Indian Missiles and Munitions Discussion

[ramana]

Negi, Static stabilty is when the Center of Pressure is aft or behind the center of gravity. The addition of fins make that possible and prevents tumbling. BTW, way back in 1999 I wrote a Short Note on Iron Bombs

[Indranil]

My theory is very simple. The deployment of all the 4 fins have to be in perfect sync. If any one fin and it's opposing fin is out of sync, then the differing angle of attacks while deploying is creating asymmetric drag leading to the wobble.

I think one way to solve this problem is to make the deployment faster, i.e. the fins should start to deploy faster and should deploy at a much faster rate. Here are some pics of GBU-12. Check how quickly the fins are deployed.


You can see that there might be roll but no wobble.


On the contrary a slower deployment after release from an internal bay of F-35 shows the wobble.

[vasu raya]

From the tarmak article,

Sudarshan has onboard a flight control computer with MEMS-based (microelectromechanical systems) rate gyros. It also has high-precision linear ball-lead-screw actuators (to move the control surface). The four tail fins get deployed during the flight. A next-generation bomb (NG-LGB) studded with new technologies is in the pipeline, but the scientists need to address the problem of rolling of the bomb, after its release.The range of Sudrashan now is around 9 km, if dropped from a normal altitude, and for the NG-LGB we hope to increase the range to 50 km

isn't the roll corrected by rear fins such as these that move on an axis perpendicular to the test article,

http://upload.wikimedia.org/wikipedia/c ... tion_2.JPG

btw, if Kanson and Indranil say that the wobble is just a minor thing, I would believe it

[Prem Kumar]

With the wobbles (for both Sudarshan & some of the Paveway clips), how does the LGB even achieve a 10m CEP?

Its not following a ballistic path. Is the fire control computer smart enough to adjust for the wobble and get the LGB in the approximate "box" near the target, from where the seeker can "see" the laser spot? If its lock on before launch, the seeker field of view must be decently big for the LGB to continue seeing the target even after all the wobbles

[Indranil]

isn't the roll corrected by rear fins such as these that move on an axis perpendicular to the test article,

The comparison will not be correct. For the AAD the fins are actuated. On the LGB, they are only for directional stability. So they do arrest the roll, but that is not "active" control.

btw, if Kanson and Indranil say that the wobble is just a minor thing, I would believe it

Nanha mujaheed here. I am learning on the way.

[Indranil]

With the wobbles (for both Sudarshan & some of the Paveway clips), how does the LGB even achieve a 10m CEP?

Its not following a ballistic path. Is the fire control computer smart enough to adjust for the wobble and get the LGB in the approximate "box" near the target, from where the seeker can "see" the laser spot? If its lock on before launch, the seeker field of view must be decently big for the LGB to continue seeing the target even after all the wobbles

No, Sudarshan definitely must be stabilizing after a while. The concern is if it breaks lock before stabilization.

To answer the FOV question, the nose on the LGB can swivel.

[vasu raya]

vasu raya wrote:
isn't the roll corrected by rear fins such as these that move on an axis perpendicular to the test article,

The comparison will not be correct. For the AAD the fins are actuated. On the LGB, they are only for directional stability. So they do arrest the roll, but that is not "active" control.

OTOH Negi says that the strake fins on dumb bombs cause them to roll in a way giving directional stability, even the tarmak article says that Sudarshan has roll problem even after the larger fin deployment, so really asking if the fins can be actuated like the AAD ones to arrest the roll?

[Indranil]

OTOH Negi says that the strake fins on dumb bombs cause them to roll in a way giving directional stability,

Of course that can be done. If all the fins are generating lift, then bomb will roll.

so really asking if the fins can be actuated like the AAD ones to arrest the roll?

No. They don't need to be actuated. The canards on the nose are already actuated for that.

[shiv]

tarmak

http://tarmak007.blogspot.in/2013/02/blog-post.html

Falling bodies stabilize at about 55 m/s - which is pretty slow - about 200 kmph. The Jaguar is probably doing 500 kt or about 900 plus kmph. The camera wobble suggests significant buffeting by turbulence. The wobbling of the bomb and even tumbling could occur at such speeds.

However the bomb does go decidedly nose down (It "knows" which way to go )and visibly decelerates and would probably have stabilized in a few seconds after deceleration to less insane velocities (for a dumb bomb) . It is probably a good idea that the aerofoil near the tail generate some lift - that would lift the tail and drop the nose ensuring that the bomb does not go nose up and hit the aircraft.

[shiv]

Truely CHanakyian, reduce missile weight by half but manage to keep the same range.

If the warhead weight is reduced, the propellant weight can be reduced too.

[vasu raya]

Indranil, here is a image of JDAM-ER (with main wings folded) which is most likely the direction the Sudarshan family's NG-LGB with 50km range is going to go,

http://www.deagel.com/library1/medium/2 ... 800027.jpg

and then there is talk of standardizing the tail piece across various kit configurations using adapters.

[Prem Kumar]

No, Sudarshan definitely must be stabilizing after a while. The concern is if it breaks lock before stabilization.

To answer the FOV question, the nose on the LGB can swivel.

The bolded part is the concern. After the rolling stops, you can see the amount of lift that is generated in some of the Paveway videos. Must be really dangerous for the aircraft, if the thing is not designed right.

Given the amount of buffetting after the drop, followed by the lift, the swiveling head would have to go through some serious conical search patterns before it will detect the laser reflection. Just the fact that Sudarshan can achieve a 10m CEP after all this is a pretty serious achievement.

Wiki on Paveway 2 or 3 talks about the ability of the pilot to turn on the seeker in the LGB after some period of unguided flight in a long range, toss bombing deloyment. The other option seems to be the line of sight, non-ballistic, shorter range deployment

[nits]

Ahead of Nirbhay launch, DRDO staff gagged

The Defence Research and Development Organisation (DRDO), Bangalore, has launched probably one of the most secretive operations in recent times ahead of the upcoming maiden test of Nirbhay, a subsonic cruise missile.

Sources confirmed to Express on Wednesday that the missile has reached the Interim Test Range (ITR) in Chandipur in Odisha after its long journey from Bangalore by road. The tentative launch date is now fixed for March 10 and the campaign activities will enter the last lap in the coming days.

But DRDO officials in Delhi, Bangalore and Hyderabad have gone into a shell, working on a common script and refusing to reveal any details of the launch.

“The DRDO headquarters had to answer some queries recently over too many sensitive matters appearing in the media. These are national programmes and the DRDO has been told to adopt a tied-tongue policy,” a top official with the Ministry of Defence (MoD) said.

The Services too have expressed their displeasure of too many DRDO officials interacting with the media, ahead of critical launches.

Nirbhay will have its maiden test from a mobile launcher with a pre-designed target set in the sea. Sources said that the R&D Engineers, Pune, a specialised arm of DRDO, have completed making changes on the launcher.

The missile was originally scheduled to be tested in October 2012, but last-minute changes on the launcher brought in delays.

With an ability to travel at a speed of 0.7 Mach and perform multiple manoeuvres, Nirbhay is the first full-fledged missile being developed in Bangalore.

Designed and developed by Aeronautical Development Establishment, Nirbhay is a two-stage missile with a range of about 1,000 km.

[negi]

OTOH Negi says that the strake fins on dumb bombs cause them to roll in a way giving directional stability

Well the fins do not induce the roll per se; as I said if there were no fins the spin across the logtitudnal axis might still be there however since there is no structure to
guide the airflow and act as a drag chute (yes fins provide stability by making use of drag very similar to use of a drag chute in concept only difference being they induce lesser drag in a more practically deployable form)
the body will also wobble; by putting a fins at rear end far from CG of the bomb one is actually making use of drag to kind of anchor the rear end as the bomb falls through the atmosphere , this reduces the wobble (throw a stone with and without a string attached to it; in case of the latter the stone will not wobble as much as the former however you will loose range due to the drag). In case of a munition which makes use of foldable fins which deploy later roll can be induced if all the 4 fins do not deploy at the same time for if one deploys before any of the other fins the unsymmetrical drag will induce a roll in theory once all four fins are deployed the body should stabilise once it reaches terminal velocity.

[SaiK]

http://video.google.com/googleplayer.sw ... 6key%3Dlh1
sudarshan drop from tramak.. interesting drop taken from a close angle.. thought it would be parabolic, the same is not clearly visible. the flight had little turbulence once dropped, and hopefully stabilized later.
--
PS: apologies to pankaj/shiv saar had already linked it.

[ramana]

News on teh Hypersonic Brahmos front and follow-on projects:

From PTI.

Efforts on to develop tech for hypersonic Brahmos

BrahMos Aerospace, an Indo-Russian joint venture, has initiated efforts to develop technology for hypersonic version of the BrahMos missile which can travel at five to seven times the speed of sound, a top company official has said.


"The company is roping in academics to develop the requisite technology before going in for designing and developing missiles which can travel at Mach 5 to 7 (five to seven times the speed of sound). It will be BrahMos II version next to the present variants of Mach 2.8 to 3.5," A Sivathanu Pillai MD & CEO of the company told PTI.

He said the IISc, Bangalore, would collaborate with the company with a 20 member scientists' team developing technologies for high temperature material required to build the missile, scram-jet propulsions and energy modules and the requisite algorithms.

A separate centre has been created for this purpose in Indian Institute of Science while its Russian counterpart, the Moscow Institute of Aviation, would produce technologies for propulsion, kinetic energy modules for the hypersonic version.

In all probability, it would take a minimum of five years for these initiatives to crystallise. In the meantime, BrahMos would work out blueprints for setting up a production centre, choice of vendors for supply of necessary components and investment structure, he said.

After these operations, BrahMos Aerospace would take up development of missiles that can come back to the originating mode after destroying the designated target, he said.

So Avatar will be follow-on.

Pillai said modernisation and expansion of manufacturing facilities at Hyderabad and Thriuvananthapuram are also on the cards since the domestic market demand is on the increase.

He said the Indian Air Force had also started placing orders for BrahMos and added that the Army and the Navy are regular customers.

Pillai was here to participate in a felicitation function held in his honour on being conferred the Padma Bhushan Award.

[ramana]

Thinking about the 50 units order for the LGB despite its roll problems shows the IAF is willing to set-up initial production capablity and the need and urgency for LGBs. The ARDE LGB is very clearly a modern design and should be productionised. the production units should have the roll problem licked. ANy timeline of when teh 50 units start showing up?

[shiv]

A certain amount of rockin and rollin may be inevitable initially

Watch this
http://www.youtube.com/watch?v=bRRXK7QnxaU

[pankajs]

India To Establish 2 Additional Missile Test Sites

NEW DELHI — India will establish two more missile testing sites to complement the existing missile testing range in the eastern state of Orissa.

The Defence Research and Development Organization (DRDO) proposes to set up the sites at Rutland Island in the Andaman and Nicobar Islands, and another one at Nagayalanka in Krishna District in the state of Andhra Pradesh.

An official of DRDO said the missile testing range in the state of Orissa is overloaded.

The new test sites will be used for both short-range and long-range missions, the DRDO official said. India is already bulking its Tri-Command based at the Andaman and Nicobar islands. The Tri-Command has been upgraded with infrastructure and additional facilities.

The Indian Navy is proposing to station a nuclear submarine and a landing deck platform at the islands in the future, a Defence Ministry source said.

The Air Force has decided to place its Russian-made Su-30MKI fighter jets in the Andaman and Nicobar islands and is increasing the number of operable airfields there.

[Aditya_V]

Not a Missile per say but still a test

Pinaka rockets successfully test-fired

[Nitesh]

This is test of the old ones already inducted, or with the extended range?

[Aditya_V]

Article says 40KM range so extended range version can be ruled out, we don't know whether accuracy, different types of warhead, user test in operation situation etc.

[SagarAg]

The Air Force has decided to place its Russian-made Su-30MKI fighter jets in the Andaman and Nicobar islands and is increasing the number of operable airfields there.

This is a good move and should be implemented at the earliest. Its a stepping stone in expanding our global reach. We also need a dedicated naval base(read submarine) at A&N islands.

[Singha]

Afaik the andamans are volcanic islands while nicobar are coral islands. If we want deep harbours, submarine caves and deep water andamans is better than nicobar perhaps. Onlee issue could be large stretches are protected tribal lands or reserved forests.

But developing some existing seaport there for naval ops should be feasible with no major hassles.

[SagarAg]

Afaik the andamans are volcanic islands while nicobar are coral islands. If we want deep harbours, submarine caves and deep water andamans is better than nicobar perhaps. Onlee issue could be large stretches are protected tribal lands or reserved forests.

I am sure IN must have thought about this and even recce the area for a possible naval submarine base. Might have encountered some feasibility issues? Who knows. One of the issues is highlighted by you saar. But I think when it comes to national security you get it, even if protected or reserved.

But developing some existing seaport there for naval ops should be feasible with no major hassles.

This is a possible quick alternative.

[koti]

The Air Force has decided to place its Russian-made Su-30MKI fighter jets in the Andaman and Nicobar islands and is increasing the number of operable airfields there.

This is a good move and should be implemented at the earliest. Its a stepping stone in expanding our global reach. We also need a dedicated naval base(read submarine) at A&N islands.

right.
Now just think what a group of TU-22M3's can do in south China sea when placed there and how much of a capability leap they could have offered the IN.

[John]

Now just think what a group of TU-22M3's can do in south China sea when placed there and how much of a capability leap they could have offered the IN.

Tu-22m3 never seems to go away It make very little sense to spent $$$ to purchase tu-22m3 for maritime strike when Flankers can fill that same role. Not to mention all the strings that will come attached with it.

[member_23370]

Tu-22M3 are too long in the tooth and a maintenance nightmare.

[ramana]

With the wobbles (for both Sudarshan & some of the Paveway clips), how does the LGB even achieve a 10m CEP?

Its not following a ballistic path. Is the fire control computer smart enough to adjust for the wobble and get the LGB in the approximate "box" near the target, from where the seeker can "see" the laser spot? If its lock on before launch, the seeker field of view must be decently big for the LGB to continue seeing the target even after all the wobbles

From a description by the Paveway designer, the article drops for 2-3 seconds in ballistic phase before the seeker acquires the signal and then transition where it zig zags for 3-5 secs and then coasts/glides/flies into a conical window and the seeker guides it to the target in about 10-15 secs still zig-zagging but with less amplitude and less often.

No lock before launch.

The important thing to note is DRDO version has a computer and MEMs gyroscope allowing it to have Paveway III features. Once the roll issue is mitigated, it could be a very potent system.

We need to wait for more press release (might have been buried in DDM failing to catch the nuances) to understand if on-off control or proportional control(PC) is used. With all that computer and MEMs gyroscope it could be PC. PC will give it more complexity and more flexibility.

[Karan M]

Folks here are reading far too much into a simple one line description of a possible issue reported by the lay media. The basic thing is that a 9 km range is barely sufficient against MANPADS, whereas a 50 km range would put a Sudarshan MK2 out of reach of even the SPADA-2000 which is currently Pakistan's premier AD system. A trial batch of Sudarshan's is hence OK, and its reasonable to surmise that the ADE can address this problem. Indian weapons design has progressed by leaps and bounds over the past two decades and there is a substantial pool of both design & available subsystems to complement the designs.

Also, I would question the assumption that the IAF is not PGM aware or does not have large stocks. They most definitely do want PGMs and would like to have more, but given a target list of tens of thousands in a full blown conflict, maintaining large inventories is always going to be a challenge. Which is why Sudarshan is such a critical program.

India currently has several types of LGBs (Israeli & limited American stocks), plus many optically guided long range PGMs of Russian origin. These are phenomenally accurate, but are best employed against fixed targets. Going by SIPRI & other numbers would be inaccurate, as the actual numbers will be very hard to deduce from the open press, which SIPRI too relies upon.

Coming to where PGMs are used & whether dumb bombs are of relevance, a recent report mentioned the RAF is transitioning or has already decided to transition to a completely PGM force.
The benefits are worth the cost.

[Singha]

wouldnt medium alt delivery mean the air is clear of hostile fighters and MRSAMs taking potshots ?
fine for RAF to pound some "rebels" or "insurgents" with zero means to strike back, not so fine when going in over Cheen or TSP?

so far our SEAD capabilities are between weak and zero - a few KH31P and armat missiles here and there, no rivet joint, no growlers to accompany...I think a move to medium alt PGMs will need to be tied into a much bigger SEAD machinery across the IAF..a jaguar is survivable skimming the treetops, not so when flying at 15,000ft.

a squadron of 20 ac is a 3 billion dollar investment if you consider loaded cost of a fighter as $100mil each, and then training, salary, ground support infra, munitions, service contracts....imo we would need atleast 60 SEAD ac to make some impression on the problem.

all the fancy PGM delivery we have seen on TV since desert storm has been against absolutely zero/minimal opposition from the ground other than AA gunnners and SAM operators firing away blindly at night after losing their radars and networks. looks cool. but cheen will throw a lot of J10 and Su27 into the fight all with BVR missiles. someone needs to deal with that also. serbia did try to scramble a few fighters and fight back on day1 but lost some planes to the combo of E3 and amraam and went underground thereafter. iraq also ran a few slash and run attacks using Mig23 and Foxbats before bulk of its AF went into permanent exile and boneyard in Iran.

[Misraji]

Two very cool discussions on Paveway vs JDAM

1. Control Surfaces
2. JDAM general

Salient points
- JDAM has canards in front vs Fins in rear for Paveway
- JDAM is primarily INS guided with GPS for correction (even without GPS it seems to reach its target effectively for 2000lb bomb)
- Paveway was built for short-range+high-manouevering as opposed to much smoother trajectory of JDAM

--Ashish

[Misraji]

all the fancy PGM delivery we have seen on TV since desert storm has been against absolutely zero/minimal opposition from the ground other than AA gunnners and SAM operators firing away blindly at night after losing their radars and networks. looks cool. but cheen will throw a lot of J10 and Su27 into the fight all with BVR missiles. someone needs to deal with that also. serbia did try to scramble a few fighters and fight back on day1 but lost some planes to the combo of E3 and amraam and went underground thereafter. iraq also ran a few slash and run attacks using Mig23 and Foxbats before bulk of its AF went into permanent exile and boneyard in Iran.

A-2-A opposition remains a problem for both PGMs vs Dumb-bombs.
The ground opposition is the problem that can be solved.
JDAM does not need to be guided all the way to the target while LGB does.

--Ashish

[Pratyush]

Wrt sudershan, how do we know form the released images that the weapon did not hit the designated aim point. Ie. The laser was pointin to the ground and not the target. Thus showing a near miss. Where, the target was hit, with accuracy.

[Singha]

>> A-2-A opposition remains a problem for both PGMs vs Dumb-bombs

true. but a lo-lo-lo bombing run will not need to climb to 10-15,000ft to drop the bombs assuming it ingressed through contested airspace at low level and intends to eggress that way again.

one soln for PGM delivery from treetop level the MBB DASA developed was a dispenser family called Mjoelnir upto 1400kg

http://www.x-plane.org/home/urf/aviatio ... jolner.htm

Range when launched at 50 m altitude and Mach 0.9 is more than 10 km in the direction the aircraft is flying, or 5 km to the side of the aircraft's path. Navigation is by INS and radar altimeter.
----------------
atleast against non-hardened targets maybe this approach makes sense for India

[Lalmohan]

mjoelnir - the hammer of thor
or the vajra?

[sarabpal.s]

all the fancy PGM delivery we have seen on TV since desert storm has been against absolutely zero/minimal opposition from the ground other than AA gunnners and SAM operators firing away blindly at night after losing their radars and networks. looks cool. but cheen will throw a lot of J10 and Su27 into the fight all with BVR missiles. someone needs to deal with that also. serbia did try to scramble a few fighters and fight back on day1 but lost some planes to the combo of E3 and amraam and went underground thereafter. iraq also ran a few slash and run attacks using Mig23 and Foxbats before bulk of its AF went into permanent exile and boneyard in Iran.

If you want know more about Anti radar operation bu USAF than read this

http://www.amazon.com/Viper-Pilot-Memoi ... B007HBTAP6

Beautiful described how wild-weasel decimate Iraqi Radars and there missile

[shiv]

If you want know more about Anti radar operation bu USAF than read this

http://www.amazon.com/Viper-Pilot-Memoi ... B007HBTAP6

Beautiful described how wild-weasel decimate Iraqi Radars and there missile

Sabarpalji? Rs 903 to find out how US beat Iraqi radar? Not good value for money.

[Lalmohan]

better reading is how serbs managed to hide from US radars

[sarabpal.s]

If you want know more about Anti radar operation bu USAF than read this

http://www.amazon.com/Viper-Pilot-Memoi ... B007HBTAP6

Beautiful described how wild-weasel decimate Iraqi Radars and there missile

Sabarpalji? Rs 903 to find out how US beat Iraqi radar? Not good value for money.

hahaha, need link pm me

BTW they fight with radar and beat it