reference?
2. Same for K4?

Curious that A3s basic info like diameter & wt are consistently reported by various media & govt along with pictures. While for K4 the dia and weight are ambiguous and no picture.

With improvements in precision, they have decreased the payloads across the board: in Agni 2P, Agni 5. So, a modified Agni 3 would also have lower payload. If that is the case, a modified Agni 3 can be made much lighter

.
1. Let us assume the previous A2 & A3 accuracy was 200m and now the accuracy is 40, has that reduced the yield requirement by a factor of two ? and tomorrow if the accuracy is 1m how much lower yield will be ok?
2. The suggested lower payload is due to lower yield or warheads with higher yield to weight ratio?
3. What is forcing indian weaponeers to freeze the number of warhead on missile and not provide for more petals count?

As I try to answer the above, in my mind A3 and K4 are different pupose missiles, not needing to be boxed into a common payload to range performance matric.

I am saying something simple. Imagine a modified 2-stage Agni 3. If we decrease the payload to 1.2 tonnes and the inert weight of the second stage using composite casings and lighter subsystems, then the weight savings would be almost the same as the overall weight of the Agni-Vs third stage (2.5 tonnes). Avinash Chander said so in an interview reported above. So now, what would be the propellant mass required for the second stage of Agni 3 to eject the 1.2 Ton payload at 4.2 km/s? Working backwards what would be the propellant mass required for the first stage given the significantly lighter second stage

.

You give me the following and can tell approx weight of the booster & 2nd stage
1. weight of the 3rd stage + its mass fraction ,
2. the payload-mass
3. the desired range,
4. Mass fraction of booster & second stage (guesstimate based on assumed drdo mastery )

I think the only difference between Agni 2P (4) and Agni 3 modified is form factor. Instead of having a slim slender profile of the Agni 4 (1.2 mtrs wide and 20 mtrs long), the modified Agni 3 is 2 mtrs wide and about 12 mtrs long. It is slightly heavier because it can throw slightly heavier payload (1.2 tons instead of 0.8-1.0 tonne) than Agni 4. Therefore, its reported weight of 22 tons just over 17 tons of Agni IV is completely believable!

Let us wait for more data and a picture. Till then meditate on Agni-3SL by a disreputable future teller.

[Haridas]

Probably the most important factor is the pressure on propellant grains which is much higher in maraging casing because it’s a lot more stiff material. Composits expand which lowers pressure experienced by grains, this allows better energy density grain arrangement and chemicals. The thickness and fiber orientation can be changed both axislly ir radially to the most stressed area allowing more loading/faster burn.

How much case expansion as %age ?
How can solid fuel grain (that has pencil eraser type elasticity) experience any lower pressure that is not same as chamber pressure (~50 bar) ?

[kurup]

350 km range missile test from ITR on 21 Feb ,

https://twitter.com/kurup89/status/964490932883152896

[kurup]

1500 km range missile test from ITR on 20/22 Feb ,

https://twitter.com/kurup89/status/964491226215952384

[Karthik S]

1500 km range missile test from ITR on 20/22 Feb ,

https://twitter.com/kurup89/status/964491226215952384

Nirbhay?

[JayS]

Ramjet design used by Akash it based on SA6 which is bit dated the burn time for Brahmos liquid fueled Ramjet is far greater. Another advantage of liquid fueled Ramjet is that it can be throttled.

Whether the solid fueled Akash/SA6 can be throttled or not is matter of great debate. In theory, there is a primary combustion wherein the oxidized solid grains are changed into gas which are even more combustible. These gases are then introduced into the secondary combustion chamber through a valve wherein they burn with the air injected through the ram ducts. In theory, the amount of gas injected into the secondary chamber can be throttled using the valve. But there are limits to this. Once the primary combustion has started, it cannot to stopped and reignited like in a liquid ramjet. There are limits on pressure etc.

None-the-less, the Isp of this kind of solid ramjet has been found to be as high as liquid ramjets. In literature, you can find it to vary between 400 to 1000. That's much higher solid rocket motors.

So Akash is Solid Fuel Ducted Rocket design basically. Any idea of fuel composition...? Generally metallic particles would be used as energy booster. Al/Mg are easy to burn. But Boron have more energy density, though burning it is a challenge.

[kurup]

1500 km range missile test from ITR on 20/22 Feb ,

https://twitter.com/kurup89/status/964491226215952384

Nirbhay?

Or Agni1P ....... Testing area looks more suited for BM test

[Karthik S]

Thanks, there were series of nirbhay tests planned in Nov. No word after that yet.

[Neela]

REVEALED: Aggressive New Plans For India’s Nirbhay Cruise Missile

For starters, in January, the Indian Air Force officially expressed interest in an air-launched version of the Nirbhay, tentatively designated Nirbhay-A for the stand-off air to ground role for its Su-30 MKI jet platform, solidifying its support with a stated interest in acquiring at least 40 systems once it is proven. IAF chief Air Chief Marshal B.S. Dhanoa is understood to have designated a Group Captain-rank officer to be embedded with the new effort and help accelerate development of the air-launched Nirbhay for the area attack role. Both the IAF and DRDO have mutually agreed on a target of 2020 for first drop (weapon release) and 2021 for first test launch

But it’s in the Indian Navy’s requirement for the Nirbhay that the missile will really be pushing the proverbial boat out. Simply put, the navy is significantly hungrier for range and wants a version of the Nirbhay that tops its current 1,000 km figures. An Indian Navy source confirmed this, saying the navy is interested in a Nirbhay variant with a maximum range of at least 1,500 km to ‘account for the various types of strike missions that may need to be undertaken with a stand-off system, including land attack’.

“We are developing the three versions of Nirbhay now. The Manik engine should be ready for testing in two years. By the time user trials begin, we hope to be in a position to offer Manik-powered Nirbhay, at which point the system will be over 95% indigenous. This is a major task for us since this is something we have to prove to the world,” Christopher says.

[Indranil]

So Akash is Solid Fuel Ducted Rocket design basically. Any idea of fuel composition...?

~ 3.5 kgs per second.

Generally metallic particles would be used as energy booster. Al/Mg are easy to burn. But Boron have more energy density, though burning it is a challenge.

I read this long time back. Somebody who had worked in this field had posted his resume online. I think the booster is HTPB+Al.

In general, Akash can be optimized quite a bit. Only about 225 + 60 kg of the missile is fuel + warhead. Meaning: the airframe + guidance systems weigh ~450 kgs! They know how to make much more miniaturized systems now. Therefore, I expect Akash NG to be lighter and smaller, while it increases range to 50 kms. As proof, here is what I had posted some time back

Future Astra is not based on the Brahmos motor at all. If anything there are lessons learnt from Akash. But the motor and fuel in general is very different.

Meanwhile, Akash NG will most likely be canisterized. The inside of that canister (for testing its short burn motor) measures 367 mm X 367 mm X 4863 mm. There will be a guide rail on the top, and one wing rail each on the two sides. Draw your own conclusions.



Courtesy: DRDL tender.

So at least it will be 1 mtr shorter in length with a marginal reduction in diameter.

[Indranil]

1. Could you tell me the A3 range - payload spec that you believe is true and it's web reference?
2. Same for K4?

Curious that A3s basic info like diameter & wt are consistently reported by various media & govt along with pictures. While for K4 the dia and weight are ambiguous and no picture.

Neither the modified Agni 3 nor the K4 has ever been shown to the public eye. Both have been acknowledged by Chander, Saraswat, Thomas, Sekaran and Reddy in different interviews. My theory is that they are the IRBMs that we have actually fielded as road mobile units. Moving a 20 mtr long missile like Agni 4/Agni 2 by road is not easy. It is a pity that I have lost the K4 tender document. But IIRC, it is 2 mtr diameter, about 12 mtr length, weighing about 20 tons. In all likelihood, Tratec won that tender (as they have built of Agni Trailers) and its mention of 25-ton missile TEL without a picture in its product line is quite revealing.

1. Let us assume the previous A2 & A3 accuracy was 200m and now the accuracy is 40, has that reduced the yield requirement by a factor of two ? and tomorrow if the accuracy is 1m how much lower yield will be ok?
2. The suggested lower payload is due to lower yield or warheads with higher yield to weight ratio?
3. What is forcing indian weaponeers to freeze the number of warhead on missile and not provide for more petals count?

Actually, the drift was much more than 200 mtrs earlier. They had abysmal accuracy with their hardware sensors and came up with some great software solutions to overcome some of these deficiencies. But even then then, the initial Agnis/Prithvis had a drift of about 0.01-0.03% of range. The decrease in payload is not my words. Here is what Avinash Chander:

Source
Avinash Chander said, “Megaton warheads were used when accuracies were low. Now we talk of (accuracy of) a few hundred metres. That allows a smaller warhead, perhaps 150-250 kilotons, to cause substantial damage. We don’t want to cause wanton damage (with unnecessarily large warheads).”

As I try to answer the above, in my mind A3 and K4 are different pupose missiles, not needing to be boxed into a common payload to range performance matric.

There is a possibility that they optimized Agni 3 to carry more petals, instead of weighing less overall. But it is unlikely that they are fielded that way now, because hardware realization of petals is ongoing. Agni VI is supposed to have a payload of 2.5-3 tons for support of 4-6 petals.

You give me the following and can tell approx weight of the booster & 2nd stage
1. weight of the 3rd stage + its mass fraction ,
2. the payload-mass
3. the desired range,
4. Mass fraction of booster & second stage (guesstimate based on assumed drdo mastery )

1. Only two stages. First stage: mass fraction 0.88. Second stage: mass fraction: 0.92. Same figures as Agni 4.
2. Payload mass 1.2 tons
3. 3500 km
4. 3:1

[Gagan]

https://www.youtube.com/watch?v=MBneQB-_F1s

[sudeepj]

Finally seeing some Indian TELARs.. B-)

[Haridas]

You give me the following and can tell approx weight of the booster & 2nd stage
1. weight of the 3rd stage + its mass fraction ,
2. the payload-mass
3. the desired range,
4. Mass fraction of booster & second stage (guesstimate based on assumed drdo mastery )

1. Only two stages. First stage: mass fraction 0.88. Second stage: mass fraction: 0.92. Same figures as Agni 4.
2. Payload mass 1.2 tons
3. 3500 km
4. 3:1

Q1 needs answering. After you make your computations what is the assumed Weight of 3rd (upper stage) and it's mass fraction?
Q4 was answered by you as: `First stage: mass fraction 0.88. Second stage: mass fraction: 0.92" ; this is not possible if both stages are composite. Booster MF will always be better than the stage above it. Pls recheck and advise.

I presume dia is 2 m.

[Indranil]

1. I am speaking of a 2 stage Agni 3. No third stage at all.
2. First stage booster is made out of maraging steel mass fraction of 0.88. I get this number from Agni 4. They came out with a variant which allowed them to go up from 0.86 to 0.88.
3. Second stage is made out of wound glass-composites with a mass fraction of 0.92. Again number if from Agni 4. The use of composites there improved the mass fraction from 0.85 to 0.92.

[chetak]

nice touch with the poojari.

Agni-V launch

[hnair]

https://www.youtube.com/watch?v=MBneQB-_F1s

Adorable little wheels on that tractor. Wonder what is the purpose of this vehicle, since this does not look like a cross-country play or even long-distance roll?

Pull the TEL out of a tunnel and fire?

Haridas-saar, good to see you. Been a while

[prasannasimha]

^ This is not for cross country mobility like the ones on the Russian Steppe but for cross road mobility in various "depot"s and this will not be the actual open trailer but obviously covered and camouflaged

[prasannasimha]

This test was likely a tight corner turn test

[shiv]

This test was likely a tight corner turn test

Republic day parade. Voice says "Parade mein hoon". People wearing warm jackets

What year was this displayed?

[abhik]

Probably based on some commertial off the shelf solution (the recently posted A5 one is also similar) for heavy oversized cargo like below: -
https://www.youtube.com/watch?v=uiRNJ2LauQ4