JF-17 Thunder Multirole Fighter [Thread 7]

[Trango Towers]

Aren't the JIGS and procedure provided by CAC ? or are you implying that PAC is not following the proper procedures set forth to produce the modules / parts ?

At the end these are same folks that have kept the M-III/V flying for so long.

Also on side note, weren't the wings strengthen for B-III, could be the reason that Block-I & Block-II may have had wing structural issues due to loading ? I am just grasping for straws here though, as the saying goes ' too thin.'

I am sorry but what you have written regarding wing loading is twaddle.
As someone who has done structural design work on the A310, A320 and A330 I know how over designed the wing loading is outside the max flight envelope. So this is absolute rubbish.
Someone has suggested an issue with flutter due to store. But during testing the test pilot would have to be a moron not to reduce speed or eject the store when severe flutter was encountered.
People are writing bs like professionals are stupid who do this for a living and pdf self proclaimed experts are the real deal.

 

[Trango Towers]

Theoratically it can go, but practically PAF hasnt pushed any JF-17 to beyond 1 mach. Can be multiple resaons, one being the stress on the aluminum frames and resultant considerable decrease in JF-17 airframe life considerably which Indian newspaper reported also

Consider this news of Indian newspaper, the amount of hacking they have done, it was expected they will leak such news

[Exclusive] 40% of Pakistan's frontline fighter jets docked for a variety of reasons | India News

There are problems with the fuselage, with cracks being detected in the lower fairing skin. This is an area that is most affected by G or gravity-related pressures.

www.timesnownews.com

P.S Just before someone attack Indian source, German refusing engines for Pakistani subs was first reported by Indian newspapers. They are hacking PAC, MoF, and dozens of others government institutions. There was a hacker on Twitter who used to share Pakistani Army documents and images which he hacked. This week some hacker got into webex session of IMF and Pakistani MoF delegation.

https://twitter.com/x/status/1504895714043863044

Honestly what planet are you on.

Can you enlighten us where yiu are getting this nonsense from? Can you prove the jf17 has never been beyond mach 1? Sources etc
What are your engineering qualifications to comment of structural matters.
I am a stress engineers who worked for British aerospace and at what was then DRAE Farnborough as a research scientist. Do enlighten me.

I have never read so much collective nonsense anywhere.

@waz @The Eagle is this so called self made PDF expert here to just rubbish jf17 what an agenda? Misleading people with zero evidence to justify his statements.

 

[SQ8]

I should have been more precise. Yes you are right. My point was Going supersonic will eventually put more stress on JF-17 airframe which has less composite materials, hence my educated guess, they wont fly it supersonic. As even Indians reported the crack issues JF-17 faced couple years ago.

Lets delink supersonic speeds to the core issue of airframe stress. The aircraft is stressed to +8/-3gs but at particular loads and airframe stress levels. The JF-17 can go supersonic today and does so but in a rather clean configuration - its FLCS will prevent it from exceeding those stress limits at maneuvering regardless of the speed whenever they are approaching. The FLCS is also aware when additional loads at KNOWN stress points are applied to adjust limits accordingly.
What the PAC did was put on equipment at UNKNOWN load points and then fly the aircraft with the FLCS unaware and the result was inevitable.


Airframe cracks occur in all aircraft including the F-16 out to F-15s which required millions of dollars to destress the airframe. If an aircraft is flown is extreme profiles consistently it will go beyond the average stress hours faster.. case in point is the F-16N which reached its airframe life much faster than all other ones due to constant ACM training use. However, a lot also came down to PAC manufacturing and figuring out techniques to get an airframe built on 1980s manufacturing ideals to at the least the 90s.

The Tejas, while having its own plethora of QA issue was at least built on much more modern lines.

 

[MastanKhan]

That is a misnomer - that first crash was because they were supersonic and had equipment attached to the wings to measure performance for a local simulator. They overstressed the airframe trying transonic and supersonic turns which was not within OEM recommended stress regime.

Basically, PAC screwed up

Hi,

Thank you for the post.

 

[MastanKhan]

Hi,

A machine has been designed, produced, made operative and then it is put through its paces to see what it can do.

The first flight tests are that it meets the generals criteria of all initial design parameters---after that the test increase in severity and endurance---.

Till all the tests have made thru the required integrity stage---the aircraft is put into operational service.

As it is a fighter aircraft---its abilities and capabilities will be further tested to take to the next level by a make it or a break it test.

All this tests are normal and they are done to check the structural integrity of taking the machine way beyond its ability to to withstand stress

Decades ago an american general has been known to state during a test drive of a new military vehicle which rolled over and he got injured in the head that if it had not rolled over during his ride---the field test design conditions were not HARSH ENOUGH.

So---someone comes out with this news---and all the young pakistani plethora are running around confused like headless chicken.

Fighter aircraft have to be to be flown beyond their structural capabilities---and if the aircraftis destroyed in the process---so be it---.

Many an F16 had succumbed to extreme flying in the early stages of aircraft production.

 

[LKJ86]

Via @航空工业 from Weibo

 

[Eagle_Nest]

View attachment 839638
Via @航空工业 from Weibo

What is it saying?

 

[Farhan Bohra]

Lets delink supersonic speeds to the core issue of airframe stress. The aircraft is stressed to +8/-3gs but at particular loads and airframe stress levels. The JF-17 can go supersonic today and does so but in a rather clean configuration - its FLCS will prevent it from exceeding those stress limits at maneuvering regardless of the speed whenever they are approaching. The FLCS is also aware when additional loads at KNOWN stress points are applied to adjust limits accordingly.
What the PAC did was put on equipment at UNKNOWN load points and then fly the aircraft with the FLCS unaware and the result was inevitable.


Airframe cracks occur in all aircraft including the F-16 out to F-15s which required millions of dollars to destress the airframe. If an aircraft is flown is extreme profiles consistently it will go beyond the average stress hours faster.. case in point is the F-16N which reached its airframe life much faster than all other ones due to constant ACM training use. However, a lot also came down to PAC manufacturing and figuring out techniques to get an airframe built on 1980s manufacturing ideals to at the least the 90s.

The Tejas, while having its own plethora of QA issue was at least built on much more modern lines.

There were system integration problems, indeed. But I don't know that anyone ever said, even CAG about QA/QC for Tejas. More so they going for 6000 and 10000 hours of stress tests for certifying the airframe, if there is such problems, they won't be going for such stress tests.

I never heard of this,, even from the worst critique, actually all praise about this aspect. Can you post some material about it?

 

[SQ8]

There were system integration problems, indeed. But I don't know that anyone ever said, even CAG about QA/QC for Tejas. More so they going for 6000 and 10000 hours of stress tests for certifying the airframe, if there is such problems, they won't be going for such stress tests.

View attachment 839658


I never heard of this,, even from the worst critique, actually all praise about this aspect. Can you post some material about it?

I cannot - my source is here on the forum and a colleague from my UK Post graduate studies.

QA issues in parts delivered to HAL.

 

[ghazi52]

.,.,.,

 

[MIRauf]

I am sorry but what you have written regarding wing loading is twaddle.
As someone who has done structural design work on the A310, A320 and A330 I know how over designed the wing loading is outside the max flight envelope. So this is absolute rubbish.
Someone has suggested an issue with flutter due to store. But during testing the test pilot would have to be a moron not to reduce speed or eject the store when severe flutter was encountered.
People are writing bs like professionals are stupid who do this for a living and pdf self proclaimed experts are the real deal.

I am not sure what you are going off about, all I did was ask a question in my last line based up on the conversation taking place. After reading last couple of your posts on this conversation makes me think that you have an issue with certain PDF Think Tank, why take it out on me ?

Don't like my question ? ignore it or answer it so we could learn just as SQ8 answered in his posts.

PS: You Mad Bro ?

 

[Trango Towers]

I am not sure what you are going off about, all I did was ask a question in my last line based up on the conversation taking place. After reading last couple of your posts on this conversation makes me think that you have an issue with certain PDF Think Tank, why take it out on me ?

Don't like my question ? ignore it or answer it so we could learn just as SQ8 answered in his posts.

PS: You Mad Bro ?

View attachment 840127

I have an issue with pdf think tank...news to me. Care to name the think tank?
No I am not mad at you? Why would I be?
I just think you should understand the basics of design b4 going off on assumptions.
People have zero understanding of how over designed structures really are. For example someone said jf17nis stressed to +8g and -3g. That's the envelope but stressing is done way beyond the envelope taking i account of critical and unlikely events

 

[MIRauf]

I have an issue with pdf think tank...news to me. Care to name the think tank?
No I am not mad at you? Why would I be?
I just think you should understand the basics of design b4 going off on assumptions.
People have zero understanding of how over designed structures really are. For example someone said jf17nis stressed to +8 naf -3. That's the envelope but stressing is done way beyond the envelope taking inside account critical and unlikely events

Good Sir, My apologizes for asking a question that caused you to go into a tirade, here to hoping that you didn't pop a vane or two due to that. As you are so knowledgeable per you posts that I do nod my head in your admiration, however I also do hope that you are not in academia at this time or at any time as I would feel real sorry for the students.

Please read your posts # 13,417 & 13,428, seek some medical help, too much anger is not good for health. Learn to ignore people you deem not worth of your time or worth explaining or providing correct answer(s) even if it pi$$e$ the daylight out of you, online forum phew phew is not worth popping a vane or two over.

PS: I asked a question, never assumed anything or didn't mean it to come as such. Sorry if it caused you to pop a vane or two as such was not my attention. It seems you anger got the best of you and took it out on 'we,' I would love to buy you a 'Cold One, soft drink' so you could chill a bit, perhaps some day we may cross path IRL and I will or best yet to hoping 'never.'

On a side note, not relevant to topic here. Richard Sherman to Tom Brady. 'You Mad Bro' ? after victory in 2012 SB, a classic in NFL.

 

[Bilal Khan (Quwa)]

Hi,

You don't deserve to know and neither is anyone else when it comes to weapons and weapons systems and you know it as well. What were you thinking when you wrote that comment?

I was thinking of the standards of the country you live in as opposed to the country you're talking about. @SQ8

 

[Bossman]

I should have been more precise. Yes you are right. My point was Going supersonic will eventually put more stress on JF-17 airframe which has less composite materials, hence my educated guess, they wont fly it supersonic. As even Indians reported the crack issues JF-17 faced couple years ago.

So now Indian are responsible for fatigue testing of JF17