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They are must have as one dont know a registered person be a noob!!
They are must have as one dont know a registered person be a noob!!
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General Questions Thread:
nightcrawler- Posts : 522
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Join date : 2010-08-20
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nightcrawler- Posts : 522
Points : 634
Join date : 2010-08-20
Age : 35
Location : Pakistan
At an early stage of the fighter's development it became obvious that the MFI was a lot different from the American fifth-generation fighters. For instance, the Mikoyan fighter had a variable ventral air intake from the start, whereas the F-22 had non-adjustable two-shock lateral intakes optimized for supersonic cruise and the rival Northrop/General Dynamics YF-23 had non-adjustable dorsal intakes. Soviet aerodynamicists believed a ventrally located intake offered certain advantages during vigorous manoeuvres, minimizing the danger of an intake stall during high-G turns and high-alpha flight. Also, the tail-first layout maximized lift and the canards performed a pitch damping function at critical AoAs. By comparison, the F-22 and YF-23 utilised a more conventional layout with trapezoidal wings and stabilators.
Source:
Russian Fifth-Generation Fighter
Technology Demonstrators
Yefim Gordon
Original translation by Dmitriy Komissarov
Question is simple; is Soviet thinking while choosing from 3 given air intakes is correct & why US think otherwise??
GarryB- Posts : 40540
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The American focus was on stealth, which is funny because they ended up picking the more conventional more manouverable and least stealthy of the two aircraft developed.
If you squint the F-22 is basically a Mig-25 in layout and not very radical looking at all. The YF-23 on the other hand I find rather more interesting though not exactly radical either.
The focus for the Russian aircraft was on manoeuvrability first with reduced RCS as a bonus feature.
The Russian aircraft are also likely to have a higher speed requirement... compare the F-18s Mach 1.8 max flight speed to the Mig-29s Mach 2.35 as an example.
Of course we have not seen the final service T-50 yet and there is always the talk of plasma stealth.
One common misnomer about plasma stealth is that it is hot and would give the target away in IR frequencies. I have a plasma ball that generates a fascinating light show, by passing very high voltages through rare gas to make a light show.
Even a hand held people zapper can generate enormous voltages (at very low current) so it is not rocket science to think they might have developed something new.
If you squint the F-22 is basically a Mig-25 in layout and not very radical looking at all. The YF-23 on the other hand I find rather more interesting though not exactly radical either.
The focus for the Russian aircraft was on manoeuvrability first with reduced RCS as a bonus feature.
The Russian aircraft are also likely to have a higher speed requirement... compare the F-18s Mach 1.8 max flight speed to the Mig-29s Mach 2.35 as an example.
Of course we have not seen the final service T-50 yet and there is always the talk of plasma stealth.
One common misnomer about plasma stealth is that it is hot and would give the target away in IR frequencies. I have a plasma ball that generates a fascinating light show, by passing very high voltages through rare gas to make a light show.
Even a hand held people zapper can generate enormous voltages (at very low current) so it is not rocket science to think they might have developed something new.
nightcrawler- Posts : 522
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@GarryB
From a US soldier
This is an interesting and as it happens, an accurate observation. Most forums thrive on the turning fight, endlessly discussing "Cobras", turn rate and radius, thrust to weight, HOB missiles, super-maneuverability. The reality is, we had a preview of the modern air war in Desert Storm.
At the time, we practiced the turning fight, as it was both necessary to know how to do it, and it is a perishable skill. Probably 40% our work was radar search/sort/shoot, and 60% maneuvering.
I was transferred out, then my squadron was sent to Desert Storm. I talked with many of the guys later. What they said was something like this: "I don't know how or why it happened, but we went from flying at 420 knots, corner velocity, and instead went in at 600+ knots. We were hauling a** everywhere we went. The radar methodology went perfectly. The AIM-7's were almost flawless. When we merged with survivors, rather than attempt protracted turning, we depleted energy with high-G turns to put AIM-9's on guys, then we got out, fast. Short, sharp fights."
The fights were hit and run. It is stupid and dangerous to linger in an area, and give a low-tech fighter a chance at a visual shot, or air defense to figure out what is going on, and start launching SAMs.
That, I think, is the future. Maneuverability has taken a giant back seat to sensors, radar, datalinking, and BVR missile lethality. And that means pretty much everything seen at an airshow demo is antiquated to a degree. It is the stuff we cannot see that is important.
There will always be the need for a turning fight. If assigned a point-defense mission, that means you stay and fight until you either die, or the enemy is defeated. But overall, there has been a quiet paradigm shift in how air to air is fought.
From a US soldier
GarryB- Posts : 40540
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It seems the preview of modern air war is a case where US and allied forces totally dominate their enemy and have full C4IR with no interference.
In which case using situational awareness and hitting them from long range and then swooping in and cleaning up the remains might be a good method.
Not so good when the other guy has weapons that threaten your AWACS and JSTARS, when the other guy has effective BVR missiles as well, and indeed when the enemy might coordinate their airforce and ground forces to set up SAM traps and other tactics to make it much more difficult to get the job done.
The first step in any attack is to break the defence. That doesn't mean flying in and shooting down all his planes, it means sneaking in with stealth aircraft and cruise missiles and blowing up his communications hubs and HQs.
For a coalition force it is easy to get local superiority in numbers... he doesn't know which target you will hit first and you will hit multiple targets at once so he can't concentrate his forces in any one place and get numbers parity.
The US and allied forces weren't using all their forces, just their best and best equipped.
Works against Iraq... will that still work against China or Russia?
In which case using situational awareness and hitting them from long range and then swooping in and cleaning up the remains might be a good method.
Not so good when the other guy has weapons that threaten your AWACS and JSTARS, when the other guy has effective BVR missiles as well, and indeed when the enemy might coordinate their airforce and ground forces to set up SAM traps and other tactics to make it much more difficult to get the job done.
The first step in any attack is to break the defence. That doesn't mean flying in and shooting down all his planes, it means sneaking in with stealth aircraft and cruise missiles and blowing up his communications hubs and HQs.
For a coalition force it is easy to get local superiority in numbers... he doesn't know which target you will hit first and you will hit multiple targets at once so he can't concentrate his forces in any one place and get numbers parity.
The US and allied forces weren't using all their forces, just their best and best equipped.
Works against Iraq... will that still work against China or Russia?
nightcrawler- Posts : 522
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@GarryB
yep you make a point!!
Especially after that our country has recruited some HQ9 Chinese reverse engineered Russian SAMs; we are quiet satisfied with their performance against major 4gen fighters & thank GOD something to take care of that SU-30 (dont be rude our sole enemy is India
). Also we are going to induct SPADA SAM by MBDA
http://www.defensenews.com/story.php?i=4086243&c=AIR&s=TOP
yep you make a point!!
Especially after that our country has recruited some HQ9 Chinese reverse engineered Russian SAMs; we are quiet satisfied with their performance against major 4gen fighters & thank GOD something to take care of that SU-30 (dont be rude our sole enemy is India
). Also we are going to induct SPADA SAM by MBDA http://www.defensenews.com/story.php?i=4086243&c=AIR&s=TOP
GarryB- Posts : 40540
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Hope you never have to use them... 
And I mean that.
I am interested in military equipment, specifically Russian and Soviet, but I am under no illusions that war is about the violent application of force by one side to get something they can't get another way. War cares nothing for who is right or wrong, who is good or bad. My main problem with the US is that they take the war option too lightly without acknowledging that sometimes the collateral damage is worse than the problem.
Back to the original topic I think he is misunderstanding some of those airshow tricks too.
A modern AAM like Python 5 can be launched off a wing pylon and follow a very close closing target over the shoulder and hit it behind the launch aircraft. It is a very nice party trick, but even better would be to be able to yank back on the stick as the target flys past and yaw your nose up and over like a cobra manouver and fire a missile straight off the rail at the target now in front of you even though you are in a super stall. The simple fact is that a missile running down a pylon and off directly at a target does not need to be pulling a high g turn in the first few seconds of its flight when its rocket motor is burning the high calorie high impulse fuel. It is accelerating to its top speed directly towards the target which means it will get to the target much quicker and no manouver should be possible by the target to evade it because it is in the centre of the missiles field of view so any turn the plane can pull the missile should be able to match.
In comparison a Python 5 has just been fired off the launch aircrafts' wing and pulled a 180 degree turn over the shoulder to look for the target, if that target has turned down and done a half loop back towards the aircraft that just launched the missile the Python will have to continue that turn into a full circle which might break lock or out turn the missile.
And I mean that.
I am interested in military equipment, specifically Russian and Soviet, but I am under no illusions that war is about the violent application of force by one side to get something they can't get another way. War cares nothing for who is right or wrong, who is good or bad. My main problem with the US is that they take the war option too lightly without acknowledging that sometimes the collateral damage is worse than the problem.
Back to the original topic I think he is misunderstanding some of those airshow tricks too.
A modern AAM like Python 5 can be launched off a wing pylon and follow a very close closing target over the shoulder and hit it behind the launch aircraft. It is a very nice party trick, but even better would be to be able to yank back on the stick as the target flys past and yaw your nose up and over like a cobra manouver and fire a missile straight off the rail at the target now in front of you even though you are in a super stall. The simple fact is that a missile running down a pylon and off directly at a target does not need to be pulling a high g turn in the first few seconds of its flight when its rocket motor is burning the high calorie high impulse fuel. It is accelerating to its top speed directly towards the target which means it will get to the target much quicker and no manouver should be possible by the target to evade it because it is in the centre of the missiles field of view so any turn the plane can pull the missile should be able to match.
In comparison a Python 5 has just been fired off the launch aircrafts' wing and pulled a 180 degree turn over the shoulder to look for the target, if that target has turned down and done a half loop back towards the aircraft that just launched the missile the Python will have to continue that turn into a full circle which might break lock or out turn the missile.
nightcrawler- Posts : 522
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@GarryB
Isn't this normally will be the case?? I mean for a normal talented pilot this statement holds true that he got no chance against BVR
The simple fact is that a missile running down a pylon and off directly at a target does not need to be pulling a high g turn in the first few seconds of its flight when its rocket motor is burning the high calorie high impulse fuel. It is accelerating to its top speed directly towards the target which means it will get to the target much quicker and no manouver should be possible by the target to evade it because it is in the centre of the missiles field of view so any turn the plane can pull the missile should be able to match.
Isn't this normally will be the case?? I mean for a normal talented pilot this statement holds true that he got no chance against BVR
GarryB- Posts : 40540
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Sorry I was talking about a very specific situation.
The Python 5 missile has the ability to lose sight of its target.
This means that if you are flying directly towards a target and that target is flying towards your direction (but not specifically at you or you will crash into each other) if you get a lock and fire with a Python 5 just as he is passing you the missile will launch forward off the rail and then turn 180 degrees over your wing to turn and fly directly back and chase his aircraft.
During the first critical seconds of your missiles burn the missile is wasting energy in a very hard turn.
If he was in a Flanker with an R-73 and he pulled a cobra so his nose is yanked back past the vertical and is facing backwards in the direction he came from as the enemy plane flys past and you fire your missile directly at the target when you get your lock your missile will have much more energy because although it is flying backwards initially it is accelerating backwards without performing a hard high g turn.
Range will be reduced because of the initial backwards flight but not so reduced as the missile that has to pull the hard turn on launch.
The Python 5 missile has the ability to lose sight of its target.
This means that if you are flying directly towards a target and that target is flying towards your direction (but not specifically at you or you will crash into each other) if you get a lock and fire with a Python 5 just as he is passing you the missile will launch forward off the rail and then turn 180 degrees over your wing to turn and fly directly back and chase his aircraft.
During the first critical seconds of your missiles burn the missile is wasting energy in a very hard turn.
If he was in a Flanker with an R-73 and he pulled a cobra so his nose is yanked back past the vertical and is facing backwards in the direction he came from as the enemy plane flys past and you fire your missile directly at the target when you get your lock your missile will have much more energy because although it is flying backwards initially it is accelerating backwards without performing a hard high g turn.
Range will be reduced because of the initial backwards flight but not so reduced as the missile that has to pull the hard turn on launch.
nightcrawler- Posts : 522
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while discussing the German MiG29s versus US F-16 drills my friend mockingly asked me
He asked
What is the answer??
why a clock is so prominently displayed in the Mig-29's cockpit?
He asked
why is it "prominently displayed" in the center console typically reserved for important gauges that the pilot must continuously monitor. In the F-16 the clock is placed in the "right auxiliary* console"
What is the answer??
GarryB- Posts : 40540
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In the older model Mig and Sukhoi fighters the engagement of enemy targets was not all software driven and the pilot had to manage the illumination of the target manually.
The clock was needed at that time to ensure that the target was illuminated when the missile got to the target area.
It is not as if the pilot would fly with his eyes fixed on the clock till impact, he would work out how long to illuminate the target based on its range and his and the targets altitude and the weapon to be fired and he would press a button to illuminate the target and fire a Semi active radar homing missile. After a given time he would then switch off the illumination because the missile had either hit or missed.
It was only required for SARH missiles and these were generally only used in longer ranged shots. Close range targets were engaged with shorter range fire and forget Heat seeker missiles.
More sophisticated western aircraft had this automated and would include a seconds to impact countdown often on the HUD.
Western pilots seem to make a big deal out of this but really it is the difference between using a compass to find north and a GPS receiver... they both perform the same function but only one works when the power fails.
The clock was needed at that time to ensure that the target was illuminated when the missile got to the target area.
It is not as if the pilot would fly with his eyes fixed on the clock till impact, he would work out how long to illuminate the target based on its range and his and the targets altitude and the weapon to be fired and he would press a button to illuminate the target and fire a Semi active radar homing missile. After a given time he would then switch off the illumination because the missile had either hit or missed.
It was only required for SARH missiles and these were generally only used in longer ranged shots. Close range targets were engaged with shorter range fire and forget Heat seeker missiles.
More sophisticated western aircraft had this automated and would include a seconds to impact countdown often on the HUD.
Western pilots seem to make a big deal out of this but really it is the difference between using a compass to find north and a GPS receiver... they both perform the same function but only one works when the power fails.
nightcrawler- Posts : 522
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TVC -vs- JHMCS ?
Hi Folks.
What is your opinion about a Dogfight or WVRC scenario between an air craft with Thurst vectoring like Su-30MKI and an air craft like F-16C/D , F-35 JSF with JHMCS Powered by of bore sight infrared Guided missiles ?
Does TVC has an edge over JHMCS or JHMCS powered by its off bore sight infrared guided missiles will undermine the supermenuverability of Sukhoi's ?
Please share your Ideas.
Hi Folks.
What is your opinion about a Dogfight or WVRC scenario between an air craft with Thurst vectoring like Su-30MKI and an air craft like F-16C/D , F-35 JSF with JHMCS Powered by of bore sight infrared Guided missiles ?
Does TVC has an edge over JHMCS or JHMCS powered by its off bore sight infrared guided missiles will undermine the supermenuverability of Sukhoi's ?
Please share your Ideas.
GarryB- Posts : 40540
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The Su-30MKI already has a helmet mounted sight and high offboresight AAMs so the real question is what effect TVC has in combat.
There is an old adage that speed is life in air to air combat but that is based on the fact that speed is energy... energy you can turn into height, or to retain the ability to manoeuvre rapidly.
With TVC you have the ability to point your nose and therefore also your main sensors and weapons without regard to where you happen to be flying.
Even with high offboresight missiles pointing your missiles directly at your target to fire them gives your missiles a much better chance of hitting their target and makes the chance of the target evading your missiles much smaller.
Very simply if you suddenly see a target to your left in a non TVC aircraft you can look and lock and fire an AAM almost instantly but the first crucial few seconds of AAM fuel burn will be wasted by the missile in a hard turn towards the target aircraft, while the aircraft that launched the missile will continue flying forward.
Odds are however the reason you suddenly spotted that aircraft was because it had just fired upon your aircraft so after you fire you will be trying to turn hard to try to evade the missile fired.
In a TVC aircraft when you see the target you can still lock it up with your HMS but you can yank your nose around to point directly at the target and then fire and then complete the turn and head directly back in the opposite direction you were flying and pop flares etc etc.
Your missile will have lots of energy and speed because it hasn't made any hard turns and you will be heading in the opposite direction that you were heading so the missile the enemy fired is now turning hard because the previous intercept point it was heading for that was in front of your aircraft is now shifting in the opposite direction. A turn 20 degrees or so flight angle toward the enemy fighter will increase the closing speed of the missile making its turning angle sharper.
To be brutally honest however it really wont matter too much as WVR missiles are deadly and if both aircraft fire then both aircraft will probably die.
You can make up lots of little scenarios where one sees the other or doesn't to get either aircraft to win, but it really comes down to skill and assets.
Who has AWACS coverage, why didn't either aircraft use BVR missiles? etc etc.
There is an old adage that speed is life in air to air combat but that is based on the fact that speed is energy... energy you can turn into height, or to retain the ability to manoeuvre rapidly.
With TVC you have the ability to point your nose and therefore also your main sensors and weapons without regard to where you happen to be flying.
Even with high offboresight missiles pointing your missiles directly at your target to fire them gives your missiles a much better chance of hitting their target and makes the chance of the target evading your missiles much smaller.
Very simply if you suddenly see a target to your left in a non TVC aircraft you can look and lock and fire an AAM almost instantly but the first crucial few seconds of AAM fuel burn will be wasted by the missile in a hard turn towards the target aircraft, while the aircraft that launched the missile will continue flying forward.
Odds are however the reason you suddenly spotted that aircraft was because it had just fired upon your aircraft so after you fire you will be trying to turn hard to try to evade the missile fired.
In a TVC aircraft when you see the target you can still lock it up with your HMS but you can yank your nose around to point directly at the target and then fire and then complete the turn and head directly back in the opposite direction you were flying and pop flares etc etc.
Your missile will have lots of energy and speed because it hasn't made any hard turns and you will be heading in the opposite direction that you were heading so the missile the enemy fired is now turning hard because the previous intercept point it was heading for that was in front of your aircraft is now shifting in the opposite direction. A turn 20 degrees or so flight angle toward the enemy fighter will increase the closing speed of the missile making its turning angle sharper.
To be brutally honest however it really wont matter too much as WVR missiles are deadly and if both aircraft fire then both aircraft will probably die.
You can make up lots of little scenarios where one sees the other or doesn't to get either aircraft to win, but it really comes down to skill and assets.
Who has AWACS coverage, why didn't either aircraft use BVR missiles? etc etc.
nightcrawler- Posts : 522
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What is happening in these figures ??
GarryB- Posts : 40540
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http://www.michaelyon-online.com/the-kopp-etchells-effect.htm
and
http://www.vtol.org/f65_bestPapers/productSupport.pdf
11. (pdf) Office of Naval Research Broad Agency Announcement(BAA): Advanced Helicopter Rotor Blade Erosion Protection, United States Department of the Navy, Office of Naval Research, p. 3, BAA 08-011, retrieved 2009-09-02, "Although both Ni and Ti are hard metals, their hardness values are significantly lower than that of sand, which is primarily made up of quartz. This hardness differential results in the excessive erosion/degradation of rotor blades in desert environments. An equally important problem with Ti protection is that a visible corona or halo is generated around the rotor blades at night from the sand impacting the Ti leading edge and causing Ti to spark andoxidize."
and
http://www.vtol.org/f65_bestPapers/productSupport.pdf
11. (pdf) Office of Naval Research Broad Agency Announcement(BAA): Advanced Helicopter Rotor Blade Erosion Protection, United States Department of the Navy, Office of Naval Research, p. 3, BAA 08-011, retrieved 2009-09-02, "Although both Ni and Ti are hard metals, their hardness values are significantly lower than that of sand, which is primarily made up of quartz. This hardness differential results in the excessive erosion/degradation of rotor blades in desert environments. An equally important problem with Ti protection is that a visible corona or halo is generated around the rotor blades at night from the sand impacting the Ti leading edge and causing Ti to spark andoxidize."
nightcrawler- Posts : 522
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Thnx for replies.
I have another observation
Why TURBOJETs are preferred over Turbofans in Antiship missiles.
With the exception of (as far as I know )
& (not yet confirmed)
also
what is the bold part referring to??
all other use turbojets than turbofans.
I have another observation
Why TURBOJETs are preferred over Turbofans in Antiship missiles.
With the exception of (as far as I know )
- RGM/UGM-109B Tomahawk Anti Ship Missile (TASM) - radar guided anti-shipping variant
- Kh-35E Uran (SS-N-25 'Switchblade', 3M24)
& (not yet confirmed)
http://www.ausairpower.net/DT-Regional-ASCM-1207.pdfThe YJ-62 is likely to become the primary PLA-N anti-shipping missile of domestic origin, as it provides a large airframe with considerable long term growth potential, including significant range improvements with a future turbofan engine.
also
The more advanced 3M-54E combines the subsonic cruise airframe of the 3M-54E1/3M-14E with a Mach 2.9 rocket propelled guided payload. The 3M-54E approaches from under the radar horizon using the radar seeker to detect its target. Once locked on, it discards the cruise airframe, fires its rocket motor, and accelerates to Mach 2.9 at a sea kimming altitude of 15 feet.
what is the bold part referring to??
all other use turbojets than turbofans.
GarryB- Posts : 40540
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Why TURBOJETs are preferred over Turbofans in Antiship missiles.
Tricky question.
First start with a simple jet engine 101 class.
The simplest and most basic jet engine is the ramjet. If you think of a tube that starts out wide and then narrows a little in the middle and then expands a little at the rear that is basically a ramjet engine. Air comes in the front and as the tube narrows the air is compressed which makes it heat up. Fuel is added here and ignited which makes the air much hotter and makes it expand rapidly. The air coming in the front prevents it blowing forwards so it blows out the back at high velocity generating thrust. Thrust is controlled by increasing fuel supply and changing the shape of the exhaust nozzle.
A Scramjet is a more sophisticated ramjet that burns fuel supersonically and so the air coming into the intake can come in at any speed. A ramjet will constrict the intake as the flight speed exceeds supersonic speed so the air will still be burnt subsonically. A ramjet will choke on supersonic air but can operate up to about mach 3-4 just fine by reducing the size of the intake so less air gets in and it slows down before it gets to where the fuel is burnt.
A Scramjet could fly theoretically at any speed in air and could be used to fly to the edge of space up to orbital speeds. (once in space of course the lack of air will mean you will need a rocket engine for flight control and reentry etc).
If you put a long metal rod down the centre of the tube and put blades in them you have a turbojet engine. As you increase the fuel supply to the blades where the tube is narrow (called the combustion chamber or hot section) the blades spin faster and because they are connected to the blades at the front it sucks in more air which means more fuel can burn efficiently increasing thrust.
If you extend that metal rod or drive shaft down the centre of the tube so that it sticks out the front of the engine and you put enormous propeller blades on that shaft that are much wider than the widest part of the tube then you have a type of jet engine called a turboprop... like the jet engines used on the Bear bomber.
The primary thrust is generated by the large front blades and while the jet engine does produce thrust itself its main function is to turn the main propeller blades.
Of course the problem there is that external blades lose efficiency when the blade tips are supersonic because they stop generating lift or propulsion and start generating drag and noise. The Bear is the fastest propeller driven aircraft in the world and its flight performance is very similar to the B-52 because the Bear uses a very coarse propeller setting and a slower rotation rate so the tips are not supersonic.
A turbofan engine is like a turboprop except the external blades are only about twice the width of the turbojet engine that is powering the blades and there is another larger tube around the front blades.
The advantage of turbofans is that they move a much larger volume of air when they operate and a lot of that air is actually cold dense air that doesn't go through the turbojet engine. This is called bypass air and an engine bypass ratio shows how much dense cold air travels through the engine compared to the hot stuff that goes through the turbojet. One huge advantage of turbofans is that this cold dense air still has its oxygen in it so when fitting a device like an afterburner then the AB is much more efficient at increasing thrust than when used with a turbojet because there is more oxygen and cold air that can be superheated by basically injecting fuel into the exhaust.
Pros and cons... turbojets run hotter and have higher exhaust speeds so if you want to go supersonic a turbojet or a very low bypass turbofan is a good choice. Turbojets are smaller and cheaper to make. Turbofans are generally more fuel efficient especially at subsonic speeds. Turbofans need width to have large front fans for good airflow.
what is the bold part referring to??
The supersonic model of Klub is a two stage missile. The subsonic jet powered cruise part of the missile has a payload. This payload is a rocket that includes the seeker, the warhead and flight controls and a rocket motor. When the subsonic jet powered cruise missile part of the system gets to lock on range it launches its payload that flys to the target.
A bit like ASROC except instead of a dumb ballistic rocket carrying a guided torpedo to the vicinity of the target sub and dropping it in the water it is a jet powered cruise missile carrying a rocket powered AShM.
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@GarryB
that is my major concern. Relative to sea turbojets are more prone to be detected by the temp gradients than turbofan but yet still new gen anti-ship missiles like MBDA SPADA; Exocet are all turbojet powered.
The above phenomenon is more advantageous in Turbofan than turbojets...But what I feel turbojets are more used because they would be more stealthy in aerodynamic physics than the protruded turbofans
turbojets run hotter and have higher exhaust speeds
that is my major concern. Relative to sea turbojets are more prone to be detected by the temp gradients than turbofan but yet still new gen anti-ship missiles like MBDA SPADA; Exocet are all turbojet powered.
The above phenomenon is more advantageous in Turbofan than turbojets...But what I feel turbojets are more used because they would be more stealthy in aerodynamic physics than the protruded turbofans
GarryB- Posts : 40540
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Modern IR systems are not limited to 1,000 degree exhaust temperatures only.
Modern IR systems generate an image and can spot slightly warmer than background objects easily.
If you have ever seen one of those videos of thermal cameras being used on police helos at night to find people the people glow white while the background it largely black. The reason for this is that they are calibrated that way and could just as easily be set to show the black background as white and the human temperature objects as black.
In fact many commercial thermal sights have this as a feature because with most things displayed as white it looks more like a daylight image that makes navigation easier. Reverse the polarity and it goes into hunting mode where warm bodies become very easy to spot like a human or animal.
What I am trying to say is that a guy standing on the bridge of a ship in complete darkness looking through thermal binoculars will see a bright spot on the horizon that is a cruise missile... from the front the exhaust plume will look fairly similar between a turbojet and a turbofan, it is the front of the missile heated by air friction and any radar in the nose operating generating more heat that will be detected first. The friction heating will not be hundreds of degrees but human skin is not hundreds of degrees either and it appears white on most thermal sights. At night at sea the sea temperature will not be 30 degrees C so a missile or a person in the water will stand out.
The main reason in my opinion to go for a turbofan would be extra range for a subsonic missile the lower exhaust velocity is not important.
Modern IR systems generate an image and can spot slightly warmer than background objects easily.
If you have ever seen one of those videos of thermal cameras being used on police helos at night to find people the people glow white while the background it largely black. The reason for this is that they are calibrated that way and could just as easily be set to show the black background as white and the human temperature objects as black.
In fact many commercial thermal sights have this as a feature because with most things displayed as white it looks more like a daylight image that makes navigation easier. Reverse the polarity and it goes into hunting mode where warm bodies become very easy to spot like a human or animal.
What I am trying to say is that a guy standing on the bridge of a ship in complete darkness looking through thermal binoculars will see a bright spot on the horizon that is a cruise missile... from the front the exhaust plume will look fairly similar between a turbojet and a turbofan, it is the front of the missile heated by air friction and any radar in the nose operating generating more heat that will be detected first. The friction heating will not be hundreds of degrees but human skin is not hundreds of degrees either and it appears white on most thermal sights. At night at sea the sea temperature will not be 30 degrees C so a missile or a person in the water will stand out.
The main reason in my opinion to go for a turbofan would be extra range for a subsonic missile the lower exhaust velocity is not important.
nightcrawler- Posts : 522
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ThnxxWhat I am trying to say is that a guy standing on the bridge of a ship in complete darkness looking through thermal binoculars will see a bright spot on the horizon that is a cruise missile... from the front the exhaust plume will look fairly similar between a turbojet and a turbofan, it is the front of the missile heated by air friction and any radar in the nose operating generating more heat that will be detected first. The friction heating will not be hundreds of degrees but human skin is not hundreds of degrees either and it appears white on most thermal sights. At night at sea the sea temperature will not be 30 degrees C so a missile or a person in the water will stand out.
Why did administrators dont listen to me...
They just have to introduce thanks button after each reply!!!
But what I feel turbojets are more used because they would be more stealthy in aerodynamic physics than the protruded turbofans
Garry will lov if you comment on this too
GarryB- Posts : 40540
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A protruding jet engine looks really bad from a RCS perspective, and it pretty much is, however what it does do is gives a lot more space inside the airframe for stuff.
Inside the missile there is the physical area for the engine and the lowering gear and that is it. With most aircraft an engine will take up most of the rear of the aircraft and then intake trunk will take up even more space.
By fitting the engine to hang externally you just lose space for the engine itself and when the engine is deployed it has excellent airflow characteristics.
Note this is OK for subsonic aircraft like a Boeing 747... for the engine it is like the difference between breathing in through a straw or straight from your mouth.
For a plane like a Tu-22M3 it needs intake trunks that allow for the restriction of air coming in to the engine so that it doesn't go into the engine intake at supersonic speeds.
The Tu-22 has engine pods on the tail base and has relief doors so that if the air is coming in too fast the doors in the sides of the engines near the front can open and reduce the airflow into the combustion chamber so that it is subsonic or the engine will choke.
Basically the missile you showed with the underslung engine the designers have decided to evade the enemy air defence by flying very low and so instead of a low RCS it is basing its survival on the radar horizon.
The missile it is based on is the Kh-59M, which has the NATO codename AS-18 KAZOO which has an optical nose and needs a datalink pod to operate. Basically you fire the missile in the direction of the target and when the missile approaches the target area it turns on its TV camera and sends back a digital video signal. For this purpose it has a narrow band transmitter in its tail facing back directly at the launch aircraft. This would make a conventional engine placement difficult.
The weapons officer in the launch aircraft then looks at the video and then moves the crosshairs onto the target and transmits the signal. The missile will then guide itself into the target highlighted all without emitting radar signals.
I believe the US equivelent is called SLAM-ER. (The Kh-59 has the NATO codename AS-13 KINGFISHER and has a shorter range comparable to SLAM).
Inside the missile there is the physical area for the engine and the lowering gear and that is it. With most aircraft an engine will take up most of the rear of the aircraft and then intake trunk will take up even more space.
By fitting the engine to hang externally you just lose space for the engine itself and when the engine is deployed it has excellent airflow characteristics.
Note this is OK for subsonic aircraft like a Boeing 747... for the engine it is like the difference between breathing in through a straw or straight from your mouth.
For a plane like a Tu-22M3 it needs intake trunks that allow for the restriction of air coming in to the engine so that it doesn't go into the engine intake at supersonic speeds.
The Tu-22 has engine pods on the tail base and has relief doors so that if the air is coming in too fast the doors in the sides of the engines near the front can open and reduce the airflow into the combustion chamber so that it is subsonic or the engine will choke.
Basically the missile you showed with the underslung engine the designers have decided to evade the enemy air defence by flying very low and so instead of a low RCS it is basing its survival on the radar horizon.
The missile it is based on is the Kh-59M, which has the NATO codename AS-18 KAZOO which has an optical nose and needs a datalink pod to operate. Basically you fire the missile in the direction of the target and when the missile approaches the target area it turns on its TV camera and sends back a digital video signal. For this purpose it has a narrow band transmitter in its tail facing back directly at the launch aircraft. This would make a conventional engine placement difficult.
The weapons officer in the launch aircraft then looks at the video and then moves the crosshairs onto the target and transmits the signal. The missile will then guide itself into the target highlighted all without emitting radar signals.
I believe the US equivelent is called SLAM-ER. (The Kh-59 has the NATO codename AS-13 KINGFISHER and has a shorter range comparable to SLAM).
nightcrawler- Posts : 522
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NB:Image f isn't shown properly here; right click on image & open it in new tab or windows of your internet browser
Two parts that really intrigue me are
- Engine Inlets
- Plasma Ports
Regarding the 1st one; is there any difference b/w air intakes & Engine Inlets that are labeled in fig. (because yellow arrows dont mention the big air intakes)
Regarding 2nd; we had a talk about these magical things stealth tech before & many senior members refrain talking about it CLEARLY. I was of the view which was referenced in a book (I will reproduce the source if req.) that it was something Chemical in nature; while others related it with Radar science. Having this fig. I suppose people here can make me understand in a better/CLEAR way
GarryB- Posts : 40540
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Regarding 2nd; we had a talk about these magical things stealth tech before & many senior members refrain talking about it CLEARLY. I was of the view which was referenced in a book (I will reproduce the source if req.) that it was something Chemical in nature; while others related it with Radar science. Having this fig. I suppose people here can make me understand in a better/CLEAR way
There are two main ways to generate a plasma that we know of. One is heating material up to very high temperatures, which makes the electrons run free, no longer bound to the nucleus of the atom. This ionises the gas which blocks radio waves.
The other method is similar to that used in plasma balls that look like lightening balls where you put your hand on them and lightning comes from the centre to make patterns on the inside of the glass ball where your hand touches the glass. This relies on high voltage and very rare gases.
It is the latter that the Russians are talking about... high voltage plasma. They already have a plasma stealth system supposedly for the Su-34. Very simply the idea of creating a plasma field around an entire aircraft is difficult, but filling the radome of an aircraft with rare gasses and running an electrical current through it to make plasma is not that hard... the power already goes to the nose to power the radar anyway.
Obviously to use the radar you would need the plasma system turned off, but you could turn it on and off like a light switch. The obvious problem is that when it is turned on you can't transmit or receive radar, but it should significantly reduce RCS from the front when on.
I should also remind you that this plasma vent and other stuff is all speculative with regard to the T-50 because this is an early prototype model likely not fitted with most operational stuff yet.
They are going to make 10 more aircraft to test various things quickly and these aircraft will more likely be closer to full standard, though not necessarily all the same either. They might have one that tests full stealth that they keep secret for example.
GarryB- Posts : 40540
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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.
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.
havok- Posts : 88
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Join date : 2010-09-20
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
http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html
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.
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 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...Plasma antennas behave much like solid metal antennas because electrons flow freely in the hot gas, just as they do in metal conductors.
http://csep10.phys.utk.edu/astr161/lect/earth/atmosphere.html
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...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 layers that pass through EM waves could be construed as 'absorbers', as in radar absorbers, because what are radar signals but EM waves, nyet?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.
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.