LCA Tejas vs JF-17 Thunder

[p2prada]

The links say that JF-17 B2 and B3 are being developed by Chinese.

B2 with the 9300Kgf engine is equivalent to our LCA Mk1. B3 will be equivalent to LCA Mk2.

And Klimov has been contracted to develop an improved variant of RD-93 with 9300 kgf .

This is kind of at the same level as what we have on LCA mk1.

Also, can the B2 and B3 feature quadruplex FBW or once the airframe is
constructed, it is not possible to do it?

It can be done.

Also, to what extent composites can be added to the airframe and how much time usually it would require?

Depends on how much they are willing to spend.

They can do it in a major way on the B3. B2 and B1 can be subsequently upgraded during MLUs, like how MKIs will also have composites after MLUs.

PAF's current intention is to replace their F-7s and Mirage-3/5s with the JF-17. Meaning they are going to upgrade their fleet with an aircraft which is better than Mirage-3/5, F-7 etc at as low a cost as possible. They are not trying to do what IAF is doing, that is to replace late 3rd gen aircraft with next gen aircraft.

 

[gokussj9]

B2 with the 9300Kgf engine is equivalent to our LCA Mk1. B3 will be equivalent to LCA Mk2.



This is kind of at the same level as what we have on LCA mk1.



It can be done.



Depends on how much they are willing to spend.

They can do it in a major way on the B3. B2 and B1 can be subsequently upgraded during MLUs, like how MKIs will also have composites after MLUs.

PAF's current intention is to replace their F-7s and Mirage-3/5s with the JF-17. Meaning they are going to upgrade their fleet with an aircraft which is better than Mirage-3/5, F-7 etc at as low a cost as possible. They are not trying to do what IAF is doing, that is to replace late 3rd gen aircraft with next gen aircraft.

Are you assuming that B3 will be same as Mk2 or you read the B3 specifications somewhere?

 

[p2prada]

Are you assuming that B3 will be same as Mk2 or you read the B3 specifications somewhere?

Merely the timeline, level of tech maturity on both sides, similar size of the airframe, engine capacity.

Both aircraft won't be Gripen NG and both aircraft are touted to have 5th gen technology like AESA and internal EW suite which make them very similar.

 

[gokussj9]

Merely the timeline, level of tech maturity on both sides, similar size of the airframe, engine capacity.

Both aircraft won't be Gripen NG and both aircraft are touted to have 5th gen technology like AESA and internal EW suite which make them very similar.

What specific advantages does an FBW system provides in terms of ease of flying and maneuvering the aircraft and attack capabilities+airframe? If JF-17 does not have a FBW in all three dimensions, then is it not still 3rd generation?

 

[p2prada]

What specific advantages does an FBW system provides in terms of ease of flying and maneuvering the aircraft and attack capabilities+airframe?

It depends on what you are comparing to. Are you comparing digital vs analog or merely FBW vs mechanical or hydraulics?

FBW allows the pilot to control the moving surfaces of the aircraft electrically, while mechanical or hydraulics is similar to what you will find in old car steering wheels. FBW is like modern power steering on cars. Meaning the pilot needs minimal effort to move the control surfaces like elevators and rudders.

In FBW, pilot data is fed into a computing device which then initiates the actuators connected to the moving surface.

Digital FBW goes one step forward. It used powerful computers which is fed information from not just the pilot, but also various other equipment on board like altimeter, pitot tube etc. Meaning if the pilot is trying to fly recklessly, the FBW will not allow the pilot to perform the maneuver. For eg: if he is too close to the ground, the altimeter information is fed to the computer automatically and the computer takes away control from the pilot for a brief time. The same if pilot tries to exceed AoA. Meaning it reduces the effects of pilot induced oscillations.

FBW is slowly replacing pilot input is many maneuvers, like future aircraft may land and take off on their own without needing pilot input. When landing, especially with large loads, it creates a lot of stress on the aircraft. Pilots don't always make perfect landings to reduce that stress. Take away pilot control and pretty much every landing will be perfect and will increase service life.

Digital FBW also removes the need for an aircraft to be stable, like Mig-29A is. This increases its scope for enhanced maneuverability. Meaning when an aircraft is unstable, the computer tries and maintains level flight without needing pilot input (it is humanly impossible to keep an unstable aircraft steady) and the pilot can use the additional maneuverability in dog fights.

If JF-17 does not have a FBW in all three dimensions, then is it not still 3rd generation?

JF-17 has FBW in pitch, roll and yaw. On Block 1 the system is quadruplex digital in pitch and duplex analog in roll and yaw. I think B2 will have full quadruplex digital FBW in all axes.

The Chinese went about it the right way. ADA tried doing too much in too little time and is paying for it. They should have taken Dassault's offer of an analog system back in 1989. IAF never even asked for a digital FBW.

 

[gokussj9]

@p2prada from the wiki link it says jf17 has conventional controls in yaw and roll axis and.fbw in pitch axis. That means it is not fully fbw.

 

[farhan_9909]

Only till Pt-03

The PT-04 saw redesigning in 2005.Which also resulted in a complete Quadruplex FBW in all axis

And has also been confirmed by cobrato itself

If one has access to Janes and opens up the 2005 dec extract..the time when Pt-04 was to roll out it mentioned the production variant will have complete fbw in all axis as planned

 

[gokussj9]

@p2prada,

I remember this post a while back from @Vladimir79 regarding Vixen AESA radar on JF 17

I might have given it a second thought to the statement if you said J-10, but JF-17 is just a laugh. Vixen will weigh at least an extra 100kg compared to Grifo S7 decreasing an already weak payload. The power requirements of a 1000T/R module X-band AESA will not be met by JF-17, especially when they are increasing Gripen's current PP by 40%. You might stick Vixen 500E on it, but that is just an underperforming AJT radar.

So according to him, JF-17 is too under powered for an AESA radar. Will the new engine be able to compensate for that?

 

[p2prada]

@p2prada,

So according to him, JF-17 is too under powered for an AESA radar. Will the new engine be able to compensate for that?

Yeah, very accurate. A single engine in the RD-93 class cannot power AESA. It is the same for LCA Mk1 as well. It is practically impossible.

Only with a new engine can the JF-17 be able to power an AESA.

The current powerplant on both F-404 and RD-93 is of the 30-40KVA class. On Mk2 the powerplant will be between 50-60KVA class. Almost double.

 

[ersakthivel]

What is the power needed for ASEA radar of 650 mm dia as the one in tejas?

 

[Rahul Singh]

Not exactly. IIRC, news reports changed figures from "greater than" 90KN to 95-100KN. Today it may be 110KN, which is still unreported.

But how much more can you possibly improve from the original requirement of 17 deg, the basic design is still the same. You want to improve it to 19deg, like Mirage-2000, go ahead.

LCA won't be required for turning fights anyway. Shoot and scoot. The same as what the Mig-21 is meant to do. Maybe it can get into a turning fight with aircraft like J-10/F-16/JF-17, but not when core air superiority support will be from Flankers and J-20, at least on the Chinese side.

So that would mean EJ participation was scam and this was in effect a single vendor deal? A scam wow! Why is everybody sleeping then?

From what it is unofficially known F-414 was not even IAF requirement.

Dog fight capability: Well LCA was designed light and unstable for some purpose and that probably was good agility which with powerful engine is maneuverability.

And LCA is associated with Mig-21 only because it is to replace it other than this there are absolutely no relations.

Can you give me some source on figures with dates please, so i can talk.

 

[p2prada]

So that would mean EJ participation was scam and this was in effect a single vendor deal? A scam wow! Why is everybody sleeping then?

From what it is unofficially known F-414 was not even IAF requirement.

Dog fight capability: Well LCA was designed light and unstable for some purpose and that probably was good agility which with powerful engine is maneuverability.

And LCA is associated with Mig-21 only because it is to replace it other than this there are absolutely no relations.

Can you give me some source on figures with dates please, so i can talk.

Don't think of LCA as an unstable aircraft and hence a very good dog fighter. With a STR of 17 deg the aircraft should never allow itself to get into a turning fight. It should be like the Mirage-2000, get the first missile in and try to get the second one in if the first misses. Or get the hell out. LCA has a high ITR like Mirage-2000.

Haven't you seen so many French interviews where they always say they need to finish the fight within a minute or else they will get bogged down due to the large wings and high drag. Meaning they don't want a turning fight.

Anyway, it seems the F-414INS6 is a 98KN engine, not 110KN.

 

[Rahul Singh]

Don't think of LCA as an unstable aircraft and hence a very good dog fighter. With a STR of 17 deg the aircraft should never allow itself to get into a turning fight. It should be like the Mirage-2000, get the first missile in and try to get the second one in if the first misses. Or get the hell out. LCA has a high ITR like Mirage-2000.

Haven't you seen so many French interviews where they always say they need to finish the fight within a minute or else they will get bogged down due to the large wings and high drag. Meaning they don't want a turning fight.

Anyway, it seems the F-414INS6 is a 98KN engine, not 110KN.

Don't restrict dog fight only to STR, it is not after all WW2 when Mustang and Me-109 would lure each other into wagon wheel and killing one with poorer STR?

I don't know if LCA had just 17 degree STR or more but i do know dog fight is much more than STR, dog fight is about loop also, its about ITR also, quick reversal, ability to quickly bleed energy and gain also call accleration.

In a classic dog fight when and enemy will bank and turn LCA will pitch and climb when a conventional two wing design will use its low stall speed to stay behind foe, LCA will do Yo-Yo to stay behind......

Anyway, it seems the F-414INS6 is a 98KN engine, not 110KN.

For your own convenience...... following link which has been posted many times before says otherwise.

"The F414-INS6 is the highest-thrust F414 model

 

[p2prada]

Don't restrict dog fight only to STR, it is not after all WW2 when Mustang and Me-109 would lure each other into wagon wheel and killing one with poorer STR?

I don't know if LCA had just 17 degree STR or more but i do know dog fight is much more than STR, dog fight is about loop also, its about ITR also, quick reversal, ability to quickly bleed energy and gain also call accleration.

In a classic dog fight when and enemy will bank and turn LCA will pitch and climb when a conventional two wing design will use its low stall speed to stay behind foe, LCA will do Yo-Yo to stay behind......

So what? It cannot be sustained. It doesn't make sense for LCA to stay in such a fight like the F-16. Kill or get out, that's the mantra for LCA.

Even after ITR, loop, yo-yo etc LCA will bleed more energy than, say, JF-17. To regain energy everytime, LCA will have to either resort to full military power or go into afterburner. Fuel isn't in unlimited supply for such maneuvers.

For your own convenience...... following link which has been posted many times before says otherwise.

"The F414-INS6 is the highest-thrust F414 model

Follow Austin and my discussion in this thread instead.

http://defenceforumindia.com/forum/indian-air-force/45058-ada-lca-tejas-mark-ii-13.html#post722642

 

[Decklander]

F414INS6 also has been tested for and certified for AVEN thrust vectoring nozzles. With no change in design or weight anjd still using fuel as nozzle actuating means instead of hydraulics.

 

[ersakthivel]

Don't restrict dog fight only to STR, it is not after all WW2 when Mustang and Me-109 would lure each other into wagon wheel and killing one with poorer STR?

I don't know if LCA had just 17 degree STR or more but i do know dog fight is much more than STR, dog fight is about loop also, its about ITR also, quick reversal, ability to quickly bleed energy and gain also call accleration.

In a classic dog fight when and enemy will bank and turn LCA will pitch and climb when a conventional two wing design will use its low stall speed to stay behind foe, LCA will do Yo-Yo to stay behind......

For your own convenience...... following link which has been posted many times before says otherwise.

"The F414-INS6 is the highest-thrust F414 model

The Tejas mk1 can easily take on any fighter in the south Asian skies.

SO it can easily take on the J-10/F-16 and various other chinese twin engined Sukhoi- clones, when it comes to the defence of Indian skies.It frees other costly assets of Sukhoi-30 MKI and RAFALE to take on their strike roles. It is the near future threat perception scenario faced by India.When Chimese induct J-20 and J-31 in large numbers , nothing precludes us from inducting large number of FGFA and AMCA versions to conter them,

[
Chinese are still making and inducting J-10s , and various sukhoi clones in full swing. As long as these 4th gen fighters serve in the PLAF we can use tejas mk-1 to counter them.


Another important point is tejas mk-2 is primarily developed to cater for the Indian navy's needs. Otherwise tejas mk-1 is good enough to do duty in IAF from today itself.There is a false impression that Tejas mk-1 is underpowered , and failed to meet the original IAF needs and mk-2 is being developed to remedy this.

Truth is exact opposite.

this is what the original ASR from the horse's mouth.

Tejas - Feature - The Light Combat Aircraft Story by Air Marshal MSD Wollen (Retd)

Space constraints prevent any meaningful description of materials, technology, facilities, processes developed for execution of the project. Military aviation enthusiasts may read a monograph on Aeronautical Technology that has attained maturity through DRDO efforts; much of this technology finds application in the LCA project. The monograph was brought out at Aero India 1998. The LCA is tailless with a double-sweep delta wing. Its wing span is 8.2 m, length 13.2 m, height 4.4 m. TOW clean 8.500 kg, MTOW 12500kg. It will be super-sonic at all altitudes, max speed of M 1.5 at the tropopause. Specific excess power and g-over load data has not been published. Maximum sustained rate of turn will be 17 deg per sec and maximum attainable 30 deg per sec. Funds have been sanctioned for a Naval LCA. PD and studies in critical technology areas have commenced. The aircraft will be powered by a Kaveri engine (more information follows) and is to operate from the Indian Navy's Air Defence Ship, under construction. Launch speed over a 12 deg ramp is 100 kts; recovery speed during a no flare deck landing, using arrester gear, is 120 kts. Take off mass 13 tonne, recovery mass 10 tonne. Most stringent requirements are that the airframe will be modified: nose droop to provide improved view during landing approach; wing leading edge vortexes (LEVCON) to increase lift during approach and strengthened undercarriage. Nose wheel steering will be powered for deck maneuverability.

Top speed of the original ASR is 1.5 mach STR 17 deg . Both have been exceeded by tejas mk-1 within it's partially opened capabilities for IOC.

Tejas completes a full vertical loop in aeroindia 2013 video posted by rahulrsd1 in under 20 seconds within the 6G limitations of partially opened flight envelope.It means an STR of about 18 deg a deg more than the specified 17 deg in original ASR.

people seem to forget that that STR is a combination of three factors

1.AOA
2.Thrust to weight ratio
3.Wingloading.

In wingloading and Thrust to weight to ratio tejas mk-1 exceeds mirage-200-5 by more than 10 percent.

As naval test pilot said in Aeroindia 2013, LCA has been tested to 22 deg AOA. And a couple of more degs is quite normally achievable as per design spec.Originally tejas mk-1 retains significant rudder authority evn at 30 ded AOA as per PDF posted by NAL.

So Tejas mk-1 with 24 deg AOA within FCS limit along with better than Mirage TAR and Wingloading can easily outperform any fighter in combat performance.

As you said close air combat is no longer turning wagon wheels. It is ITR and sharp nose pointing capability coupled with a WVR shot from HMDS assisted high off bore sight missile. SO no way and deg shortfall in STR is going to hobble tejas mk-1 in this dpt. As due to high TWR and low wing loading it can have a comparable ITR to do this HMDS shot.

I don't know whether there is another revised ASR from IAF which Tejas mk-1 failed to meet.

Tejas mk-1 sigificantly exceeeds the original ASR set by IAF in the 1986.Because the navy wanted a higher powered version for carrier duty the mk-2 is being developed. SO considering he improvement in performance to Grippen NG or E/F level IAF too decided to back it.

Otherwise the present Tejs mk-1 is no pushover in south Asian skies. With reliable american engines and 120 km range detection and tracking radar along with lowest RCS among it's asian peers , coupled with exceptional handling abilities it sits above the 80 percent of the fighters that comprise the IAF , PAF, PLAF fleet of obsolete to near obsolete fighters belonging to 3rd generation and below.

In the debate about DBO occupation by PLA in ladakh a blurb says that china can throw 21 squadrons of fighters against IAF. Tejas mk-1 alone will be more than capable of taking them on in a fighter group comprising SuKHOI-30 MKI and other EW fighters with ease.Thsi combined fighter tactics are being validated by IAF in the recently held Red flag exercise when IAF used Su-30 MKI in a group with Su-30 MKI.I

J-10 cannot take off with full loads in high himalayan conditions and manuever as good as mk-1 because it has a high wing loading and lower TWR than mk-1 tejas.

The range is not a problem. As the primary duty of the IAf tejas mk-1 is to oerate within it's range in the defencs of the indian skies.

 

[Rahul Singh]

So what? It cannot be sustained. It doesn't make sense for LCA to stay in such a fight like the F-16. Kill or get out, that's the mantra for LCA.

Even after ITR, loop, yo-yo etc LCA will bleed more energy than, say, JF-17. To regain energy everytime, LCA will have to either resort to full military power or go into afterburner. Fuel isn't in unlimited supply for such maneuvers.

So its about fuel now? Like i said in is no more WW2 where one better STR gets to beat other.

Anyway are you saying with lighter airframe weight and greater thrust LCAs at MK-2 the STR will not be better? Hell at atleast 65 KN dry LCA has far better TWR than any fighter of light class and better TWR also means better sustained rate.

No, loop isn't all loss maneuver, the gravity takes care for lost energy in any dissimilar dog fight this one maneuver will be used by LCA to counter for others flat turn and it is where deltas excel. Heck one who is better at loop gets to hold purge and gets to attack enemy at greater speed and at wider angle than flat turning jet which has just lost all its energy.

BTW you are still due to give me source of the yours which says LCA has 17 deg STR......

Follow Austin and my discussion in this thread instead.

http://defenceforumindia.com/forum/indian-air-force/45058-ada-lca-tejas-mark-ii-13.html#post722642

Give me the link which says otherwise.

 

[ersakthivel]

Only till Pt-03

The PT-04 saw redesigning in 2005.Which also resulted in a complete Quadruplex FBW in all axis

And has also been confirmed by cobrato itself

If one has access to Janes and opens up the 2005 dec extract..the time when Pt-04 was to roll out it mentioned the production variant will have complete fbw in all axis as planned

there are many versions of fly by wire. Fly by wire simply means the pilot pulls the stick and his effort is converted into electrical or digital signals and the hydraulics of control surfaces obey the signal.That's all.

the british tried fly by wire in jaguar . the french tried it on old Mirage-IIIs.

So there is nothing wrong in china trying the same tech in J8II ACT ---the replacement of J8ACT and retired in early 2000s and mastering it. And this tech is bolted on to JF-17 from prototype -2 or 3 stage is completely agreeable.

But what is the most challenging effort is to use this fly by wire tech with full digital FCS along with complicated control laws to control the flight behavior of a DYNAMICALLY UNSTABLE FLIGHT PROFILE PLATFORM LIKE TEJAS.

IMHO the prototypes mentioned above are stable flight profile fighters meaning that they oppose the pilot's effort to maneuver the fighter and naturally return to the level flight once the pilot eases the stick. IMHO JF-17 belongs to this clause.if you have any evidence to the contrary do post.



So FCS and Fly by wire based on control laws for those stable flight profile is not demanding.IMHO Jf-17 belongs to this clause.
you just cannot add a dynamically unstable flight profile to a fighter as stable flight profile one like JF-17, may be you can add a bit more of maneuverability by relaxing stability to some extent in some axes.

But you cannot fundamentally change the fighter flight profile after prototype stage.IMHO if you want that you have to go for complete redesign. If you have any links to support such complete redesign please post.

It will add some residual performance of course. But it can never make a stable flight profile fighter to equal the unstable flight profile fighters.

But dynamically unstable flight profile deltas which tend to veer off in all directions if the control surfaces are not maneuvered many times in a single second is another cup of tea.

Control laws and fully digital FCS for these fly by wire system takes years to develop and validate. if you have any doubts just refer to the fligth test period of RAFALE with how many prototypes.

Tejas belongs in this clause designed as dynamically unstable flight profile delta from scratch while JF-17 is not is IMHO.

 

[ersakthivel]

So its about fuel now? Like i said in is no more WW2 where one better STR gets to beat other.

Anyway are you saying with lighter airframe weight and greater thrust LCAs at MK-2 the STR will not be better? Hell at atleast 65 KN dry LCA has far better TWR than any fighter of light class and better TWR also means better sustained rate.

No, loop isn't all loss maneuver, the gravity takes care for lost energy in any dissimilar dog fight this one maneuver will be used by LCA to counter for others flat turn and it is where deltas excel. Heck one who is better at loop gets to hold purge and gets to attack enemy at greater speed and at wider angle than flat turning jet which has just lost all its energy.

BTW you are still due to give me source of the yours which says LCA has 17 deg STR......


Give me the link which says otherwise.

why should energy bleeds matter. With one better ITR turn , it point it's nose with least effort ,

and it gets a high offbore sight WVR missile firing solution with HMDS. So where is the bleeding and yo yo loop?

The tight STR turns in JF-17 too are most fuel consuming and ultimately of no use against the HMDS high off bore sight shots.Sure the fighter won't out turn a missile in a continuous STR turn.it is an established fact.

 

[ersakthivel]

@p2prada from the wiki link it says jf17 has conventional controls in yaw and roll axis and.fbw in pitch axis. That means it is not fully fbw.

Without dynamically unstable flight profile built into the design of the airframe from scratch adding a digital any axis FBW will only give residual performance increase with reduced pilot stress and some safety measures that won't allow the pilot to pull the plane into the stall state.

It will never make it equal in close combat maneuvering to the true blue dynamically unstable flight profile platform like Mirage and Tejas. It is not for nothing that test pilots of the tejas are praising it as sharp in take off and better than mirages they operated.

The fabulously low wing loading providing great lift to drag ratio,

coupled with cranked delta dynamically unstable flight profile aerodynamic design,

high thrust to weight ratio of 1.07 enabled by composites which make more than 90 percent of the surface area and 45 percent of the weight,

One of the lowest clean config RCS among modern 4.5th gen fighters, thanks to RCS reduction effort from the start by ADA,

along with flaw less kick ass FBW,

and a large radar demanded by IAF which has the detection and tracking range of 120 km,

and future ASTR missiles with 120 km range especially to be developed for Tejas mk-1,


makes it stand in the class of EUROFIGHTER TYPHOON, RAFALE in design philosophy. Even without taking into account the boost in performance in Mk-2.

Future possible upgrades for MK-1, all within reach,

and a surefire low eight, high thrust next gen AMCA engine with lower weight and higher thrust which will have the same dimensions of the GE-404 presently on the Tejas mk-1,

which will massively improve it's loading carrying capacity and close combat fighting soecs along with the range(by permiting it to carry external CFts , since the higher power engine allows it enough power along with decent weapon load)

Along with ASEA radar and longer range BVrs,Will make it close the gap with the brand new tejas mk-2. So ADA is not selling a lemon to IAF.

It is not for nothing that ADA resisted IAf pressure to go for a souped up monkey version of the Mig-21 type and decided to bridge the gap in tech woth advanced fighter producing entities like France and EUROPE facing brickbats of monumental volume.



other than the engine tech Tejas has made India self sufficient in all other areas of fighter design.

Engine tech too is getting there, but it will take some doing and a substantial amount of time,

So the development of tejas mk-1 it will considerably reduce the work load needed for AMCA.

Saying stable fligth profile Jf-17 which has fly by wire tech in digital mode in all axis introduced from prototype -03, is equal in unstable flight profile design philosophy of Mirage-2000 and tejas is wide off the mark.

It is like sayin the FBW test fligh fighters like J8II ACT ---the replacement of J8ACT and retired in early 2000s , and the jags on which british tried their FBW tech and old mirage -III on which the french tried the fly by wire tech is equal to the Tejas mk-1 and Mirage-2000 in performance. IMHO it is simply not true.