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Chengdu J-20 5th Generation Aircraft News & Discussions

Lol,supercruise has no practical use?Now u have shown ur true mettle as a noob.

''Supersonic cruise or supercruise is a term which refers to the ability of a combat aircraft to sustain supersonic flight without using afterburning thrust.

Combat aircraft have had supersonic capability since the 1950s, exploiting afterburners to effectively multiply available thrust and thus overcome the drag rise characteristic of transonic and supersonic flight, as well as improving climb, turn and acceleration performance. The additional thrust advantage of the afterburner comes at a prohibitive price - fuel burn is multiplied severalfold as fuel is injected into the tailpipe and combusted. A byproduct of afterburner use is a dramatic increase in the aircraft's heat signature, the engine plumes becoming effectively an infrared beacon which can be detected and tracked from dozens of miles away.

In practical terms conventional gas turbine engines afford only a transient supersonic capability, one which must be used very carefully as it can expend thousands of pounds of fuel in minutes, and advertise the fighter's presence and energy state from tactically very useful distances.

Having the ability to sustain supersonic speeds without these drawbacks affords numerous advantages in combat. The first of these is that entering an engagement the supersonic fighter has a reserve of kinetic energy which a subsonic opponent does not have. As a result the supersonic fighter can often dictate the terms of the engagement.

More importantly, sustained supersonic speed presents genuine problems in engagement kinematics for an opposing conventional fighter. Even in Beyond Visual Range (BVR) combat, air to air missiles have kinematic limitations. To effect a kill a fighter must position itself so the target falls into a 'no escape zone' for the missile type being used. Unless this precondition is met, the missile will likely run out of energy and be unable to engage the target.

In classical intercept geometries, fighters are typically vectored into a head to head closing geometry upon which the player with the earliest firing opportunity, whether afforded by longer radar/missile range, or supporting networking capability, has the advantage. Where both fighters have matched conventional kinematic capabilities, the game well and truly revolves around incremental advantages in missile capability, or situational awareness, provided by onboard or offboard sensors.

This delicate balance, and the advantages yielded by incremental imbalances in missile and sensor technology, will collapse once one of the fighters has the capacity to sustain supersonic speeds. As a result, even modest heading changes by the supersonic fighter, when positioning for the engagement, will force the conventional fighter to go into afterburner early, and typically will create enough separation to ruin the conventional fighter's missile shot geometry. In effect, conventional fighters flying against fighters with sustained supersonic capability usually do not get good opportunities for BVR missile shots. Only a very significant advantage in the kinematic performance of the missiles carried by conventional fighters can offset the advantages held by the player with sustained supersonic capability.

The reality is that the situational awareness advantages afforded by modern ISR and networking capabilities only work where the fighters using them have kinematic parity with their opponents. Once the opposing fighter has a significant kinematic advantage, the tables may well be turned. Given that most modern fighter fleet operators have AEW&C capabilities, or are acquiring AEW&C capabilities, the line of argument which presents AEW&C and networking as an air combat panacea is little more than nonsense. driving the capability contest yet again into other areas - and supersonic cruise will be the next arena in the global competition for air superiority.

Achieving genuine supersonic cruise capability hinges on two technological prerequisites. The first is having a powerplant which develops enough dry thrust at altitude to offset supersonic airframe drag. The second is having an airframe design built for low supersonic drag. Unless both conditions are met, supersonic cruise capability is not achievable.

The airframe issues dictate a wing design typically with 45 degrees or more of leading edge sweep, and suitable fuselage area ruling. Moreover, weapons must be carried internally or in a semi-conformal or conformal arrangment, to avoid a supersonic drag penalty. Pylon mounted missiles are not the preferred strategy. To date, airframe aerodynamics have not been the obstacle in the supercruise game. Engine capabilities have remained the principal obstacle.

A turbofan engine designed for supersonic cruise will be characterised by a much higher turbine inlet temperature than contemporary 'conventional' fighter engines. It is this operating cycle which permits the engine to sustain higher dry thrust ratings at high altitudes. This has also proven to be the primary obstacle to date in building supercruise engines, as it requires advanced materials and advanced turbine cooling techniques.

The first service to recognise the importance of supercruise was the US Air Force, which incorporated supercruise into the early requirements definition of the Advanced Tactical Fighter (ATF) program, which eventually coalesced into today's F/A-22A Raptor. An extensive and expensive engine technology research and development effort led to the design of the Pratt and Whitney F119-PW-100 engine which powers the F-22A. Delivering around 35,000 lbf of afterburning thrust, the F119-PW-100 is the most powerful fighter engine manufactured in the Western world. The simplest qualitative measure of the F119-PW-100's performance is that this engine has a dry thrust performance envelope matching the afterburning thrust envelope of the F100-PW-100 series engines fitted to the F-15C/E and many F-16 variants.

As a result the F-22A is the only production fighter in existence with a genuine supersonic cruise capability and the enormous kinematic advantages this affords in combat. This analyst had the opportunity to discuss the practical aspects of supercruise capability with one of the F-22A test pilots some years ago. Not only were chase fighters unable to keep up, but in mock intercepts flown by F-16Cs and F-15Cs against development F-22A airframes, even modest 20 degree heading changes caused the teen series fighters to abort their intercepts, having burned their fuel down to bingo levels.''


Supercruise is great advantage for stealth aircraft as it preserves its stealth signature longer without having to switch on afterburner.

Yet F-35 cant supercruise.:laugh:
Stupid americans must not have read your words.
 
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Good lord dat Indian math. Its 2 100kn engines to one 191 kn engine. Guess its too hard to figure out which plane produces more thrust.
 
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Yet F-35 cant supercruise.:laugh:
Stupid americans must not have read your words.

Indeed it can't as its not meant as air superiority fighter.This j-31 would have no chance vs pak fa or f-22.

Good lord dat Indian math. Its 2 100kn engines to one 191 kn engine. Guess its too hard to figure out which plane produces more thrust.

Thats what i asked gambit for,i'm not expert at this thrust and if 2 engines thrust is equal to 1 and such.If it is case of simple addition. @gambit
 
Last edited by a moderator:
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There is no practical use for supercruise in combat. Supercruise is affected by aerodynamics and thrust to weight ratio, with the emphasis on the former.



WS-13B is being developed.

WS-X.jpg

Right, and the "J31" is gonna wait for that engine in meanwhile?

Show me the Ws-13
http://www.turbineengine.org/pdf/China Aerospace Propulsion Technology china2.pdf

Indeed it can't as its not meant as air superiority fighter.This j-31 would have no chance vs pak fa or f-22.

ROFL, j-31 isnt a air superiority fighter either. ROFL.
 
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Ur talking as if ur air superiority fighter j-20 will have some epic engine that will enable it to compete with these 2?

You are changing topics like girls changing underwear. Where in my post did I mention J-20 at all? Since when is J-20 mine? Typical
indian nonsens.
 
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You are changing topics like girls changing underwear. Where in my post did I mention J-20 at all? Since when is J-20 mine? Typical
indian nonsens.

Read thread title?You brought up 'air superiority fighter' ,j-20 chinese contender.
 
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Read thread title?You brought up 'air superiority fighter' ,j-20 chinese contender.

No, Mr. Amnesia. It is you. Here, let me help you.

Indeed it can't as its not meant as air superiority fighter.This j-31 would have no chance vs pak fa or f-22.

And here is you again who mentioned J-20, not me. here kid:
Ur talking as if ur air superiority fighter j-20 will have some epic engine that will enable it to compete with these 2?


Is that your troll twin brother, or does it say air superiority fighter?

You will excuse me for asking, but do you have problems reading or remembering your words? Havnt been into a few discussions with you, I cant help notice this....There is no shame in that. I just want to know.
 
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Ur talking as if ur air superiority fighter j-20 will have some epic engine that will enable it to compete with these 2?

It does. It will be equipped with the 180 kN WS-15 engine. The engine core was completed in 2006 and was rumored to be tested in 2009.

Right, and the "J31" is gonna wait for that engine in meanwhile?

Show me the Ws-13
http://www.turbineengine.org/pdf/China Aerospace Propulsion Technology china2.pdf



ROFL, j-31 isnt a air superiority fighter either. ROFL.

The J-31 as of now does not need those engines since it is still in flight testing phase. The picture that's in front of you is already from an official release.
 
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Lol,supercruise has no practical use?Now u have shown ur true mettle as a noob.

''Supersonic cruise or supercruise is a term which refers to the ability of a combat aircraft to sustain supersonic flight without using afterburning thrust.

Combat aircraft have had supersonic capability since the 1950s, exploiting afterburners to effectively multiply available thrust and thus overcome the drag rise characteristic of transonic and supersonic flight, as well as improving climb, turn and acceleration performance. The additional thrust advantage of the afterburner comes at a prohibitive price - fuel burn is multiplied severalfold as fuel is injected into the tailpipe and combusted. A byproduct of afterburner use is a dramatic increase in the aircraft's heat signature, the engine plumes becoming effectively an infrared beacon which can be detected and tracked from dozens of miles away.

In practical terms conventional gas turbine engines afford only a transient supersonic capability, one which must be used very carefully as it can expend thousands of pounds of fuel in minutes, and advertise the fighter's presence and energy state from tactically very useful distances.

Having the ability to sustain supersonic speeds without these drawbacks affords numerous advantages in combat. The first of these is that entering an engagement the supersonic fighter has a reserve of kinetic energy which a subsonic opponent does not have. As a result the supersonic fighter can often dictate the terms of the engagement.

More importantly, sustained supersonic speed presents genuine problems in engagement kinematics for an opposing conventional fighter. Even in Beyond Visual Range (BVR) combat, air to air missiles have kinematic limitations. To effect a kill a fighter must position itself so the target falls into a 'no escape zone' for the missile type being used. Unless this precondition is met, the missile will likely run out of energy and be unable to engage the target.

In classical intercept geometries, fighters are typically vectored into a head to head closing geometry upon which the player with the earliest firing opportunity, whether afforded by longer radar/missile range, or supporting networking capability, has the advantage. Where both fighters have matched conventional kinematic capabilities, the game well and truly revolves around incremental advantages in missile capability, or situational awareness, provided by onboard or offboard sensors.

This delicate balance, and the advantages yielded by incremental imbalances in missile and sensor technology, will collapse once one of the fighters has the capacity to sustain supersonic speeds. As a result, even modest heading changes by the supersonic fighter, when positioning for the engagement, will force the conventional fighter to go into afterburner early, and typically will create enough separation to ruin the conventional fighter's missile shot geometry. In effect, conventional fighters flying against fighters with sustained supersonic capability usually do not get good opportunities for BVR missile shots. Only a very significant advantage in the kinematic performance of the missiles carried by conventional fighters can offset the advantages held by the player with sustained supersonic capability.

The reality is that the situational awareness advantages afforded by modern ISR and networking capabilities only work where the fighters using them have kinematic parity with their opponents. Once the opposing fighter has a significant kinematic advantage, the tables may well be turned. Given that most modern fighter fleet operators have AEW&C capabilities, or are acquiring AEW&C capabilities, the line of argument which presents AEW&C and networking as an air combat panacea is little more than nonsense. driving the capability contest yet again into other areas - and supersonic cruise will be the next arena in the global competition for air superiority.

Achieving genuine supersonic cruise capability hinges on two technological prerequisites. The first is having a powerplant which develops enough dry thrust at altitude to offset supersonic airframe drag. The second is having an airframe design built for low supersonic drag. Unless both conditions are met, supersonic cruise capability is not achievable.

The airframe issues dictate a wing design typically with 45 degrees or more of leading edge sweep, and suitable fuselage area ruling. Moreover, weapons must be carried internally or in a semi-conformal or conformal arrangment, to avoid a supersonic drag penalty. Pylon mounted missiles are not the preferred strategy. To date, airframe aerodynamics have not been the obstacle in the supercruise game. Engine capabilities have remained the principal obstacle.

A turbofan engine designed for supersonic cruise will be characterised by a much higher turbine inlet temperature than contemporary 'conventional' fighter engines. It is this operating cycle which permits the engine to sustain higher dry thrust ratings at high altitudes. This has also proven to be the primary obstacle to date in building supercruise engines, as it requires advanced materials and advanced turbine cooling techniques.

The first service to recognise the importance of supercruise was the US Air Force, which incorporated supercruise into the early requirements definition of the Advanced Tactical Fighter (ATF) program, which eventually coalesced into today's F/A-22A Raptor. An extensive and expensive engine technology research and development effort led to the design of the Pratt and Whitney F119-PW-100 engine which powers the F-22A. Delivering around 35,000 lbf of afterburning thrust, the F119-PW-100 is the most powerful fighter engine manufactured in the Western world. The simplest qualitative measure of the F119-PW-100's performance is that this engine has a dry thrust performance envelope matching the afterburning thrust envelope of the F100-PW-100 series engines fitted to the F-15C/E and many F-16 variants.

As a result the F-22A is the only production fighter in existence with a genuine supersonic cruise capability and the enormous kinematic advantages this affords in combat. This analyst had the opportunity to discuss the practical aspects of supercruise capability with one of the F-22A test pilots some years ago. Not only were chase fighters unable to keep up, but in mock intercepts flown by F-16Cs and F-15Cs against development F-22A airframes, even modest 20 degree heading changes caused the teen series fighters to abort their intercepts, having burned their fuel down to bingo levels.''


Supercruise is great advantage for stealth aircraft as it preserves its stealth signature longer without having to switch on afterburner.

Supercruise is a testament to the aircraft's aerodynamics and somewhat thrust to weight ratio, but pragmatically speaking such a feat is not useful in actual combat. Supercruise is the ability to maintain supersonic flight without engine reheat, which is barely fast enough when compared with modern maximum speeds. Kinetic energy can be maintained by supercruise or by engine reheat, sometimes with the latter being more useful since it can provide rapid variation of thrust in a short time period. In fact there has been no case in history where aircraft maintained their cruise speed during a high intensity dogfight. In such dogfights one can be guaranteed that afterburners will be used to propel the aircraft to its highest speed, at which point preservation of kinetic energy is no longer a concern since the aircrafts' speed in a fight will outstrip that of cruise speed.

It can somewhat "preserve" the IR stealthiness of an aircraft but that is no different if the aircraft simply went in at subsonic speeds. In fact level flight at subsonic speeds tend to save a lot more fuel.

Your talk of two fighters going head on is impractical. It takes two to tango and if one aircraft goes supersonic, then it will too have to face the threat of closing in on the enemy fast; it is the combined relative velocities of the two aircraft that matter, not just one. And none of that has any effect on the early detection and shoot capabilities of the parties.
 
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Indeed it can't as its not meant as air superiority fighter.This j-31 would have no chance vs pak fa or f-22.

And how do you know that the J-31 doesn't have a mass low enough to maintain a good thrust to weight ratio? Secondly, we have yet to consider the avionics, relative observability, and a thousand other factors before one can even begin to draw out a potential scenario. Stop jumping to conclusions based on one unproven assumption that the J-31 cannot supercruise (which is completely up to debate).
 
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Hmmm another Chinese product.....no guarantee no warranty........nobody knows how long will it last.....

It'll last longer than people's tolerance of your idiocy, that's for sure.
 
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No, Mr. Amnesia. It is you. Here, let me help you.

Indeed it can't as its not meant as air superiority fighter.This j-31 would have no chance vs pak fa or f-22.

And here is you again who mentioned J-20, not me. here kid:



Is that your troll twin brother, or does it say air superiority fighter?

You will excuse me for asking, but do you have problems reading or remembering your words? Havnt been into a few discussions with you, I cant help notice this....There is no shame in that. I just want to know.

And bringing up j-20 in a thread titled j-20 is wrong?LOL.
I also brought up raptor and pak-fa not only j-20.All 5 were brought up as these are the only 5th gen fighters revealed atm.
I also remember u from the other discussion where u ran away.
 
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Supercruise is a testament to the aircraft's aerodynamics and somewhat thrust to weight ratio, but pragmatically speaking such a feat is not useful in actual combat. Supercruise is the ability to maintain supersonic flight without engine reheat, which is barely fast enough when compared with modern maximum speeds. Kinetic energy can be maintained by supercruise or by engine reheat, sometimes with the latter being more useful since it can provide rapid variation of thrust in a short time period. In fact there has been no case in history where aircraft maintained their cruise speed during a high intensity dogfight. In such dogfights one can be guaranteed that afterburners will be used to propel the aircraft to its highest speed, at which point preservation of kinetic energy is no longer a concern since the aircrafts' speed in a fight will outstrip that of cruise speed.

It can somewhat "preserve" the IR stealthiness of an aircraft but that is no different if the aircraft simply went in at subsonic speeds. In fact level flight at subsonic speeds tend to save a lot more fuel.

Your talk of two fighters going head on is impractical. It takes two to tango and if one aircraft goes supersonic, then it will too have to face the threat of closing in on the enemy fast; it is the combined relative velocities of the two aircraft that matter, not just one. And none of that has any effect on the early detection and shoot capabilities of the parties.

Another noob at work,btw that article was from ausairpower..a favourite destination of chinese forumers.
Without supercruise -
IRST tracker will detect u further and faster.
U enter battle far lower on kinamtic enrgy than ur opponent who is then at an advantage[KE] affects missile performance.
Non supercruising fighters will have severe problems getting BVR lock on supercruising fighters.
Supercruising fighters have advantage in missile no escape zone range.

And how do you know that the J-31 doesn't have a mass low enough to maintain a good thrust to weight ratio? Secondly, we have yet to consider the avionics, relative observability, and a thousand other factors before one can even begin to draw out a potential scenario. Stop jumping to conclusions based on one unproven assumption that the J-31 cannot supercruise (which is completely up to debate).

Very well,let's wait for the demo to come to life.
 
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