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    General Questions Thread:

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    GarryB
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    Re: General Questions Thread:

    Post  GarryB on Sun Nov 07, 2010 1:52 am

    Inlets and intakes are different.

    An intake is the normal way air enters the engine.

    Sometimes however the engine needs more air so the inlets are released and they get sucked open and let more air in. Or sometimes there is too much air coming in and they let air leak out before it gets to the engine.



    In the above picture you can see the inlets are closed because there is enough air getting to the engines through the normal air intakes for the takeoff.



    In this picture the inlets are open because the engines are in a low thrust setting and are probably not using all the air coming in the intakes so air leaks out the inlets to reduce the air pressure in the intake.

    At high altitude at low speed they will likely open to increase pressure.

    IronsightSniper
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    Re: General Questions Thread:

    Post  IronsightSniper on Sun Nov 07, 2010 2:19 am

    GarryB wrote:
    It's written by an American.

    My point was that it really doesn't give use any useful information except that the Georgians are crapping themselves and want to be rearmed so they can have another go so I really don't see the point of posting it.

    I will never get the minutes it took to read it back.

    In comparison the other articles were interesting and useful and more on topic.


    So it wasn't propaganda after all.

    Great! russia

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    Re: General Questions Thread:

    Post  havok on Sun Nov 07, 2010 7:49 am

    Folks,

    Here is the proverbial straight dope on this 'plasma stealth' tale...

    http://www.science20.com/news_account/stealth_antenna_made_of_gas_impervious_to_jamming
    Plasma antennas behave much like solid metal antennas because electrons flow freely in the hot gas, just as they do in metal conductors.
    Plasma antenna technology is nothing new. It has been around for decades. But in order to understand how a plasma antenna works, and naturally in concept how 'plasma stealth' works, one must understand something more basic, more mundane...

    http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html
    The structure of the ionosphere is strongly influenced by the charged particle wind from the Sun (solar wind), which is in turn governed by the level of Solar activity. One measure of the structure of the ionosphere is the free electron density, which is an indicator of the degree of ionization.
    The Earth's atmosphere is composed of layers of ionized gases and ionized gas is -- plasma. Depending on frequency, a layer may reflect EM waves or pass through. The result of this effect is atmospheric deflections of radio signals that can travels over the horizon...

    Above the stratosphere is the mesosphere and above that is the ionosphere (or thermosphere), where many atoms are ionized (have gained or lost electrons so they have a net electrical charge). The ionosphere is very thin, but it is where aurora take place, and is also responsible for absorbing the most energetic photons from the Sun, and for reflecting radio waves, thereby making long-distance radio communication possible.
    The layers that pass through EM waves could be construed as 'absorbers', as in radar absorbers, because what are radar signals but EM waves, nyet?

    A plasma antenna does exactly that -- absorb certain freqs. The container that holds the ionized gas does nothing else except what it is designed to do. Electronic countermeasure (ECM) tactics works because there is a conductor. But if there is no antenna then there is no conductor. Switch power off to the gas and there is no plasma antenna, hence the point of the article.

    So what 'plasma stealth' does, in concept anyway, is to array around a body a chain of plasma antenna that will absorb known radar freqs, just like physical absorbers do, except the plasma antenna has greater bandwidth. It is not about creating a free plasma cloud around the body that could be stripped away by the environment -- moving air. To make this concept works, these plasma antenna should be as close to the surface as possible lest the aircraft's skin reflects the impinging radar signals, thereby defeating the purpose of the plasma antennas. But just as the Earth's atmosphere layers reflects certain freqs and pass through, or absorb, certain freqs, so will these plasma antennas in this array. Another issue is the power requirement. Power can be switched off on the side that is not being impacted by seeking radar signals. But what about when the aircraft is in an electronic dense combat environment? The best solution is a hybrid of body shaping and plasma antennas at certain locations on the aircraft's body that is known to be highly radar reflective and this technique can be applied to existing 'non-stealth' aircrafts as well.

    The US have studied this method of radar reflectivity avoidance and found it inferior to body shaping. The technology is promising but as far as military aviation goes, it is still too much in the infancy stage to be effective in deployment.

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    Re: General Questions Thread:

    Post  GarryB on Sun Nov 07, 2010 9:27 am

    So it wasn't propaganda after all.

    It claims that Russia was planning Georgias attack on South Ossetia for months in advance... and that the pilots they captured were drunk...

    Clearly propaganda... of course we hear little else from Georgia it would be a bit of a shock if it actually told the truth for a change.

    The Earth's atmosphere is composed of layers of ionized gases and ionized gas is -- plasma. Depending on frequency, a layer may reflect EM waves or pass through. The result of this effect is atmospheric deflections of radio signals that can travels over the horizon...

    It is also the reason that during reentry ground control lose contact with spacecraft. A period or window where they just have to wait to see if they are OK entering the Earths atmosphere.

    The US have studied this method of radar reflectivity avoidance and found it inferior to body shaping. The technology is promising but as far as military aviation goes, it is still too much in the infancy stage to be effective in deployment.

    Just because the Americans couldn't make it work doesn't mean no one else could. The Americans were amazed by the SHKVAL rocket propelled torpedo when it was revealed to the west, but the first operational Soviet rocket propelled torpedo entered service in the 1950s.

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    Re: General Questions Thread:

    Post  IronsightSniper on Sun Nov 07, 2010 6:24 pm

    GarryB wrote:
    So it wasn't propaganda after all.

    It claims that Russia was planning Georgias attack on South Ossetia for months in advance... and that the pilots they captured were drunk...

    Clearly propaganda... of course we hear little else from Georgia it would be a bit of a shock if it actually told the truth for a change.



    And Russia claimed the opposite, again, claims.

    It actually said that NATO/Georgian Intel Officers said that Russian pilots were drunk, not just captured ones. So, it was a Secondary source, not absolute confirmable, but nothing for you to fret about.

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    Re: General Questions Thread:

    Post  havok on Sun Nov 07, 2010 7:13 pm

    GarryB wrote:
    The US have studied this method of radar reflectivity avoidance and found it inferior to body shaping. The technology is promising but as far as military aviation goes, it is still too much in the infancy stage to be effective in deployment.

    Just because the Americans couldn't make it work doesn't mean no one else could. The Americans were amazed by the SHKVAL rocket propelled torpedo when it was revealed to the west, but the first operational Soviet rocket propelled torpedo entered service in the 1950s.
    What make you think that the US was unable to 'make it work'? The fact that you guys are debating that there is a plasma cloud or 'field' enveloping the aircraft tells me that no one knows what he is talking about as far as plasma goes, how it is generated and how it actually works. Installing a rocket into a torpedo is not a propulsion conceptual problem but an engineering one, and to date, no one has yet to envelope a slow moving car in a plasma field in a 2D environment, let alone an aircraft moving at several hundreds km/h in a 3D environment. If there is going to be an engineering effort to exploit plasma's characteristics, it is best to use the plasma antenna array path rather than excitation of surrounding gases and lose the plasma field in flight. You are confused between failure to engineer versus a comparative study between concepts. The latter often involves successful engineering efforts to support all arguments but in the end, a committee determines that there are no advantages of one idea over the other.

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    Re: General Questions Thread:

    Post  nightcrawler on Sun Nov 07, 2010 10:31 pm

    ^^
    The fact that you guys are debating that there is a plasma cloud or 'field' enveloping the aircraft tells me that no one knows what he is talking about as far as plasma goes, how it is generated and how it actually works.
    I didn't know but I know now!! Thnx\

    @ http://www.scribd.com/full/41216219?access_key=key-7231ezjke4wyynglaa0

    page.67


    I juat read from here that it was something chemical in nature

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    Re: General Questions Thread:

    Post  GarryB on Mon Nov 08, 2010 12:37 am

    It actually said that NATO/Georgian Intel Officers said that Russian pilots were drunk, not just captured ones. So, it was a Secondary source, not absolute confirmable, but nothing for you to fret about.

    I don't really care what they have to say.



    Not interested in hearing Osama Bin Ladens point of view either.

    The fact that you guys are debating that there is a plasma cloud or 'field' enveloping the aircraft tells me that no one knows what he is talking about as far as plasma goes, how it is generated and how it actually works.

    Where did anyone suggest such a thing?
    I described what Plasma was and then described a perfectly good internal use for it inside the radar invisible radome to hide the radar antenna in a strike aircraft.

    I juat read from here that it was something chemical in nature

    A cheap desktop plasma ball works best with rare earth gases which not only makes making a plasma easier but makes it look pretty in different colours too.

    Regarding the photo above the mention of a plasma port is speculation... it looks like a simple access panel to me or it could be an antenna for some sort of avionics item.

    I would suggest that by the time they get beyond the early prototype aircraft and get to a full standard aircraft the front and rear edges will have dogtooth shapes to reduce RCS.

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    Re: General Questions Thread:

    Post  GarryB on Mon Nov 08, 2010 12:40 am

    The US have studied this method of radar reflectivity avoidance and found it inferior to body shaping. The technology is promising but as far as military aviation goes, it is still too much in the infancy stage to be effective in deployment.

    So would that make the combination of body shaping, materials, RAM coating AND plasma stealth for certain areas invalid?

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    Re: General Questions Thread:

    Post  havok on Tue Nov 09, 2010 1:20 am

    GarryB wrote:
    The fact that you guys are debating that there is a plasma cloud or 'field' enveloping the aircraft tells me that no one knows what he is talking about as far as plasma goes, how it is generated and how it actually works.

    Where did anyone suggest such a thing?
    I described what Plasma was and then described a perfectly good internal use for it inside the radar invisible radome to hide the radar antenna in a strike aircraft.
    Radomes are frequently opened for maintenance reasons. Not a good idea.

    GarryB wrote:
    The US have studied this method of radar reflectivity avoidance and found it inferior to body shaping. The technology is promising but as far as military aviation goes, it is still too much in the infancy stage to be effective in deployment.

    So would that make the combination of body shaping, materials, RAM coating AND plasma stealth for certain areas invalid?
    Look at it this way...You can have all body shaping, all RAM, or all 'plasma stealth'. Each 'all' will require considerable investments in research and development. Each will have strengths and weaknesses over the other options. If you cannot have 'all', and no one can, then we must, and usually do, resort to incorporation. We use the other options' strengths to make up for the other's weaknesses. A body's shaping that is inferior to another's shape can -- to some degrees -- compensate via RAM or 'plasma stealth'. But what if the plasma control system failed? The problem with incorporation is increased system complexity. Some are unavoidable, some are. The trick is how to achieve the 'are'.

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    Re: General Questions Thread:

    Post  GarryB on Tue Nov 09, 2010 2:38 am

    Radomes are frequently opened for maintenance reasons. Not a good idea.

    An AESA radar will not need maintainence for years, or so its proponents claim as modules fail the performance of the radar deteriorates but only by a very little amount performance wise so a cost saving is made by not bothering with maintanence and after a time period (measured in years) the faulty modules are replaced, rather than regular scheduled maintainence.
    Another factor is that these rare gases could be incorporated as part of a transpiration cooling system so that the radome is a sealed module that can be looked at when the scheduled replacement of modules is due.
    Or conversely the plasma gas could be contained in the hollow radom in front of the radar in a sealed unit that folds open to give access to the radar antenna.

    Look at it this way...You can have all body shaping, all RAM, or all 'plasma stealth'.

    Look at it this way, any technique at a measure results in an equivelent countermeasure... if yo put all your eggs in the shaping basket what happens with improved long wave AESA radars that are not effected by shape? Or electronic techniques that might render RAM ineffective? Or indeed methods that might make plasma stealth counter productive? Developing and using as many types of stealth as you can and applying them to their strengths and to counter the weaknesses of other methods simply makes sense.

    A good example is the western use of towed decoys. That is great because chaff slows down too fast and is rejected because it travels too slow. Another solution however is a 30mm or 23mm cannon shell where the shell has an external surface covered in corner reflectors so instead of having a tiny RCS its RCS is actually rather large and its aerodynamic shape and weight means it retains speed well, though its ballistic dive could be a problem unless the aircraft firing the shell dives too.
    Same problem, different solution... it is the superiority complex of the west that thinks its way is right.
    For IR guided missiles there is a flare shell and in the case of the Tu-22M3 the gun firing the shells can "deploy" 50 flares a second mixed with "chaff" shells. Simple to reload and maintain.

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    Re: General Questions Thread:

    Post  havok on Tue Nov 09, 2010 4:24 am

    GarryB wrote:
    Radomes are frequently opened for maintenance reasons. Not a good idea.

    An AESA radar will not need maintainence for years, or so its proponents claim as modules fail the performance of the radar deteriorates but only by a very little amount performance wise so a cost saving is made by not bothering with maintanence and after a time period (measured in years) the faulty modules are replaced, rather than regular scheduled maintainence.
    Another factor is that these rare gases could be incorporated as part of a transpiration cooling system so that the radome is a sealed module that can be looked at when the scheduled replacement of modules is due.
    Or conversely the plasma gas could be contained in the hollow radom in front of the radar in a sealed unit that folds open to give access to the radar antenna.
    Wrong...This is clearly spoken from a position of ignorance, particularly aviation maintenance. On any radar, peripheral components are usually the cause of maintenance issues before the antenna array itself.

    For example...

    http://www.chomerics.com/products/waveguide_gaskets.htm
    For effective EMI shielding and pressure sealing for choke, cover and contact flanges, Chomerics' waveguide gaskets ensure low insertion, low flange leakage, maximum heat transfer and minimum outgassing. Chomerics provides conductive elastomer waveguide gaskets to fit standard UG, CPR, and CMR flanges. They can also be custom designed to meet special requirements.

    http://events.nace.org/library/corrosion/cases/antenna.asp
    Condensed moisture from humid air ingress was responsible for inducing corrosion within the aft radar antenna from an RAAF P-3C Orion maritime surveillance aircraft. Porosity in the silver-plating of a flexible brass waveguide allowed moisture to penetrate to the brass substrate and cause dezincification. The moisture also induced corrosion of some of the AA-6061 aluminum alloy waveguides. An investigation determined that moisture ingress occurred at a waveguide flange, possibly from the failure of a seal.
    Waveguides are standard means of power transmission in radar systems and the seals between connections are quite often the cause of performance degradation. These and other peripherals must have periodic maintenance (PM) done to prevent the system from reaching that failure. The list is considerable. In peacetime, we have stricter maintenance requirements for obvious reason: war. In other words, should there be a time for war, we want to deploy with the best possible weapons systems and there is no other time to prepare for that potential than in peace. This is also applicable to flight controls, engines, environmental, structures, and electrical. In war, we do not have the luxury of preventative maintenance in all of those systems. In the USAF, we have gradations of aircraft status that we allow flight. Code One is when an aircraft is considered problems free. Code Two is when a system degradation does not impair overall aircraft flight capability. Code Three is when a problem is serious enough to cause loss of human life or asset destruction. In peacetime, we do not fly if there is a particular system degradation that will cause an aircraft to have Code Two status. But in war time, we will make that allowance. Code Three is obvious enough but most maintenance justifications from post flight debrief will be of Code Two category and sufficient to ground the aircraft from tomorrow's flight schedule.

    I know you are desperate to salvage your argument but you are defying known practices and decades of experiences worldwide. Russia is not immune from 'the real world'.

    GarryB wrote:
    Look at it this way...You can have all body shaping, all RAM, or all 'plasma stealth'.

    Look at it this way, any technique at a measure results in an equivelent countermeasure... if yo put all your eggs in the shaping basket what happens with improved long wave AESA radars that are not effected by shape?
    Wrong...ALL freqs are affected by target body shapes and dimensions. The issue is the degree of target resolutions.

    GarryB wrote:Or electronic techniques that might render RAM ineffective? Or indeed methods that might make plasma stealth counter productive?
    Do you even know basic radar detection principles to make these statements? I doubt it.

    GarryB wrote:Developing and using as many types of stealth as you can and applying them to their strengths and to counter the weaknesses of other methods simply makes sense.
    In principle...Yes. But in reality, complex systems have greater system failures, not just in frequency but also in severity. An aircraft that is capable of deploying complex countermeasures against radar detection but require financially excessive manhours and manpower to maintain is just as bad as having nothing at all.

    GarryB wrote:A good example is the western use of towed decoys. That is great because chaff slows down too fast and is rejected because it travels too slow. Another solution however is a 30mm or 23mm cannon shell where the shell has an external surface covered in corner reflectors so instead of having a tiny RCS its RCS is actually rather large and its aerodynamic shape and weight means it retains speed well, though its ballistic dive could be a problem unless the aircraft firing the shell dives too.
    Same problem, different solution... it is the superiority complex of the west that thinks its way is right.
    For IR guided missiles there is a flare shell and in the case of the Tu-22M3 the gun firing the shells can "deploy" 50 flares a second mixed with "chaff" shells. Simple to reload and maintain.
    You have a gross misunderstanding of chaff and how it works. If the radar view is overwhelmed with chaff, it does not matter the chaff bloom's velocity. The West cannot alter the laws of physics. It is too bad for the rest that we know how to exploit those laws better than others can.

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    Re: General Questions Thread:

    Post  GarryB on Tue Nov 09, 2010 11:29 am

    Wrong...This is clearly spoken from a position of ignorance, particularly aviation maintenance. On any radar, peripheral components are usually the cause of maintenance issues before the antenna array itself.

    So what? Why would you open the Radome if you were working on radar electronics? You open the Radome to expose the antenna... and as I said there is no reason why a seal pocket in the radome could not be filled with the required gasses.

    Regarding accessing the antenna:
    As a benchmark, typical conventional fighter radars have Mean Times Between Failure (MTBF) of around 60 to 300 hours - AESA radars push the MTBF into the 1,000 hours or better class. Rather than several repairs annually to the radar, the AESA will see the radar needing repair only once every several years of operation. If we assume an annual flying rate of around 200 hours, on average the AESA needs to be repaired once every five years! From a support costs perspective, this means much reduced cost of ownership for fighter fleet operators who transition to the technology.

    http://www.ausairpower.net/aesa-intro.html

    I know you are desperate to salvage your argument but you are defying known practices and decades of experiences worldwide. Russia is not immune from 'the real world'.

    I am glad you are not making this personal...

    Wrong...ALL freqs are affected by target body shapes and dimensions. The issue is the degree of target resolutions.

    In practical terms long wave radar waves are not redirected away from the emitter by shaping.

    Do you even know basic radar detection principles to make these statements? I doubt it.

    You are an expert on Russian development clearly because you know all about plasma stealth. Just like my great great great great great grandfather was an expert on flying because he knew people would never be able to fly from country to country in aeroplanes... if you move faster than 30 miles an hour... well you couldn't breath at that speed!

    An aircraft that is capable of deploying complex countermeasures against radar detection but require financially excessive manhours and manpower to maintain is just as bad as having nothing at all.

    Sounds like a good argument against the 2 billion dollar a piece B-2s...

    It is too bad for the rest that we know how to exploit those laws better than others can.

    Yes, the super west... truth, justice, and oil wasn't it?

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    Re: General Questions Thread:

    Post  IronsightSniper on Tue Nov 09, 2010 4:32 pm

    GarryB wrote:

    Yes, the super west... truth, justice, and oil wasn't it?

    Nice Ad Hominems Garry, but you aren't really defending your point.

    Anyways, because you don't really care what they said then I think the first thing Russia needs to do is take away that alcohol from their pilots! censored

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    Re: General Questions Thread:

    Post  GarryB on Wed Nov 10, 2010 2:48 am

    Anyways, because you don't really care what they said then I think the first thing Russia needs to do is take away that alcohol from their pilots!

    I am interested in facts about the Russian AF, not the whinings of the team that came second.

    There were a lot of problems highlighted for the Russian air force to deal with in that little police action with Georgia but no real issues were even mentioned in that article.

    Real problems were communication and recon.

    In other areas they excelled. I mean lets face it... how hard should it have been for the Georgians to shell a city while at the same time send a force to the Roki tunnel with enough demolition equipment to bring down half a kilometre of it?
    It is forgotten that there were actually two conflicts taking place here... first the Georgian invasion of South Ossetia which triggered the Abkhazian invasion of Georgia to take back land Georgia occupied. The Abkhazian attack on Georgia was not supported by the Russians the Abkhazians pushed the Georgians back all by themselves. Lets face it, the Russians weren't there to protect the Abkhazians from the Georgians... it was the other way around... they were there to protect the Georgians from the Abkhazians. : I love you

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    Re: General Questions Thread:

    Post  IronsightSniper on Wed Nov 10, 2010 3:54 am

    Well, maybe you should read it again, if Russian pilots were drunk and off course or using ineffective altitudes, that's some serious problems! Considering that RUAF losses were done mostly by Russian export equipment, they should work on their Counter-Counter warfare tactics! It is not whining you must understand, but facts (sources were NATO/Georgian Intel Officers).

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    Re: General Questions Thread:

    Post  GarryB on Wed Nov 10, 2010 6:48 am

    It is not whining you must understand, but facts (sources were NATO/Georgian Intel Officers).

    How would they know if Russian pilots were off course?

    There are plenty of areas the Russians have identified as problems and they are working on them.

    Do you think the 11/9 attacks should be used to evaluate US air defences?

    This was a surprise attack by a cowardly enemy, would you like me to post some Al Aquada "Expert" evaluation of US air defence efficiency and performance?

    What if they said the average age of the firemen that were killed when the buildings collapsed was older than average so perhaps it was the US government that was behind it. This wasn't the first attack on the building afterall.
    Maybe some of the firemen might have been at a bar having a drink when the first plane hit but were close enough to do something about it so they turned up for duty anyway. Is their boss going to say... "Hey you have been drinking... there are up to 30,000 people in those buildings that need our help but you have had a beer so you can't help... go home."
    Remember there is no independant confirmation of this... just the word from Al Quada... and BTW they fear the US military might respond so please send weapons so that when they do attack that AQ can give them a bloody nose.

    I will say again... I don't believe Georgian propaganda and I give no weight to anything coming from them or their government.

    Of course as a westerner I am used to this BS... for most of the post WWII period it was believed the Soviets didn't have a decent fighter aircraft and that the Polikarpovs and lend lease aircraft were all they had. Even then the west believed the Polikarpov I-16 was called the Rat or the Fly... which was the name their Spanish enemies named them.
    For most of the early cold war period we got the west german view of the eastern front conflict and surprise surprise... it seems we thought the Soviets won because of numbers and the winter and Hitlers mistakes. It is strange that numbers really didn't help the Chinese against the Japanese during the same period.

    You say I should listen to all sources, well in theory that has merit but considering the source I will politely decline.

    (Hope I didn't cause offence at the 11/9 reference above, but I think it puts things in perspective... nobody likes unprovoked attacks.)

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    Re: General Questions Thread:

    Post  nightcrawler on Thu Nov 11, 2010 3:09 pm

    J-10 has been deployed in Xizang (Tibet)

    The cover, according to Chinese BBS, was supposed to protect the planes from high levels of ultraviolet rays in Tibet. Excessive radiation could weaken the titanium and cause the rubber wheels to weaken.
    Why dont they just build hangers??

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    Re: General Questions Thread:

    Post  nightcrawler on Sat Nov 13, 2010 4:47 pm

    [QUOTE=sorter;2982084]

    Notice the folding rear fins and fact that they are at 45 degrees X relative to the intake.


    But clearly the rear fins r "+"

    Now provided that former missile is oldy with respect to the latter one; I am confused at this
    A design progression where the "x" fins didn't work out so they changed to non-folding "+" fins which probably give more range (less drag?, less weight?) but take up more space?[/QUOTE]


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    Re: General Questions Thread:

    Post  GarryB on Mon Nov 15, 2010 1:26 am

    They might simply have made the change to simplify manouvering with horizontal and vertical control surfaces climb an dive controls can be applied with just moving two surfaces instead of all four, while turning in the horizontal plane will likely require the two vertical surfaces plus a little bit adjustment as a horizontal turn often leads to the outer wing surface moving faster than the inner wing surface which causes some roll, but that can easily be corrected.

    In very long range flights I would think that horizontal control surfaces would make trimming the tail slightly down much easier and simpler. The other alternative would be nose mounted canards lifting the nose so the main wings can generate lift and keep the missile airborne.

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    Re: General Questions Thread:

    Post  Austin on Mon Nov 15, 2010 11:22 am

    Can some one explain how DAS on JSF can be used to guide AAM missile ?

    As far as I know any IR/TI system still needs ranging to the target which is done by laser range finder or radar , but DAS does not have any ranging system still it claims to guide WVR missile.

    Here is a video on das and shows how it works


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    Re: General Questions Thread:

    Post  IronsightSniper on Mon Nov 15, 2010 12:38 pm

    I'm completely new to the DAS, but as I see it, I think it's just multiple IRSTs bundled into one to provide said all around coverage.

    Although, I'm probably wrong.

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    Re: General Questions Thread:

    Post  Vladimir79 on Mon Nov 15, 2010 10:15 pm

    Austin wrote:Can some one explain how DAS on JSF can be used to guide AAM missile ?

    As far as I know any IR/TI system still needs ranging to the target which is done by laser range finder or radar , but DAS does not have any ranging system still it claims to guide WVR missile.

    I don't think you need laser range finders to launch an AIM-9X. It is not a BVRAAM like MICA IR where Rafale has to laze the target to triangulate distance, bearing and altitude. It is WVRAAM that just needs a general direction where to go. Once the seeker picks up the target it should take care of itself. DAS would not be usable with AMRAAM or even an IR AMRAAM if they develop one.

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    Re: General Questions Thread:

    Post  GarryB on Tue Nov 16, 2010 6:09 am

    The IRST on the Mig-29 and Su-27 are directly linked to the radar, so in theory an IRST lock means you can slew the radar directly at the target without scanning. A short ranging pulse of a fraction of a second will give ranging data.

    With multiple sensors you could simply use triangulation, and even with one sensor over time if you keep taking readings you can determine the location of the target the same way submarines do passively with sonar.

    Direction of travel could be estimated from signal brightness and estimated distance, but there would not be much chance of determining range by counting propeller rotation... Smile

    Networking several IRSTs together will give a vector which can be used to triangulate position too.

    BTW the video is a little strange in that it shows an attack by an SA-4 battery, whose missiles seem to be defeated by flares. The battery is then defeated by destruction of a launch vehicle instead of the radar vehicles the launch vehicles use to target aircraft.

    The video however simply shows the use of lock on after launch short range AAM in the over the shoulder launch mode that can only effectively be used against very very close targets... ie targets that have just flown by.
    This is similar to the R-73 with IRST except these missiles have a datalink with the aircraft so they can get a lock on after they are launched.

    As Vlad mentions no use for very long range missiles... and actually something Python 5 is doing already.

    New Russian AAMs will have the same capability because they will be launched from a missile bay so they can't be locked on before launch either.

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    Re: General Questions Thread:

    Post  Austin on Tue Nov 16, 2010 7:44 am

    GarryB , my question was with respect to DAS ability to get a 360 * LOAL capability and that too in all passive mode , a great capability in dog fight if that works as advertised.

    No aircraft till date has such capability more so in all passive mode.

    The PAK-FA will have a 360 * capability due to side and wing radar but its an all active approach which can warn the target early on.

    I think they need to develop DAS like all passive capability for PAK-FA , a mini ols on the body of aircraft with wide IIR capability will be good to have on PAK-FA

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