South Korean KF-21 nearing first flight.

Military aircraft - Post cold war aircraft, including for example B-2, Gripen, F-18E/F Super Hornet, Rafale, and Typhoon.
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Corsair1963

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Unread post03 Aug 2022, 02:27

charlielima223 wrote:
Corsair1963 wrote:If, the current KF-21 had an internal weapons bay. Which, would make it a true 5th Generation Fighter. It would be something to get excited about.


Yet, in the current form is it really any better than your standard 4.5 Generation Fighter? (Gripen E, Rafale, Typhoon, or Super Hornet)


I would say the KF-21 is more like a gen 4.75 with potential to be a 5th gen down the road. I say this merely on the fact that compared to the aircraft you mentioned, the KF-21 appears to have designed a competently stealthy outermold. I would make a SWAG that it's stealth attributes is far greater than current 4.5 or 4.5+ fighters but substantially less than seen on 5th gen.
In terms of avionics, who knows. South Korea does have a very advanced and robust tech base and industry however so I wouldnt count them completely out in that regard.



Hopefully, South Korea is pushing hard for the more capable Blk II / III with the internal weapons bay. Yet, even in that case wonder how much fuel it will be able to carry? Which, is a big factor for the types success.........
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hkultala

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Unread post03 Aug 2022, 05:23

aaam wrote:
ricnunes wrote:
aaam wrote:Gripen E has only one engine, but KF-21s empty weight is 48% heavier.


Which means that the KF-21 has a better Thrust-to-Weight Ratio (TWR) than the Gripen E.
If the KF-21 empty weight was to be 100% heavier than the Gripen E then they would have the same/similar TWR.


Although the most relevant comparisons is at the two aircraft's respective combat weights, and you'd also have to take into account Gripen E's lower drag, the T/W ratio of the KF-21 may indeed be higher. But, with respect, who cares?


Do you seriously think Gripen has drag which is less than half of the drag of KF-21?

It's not only T/W ratio that is better in KF-21, it's ALSO the thrust/drag ratio.

Taking into account Drag only makes this WORSE for Gripen

What I am taking issue with is your assertion that Gripen E/F "needs" the F414 Enhanced Engine. The plane was designed around an engine of the F414's performance.


.. and was planned to weigh about tonne less than it finally ended up weighing.

Also, they may have expected the F414 EPE to materialize.

With that engine, if it does what is intended for it, meets its promises and expectations (which are naturally different than what the KF-21's are),


Yes. The intentions, promises and expectations of the original Gripen was the have the performance of Viggen (3rd gen fighter from 1970's) but to have better electronics and to be cheaper to fly.

Other countries actually wanted their 4th and 5th gen aircraft to have better performance than their 3rd gen fighters, but not Sweden. 3rd gen performance was enough for them.

When the goals are very low, it's easy to accomplish them.

then the engine is just fine.


Yes, for equaling the performance on 1970's fighters, the engine is fine.

To equal performance of 1980's or 2020's fighters, the engine is not fine.

The F414 Enhanced may be a nice to have, assuming there aren't some penalties that comes with it elsewhere, but it isn't a "need".


It isn't a "need" when 1970's performance is enough.

But what if 1970's performance is not enough?
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jessmo112

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Unread post23 Sep 2022, 13:29

Naval version incoming.

https://breakingdefense.com/2022/09/wit ... val-plans/

If I was in charge, I would have a high low mix if F-35B and KF-21N. The pacific will be crawling with stealth aircraft by 2030.
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milosh

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Unread post26 Sep 2022, 09:01

Corsair1963 wrote:With just four Meteors the KF-21s would offer better performance. Yet, in the real world it will likely carry a number of stores under actual combat conditions. Just like the other aforementioned 4.5 Generation Types.

Honestly, hard to see much benefit.....


Yeap. While KF-21 in AA configuration is like Typhoon (quite clean) but in AG it would need to carry lot more, you start hanging ordinances, you would need to add fuel tanks, and I don't think Korea really worried about NK airforce so it is more for SEAD and strike missions so clean configuration isn't really option for those missions.

On other hand they next block will have functional weapon bay.
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Corsair1963

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Unread post26 Sep 2022, 09:40

milosh wrote:
Corsair1963 wrote:With just four Meteors the KF-21s would offer better performance. Yet, in the real world it will likely carry a number of stores under actual combat conditions. Just like the other aforementioned 4.5 Generation Types.

Honestly, hard to see much benefit.....


Yeap. While KF-21 in AA configuration is like Typhoon (quite clean) but in AG it would need to carry lot more, you start hanging ordinances, you would need to add fuel tanks, and I don't think Korea really worried about NK airforce so it is more for SEAD and strike missions so clean configuration isn't really option for those missions.

On other hand they next block will have functional weapon bay.


If, South Korea was smart she would expedite the development of the Block III with internal weapon bays.Because without them the KF-21 is really just another 4.5 Generation Fighter.

:shock:
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ricnunes

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Unread post26 Sep 2022, 16:12

Corsair1963 wrote:If, South Korea was smart she would expedite the development of the Block III with internal weapon bays.Because without them the KF-21 is really just another 4.5 Generation Fighter.

:shock:


I agree.

Which leaves my think that since a full weapons bay (like the F-35 for example) is "too complicated" (or too expensive) for the initial KF-21 versions why didn't the Koreans implements a more simplistic internal weapon carriage arrangement like for example the one found in the F-101 which had small "weapon bays" (4 of them in this case) with rotating doors where each of these small "weapon bays" could only carry a single missile.
Basically like this:
Image

So and IMO, the initial variants of the KF-21 could have a similar arrangement (to the one of the F-101) with also 4 small "weapon bays" with rotating doors where each one of these small "weapon bays" could carry for example one (1) AMRAAM or Meteor or one (1) SDB.
This way the initial KF-21s could carry for example 2 AMRAAMs/Meteors and 2 SDBs (or 4 AMRAAMs/Meteors or 4 SDBs), all internally and cheaper and simpler than a "full weapons bay".
Of course this is a limited loadout but IMO a better arrangement compared to carrying all the A2G weapons externally specially when advanced enemy air defences are very active and in place.
“Active stealth” is what the ignorant nay sayers call ECM and pretend like it’s new.
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milosh

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Unread post26 Sep 2022, 17:40

Guys, KF21 have internal space for big weapon bay but in block one it isnt build in probable they need time to test it. So it wouldnt be logical to design some another bay just so KF21 could carry weapons internally.

I dont see what is problem when weapon bay is tested, all block 1 got it as upgrade.
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ricnunes

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Unread post26 Sep 2022, 17:47

milosh wrote:I dont see what is problem when weapon bay is tested, all block 1 got it as upgrade.


As far as I know, no.
KF-21 Block 1 won't be retrofitted with a weapon bay.
Probably not even Block 2 will have or be retrofitted with weapon bays.

And weapon bays aren't something that you can simply "retrofit" in.
“Active stealth” is what the ignorant nay sayers call ECM and pretend like it’s new.
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milosh

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Unread post26 Sep 2022, 18:16

ricnunes wrote:
milosh wrote:I dont see what is problem when weapon bay is tested, all block 1 got it as upgrade.


As far as I know, no.
KF-21 Block 1 won't be retrofitted with a weapon bay.
Probably not even Block 2 will have or be retrofitted with weapon bays.

And weapon bays aren't something that you can simply "retrofit" in.


They left empty space for them you can clearly see it on prototype production line. It would be huge waste if they dont plan to upgrade them with bays in future.

https://www.secretprojects.co.uk/proxy. ... b9f62652b5
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ricnunes

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Unread post26 Sep 2022, 23:43

milosh wrote:They left empty space for them you can clearly see it on prototype production line. It would be huge waste if they dont plan to upgrade them with bays in future.

https://www.secretprojects.co.uk/proxy. ... b9f62652b5


Just because there's an empty space inside the KF-21 which is meant for internal weapon bays for Block 3, doesn't mean that weapon bays will ever be retrofitted in Block 1 and 2.
For starters there are more improvements planned for Block 3 beside the weapon bays. For instance internal FLIR/EO sensors and stealthy IRST (perhaps integrated with the internal FLIR/EO?) and further refinements to the aircraft's shape and materials in order to further reduce its RCS seem to be planned.
Retrofitting all of this in Block 1 and 2 while in theory being possible it may not and probably is not feasible. It's probably better just to build new Block 3's instead of retrofitting old Block 1 and 2.
“Active stealth” is what the ignorant nay sayers call ECM and pretend like it’s new.
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Corsair1963

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Unread post27 Sep 2022, 01:20

ricnunes wrote:
milosh wrote:They left empty space for them you can clearly see it on prototype production line. It would be huge waste if they dont plan to upgrade them with bays in future.

https://www.secretprojects.co.uk/proxy. ... b9f62652b5


Just because there's an empty space inside the KF-21 which is meant for internal weapon bays for Block 3, doesn't mean that weapon bays will ever be retrofitted in Block 1 and 2.
For starters there are more improvements planned for Block 3 beside the weapon bays. For instance internal FLIR/EO sensors and stealthy IRST (perhaps integrated with the internal FLIR/EO?) and further refinements to the aircraft's shape and materials in order to further reduce its RCS seem to be planned.
Retrofitting all of this in Block 1 and 2 while in theory being possible it may not and probably is not feasible. It's probably better just to build new Block 3's instead of retrofitting old Block 1 and 2.


I don't think he was suggesting they would retrofit earlier Block I/IIs. Simply they left space for the weapon bay in the initial design and not to use it is a waste........
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Corsair1963

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Unread post27 Sep 2022, 01:44

ricnunes wrote:
Which leaves my think that since a full weapons bay (like the F-35 for example) is "too complicated" (or too expensive) for the initial KF-21 versions why didn't the Koreans implements a more simplistic internal weapon carriage arrangement like for example the one found in the F-101 which had small "weapon bays" (4 of them in this case) with rotating doors where each of these small "weapon bays" could only carry a single missile.


F-101B

F101A.jpeg



F101B.jpg
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hornet1129

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Unread post27 Sep 2022, 04:54

Block I is intial version for the A2A only, Block II will get the A2G capability. Block III is still unknown because it is not actually ordered.

It is definitely hard to make the Block I or Block II as the 5th Gen fighter so they must make almost new one based on the Block II design.
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Unread post27 Sep 2022, 12:37

Fuel fraction tends to be significantly higher in 5G fighters. That extra space can be used for an even larger fuel fraction.
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milosh

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Unread post27 Sep 2022, 13:58

madrat wrote:Fuel fraction tends to be significantly higher in 5G fighters. That extra space can be used for an even larger fuel fraction.


Nothing is inside, just that reinforcing box. I see link photo isn't okey, SPF probable do a lot not to allow sharing photos even though it isn't their photo either.

I will put link directly to photo.

https://defenceforumindia.com/attachmen ... jpg.84631/
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