JF-17 Block-3 -- Updates, News & Discussion

[Dazzler]

@GumNaam @Dazzler

Is it possible that some of the Block-II may have been re-equipped with the air-cooled Letri LKF601E AESA instead of retrofitting them with KLJ-7A?
Otherwise not too much of a difference would remain between blocks II and III ... and there would not be much of a justification for the protracted delay in coming out with the block III ???

Lkf had cooling related issues.

 

[Eagle_Nest]

By the end of this year or early next.
Klj-7A was tested during an undisclosed foreign exercise.

It uses hybrid cooling. Can be refitted on blk 2.

AOA.. which version of klj7A selected?

 

[Cookie Monster]

@GumNaam @Dazzler

Is it possible that some of the Block-II may have been re-equipped with the air-cooled Letri LKF601E AESA instead of retrofitting them with KLJ-7A?
Otherwise not too much of a difference would remain between blocks II and III ... and there would not be much of a justification for the protracted delay in coming out with the block III ???

It would be better to have commonality with the same type of radar for block 2 and 3...
...I wouldn't care about the justification for delays if commonality can be achieved. All is well that ends well.

 

[GumNaam]

It would be better to have commonality with the same type of radar for block 2 and 3...
...I wouldn't care about the justification for delays if commonality can be achieved. All is well that ends well.

agreed. commonality has an inherent advantage of less maintenance costs.

 

[aliyusuf]

It would be better to have commonality with the same type of radar for block 2 and 3...
...I wouldn't care about the justification for delays if commonality can be achieved. All is well that ends well.

So, I am willing to wait and see how things turn out.
But, it does warrant a query on the net advantages that Block-III brings over the Block-II, apart from the so-called potentially common radar between the two, and whether the delays encountered reflect some short-sightedness in the planning and execution of the entire process. If commonality was sought, then the radar development shouldn't have taken such an arduous path and Block-III specs finalization shouldn't have taken so much time.

 

[Cookie Monster]

So, I am willing to wait and see how things turn out.
But, it does warrant a query on the net advantages that Block-III brings over the Block-II, apart from the so-called potentially common radar between the two, and whether the delays encountered reflect some short-sightedness in the planning and execution of the entire process. If commonality was sought, then the radar development shouldn't have taken such an arduous path and Block-III specs finalization shouldn't have taken so much time.

The delay can still be justified...
...bcuz here we are assuming that KLJ7A was ready to go as a plug and play...
...with no issues whatsoever with software not being up to the mark(as per PAF's wishes), no issues with cooling, no issues with power output requirements for the AESA, etc.

Sure if all these things didn't pop up...and KLJ7A was indeed just plug and play...then yeah I can see how the delay can be unjustified. However it is much more likely that the additional time was bcuz each system that was an improvement in block III had to be tailored to JF17. We have to keep in mind that while the Chinese already have this tech...it is not something they have deployed onboard their JF17s(bcuz they have none in service). Both China and PAF end up working together to figure out the next steps...which inevitably ends up taking some amount of time(as is normal).

 

[GriffinsRule]

If I may opine on the Gs comparison between aircraft with my limited knowledge. Feel free to correct me if I am wrong but there are a couple of things that impact maximum Gs an aircraft can pull. For an apples to apples comparison, two exact same designs, say F-15A vs the latest F-15EX, the newer jet will be able to sustain more instantaneous Gs without damaging the airframe. Just like a human has to deal with the G forces, same applies to structures holding an aircraft together. Heavier metallic parts will experience more of a weight gain at higher Gs than lighter parts and thus composite airframe might do better due to their lighter yet stronger structure. JF-17 being a mostly all metal construction jet will have more parts prone to failure vs say a Rafale that has more composites and potentially lighter or better designed parts.

On the Gs themselves, any jet can be pushed beyond the max allowable Gs in an emergency situation, say when trying to avoid a missile or a collision. In those situations, it's worth the risk if damage to the jet and potential risk of injury to the pilot but to save his life. F-4s in Vietnam sometimes pulled in excess of 12Gs to avoid SAMs. The aircraft otherwise is rated as an 8.5G jet, and that too at in a clean jet with speeds below .8mach.
When you pull extremely high Gs, you could have the jet come apart in mid-air. And I bet you it has happened before. Rivets or glue holding parts will come apart, engine mounts could break, etc etc. If you do that in a jet that has fatigue built up already in airframe due to prior high Gs, you are at an even greater risk. This is the reason why air forces employ all types of methods and even built in sensors now to measure and record G forces and fatigue on parts. Fractured Mechanics is an applied science. Lots of info for novices like me out there. https://flightsafety.org/asw-article/assessing-the-sensors/

The other thing to keep in mind in engineering itself. When designing extremely high performance things like fighter jets, every inch and ounce matters. If the idea is to stay within the confines of costs, capability and materials available, you design around those. Over engineering say beyond the parameters, say for 11G vs 9G means higher costs, more complicated design, all for a very marginal increase in performance. We already have a sphere where most aircraft operate most of the time and much smarter people then us have realized what is important in terms of parameters and current technology.

One last thing I'll mention here is an additional risk when pulling high Gs. It can often result in loss of situational awareness for the pilot and they can lose their life by plowing right into the ground as well. That's why the trend has been towards safety vs pure performance in the last three decades.

 

[aliyusuf]

The delay can still be justified...
...bcuz here we are assuming that KLJ7A was ready to go as a plug and play...
...with no issues whatsoever with software not being up to the mark(as per PAF's wishes), no issues with cooling, no issues with power output requirements for the AESA, etc.

Sure if all these things didn't pop up...and KLJ7A was indeed just plug and play...then yeah I can see how the delay can be unjustified. However it is much more likely that the additional time was bcuz each system that was an improvement in block III had to be tailored to JF17. We have to keep in mind that while the Chinese already have this tech...it is not something they have deployed onboard their JF17s(bcuz they have none in service). Both China and PAF end up working together to figure out the next steps...which inevitably ends up taking some amount of time(as is normal).

I agree with what you are saying, regarding issues faced during KLJ-7A stabilization. But then the work should not have been linked specifically with Block-III and work could have started much earlier. Instead of 62 Block-II's we could have gone ahead and ordered 100 instead. The last 38 with KLJ-7A. The decision could have been taken by the time the last dozen or so of the 62 Block-II's were being built. We could have beaten the IAF in fielding an AESA equipped fighter. Gradually a really comprehensive retrofit to the earlier Block-II's could have taken place. Block-III could have come out later with much better specs and more bells and whistles.

 

[Vapour]

We could have beaten the IAF in fielding an AESA equipped fighter.

That did happen, has been confirmed by @airomerix & @The Eagle that a couple of Block-IIs operating in or near the theater were AESA equipped on the 27th.

 

[aliyusuf]

That did happen, has been confirmed by @airomerix & @The Eagle that a couple of Block-IIs operating in or near the theater were AESA equipped on the 27th.

If @airomerix had meant those Thunders were equipped with KLJ-7A, then all the more reason for consternation that it is going to take us 3 years hence to induct Block-III. By the way, if memory serves me right, KLJ-7A was finalized some months later.

P.S.

In my humble opinion, just two jets do not make an AESA equipped Air Force.

 

[Dazzler]

AOA.. which version of klj7A selected?

Classified

 

[PakShaheen79]

Classified

Makes perfect sense. PAF is not going to leash out every detail about Block-III. Lots of guess work or patience will be only options. Only thing that is bothering is that why there is no pic or vid release from PAC about Block-3. I was hoping that a couple of Block-3s will be in testing by now. I think they are but just we don't have any info regarding this.

@aliyusuf You got a point if that information regarding 2 block-2 with AESA is true, but there is another possibility. May be PAF wanted to go on that route of having 100 B2s before B3 gets mature, but performance of AESA on those block2s were not up to the required mark hence the decision was made to cut the number to 62 and wait for B3s instead.

 

[aliyusuf]

Makes perfect sense. PAF is not going to leash out every detail about Block-III. Lots of guess work or patience will be only options. Only thing that is bothering is that why there is no pic or vid release from PAC about Block-3. I was hoping that a couple of Block-3s will be in testing by now. I think they are but just we don't have any info regarding this.

@aliyusuf You got a point if that information regarding 2 block-2 with AESA is true, but there is another possibility. May be PAF wanted to go on that route of having 100 B2s before B3 gets mature, but performance of AESA on those block2s were not up to the required mark hence the decision was made to cut the number to 62 and wait for B3s instead.

That point of view can only be plausible if the Block-III is coming with new engines and/or extensive use of composites to reduce weight. Neither is confirmed from a reliable source yet.

 

[PakShaheen79]

That point of view can only be plausible if the Block-III is coming with new engines and/or extensive use of composites to reduce weight. Neither is confirmed from a reliable source yet.

Yes. You are right on this account. But then again, it hasn't been denied as well. So chances for both opportunities are 50/50 at this point in time, but we know for a fact that there is a factory in Russia making new variant of RD-93 aka RD-93MA and that engine is for export. Rest we can connect the dots. Anyhow, as i said earlier, PAF will be v tight lipped on Block-IIIs.

 

[siegecrossbow]

By the end of this year or early next.
Klj-7A was tested during an undisclosed foreign exercise.

It uses hybrid cooling. Can be refitted on blk 2.

Any additional info on the assessment or are you not allowed to say more?