Quote:SSridhar
Quote: SaiK wrote:looking at the nozzle exhaust, what is the science behind :-
1. The flame is visible only from meters away from the nozzle?
2. The dia or size of flame is much narrower than the nozzle dia?
The plume signature is determined by a number of things such as propulsion systems, propellants, nozzle geometry etc. The plume exits the nozzle at supersonic velocity. There are two parts of the plume which are of interest, the periphery and the central part (aka inviscid inner core). They both hit a shock wave subsequently. The periphery hits an oblique shock wave and the flow direction is bent. The central core part passes through a shock wave that is perpendicular to the incoming supersonic flow that results in no change in direction. This boundary is known as Mach Disk. These cause the typical diamond shape.
The inviscid inner core which is also fuel rich had not yet mixed with the air unlike the peripheral flow which burns with the oxygen in the air. At Mach Disk, the inner core reduces in velocity but increases in temperature and pressure and burns with the oxygen in the air. Hence we see the flame a few feet/metres away from the nozzle. The flow beyond Mach Disk becomes subsonic and again increases to supersonic. This pattern is repeated.
IIRC SSridhar is mixing the inner and peripheral flow in the explanation above. The core flow is optimally mixed ( Stoichiometric ratio of fuel and exidizer) and burm at maximum efficiency while peripheral flow is intentionally fuel rich (excess fuel as used as coolenat to save the nozzle throat material from melting/ablating).
"Ramana: A reconfigured 3 stage Agni-V can place 700 Kg satellite in 400 km altitude orbit at 110 degree inclination"
Arunji, did'nt you say 550 kg to a 200 km orbit some pages back in this thread (with conservative assumptions)? Maybe we should be conservative about these estimates. There are some media reports that A-III uses maraging steel motor cases only and composite cases will be introduced only with A-V....
KrishG on BR says 200-250 kg for a modified 3-stage A-III. This may be for A-III+SUM. The Start LV, which is a topol icbm+4 th stage does 632 kg to 200 km LEO...with three stages, the payload will be much less...
If you want to put a sat in orbit, it has to be atleast 500km in the most conservative estimates for the life line of sat.Anything lower than that orbit will reduce the life of the sat.And a 200km orbit? what could be the possible life span for a sat in such orbit? maybe months? with galons of fuel onboard for station keeping?
1) In the VKS interview:
Quote:You have also been quoted as saying that we donââ¬â¢t need to build and store missiles as we have the capability to convert two weapon systems at short notice. The question is, a certain number of missiles will always need to be made and stored as, after all, how short is the short notice. Would you agree with this?
This statement was made to the media in the context of the Agni missile. You will appreciate that the Agni class of system is not a tactical missile. When you talk of strategic missiles and you donââ¬â¢t have a threat today for these class of weapon system, and I was saying this in the context of an ICBM then there is no need to make and store these weapons.
What he is saying is he can build at short notice that class of vehicles for which there isnt a current need.
2)Chandragupta the idea is to launch quick reaction sats to provide coverage and not for normal sat launches which are in long life orbits.
3) Converting a missile to a sat launch is very energy intensive. You will be surprised how quickly the sat weight drops vs throw weight. The reason is orbital injection velocity is > 7km/sec and missile throw weight velocity is less.
4) A "non-test" test of missile capability is to demonstrate its sat launch capability to 400km orbit. It sends the signals witout alarming people.
[quote name='Kritavarma' date='10 March 2010 - 07:23 PM' timestamp='1268228711' post='105036']
"Ramana: A reconfigured 3 stage Agni-V can place 700 Kg satellite in 400 km altitude orbit at 110 degree inclination"
Arunji, did'nt you say 550 kg to a 200 km orbit some pages back in this thread (with conservative assumptions)? Maybe we should be conservative about these estimates. There are some media reports that A-III uses maraging steel motor cases only and composite cases will be introduced only with A-V....
[/quote]
I guess I should specify the stage configuration when I report Agni-V's satellite capability. This one is for this confign.
Code: Payload = 750.0 Kg, Number of Stages = 4, Simulation Time Granularity = 0.100 Second
Launch Direction = 110 degrees-North, Launch Latitude = 22.00 degrees
Segment-Name ISP(Vac) ISP(SL) Stage-Mass Fuel-Fract Burn-Time Thrust-Direction Diameter Length ThrustOverdrive OverdrivePeriod
Stage1 269.0 237.0, 33,000.0 0.900 080.0 Sec 50.0 Degree 2.00 Meter 07.00 Meter 15.00 % 20.00 %
Stage2 290.0 190.0, 14,000.0 0.870 060.0 Sec 25.0 Degree 2.00 Meter 03.50 Meter 10.00 % 10.00 %
PayloadAdaptor 000.0 000.0, 00,150.0 0.700 001.0 Sec 00.0 Degree 2.00 Meter 03.30 Meter 00.00 % 00.00 %
Stage3 290.0 200.0, 03,500.0 0.850 030.0 Sec 10.0 Degree 2.00 Meter 02.00 Meter 00.00 % 00.00 %
[quote name='Chandragupta' date='10 March 2010 - 10:47 AM' timestamp='1268197767' post='105023']
May be not Arun.
Even an A-III with no modification is reaching a peak height of 350km with 2500KG payload capability.
Maybe your numbers need some alteration?
[/quote]
I am talking of orbital flight, you are talking few sub-orbital BM flight.
[quote name='Austin' date='10 March 2010 - 07:45 AM' timestamp='1268186843' post='105017']
Couple of points
We can now conclude that the definitive variant of PAD will be the all solid fuel PDV with IIR seeker , the PAD acted as Proof Of Concept Interceptor Vehical plus provided a quick deployable solution to deal with Pak threat
The PDV with greater than interception altitude of 100 km should be capable of intercepting LEO satellites with modification
VKS backed down on his we are better than China perhaps with some nudge from GOI ?Now he says China is better
AAD-1 and AAD-2 clearly designed to deal with higher IRBM,full ICBM threats , its also good to know we are working on Sat based EW system and integration with AWACS and other assets.
[/quote]
On this discussion a response received from a friends via email:
Quote:Definitely told to hold off many details. His earlier statements - some of which I was privy to a public event, were much more forceful and categorical. The GOI apparently didnt like him being forthright.
Interesting that they plan for Tx/Rx modules from outside for the new LRTRs - possibly x band which given timelines, makes sense (we are following the same approach for the first batch of AESAs for the LCA Mk2).
Quote:Guys, got a chance to read this in detail.
The interview is pathbreaking - he clearly lays out the information albeit some aspects are still wink nod nudge nudge.
The solid fuelled advanced PDV (the IIR is where India has said we will cooperate with anyone necessary - Boeing, Raytheon et al work with IAI for the Arrow advanced IIR seeker for its HTK vehicle) will be logistically less cumbersome and far more mobile than the Prithvi based one. We already know how to make IIR seekers - Nag e.g. - we need capabilities viz manufacturing the detection sensor.
The PDV also elevates the local BMD program to state of the art across the board - our desi forces are not always impressed with performance alone, and often get sidetracked by discussions about BBC - best of brochure claims, which is then acrimoniously played out by a willing media, and ruins the deterrence effect of solid technology achievement and deployable capability.
The next series of advanced radars which follow on from the LRTR with the AAD-1 and AAD-2, when mass manufactured have the ability to take the game away from the PRC support of Pak. It is by no means certain that all the TRM modules will be imported or the computers. From what I know, this was what was expected of the LRTR/MFCR as well, instead we developed our own systems over time. His statements indicate that the LRDE has been given a very short timeline for quick induction & hence the need to crimp corners (eg balance indigenization versus having a ready system ASAP). There are two ways to get these systems - either commercially or via a strategic partner with relatively modern fabs. It will be interesting to see which approach is preferred.
Now, what he has not mentioned but which is equally critical, is the cruise missile syndrome. Pak f.e. is now counting on increased numbers of BMs and CMs for deterrence.
Saraswat clearly notes that the BMD system is being tied into the indigenous IACCS which is a big win. A total of x aerostats have been ordered so far, which basically act as cheap "eyes in the sky". The indigenous AEW&C should have a range of around 100+ km against a CM target which is adequate time for an interception, giving a time of around 12 minutes for interception if it is travelling at a high speed of 500 mph. As a case in point, the BMD system itself reacts w/in a window of a couple of minutes.
A total of ~20 AWACS are required for round the clock surveillance, and because of which indigenous development is now critical and supported by the IAF (cost).
The Akash, Barak-8/LRSAM and AAD, AAD-1 are capable of intercepting very low flying targets as well. The IACCS will be up and running by 2011. All in all, the basic building blocks of deterrence from nuke blackmail are being put in place, with the IAF estimating ~2022 for its SAGW assets to be totally replenished, and by which time the BMD should also be in production.
Hopefully all this will give the next GOI some guts versus the current WKK currently running the GOI and they will finally stand up to the terrorists and not kowtow to them. One hopes. :-(
[quote name='Arun_S' date='10 March 2010 - 03:46 PM' timestamp='1268257118' post='105055']
I guess I should specify the stage configuration when I report Agni-V's satellite capability. This one is for this confign.
Code: Payload = 750.0 Kg, Number of Stages = 4, Simulation Time Granularity = 0.100 Second
Launch Direction = 110 degrees-North, Launch Latitude = 22.00 degrees
Segment-Name ISP(Vac) ISP(SL) Stage-Mass Fuel-Fract Burn-Time Thrust-Direction Diameter Length ThrustOverdrive OverdrivePeriod
Stage1 269.0 237.0, 33,000.0 0.900 080.0 Sec 50.0 Degree 2.00 Meter 07.00 Meter 15.00 % 20.00 %
Stage2 290.0 190.0, 14,000.0 0.870 060.0 Sec 25.0 Degree 2.00 Meter 03.50 Meter 10.00 % 10.00 %
PayloadAdaptor 000.0 000.0, 00,150.0 0.700 001.0 Sec 00.0 Degree 2.00 Meter 03.30 Meter 00.00 % 00.00 %
Stage3 290.0 200.0, 03,500.0 0.850 030.0 Sec 10.0 Degree 2.00 Meter 02.00 Meter 00.00 % 00.00 %
[/quote]
Except for thrust directions and launch direction, this config file is the same as the one on pg 7 of this thread. So much altitude difference ? Also, payload in this file is the same as that of last file. So, you must say 750kg - ~200kg for guidance and navigation syatems, etc. So, is'nt orbital payload ~550 kg rather than 700 kg ?
Rocksim does not optimizes trajectory for orbit insertion, so it is an iterative thurst angle optimization effort to determine max payload to orbit. It does have feature to stop thrusting when orbit is reached.
As you correctly observe this latest simulation has different thrusting angle, and I spent time to get it to near optimum insertion trajectory, and that made the difference in reaching 400km orbit.
Yes there is overhead of control system that must be accounted for in the 750 kg payload, although the navigation system could be common and carried in satellite. On the flip up-side the mass faction of upper stage is still conservative and a BM converted to space launcher would greatly benefit if upper stage was brought to the correct proportion of previous stage with net mass of ~4.7 tonne.
In my considered view and some other people I highly value on this forum, the key point in Saraswat's statement is that some numbers of Agnis' can deliver heavy payload across all possible trajectory in BM or orbital trajectory depending on contingency.
Important to note that all future wars may be LIW.
As outlined by late Air Chief SK Mehra, in a discussion 9 years ago. Raising of multitude of Rashtirya Rifles was initiated that time and it was a new novel phenomenon then.
[size="4"][color="blue"] [/color][/size][url="http://www.hinduonnet.com/thehindu/thscrip/print.pl?file=2010031259840300.htm&date=2010/03/12/&prd=th&"][size="4"][color="blue"] Agni-V may be test-fired next year [/color][/size][/url]
Quote:Date:12/03/2010 URL:
Special Correspondent ââ¬ËIt will provide the country with second strike capability' ââ¬ËDRDO capable of designing anti-satellite system'
ââ¬ËAll future wars may be low intensity conflicts'
MYSORE: Agni-V, India's version of Inter-Continental Ballistic Missile (ICBM) with a range of more than 5,000 km, will be test-fired by early 2011, according to W. Selvamurthy, Chief Controller, R and D (Life Sciences), Defence Research and Development Organisation (DRDO).
He was interacting with presspersons here on Thursday on the sidelines of a seminar on Futuristic Food Requirement of the Armed Forces organised by the Defence Food Research Laboratory (DFRL).
Capacity
Dr. Selvamurthy said the DRDO scientists were working on Agni-V which was a three-stage solid fuelled missile and it would have a payload of one to 1.5 tonne and could carry conventional nuclear warhead. ââ¬ÅIt will address our immediate threat perception and since India has declared and adopted a no-first strike policy, Agni-V will empower the country with the second strike capability,ââ¬Â Dr. Selvamurthy said.
He described Agni as an important missile delivery system. Agni V was a surface-to-surface missile and came very close to qualify as an ICBM. Commenting on Agni-III which was test-fired successfully thrice, Dr. Selvamurthy said it had met all parameters and the armed forces would decide on the actual induction programme.
Major concern
On the development of anti-satellite system and space security imperatives, the DRDO scientist said space security was a major concern but there was no separate anti-satellite programme as such though the DRDO had the core capability of designing and developing such a system if the need arose.
He said the DRDO already had the capacity to deliver such a system based on its earlier missile delivery programmes and all that was required was to modify and transfer this to the requisite format, he added.
Dr. Selvamurthy said the DRDO had visualised future battle and conflict scenario and was gearing to meet the new changes.[color="#0000ff"] He said a brain storming session was held recently on Battle Scenario 2020 and it emerged that high intensity conflicts like the World War I and II were passé as also the Middle Intensity Conflict. He said the country's challenge would be Low Intensity Conflict (LIC) as being witnessed in Jammu and Kashmir, operations against naxalites and counter terrorism operations and hence the DRDO was launching a major initiative to support the LIC in due course through appropriate weapon delivery systems.[/color]
While the high-intensity conflicts ended with the two World Wars, the [color="#4169e1"]middle intensity conflicts too were an unlikely scenario or had a low probability in view of economic and trade issues and hence future war scenario would be low intensify conflicts,[/color] he added.
The other countries were envious of India's high GDP growth bordering on 7.5 per cent to 8 per cent and hence the country had to brace for low intensity conflicts, said Dr. Selvamurthy.
On the nuclear-biological-chemical (NBC) war scenario, Dr. Selvamurthy said the country was prepared to handle it and the Cabinet Committee recently sanctioned an additional Rs. 300 crore for developing contingency measures. He pointed out that the standard operating procedure (SOP) of command and control were in place and the guidelines for implementing the SOP were in place in addition to a quick response system.
The DRDO had developed capabilities and contributed to early detection, personal protection, collective protection, de-contamination and rescue operations. He said for aerial monitoring for nuclear devices as also chemical warheads had been developed and for battle field operations, it had developed a portable gas chromatography devise that could detect chemical vapour in the event of a chemical warfare.
Diagnostic kits
It had produced biological field antigen-based diagnostic kits apart from unmanned recce vehicle which would map contaminated zone and a remotely operated vehicle Daksh that had the capacity to diffuse any explosives.
Dr. Selvamurthy said the DRDO had developed a stand alone-stand off detection system, unmanned aerial and ground vehicle mounted with sensors to detect explosives and chemicals among others and welcomed private sector participation in the defence sector.
[quote name='Arun_S' date='11 March 2010 - 11:15 PM' timestamp='1268329029' post='105087']
Rocksim does not optimizes trajectory for orbit insertion, so it is an iterative thurst angle optimization effort to determine max payload to orbit. It does have feature to stop thrusting when orbit is reached.
As you correctly observe this latest simulation has different thrusting angle, and I spent time to get it to near optimum insertion trajectory, and that made the difference in reaching 400km orbit.
Yes there is overhead of control system that must be accounted for in the 750 kg payload, although the navigation system could be common and carried in satellite. On the flip up-side the mass faction of upper stage is still conservative and a BM converted to space launcher would greatly benefit if upper stage was brought to the correct proportion of previous stage with net mass of ~4.7 tonne.
In my considered view and some other people I highly value on this forum, the key point in Saraswat's statement is that some numbers of Agnis' can deliver heavy payload across all possible trajectory in BM or orbital trajectory depending on contingency.
[/quote]
Also you would have noted this the maximum payload possible, when laucnhed at most optimum orbital inclination. Unlike ISRO's regular satellites that are eaither launched in polar or equitorial plane that have handicap of dog leg manuvering around Sri Lanka or needling around Indonasia. In war time such constrains are less relevant.
Important to note that all future wars may be LIW.
It is well understood. Despite Red fort n Parliament attack, India did not, could not start a war. Other fact being both are nuclear armed nations. But India is amassing tanks in numbers and buying fighters as if there is no tomorrow and assuming falsely the war would break out within few years, while Russia has decided to diminish its tank strength at half, despite surrounded by Nato countries.
Quote:Ministry of Defense made an official statement that the Army does not need half of its tanks (over 10,000). Half of the remaining tanks would be used as battle tanks, while the other half would be in reserve.
Nearly four decades without a battle and our war material being decayed without a engagement. Its time we use some prudence and limit our Military purchases, for India is not a rich country, neither it is developed country. On the other hand we have billions to spend on our power resources as we import many reactors and its fuel combined. India is being forced to borrow (already we owe 242 billions) and the end result would be ruinous. If we have decided that its gonna be a LIW, India does not need to have 1000 fighters, now that we have all types of missiles in our arsenal.
03-13-2010, 07:13 AM
(This post was last modified: 03-13-2010, 07:13 AM by ramana.)
DRDO Newsletter for March 2010
Has AIII test and other details
03-13-2010, 09:38 AM
(This post was last modified: 03-13-2010, 09:44 AM by Arun_S.)
[quote name='ramana' date='13 March 2010 - 07:21 AM' timestamp='1268444607' post='105143']
[url="http://www.drdo.com/pub/nl/2010/mar10.pdf"]DRDO Newsletter for March 2010[/url]
Has AIII test and other details
[/quote]
Very cool.
It has first evidence fo Agni-III SL Submarine Launched:
Quote:At present, cassette casting and pressure casting
technologies are being developed which are ideal
for large number motor processing. Technology is
also being developed to process dual-thrust grain
to meet the boost and sustain phase requirement
during flight. To process the complicated web
geometry grains, ribbon casting has been developed
and the propulsion system was used in pop-up trial
of a missile recently. [color="#0000ff"]In a space-constrained system,
high performance index (Isp X density) propellant is
being developed by increasing solid loading[/color].<img src='http://www.india-forum.com/forums/public/style_emoticons/<#EMO_DIR#>/rolleyes.gif' class='bbc_emoticon' alt=' ' />
[color="#0000ff"]Recently, a 26-petal geometry motor with 25 kp
viscosity was cast by bottom pressure casting at 10
atm pressure and cured at 20 atm pressure which
demonstrated 5 per cent gain in performance index.[/color]
For casting intricate geometry grain, collapsible
dissolving mandrel technology is being pursuaded.
Recently,
The former is critical for Arihant's all stages of teh compact 2 m dia missile and , where as the latter for ABM booster motors.
Quote:The strategic programme of DRDO
will require further heavy lift booster in
the coming years. In another 5 years,
there will be demands from many missile
systems for composite case (carbon/
epoxy) motors. There is a need to
develop infrastructure for the production
of composite case motors in large
numbers dia. In many strategic systems,
third stage will be added, preferably
with [color="#0000ff"]low-density[/color] energetic propellants in
composite case for the range gain
I think "low-density" is typo based obfuscation.
[quote name='Arun_S' date='13 March 2010 - 09:46 AM' timestamp='1268453294' post='105146']
Very cool.
It has first evidence fo Agni-III SL Submarine Launched:
The former is critical for Arihant's all stages of teh compact 2 m dia missile and , where as the latter for ABM booster motors.
I think "low-density" is typo based obfuscation.
[/quote]
Typo it is not, unless you have something to comment!
[size="6"][url="http://news.rediff.com/report/2010/mar/13/india-likely-to-testfire-add-missile-on-sunday.htm"]India likely to testfire AAD missile on Sunday[/url][/size]
With an eye to develop a full fledged multi-layer Ballistic Missile Defence system,
India is likely to test-fire its indigenously designed and developed Advanced Air Defence missile from the Integrated Test Range off Orissa coast on Sunday.
The AAD missile is capable of destroying any hostile ballistic missile at low altitude situation, defence sources said today.
Range integration work at the ITR for the proposed trial is complete and the test is likely to be conducted tomorrow, they said.
The target missile, a modified indigenously built 'Prithvi' posing as an enemy missile, would first be lifted off from a mobile launcher from the ITR at Chandipur-on-sea and the interceptor AAD missile using a radio frequency seeker on-board would be blasted off from Wheeler Island about 70 km across the sea from Chandipur.
The missile would destroy the target in mid air over Bay of Bengal. The interception is to take place at low altitude, the sources added.
The seven-meter-long ADD interceptor is a single stage solid rocket-propelled guided missile, equipped with an inertial navigation system, a hi-tech computer and an electro-mechanical activator totally under command by the data up linked from the sophisticated ground based radars to the interceptor, defence sources said.
The interceptor missile has its own mobile launcher, secure data link for interception, independent tracking and homing capabilities and its own radars, they said.
Balasore district administration have made arrangements to temporarily evacuate about 600 families from five hamlets residing within 2 km radius of launch pad-3 of the ITR at Chandipur to nearby shelter camps as a security measure, official sources said.
[quote name='ankit-s' date='13 March 2010 - 03:26 PM' timestamp='1268473695' post='105149']
Typo it is not, unless you have something to comment!
[/quote]
Pls enlighten the utility and application of said Low density fuel, rather than developing just high energy fuel.
re Arun_S
I think you would have noticed that some recent news reports have mentioned the range of Shaurya at around 1900km, which means that it reasonably good reach. Incidentally i have still not understood the rationale for its cruise missile profile. It cruises at height of 40km which means that it would be visible to ground radar from a few hundred kmm (around 700km) so what could be the benefit?
[quote name='Arun_S' date='14 March 2010 - 07:24 AM' timestamp='1268531179' post='105159']
Pls enlighten the utility and application of said Low density fuel, rather than developing just high energy fuel.
[/quote]
Its a higher specific impulse, more thrust albeit with tankage penality. But here also they are switching to composite case which in turn means weight reduction too.
Arianeôs last stage uses low density LH2 fuel, Saturn-5 used the same on its upper stage, so is space shuttle. Not only that, just think why GSLV also uses low density fuel for its last stage.
Quote:In many strategic systems,
third stage will be added, preferably
with low-density energetic propellants in
composite case for the range gain
High density fuel may not be imperative for the last stage which has less to worry about gravitation drag than on a boost phase.
The article is 8 days old as published (website), yet without any rectification/correction.
If it were high density propellants, as is common - they would not be using an adjective preferably.......
[size="6"][url="http://www.bharat-rakshak.com/NEWS/newsrf.php?newsid=12531"]Technical snag delays missile shield test[/url][/size]
The test-fire of the indigenous Advanced Air Defence (AAD) missile has been postponed. The AAD missile was to be test-fired today (March 14) from Chandipur in Orissa. It is now likely to be test-fired on Monday.
Defence sources say that the AAD missile is capable of destroying any hostile ballistic missile. The missile shield is meant to protect major cities, nuclear power stations, space facilities and military installations.
A target missile will first be lifted off a mobile launcher in Chandipur and the interceptor AAD missile will then be blasted off Wheeler Island about 70 km across away. The seven meter long rocket-propelled missile is expected to be deployed into defence system by 2016.
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