JF-17/FC-1 Fighter Aircraft thread

[mean_bird]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

Unless there is no news, how can it be confirmed ? You only have internet forums as your guide I suppose. I've even heard that JF-17 may have Selex AESA, and French armament but how do you confirm it ?

Not just internet sources, there are newspapers, television interview, etc. As I said, I also had the honor of discussing with a senior engineer directly working on it.

The news about French RC-400, MICA etc are not just rumors. It was reported in IDEAS 2008. Here's what it said:

"The first batch of 50 JF-17 Thunder aircrafts will be equipped with the chinese/Pakistani avionics and missiles, while the later aircraft are to be equipped with more advanced radars and missiles including those of western makes. The JF-17 is said to be much more maintenance friendly compared
to the F-16 currently in service with the PAF.

Meanwhile, France has offered Pakistan its RC-400 radar and MBDA MICA missile for the aircraft. However, AESA radar of different make[B]s[/B] have also been offered to the Pakistan Air Force and the MBDA Meteor missile too is on the cards. Pakistan has begun negotiations with British, Italian,and French defence firms over potential avionics and other systems for the JF-17 Thunder aircrafts."

No it doesn't. Though nearly same in length and height, a JF-17 is not a M 2+ and 9g aircraft, and cannot carry as much load. So it's operating envelop is clearly not the same. It does not have the rigors of an F-16, even if it's operating envelop would have been the same (which it is not).

Crobato is right...they were meant to exhibit similar performance and handling. The F-16 style wings in not a mere co-incidence. It was specifically requested by PAF because they are very happy with the F-16 handling.

If you remember, an interview was posted here of a pakistani and a chinese test pilot. They both said the JF-17 handles superbly and at par if not better than the F-16 and Su-27....both of which are extremely agile and maneuverable...in the horizantal maneuvers, but fell slightly short of them in vertical ones...because of thrust.

Anyone with basic aerodynamics knowledge will tell you the JF-17 is designed to be very maneuverable , and capable of high AoA especially at lower speed...similar to F-16 and F-18.

As for you objections that its not M 2+ or 9g...well one answer...engine thrust. The F-16 has a higher thrust, hence 9g, and more payload,etc. Just the addition of DSI increased the speed from 1.6 to 1.8 and air intakes is related to supply of air to engines and not lift provided by the wings.

As an example, take a look at another ....ahem you know which one...plane that was supposedly designed for 9g but hasn't pulled more than 6g, is limited to 17° AoA (some blogs claim 23° but even that is not enough) and cannot carry its intended weapons load....why?? because ( among other factors) its overweight by atleast a ton and is underpowered.

Once again, I was talking of Kaveri vis-a-vis WS-13 and not J-8 and it's intakes (look how you skidded off once more). What is the status of WS-13 and when will it be integrated on the FC-1 ? From what PAF head Tanver Mahmod said he is looking at a western engine, so what about WS-13 ?

To be honest, I wouldn't like the JF-17 to go for the WS-13 (at this point) for one reason. Its a new engine and the JF-17 is a single engined plane.

Similar to what is happening with WS-10A....its used in J-11 but not (currently) on J-10 (correct me if I am wrong). You need to test out your engine for a while before you can risk using it on a single engine aircraft, no matter how good your design is. Sometimes, a problem surfaces only after extended use even if the engine appears to run smoothly under different tests.

The Chinese engines are progressing very well ( you should see the chart provided for the timeline of the engines in another thread). I reckon within 5-10 years, China will have a whole range of reliable, proven engines that will significantly lessen its dependence in this sector.

 

[mean_bird]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

Some new pics

 

[crobato]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

Unless there is no news, how can it be confirmed ? You only have internet forums as your guide I suppose. I've even heard that JF-17 may have Selex AESA, and French armament but how do you confirm it ?


Your ability to meander away from topics is legendary. First lerx, then fuselage diameters and now aspect ratios. OK do you think only aspect ratios decide wing shapes ? Are you saying that no other wing configuration could've been had for the JF-17 other than the one chosen ? Do you know that for a given ratio, you can have more than one design ? Heard of sweep ?

And no, it's not the ratio of wing length and width but span square and area.

Yeah, have you heard of SWEEP? Sweep is often a factor of aspect ratio. The lower the aspect ratio in delta wings the greater the sweep is.

Span square and area is determined by the plane's own requirements. That's the only valid thing. You don't expect to put the wings of one plane into another and expect that to work.

No it doesn't. Though nearly same in length and height, a JF-17 is not a M 2+ and 9g aircraft, and cannot carry as much load. So it's operating envelop is clearly not the same. It does not have the rigors of an F-16, even if it's operating envelop would have been the same (which it is not).

That shows you crap you don't what I'm talking about. I'm talking about flight regime, which is the speed and altitudes the aircraft is expected to operate. You don't have any idea that the aircraft has to assume that flight combat are most likely to happen on XXX altitude YYY speed, and you optimize both the engine intake and wing aspect ratio to get you the best performance at XXX/YYY.

Now if I'm not mistaken (and I'd like someone to confirm it) the JF-17 has even retained the typical Flaperons specific to the F-16. These are not exactly airelons but are found only on F-16.

Wrongo. There is nothing different in the fundamental principle of F-16's ailerons with any other aileron. Ailerons are ailerons, period.

Once again, I was talking of Kaveri vis-a-vis WS-13 and not J-8 and it's intakes (look how you skidded off once more). What is the status of WS-13 and when will it be integrated on the FC-1 ? From what PAF head Tanver Mahmod said he is looking at a western engine, so what about WS-13 ?

Its not likely the JF-17 will ever have a Western engine, and if the PLAAF wants to buy the JF-17, the WS-13 would be mandatory.

Jeez, you still insist that somehow the JF-17's intakes are like the J-8II's just because it has a boundary layer splitter.

Do you know that every body intake requires a boundary layer splitter, unless you use a cone shaped design like the Mirage 2000? Even the F-16's intake, if you turn it sideways, has a boundary layer splitter. All these planes have boundary layer splitters: F-5A/E, F-20, F-4 Phantom, MiG-23, MiG-27, JH-7A, Jaguar, F-18, F-22, etc,. Even the Tejas has a boundary layer splitter. Its a requisite for intakes because you don't want the boundary layer crashing into the compressor blades.

Are you insisting the JF-17's intakes has a family relationship with the J-8II's just because its square. Look again, how many square intakes are with many aircraft. I swear, Boeing and Airbus airliners have a family relationship because the engine intakes are ROUND.

The J-8II and the JF-17 works in very different manner. One is mainly a high speed interceptor aircrart. The XXX YYY flight regime of the J-8II should be optimized for high altitudes and high speed flight. The JF-17 on the other hand, is better optimized for lower to mid altitudes around 20,000ft generally and subsonic combat (preferably around Mach 0.3 to Mach 0.8), which by the way, is also where the F-16 is aiming at. It also intends to do a lot of maneuvering which means it must have air flow during the turns. That's why the intakes and the intake tunnels are not the same. FYI, the J-8II uses a variable ramp, the JF-17 is fixed in both its original design and the DSI.

For that reason, the wing design of the two aircraft are quite different, the JF-17 has a higher aspect ratio for its purpose while the J-8II has a lower one for its own purpose.

 

[Indianfighter]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

The news about French RC-400, MICA etc are not just rumors. It was reported in IDEAS 2008. Here's what it said:

"The first batch of 50 JF-17 Thunder aircrafts will be equipped with the chinese/Pakistani avionics and missiles, while the later aircraft are to be equipped with more advanced radars and missiles including those of western makes. The JF-17 is said to be much more maintenance friendly compared
to the F-16 currently in service with the PAF.

Meanwhile, France has offered Pakistan its RC-400 radar and MBDA MICA missile for the aircraft. However, AESA radar of different make[B]s[/B] have also been offered to the Pakistan Air Force and the MBDA Meteor missile too is on the cards. Pakistan has begun negotiations with British, Italian,and French defence firms over potential avionics and other systems for the JF-17 Thunder aircrafts."

OK, so it is at the same status the LCA is in. First 40 to be vanilla, while the remaining ones with western engine and French Meteor or Derby. Negotiations are on.

Yeah, have you heard of SWEEP? Sweep is often a factor of aspect ratio. The lower the aspect ratio in delta wings the greater the sweep is.

This shows how you have confused span and sweep. Aspect ratio depends on the span; for a given span, you can have many angles of sweep and consequently different wing shapes and designs. The tailing edge can also be swept or not.

Read up more on this.

You don't expect to put the wings of one plane into another and expect that to work.

I opine that, that's what has been done on the JF-17. Just look at the shapes from the top of F-16 and JF-17, they are very similar.

That shows you crap you don't what I'm talking about. I'm talking about flight regime, which is the speed and altitudes the aircraft is expected to operate. You don't have any idea that the aircraft has to assume that flight combat are most likely to happen on XXX altitude YYY speed, and you optimize both the engine intake and wing aspect ratio to get you the best performance at XXX/YYY.

If flight regimes consisted only of speed and altitude, then a J - 7 flying at M 2 alongside a J-11 has the same regime.

It depends on the weight of the fighter, g-limits, loads carried, it's size and much more. A JF-17 differs from an F-16 in all these respects (except size). The testing of it's flight regimen is obviously different.

Wrongo. There is nothing different in the fundamental principle of F-16's ailerons with any other aileron. Ailerons are ailerons, period.

No. An F-16 uses flaperons, which are not airelons. Looking at the near exact wing shapes of the F-16 and JF-17, I'd like someone to confirm whether JF-17also has the typical flaperons.

Its not likely the JF-17 will ever have a Western engine, and if the PLAAF wants to buy the JF-17, the WS-13 would be mandatory.

I was talking about the PAF. It's Air Chief specifically said they'll evaluate a western engine. He didn't mention the WS-13.

Jeez, you still insist that somehow the JF-17's intakes are like the J-8II's just because it has a boundary layer splitter.

Are you insisting the JF-17's intakes has a family relationship with the J-8II's just because its square. Look again, how many square intakes are with many aircraft. I swear, Boeing and Airbus airliners have a family relationship because the engine intakes are ROUND.

Oh, for god's sake I said China has mastered the technique of converting a MiG-21's central intake to side intakes (whatever kind they may be). This is what I said earlier, "Forget V-duct intakes or horizontal side intakes for a while. Once CAC decided that F-7's centrist intake is not needed, they put side intakes on J-8 II and FC-1 (though they may be very very very different according to you)."

 

[crobato]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

This shows how you have confused span and sweep. Aspect ratio depends on the span; for a given span, you can have many angles of sweep and consequently different wing shapes and designs. The tailing edge can also be swept or not.

WRONG Start reading up on the books. Its computed differently based on wing design.

For deltas and diamonds, aspect ratio is a ratio between wing span and wing root /2. That's why its called a ratio for god sakes. For planes with a constant chord its the ratio between the wing span / chord; if the wing has a variable chord, determine the average or mean chord, then wing span / avg. chord.

The sweep is the hypotenuse of the triangle between X= length of Wing Root, and Y = width of wing span.

If you're using different wing designs like trapezoidal or diamond, the calculations for sweep are different.

But we are talking of deltas and clipped deltas here which has strong advantages for use in fighter designs due to their **superior** rigidity, load transfer and stress handling qualities over sweep wings. With a clipped delta, you got a triangle with the edge sawed off to hold a standard short range missile.

Read up more on this.

You read up on this before you made yourself look like the f**l like you did just now.

I opine that, that's what has been done on the JF-17. Just look at the shapes from the top of F-16 and JF-17, they are very similar.

Which means nothing really, because that's all all clipped deltas and deltas look.

Look at the shapes of the Mirage III and the Delta Dagger.

If flight regimes consisted only of speed and altitude, then a J - 7 flying at M 2 alongside a J-11 has the same regime.

That shows you how little you don't know. Maximum speed is not about optimum flight regime. The flight regime is the what is the most common speed and altitude you expect the plane to engage or do its duties. No one flies at max speed all the time.

It depends on the weight of the fighter, g-limits, loads carried, it's size and much more. A JF-17 differs from an F-16 in all these respects (except size). The testing of it's flight regimen is obviously different.

Wrong here again. You assume your flight regime based on your mission and operational roles.

Furthermore, even with wing span and sweep is dictated by mission roles and flight regimens. Greater wing span favors lower speed flight lower wing span favors higher speed. Greater sweep favors higher speed, less sweep lower speed.

No. An F-16 uses flaperons, which are not airelons. Looking at the near exact wing shapes of the F-16 and JF-17, I'd like someone to confirm whether JF-17also has the typical flaperons.

Excuse me, but whatever you call it, has the same function.

I was talking about the PAF. It's Air Chief specifically said they'll evaluate a western engine. He didn't mention the WS-13.


Oh, for god's sake I said China has mastered the technique of converting a MiG-21's central intake to side intakes (whatever kind they may be). This is what I said earlier, "Forget V-duct intakes or horizontal side intakes for a while. Once CAC decided that F-7's centrist intake is not needed, they put side intakes on J-8 II and FC-1 (though they may be very very very different according to you)."

According to me is according to what is correct. Study up on how intakes are designed, will you?

The J-7's intake has absolutely nothing to do with the J-8II because the J-7's intake is intended to feed one engine. If you cut a cross section of the plane, it will be like looking at the barrel of a single barrel shotgun.

The J-8II has to feed TWO ENGINES. Right from the inlet you have to deal with double the flow. When you cut open the plane, the cross section would appear like looking down the twin barrels of a twin barrel shotgun. The original J-8I intake is a round intake that has a big divider in the middile, which makes it two actual intakes.

Now you don't know what is the difference between a fixed intake and a variable intake? The fixed intake is designed as the best compromise and balance for the most common operational and flight mission regimes of the aircraft. The variable intake is designed with the maximum speed, then determine the angles of the variable ramp to control the air flow at different airflow requirements using an air flow sensor and computer.

Even from the beginning, the J-7 actually uses a variable intake---the nose inlet actually slides back and forth, and compared to the standard MiG-21, it has more stepping increments. The JF-17 has always been fixed to start with. When you got a fixed inlet, the exact dimensions are precisely calculated for the airflow.

Another thing is, the J-7's engine tunnel and its diameter is meant to match both the diameter of the engine and its engine requirements. Once that is figured out, you wrap an airframe around it. The JF-17's engine tunnel has to match not just the diameter of the engine, which is much wider, but also is a lot more powerful with the airflow to match, and also not the least, because its a turbofan and not a turbojet which requires even more air for the bypass.

 

[mean_bird]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

OK, so it is at the same status the LCA is in. First 40 to be vanilla, while the remaining ones with western engine and French Meteor or Derby. Negotiations are on.

I do not wish to start a comparison thread here but no, they are not. The Tejas have some major problems to solve relating to AoA, pulling high g maneuvers, its massive overweight problem, etc

Radars or other avionics can be and have been upgraded on many aircrafts IF (and a big if) they choose to do so (e.g F-16, F-15 with AESA, etc). The JF-17 was specifically designed by de-linking the avionics from the airframe so upgrading them (if necessary) won't be a problem. But you cannot upgrade a plane to reduce its weight...its gonna remain like that.

Strangely enough, I haven't read or heard one PAF personal claim the engines to be underpowered ( I do not claim to have read everything so any counter-proof is welcome). The only thing I have heard them say is

1. Its Russian so they need support during difficult times, and most importantly( and repeatedly)
2. Russian engines have bad serviceability.

This shows how you have confused span and sweep. Aspect ratio depends on the span; for a given span, you can have many angles of sweep and consequently different wing shapes and designs. The tailing edge can also be swept or not.

Read up more on this.

I opine that, that's what has been done on the JF-17. Just look at the shapes from the top of F-16 and JF-17, they are very similar.

You are going by definitions but all these things are inter-related...you can't look at them independently. For example, a glider(high aspect ratio, little to no sweep) and the discovery shuttle design (low aspect ratio) will always be radically different.

The sweep angle does have proportionality with the aspect ratio if you want a certain behavior.

No. An F-16 uses flaperons, which are not airelons. Looking at the near exact wing shapes of the F-16 and JF-17, I'd like someone to confirm whether JF-17also has the typical flaperons.

A flaperon performs the action of a a flap and an aileron in one structure... I don't see what difference it makes?

 

[SteelBird]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

Strangely enough, I haven't read or heard one PAF personal claim the engines to be underpowered ( I do not claim to have read everything so any counter-proof is welcome). The only thing I have heard them say is

1. Its Russian so they need support during difficult times, and most importantly( and repeatedly)
2. Russian engines have bad serviceability.

It's strange enough, from what I've read about the JF-17. PAF wants to replace the RD-93 with the M88. RD-93 is said have thrust of 49.4 KN dry and 84.4 KN with afterburner, while M88 has 50.04 KN and 75.62 KN respectively. If RD-93 is considered underpowered, isn't the M88 even more underpowered? However, the latest version M88-Eco claims to have >90 KN, but it's only available after 2010. PAF is going to have this?

 

[Londo Molari]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

JF-17 was built around the RD-93.
The WS-13 is built for the JF-17.

Other than those 2 engines, I don't see how any other engine could be used. I would expect the French M88 would have different dimensions, and its interface connections would be in different positions, so in my opinion it is not and never was an option.

 

[Indianfighter]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

WRONG Start reading up on the books. Its computed differently based on wing design.

For deltas and diamonds, aspect ratio is a ratio between wing span and wing root /2. That's why its called a ratio for god sakes. For planes with a constant chord its the ratio between the wing span / chord; if the wing has a variable chord, determine the average or mean chord, then wing span / avg. chord.

The sweep is the hypotenuse of the triangle between X= length of Wing Root, and Y = width of wing span.

If you're using different wing designs like trapezoidal or diamond, the calculations for sweep are different.

But we are talking of deltas and clipped deltas here which has strong advantages for use in fighter designs due to their **superior** rigidity, load transfer and stress handling qualities over sweep wings.

Whoever was talking of pure deltas or trapezoids ? (you have a sure propensity to skid off the main topic and start talking something else).

The MAC of a simple delta is simply root length by 2. For a cropped one, the standard MAC equation will still be used, which is a simple integral of a function of the co-ord of the wing's edge. This is independent of any sweep or hypotenuse or whatever.

Now answer this : Do you see the sweep variable in ANY equation of aspect ratio presented by you or me so far ? It means that it is independent of the aspect ratio and given an aspect ratio, you can have other sweeps : delta (cropped or not) or non-delta (like Fulcrums). Then you'll understand the folly of your logic.

Which means nothing really, because that's all all clipped deltas and deltas look.

Look at the shapes of the Mirage III and the Delta Dagger.

I contend : Not only the cropped delta wing with flaperon, even the cropped delta alone is visible only in the F-16. No other 4th or 4.5 G fighter aircraft has a cropped delta wing. The JF-17 has virtually copied all of it + I recon even the flaperon configuration.

That shows you how little you don't know. Maximum speed is not about optimum flight regime. The flight regime is the what is the most common speed and altitude you expect the plane to engage or do its duties. No one flies at max speed all the time.

Wrong here again. You assume your flight regime based on your mission and operational roles.

The flight regime is not just decided by speed and altitude which you mistakenly claimed earlier, but by the size of the aircraft and loads carried primarily. All aircraft from FC-1 to J-11 don't fly at top speeds and top g's all the time but they do have similar speeds at which they'll fly most of their missions. Since they weigh differently and carry varying loads, they have to be designed differently.

The JF-17 DO NOT share any commonality in their weights and loads carried. Yet, they happen to have an uncannily similar wing structure (though this does not mean that different aircraft must have different wing structures).

This is NOT an indictment of the FC-1. If it has the F-16's wings and a relatively new western concept like DSI and flies well, it is well and good. No need to take offence. A flaperon is also not an airelon (it's toward the fuselage, unlike the airelon with is away from it). It is also present on the leading edge. Looking at the images of FC-1, it also has flaperon-like contours.

Now you don't know what is the difference between a fixed intake and a variable intake? The fixed intake is designed as the best compromise and balance for the most common operational and flight mission regimes of the aircraft. The variable intake is designed with the maximum speed, then determine the angles of the variable ramp to control the air flow at different airflow requirements using an air flow sensor and computer.

Even from the beginning, the J-7 actually uses a variable intake---the nose inlet actually slides back and forth, and compared to the standard MiG-21, it has more stepping increments. The JF-17 has always been fixed to start with. When you got a fixed inlet, the exact dimensions are precisely calculated for the airflow.

Another thing is, the J-7's engine tunnel and its diameter is meant to match both the diameter of the engine and its engine requirements. Once that is figured out, you wrap an airframe around it. The JF-17's engine tunnel has to match not just the diameter of the engine, which is much wider, but also is a lot more powerful with the airflow to match, and also not the least, because its a turbofan and not a turbojet which requires even more air for the bypass.

Let's abandon this particular line of discussion.

I do not wish to start a comparison thread here but no, they are not. The Tejas have some major problems to solve relating to AoA, pulling high g maneuvers, its massive overweight problem, etc.

That's all because of a low powered engine which in turn results in maneuverability issues. This will be solved in the batch succeeding the first 40 units. Besides, for the second batch it's does NOT have to choose new avionics, which I believe have not been chosen for the the FC-1 yet.

 

[crobato]

Re: JF-17/FC-1 Fighter Aircraft thread 2009

Whoever was talking of pure deltas or trapezoids ? (you have a sure propensity to skid off the main topic and start talking something else).

The MAC of a simple delta is simply root length by 2. For a cropped one, the standard MAC equation will still be used, which is a simple integral of a function of the co-ord of the wing's edge. This is independent of any sweep or hypotenuse or whatever.

Now answer this : Do you see the sweep variable in ANY equation of aspect ratio presented by you or me so far ? It means that it is independent of the aspect ratio and given an aspect ratio, you can have other sweeps : delta (cropped or not) or non-delta (like Fulcrums). Then you'll understand the folly of your logic.

No that's wrong. Computing for aspect ratio depends on the chord of the wing. For a delta its root length /2 div by wingspan. You're assuming using the square area against the wing span. There are many ways to computer aspect ratio and it depends on the type of wing.

We use deltas here because deltas and variations thereof, are the most common types dues to the superior rigidity and stress loading over any other wing.

With a delta, the sweep becomes a function of the wing span and the wing chord.

Wing span also determines flight behavior.

I contend : Not only the cropped delta wing with flaperon, even the cropped delta alone is visible only in the F-16. No other 4th or 4.5 G fighter aircraft has a cropped delta wing. The JF-17 has virtually copied all of it + I recon even the flaperon configuration.

A cropped delta is simply a clipped delta. Lavi has it, so does the F-CK-1. It simply a functional variation of the delta. The Typhoon and Rafale are other examples.

If you want a tailed delta, put wingtip rails on the wings, more or less the outcome will be the same.

In truth the FC-1 is likely to have more sweep angle on the wing than the F-16, for reasons on its own, partly to improve its top speed due to having lower engine power.

The flight regime is not just decided by speed and altitude which you mistakenly claimed earlier, but by the size of the aircraft and loads carried primarily. All aircraft from FC-1 to J-11 don't fly at top speeds and top g's all the time but they do have similar speeds at which they'll fly most of their missions. Since they weigh differently and carry varying loads, they have to be designed differently.

That's plain wrong. The flight regime is determined before hand in the concept stage of the plane, and then the design is maximized around it. The JF-17 is mainly a low to med altitude aircraft with air combat focused on the subsonic because that's how the customer wants it. The J-8II is a high altitude supersonic aircraft interceptor because that's how the doctrine demands it.

You're assuming that performance is accidental because of loads and what not. Even what a plane is specified in loading is based on intention and design.