[quote name='Arun_S' date='01 March 2010 - 01:12 PM' timestamp='1267477444' post='104690']
I think hypersonic engine will have lower ISP compared to supersonic engine.
[/quote]
How much "bulk" would that result in over and above the present BrahMos (though the higher the ISP of the liquid fuel ramjet, the lesser would be the increase in the "bulk")? While this would be dependent upon the flight path/profile, what in your estimation would be the upper and lower bounds in terms of the CM's trajectory during which the scramjet would be deployed?
Ankit-s,
I stand corrected. My gray cells are fatiging, for I forgot the last test's interception altitude.
Do I hear you say that decoys were employed in last test?
[quote name='qubit' date='03 March 2010 - 09:16 AM' timestamp='1267587517' post='104741']
How much "bulk" would that result in over and above the present BrahMos (though the higher the ISP of the liquid fuel ramjet, the lesser would be the increase in the "bulk")? While this would be dependent upon the flight path/profile, what in your estimation would be the upper and lower bounds in terms of the CM's trajectory during which the scramjet would be deployed?
[/quote]
I will have dig into my archive ( unfortunately I am short on time for that), IIRC the hypersonic injection altitude should be ~ 20 km and cruise at ~35 km.
Military ram/scram jet will use the same kerosene fuel. Exotic gas fuel is not very appealing for mil use; though ISRO will very likely use LH2.
[quote name='Arun_S' date='02 March 2010 - 09:38 PM' timestamp='1267594253' post='104745']
I will have dig into my archive ( unfortunately I am short on time for that), IIRC the hypersonic injection altitude should be ~ 20 km and cruise at ~35 km.
Military ram/scram jet will use the same kerosene fuel. Exotic gas fuel is not very appealing for mil use; though ISRO will very likely use LH2.
[/quote]
Arun_S, I'd be grateful for any figures you could prrovide. BTW, do you think that DRDO alone has the where-with-all's to design/modify a scramjet? Given the fact that even for the present BrahMos the liquid fuelled ramjet is Russian, how do you propose that DRDO provide the hypersonic BrahMos with ranges far in excess of the MTCR limit?
[size="6"]DRDO to conduct fourth test of interceptor missile[/size]
In less than two weeks, India will test its Ballistic Missile Defence shield again, by launching an interceptor missile to kill an incoming ââ¬Åenemyââ¬Â ballistic missile mid-flight.
This is the fourth time that the Defence Research and Development Organisation will be testing its interceptor missile.
While the incoming missile will lift off from the Integrated Test Range at Balasore in Orissa, the interceptor will blast off from the launch complex on the Wheeler Island, off Damra village, said V.K. Saraswat, Scientific Advisor to the Defence Minister.
A variant of the Prithvi missile will mimic the enemyââ¬â¢s ballistic missile trajectory. An Advanced Air Defence (AAD) missile will confront and kill it, in endo-atmosphere, at an altitude of less than 20 km. The launch window is between March 10 and 15. The Prithvi is a single stage, surface-to-surface missile that uses liquid fuel. The AAD is a single stage anti-ballistic missile that uses solid fuel. It is 7.5 metres long.
The DRDO scored three successes in a row when its interceptor missile tests conducted on November 27, 2006, December 6, 2007, and March 6, 2009, were on the target.
[quote name='qubit' date='03 March 2010 - 05:24 AM' timestamp='1267611397' post='104755']
Hon. Webmaster, I'd be grateful for any figures you could prrovide. BTW, do you think that DRDO alone has the where-with-all's to design/modify a scramjet? Given the fact that even for the present BrahMos the liquid fuelled ramjet is Russian, how do you propose that DRDO provide the hypersonic BrahMos with ranges far in excess of the MTCR limit?
[/quote]
Because,even before the Brahmos-II with scramjet was considered both DRDO and ISRO completed thier ground runs of thier own respective scramjet designs.Roping Russians into the program is to reduce the cost burden and shorten the timeframe.While the onlee desi hypersonic craft(supossedly long legged) will roll out lately but latestly.
And DRDO does posses a ramjet tech in terms of Akash(which is ofcourse solid propul)It is only a matter of time and consideration to bring up a modified engine to cruise....
[quote name='Arun_S' date='03 March 2010 - 12:38 AM' timestamp='1267594253' post='104745']
I will have dig into my archive ( unfortunately I am short on time for that), IIRC the hypersonic injection altitude should be ~ 20 km and cruise at ~35 km.
Military ram/scram jet will use the same kerosene fuel. Exotic gas fuel is not very appealing for mil use; though ISRO will very likely use LH2.
[/quote]
Didnt ISRO once said that it is going to use kerosene to bring down the costs?
Those using kerosene brings down the thrust value by 2.5 - 3 times compared to that of H2,but think its worth the money we put?
[quote name='qubit' date='03 March 2010 - 03:54 PM' timestamp='1267611397' post='104755']
Hon. Webmaster, I'd be grateful for any figures you could prrovide. BTW, do you think that DRDO alone has the where-with-all's to design/modify a scramjet? Given the fact that even for the present BrahMos the liquid fuelled ramjet is Russian, how do you propose that DRDO provide the hypersonic BrahMos with ranges far in excess of the MTCR limit?
[/quote]
For this you should first get a firm grip on what the MTCR and its mechanism is!
MTCR is a 34 nation (signatories) export group pact, with China n Israel as (non signatory members) verbally pledging adherence to its EXPORTING guidelines.
In other words, its all about prohibition of exporting of banned material (benchmarks established) to other nations. But something which is homegrown even with the help of MTCR member under the GUISE of consultancy, then nothing doing.
In these cases a recipient country is not held responsible but a violator nation is.
And DRDO has already ground tested its hypersonic engine, so what gives ?
Quote:During the conference, VK Saraswat, the chief controller (R&D), DRDO and chairman of the Aeronautical Society of India, made a presentation on the commercial Hyper Sonic Technology Demonstrator Vehicle. The ground test for HTDV scramjet propulsion system using kerosene as fuel has been conducted by DRDO scientists at a high speed material testing laboratory abroad and the results have been encouraging, he told reporters at the event.
![[Image: page1.JPG]](http://lh3.ggpht.com/_gnOjFM16XyA/S2XV7VqcNXI/AAAAAAAAAEk/ys3gs-tIFaA/page1.JPG)
[quote name='ankit-s' date='03 March 2010 - 05:53 AM' timestamp='1267623905' post='104769']
For this you should first get a firm grip on what the MTCR and its mechanism is!
MTCR is a 34 nation (signatories) export group pact, with China n Israel as (non signatory members) verbally pledging adherence to its EXPORTING guidelines.
In other words, its all about prohibition of exporting of banned material (benchmarks established) to other nations. But something which is homegrown even with the help of MTCR member under the GUISE of consultancy, then nothing doing.
In these cases a recipient country is not held responsible but a violator nation is.
And DRDO has already ground tested its hypersonic engine, so what gives ?
[/quote]
Hi Ankit-S, I know what MTCR is. Please correct me if I'm mistaken, but from what you've posted DRDO has ground tested it's hypersonic engine does not translate into DRDO has managed to develop a scramjet engine which will power a CM based on the BrahMos-II to 500-1000 km+ in about 5 years from today. I guess, DRDO needs to set up a technology cell and acquire as much Russian "consultancy" as possible and do so PRONTO! Without meaning to denigrate DRDO, we've seen plenty of DRDO projects which have shown "encouraging results" for decades, but which have never materialized into anything tangible!
[quote name='Arun_S' date='11 December 2009 - 09:44 AM' timestamp='1260552972' post='102909']
After the current fault is fixed, more tests are required to further increase reliability and shake out other bugs that may be lurking. It is true for all strategic missiles, including A2, A3, Shaurya, AAD and PAD (including it final avatar that is not Prithvi based).
Shying away from rapid testing as these missiles enter IOC is serious disservice to India, IMHO intense flight testing regime is critical for these missile to be of real value to national defense.
[/quote]
Arun_S,
Given the failures of the latest A-2 tests and the fact that the A-3 is for all practical purposes still undergoing testing and a good 5 years away from any serious induction, what does one have to say about the present state of India's strategic arsenal?
It appears that the only systems (delivery+weapon) that can be counted to work are the Prithvi's and a few fighter squadrons armed with 20KT fission weapons. Some estimates say that the Indian SFC has about 2 dozen A-2's, whose credibility is pretty much now under the cloud.
Given the fact that the Agni program started around 2 decades ago, the A-2 was launched in 1999, and of course....., one musn't forget the RC's POK-II "miracle", this is indeed cause for some serious alarm!
[quote name='qubit' date='03 March 2010 - 09:05 PM' timestamp='1267630034' post='104774']
Hi Ankit-S, I know what MTCR is. Please correct me if I'm mistaken, but from what you've posted DRDO has ground tested it's hypersonic engine does not translate into DRDO has managed to develop a scramjet engine which will power a CM based on the BrahMos-II to 500-1000 km+ in about 5 years from today. I guess, DRDO needs to set up a technology cell and acquire as much Russian "consultancy" as possible and do so PRONTO! Without meaning to denigrate DRDO, we've seen plenty of DRDO projects which have shown "encouraging results" for decades, but which have never materialized into anything tangible!
[/quote]
It proves beyond reasonable doubt that DRDO is capable of handling scramjet tech, as it is supposed to end up in AVATAR. And all the Brahmos-II reports are indicating that Brahmos-II will be using scramjet, so why you differ unreasonably on this simple issue?
Quote:Russia and India are encouraged enough to invest in BrahMos 2, which will use a scramjet, instead of a ramjet, in the second stage. This would double speed, and make the missile much more difficult to defend against
Quote:According to BrahMos Aerospace, the hypersonic version will have a scramjet engine in place of a ramjet, which will allow speeds in excess of Mach 6. Scramjets allow combustion to occur in supersonic airflow.
The hypersonic version will be capable of immense destructive power on account of kinetic energy resulting from its immense speed. According to BrahMos Aerospace, an object striking a target at Mach 6 will have 36 times the force of an object of the same mass striking the target at Mach 1.
I am all ears my friend - keep it coming!
[quote name='ankit-s' date='03 March 2010 - 09:10 AM' timestamp='1267635748' post='104780']
It proves beyond reasonable doubt that DRDO is capable of handling scramjet tech, as it is supposed to end up in AVATAR. And all the Brahmos-II reports are indicating that Brahmos-II will be using scramjet, so why you differ unreasonably on this simple issue?
I am all ears my friend - keep it coming!
[/quote]
Ankit-S, with all humility, your statement DRDO is capable of handling scramjet tech doesn't translate into what I said above i.e. DRDO can develop and manufacture a modification of the BrahMos-II having a range of 500-1000+ km and within 5+ years. AVATAR is an even longer way off! Perhaps (and my apologies if I am PROVEN wrong) is that DRDO has demonstrated a proof-of-principle scramjet configuration, which is quite some way off from what will be required. I'll be more than happy if I were proven wrong. So, do you have (or know where one can find) more deailed actual performance figures and dimensions of the scramjet tested by DRDO, publications, etc...? Naturally, the present state of development would not be advertized, but one can draw ballpark estimates via conservative extrapolation. BTW, in a BrahMos-II, wouldn't the Mach number of the flow into the scramjet combustor exceed Mach 2? Just asking!
[quote name='qubit' date='03 March 2010 - 10:59 PM' timestamp='1267636873' post='104781']
Ankit-S, with all humility, your statement DRDO is capable of handling scramjet tech doesn't translate into what I said above i.e. DRDO can develop and manufacture a modification of the BrahMos-II having a range of 500-1000+ km and within 5+ years. I'll be more than happy if I were proven wrong. So, do you have (or know where one can find) more deailed actual performance figures and dimensions of the scramjet tested by DRDO, publications, etc...? Naturally, the present state of development would not be advertized, but one can draw ballpark estimates via conservative extrapolation.
[/quote]
AVATAR is an even longer way off!
I agree that it IS...but you must agree TO the basic fact that AVTAR is not a missile, and its even more complex than what you think of missiles because it is single-stage REUSABLE Rocket plane capable of horizontal takeoff and landing. If DRDO has quasi perfected a Scramjet for that, then it speaks volume for your answers to be delivered. Because single-stage REUSABLE rocketplane capable of horizontal takeoff and landing is a complex technology akin to space shuttle, missiles are not that complex to maneuver.
BTW, in a BrahMos-II, wouldn't the Mach number of the flow into the scramjet exceed Mach 2? Just asking!
Quote:The minimum Mach number at which a scramjet can operate is limited by the fact that the compressed flow must be hot enough to burn the fuel, and of high enough pressure that the reaction is finished before the air moves out the back of the engine. Additionally, in order to be called a scramjet, the compressed flow must still be supersonic after combustion. Here two limits must be observed: Firstly, since when a supersonic flow is compressed it slows down, the level of compression must be low enough (or the initial speed high enough) not to slow the gas below Mach 1. If the gas within a scramjet goes below Mach 1 the engine will "choke", transitioning to subsonic flow in the combustion chamber. This effect is well known amongst experimenters on scramjets since the waves caused by choking are easily observable. Additionally, the sudden increase in pressure and temperature in the engine can lead to an acceleration of the combustion, leading to the combustion chamber exploding.
Secondly, the heating of the gas by combustion causes the speed of sound in the gas to increase (and the Mach number to decrease) even though the gas is still travelling at the same speed. Forcing the speed of air flow in the combustion chamber under Mach 1 in this way is called "thermal choking". It is clear that a pure scramjet can operate at Mach numbers of 6-8, but in the lower limit, it depends on the definition of a scramjet.
[quote name='ankit-s' date='03 March 2010 - 01:59 PM' timestamp='1267653104' post='104785']
AVATAR is an even longer way off!
I agree that it IS...but you must agree TO the basic fact that AVTAR is not a missile, and its even more complex than what you think of missiles because it is single-stage REUSABLE Rocket plane capable of horizontal takeoff and landing. If DRDO has quasi perfected a Scramjet for that, then it speaks volume for your answers to be delivered. Because single-stage REUSABLE rocketplane capable of horizontal takeoff and landing is a complex technology akin to space shuttle, missiles are not that complex to maneuver.
BTW, in a BrahMos-II, wouldn't the Mach number of the flow into the scramjet exceed Mach 2? Just asking!
[/quote]
Yeah, I know of these two limits. However, my initial guess is that a scramjet for the BrahMos-II should be designed so as to accomodate flows at least upto Mach 3+ into the combustion chamber. I'll verify this figure when I find some time, but the scramjet certainly needs to be designed for input Mach numbers > 2. Incidently, I know what AVATAR is (or what it is protrayed to be) and it's more than a couple of decades away, or even much further than that, given the streneous work ethics at DRDO!
BTW, your statement If DRDO has quasi perfected a Scramjet for that.... doesn't mean that what is most likely a proof-of-principle experiment on scramjets by DRDO comes anywhere close to perfecting a working and reliable scramjet for the Brahmos-II let alone the AVATAR! Incidently FYI the precise flight envelope of the AVATAR hasn't been finalized.
[quote name='qubit' date='03 March 2010 - 04:16 PM' timestamp='1267661315' post='104789']
Yeah, I know of these two limits you've mentioned. However, my initial guess is that a scramjet for the BrahMos-II should be designed so as to accomodate flows at least upto Mach 3+ into the combustion chamber. I'll verify this figure when I find some time, but the scramjet certainly needs to be designed for input flows having Mach numbers > 2 into the combustion chamber. Incidently, I know what AVATAR is (or what it is protrayed to be) and it's more than a couple of decades away, or even much further than that, given the exemplary work ethics at DRDO!
BTW, your statement If DRDO has quasi perfected a Scramjet for that.... doesn't mean that what is most likely a proof-of-principle experiment on scramjets by DRDO comes anywhere close to perfecting a working and reliable scramjet for the Brahmos-II let alone the AVATAR! Incidently FYI the precise flight envelope of the AVATAR hasn't been finalized.
[/quote]
03-04-2010, 06:50 AM
(This post was last modified: 03-04-2010, 08:33 AM by Arun_S.)
Qubit: Here is a ISRO news report:
[url="http://beta.thehindu.com/news/national/article139135.ece"]Advanced Technology Vehicle successfully flight-tested[/url]
T. S. Subramanian
Quote:The Indian Space Research Organisation (ISRO) on Wednesday successfully flight-tested its new-generation, high-performance sounding rocket at the spaceport in Sriharikota, near here. The Advanced Technology Vehicle (ATV- D01), weighing three tonnes at lift-off, is the heaviest sounding rocket developed by the ISRO. It carries a passive scramjet (supersonic combustion ramjet) engine combustor module as a test-bed for a demonstration of the air-breathing propulsion technology. An ISRO release said the rocket successfully flew at a velocity of more than Mach 6 (six times the speed of sound) for seven seconds. These conditions were required for a stable ignition of active scramjet engine combustor module planned in the next ATV flight.
ââ¬ÅThe successful flight-testing is a step ahead towards the advanced technology initiative from the ISRO in the area of air-breathing propulsion,ââ¬Â the release said.
The air-breathing rocket systems used the atmospheric oxygen from their surroundings and burned it with the on-board fuel to produce the forward thrust. This was in contrast to the conventional chemical rocket systems, which carried both oxygen and fuel on board, a rocket technologist said. The air-breathing rockets, therefore, are much lighter and more efficient than the conventional rockets, leading to reduction in the cost of space transportation. That is, the cost incurred to put a satellite in orbit will be much lower.
The development of scramjet engine was complex and it involved a number of technological challenges. They included mixing of very high speed air (velocity around 1.5 km a second) with fuel, achieving stable ignition and holding the flame in addition to ensure efficient combustion within the length of the combustor, the rocket technologist said.
Quote:BTW, your statement If DRDO has quasi perfected a Scramjet for that.... doesn't mean that what is most likely a proof-of-principle experiment on scramjets by DRDO comes anywhere close to perfecting a working and reliable scramjet for the Brahmos-II let alone the AVATAR! Incidently FYI the precise flight envelope of the AVATAR hasn't been finalized.
Of course its a time bound process because fighting the forces of friction is pushing aerodynamics to its limits! Rome was not built in a day right? It takes time when any technology ends up into a successful product/item. You want workable n reliable scramjet, wait for it, they are working on it (scramjet), and you n me know that extreme technical challenges are involved here (high temp/shock waves physics).
[quote name='ankit-s' date='04 March 2010 - 01:54 AM' timestamp='1267696018' post='104800']
Of course its a time bound process because fighting the forces of friction is pushing aerodynamics to its limits! Rome was not built in a day right? It takes time when any technology ends up into a successful product/item. You want workable n reliable scramjet, wait for it, they are working on it (scramjet), and you n me know that extreme technical challenges are involved here (high temp/shock waves physics).
[/quote]
Yes, and thus the rationale for my posts 249 and later. They'll need to model the hypersonic aerothermodynamics very thoroughly. I trust they have some sort of advanced simulation in place and experiments like ISRO's recent successful launch need to be carried out regularly in order to add to the data base of experimental data, especially that of the reaction kinetics amongst other issues. God willing they will succeed! Why don't we think of starting a thread dedicated to modeling issues in strategic technologies? I'm sure there are plenty of people on this forum who have a lot of experience who could contribute. Perhaps you could float this idea among senior members and get this started.
[quote name='Arun_S' date='03 March 2010 - 05:28 PM' timestamp='1267665658' post='104793']
Qubit: Here is a ISRO news report:
[url="http://beta.thehindu.com/news/national/article139135.ece"]Advanced Technology Vehicle successfully flight-tested[/url]
T. S. Subramanian
[/quote]
Arun,
Why don't we think of starting a thread dedicated to modeling issues in strategic technologies? I'm sure there are plenty of people on this forum who have a lot of experience who could contribute. Perhaps you could float this idea among senior members and forum admins, and get this started.
[quote name='qubit' date='04 March 2010 - 04:20 PM' timestamp='1267699335' post='104803']
Arun,
Why don't we think of starting a thread dedicated to modeling issues in strategic technologies? I'm sure there are plenty of people on this forum who have a lot of experience who could contribute. Perhaps you could float this idea among senior members and forum admins, and get this started.
[/quote]
Qubit: Please do the honours and start a thread. You are one of those who can provide insight and value.
|
