South Korean KF-21 nearing first flight.

Much more exciting to watch develop than a J-31.

I wonder if Indonesia paid anything yet. Last I checked (been too busy at work and lazy at home) there were issurs with Indonesia not paying part of its program development.

Either way this looks to be an interesting aircraft.

Live action testing apparently.

The fighter looks a bit Heavy for the two engines it will use. It remains to be seen if this approach to 5th generation fighters will work. It's like having the weight and bulk of an internal bay but not the benefits of carrying weapons internally.

Going nowhere fast, I'm afraid...

Rather doubt Indonesia holds up its end of the bargain, and S. Korea itself fields the F-35A - an aircraft that is far superior (today) to the likely finshed version of the KF-21 (some day). It looks to me like a rather underpowered, not so stealthy F-22. Hard to see anyone 'cept S. Korea buying it, unless they're completely shut out of the F-35 program.

It does look sharp, I'll give it that.

It looks stellar. Can't wait for it to fly.

Going nowhere fast, I'm afraid...

Rather doubt Indonesia holds up its end of the bargain, and S. Korea itself fields the F-35A - an aircraft that is far superior (today) to the likely finshed version of the KF-21 (some day). It looks to me like a rather underpowered, not so stealthy F-22. Hard to see anyone 'cept S. Korea buying it, unless they're completely shut out of the F-35 program.

It does look sharp, I'll give it that.

Yeah I get why there is skepticism when they are already flying Fat Amy. Most anything will look underpowered compared to the F-35's 40k plus pounds of thrust F-135 engine. This is their first active prototype/test model undergoing its first non static ground test. They're not going to go full hog first time out of the hanger.

The fighter looks a bit Heavy for the two engines it will use. It remains to be seen if this approach to 5th generation fighters will work. It's like having the weight and bulk of an internal bay but not the benefits of carrying weapons internally.

Two F414's have more thrust than one F135. And the plane is supposed to weight less than F-35A.

The fighter looks a bit Heavy for the two engines it will use. It remains to be seen if this approach to 5th generation fighters will work. It's like having the weight and bulk of an internal bay but not the benefits of carrying weapons internally.

Two F414's have more thrust than one F135. And the plane is supposed to weight less than F-35A.

While that's true today, the loaded, combat weight of a production KF-21 will likely be higher. Possibly much higher. History shows past combat aircraft have gained as much as 6% from prototype to production bird. Now consider gross weight is right around 38,000lbs, with max takeoff weight being around 56,000. I've read anywhere from 8,000 to 12,000lbs of internal fuel, let's call it 10,000. I think if anything, the range requirement spec increases and it's here' where it'll gain weight. Call it another 4,000lbs to 14,000.

Then consider the fact that we still haven't taken drag into account, and now your ultra-high Thrust to Weight ratio is increasingly eroded. It happens, to virtually all jets in this class.

But that isn't the real problem. The real problem is the fact it's not a VLO aircraft, though its often positioned as such. In fact "reduced RCS" is the term I've seen used to describe the Block I and II, with only the Block III promised to have a meaningful RCS reduction. And not everyone is convinced Block III gets built. It may, but its hard to see who's going to order it. If they manage a RCS something on the order of a clean SH, I think that's a big win for S. Korea. How much capability that buys you on the battlefield of tomorrow though, is questionable IMO.

But hey let's focus on the positives. It looks really, really sharp and the S. Koreans will no doubt have cutting edge avionics in it. As a stated F-4/F-5 replacement, it should be far superior (if not exponentially more expensive). Short production run, questionable Indonesian backing and lack of a big export customer will see to that...

The fighter looks a bit Heavy for the two engines it will use. It remains to be seen if this approach to 5th generation fighters will work. It's like having the weight and bulk of an internal bay but not the benefits of carrying weapons internally.

Two F414's have more thrust than one F135. And the plane is supposed to weight less than F-35A.

While that's true today, the loaded, combat weight of a production KF-21 will likely be higher. Possibly much higher. History shows past combat aircraft have gained as much as 6% from prototype to production bird. Now consider gross weight is right around 38,000lbs, with max takeoff weight being around 56,000. I've read anywhere from 8,000 to 12,000lbs of internal fuel, let's call it 10,000. I think if anything, the range requirement spec increases and it's here' where it'll gain weight. Call it another 4,000lbs to 14,000.

Then consider the fact that we still haven't taken drag into account, and now your ultra-high Thrust to Weight ratio is increasingly eroded. It happens, to virtually all jets in this class.

Including the F-35. (Which tops out at 60,000 - 70,000lb depending on the model.) This aircraft should fly rings around the F-35. If they needed more power they could just go with the F414 EPE which would net them a cool 53,000lbs thrust. That it doesn't have internal bays means it will have a larger fuel fraction of internal fuel while keep drag to a minimum with conformal carriage.

Even though it don't have operational weapon bays It have space for them:

https://pbs.twimg.com/media/El96ym6UcAA ... name=large

I doubt non weapon bays variant will carry additional fuel in space for weapon bay. KF21 don't need some superb range.

But that isn't the real problem. The real problem is the fact it's not a VLO aircraft, though its often positioned as such. In fact "reduced RCS" is the term I've seen used to describe the Block I and II, with only the Block III promised to have a meaningful RCS reduction. And not everyone is convinced Block III gets built. It may, but its hard to see who's going to order it. If they manage a RCS something on the order of a clean SH, I think that's a big win for S. Korea. How much capability that buys you on the battlefield of tomorrow though, is questionable IMO.

But hey let's focus on the positives. It looks really, really sharp and the S. Koreans will no doubt have cutting edge avionics in it. As a stated F-4/F-5 replacement, it should be far superior (if not exponentially more expensive). Short production run, questionable Indonesian backing and lack of a big export customer will see to that...

Im willing to bet this aircraft in its first operational iteration will be significantly more stealthy than a Super Hornet RCS wise. Though you cant eye ball an aircraft and determine exactly how stealthy an aircraft is, however you can atleast draw some reasonable conclusions based on publicly available data. For it appears that this aircraft has a very stealthy looking outer mold/shape design. Hell it looks like a smaller version of F-22. The Super Hornet on the other hand took the legacy Hornet design made it bigger and and put some RCS reducing measures (redesigned panels, RAM on leading edges, and redesigned intake). Even when it carries external weapons/payload I am willing to bet that the KF-21 would look smaller on a screen than a Super Hornet with similar load out.
For whatever reason South Korea didnt go full hog into VLO the first time around is anyone's guess when they have plenty of info on how (they do operate and i think they build the F-35 after all).

Potential customers is anyones guess. Will Indonesia fulfill its part of the program? who knows at this point. One potential partner or customer could be Taiwan. If I remember correctly Taiwan is not getting the F-35 despite its pleads to the US Government. Even though the KF-21 is not an F-35, this would be a decent alternative. The KF-21 already seems to be ahead of European stealth attempts as this one is now starting its live testing.
Philippines is another potential customer, though not an economic powerhouse we are seeing the Philippine military take decent strides to modernize. Already the PAF use the KAI's F/A-50. I dont know where the Philippine government is concerning their decision between Gripens and Vipers. Having a small number of these aircraft would give the PAF substantial boost for its tiny Air Force.
Middles east is a potential market. So far the US is not going to send any F-35s to any ME countries. From my understanding the UAE was offered the F-35 during the last administration (Trump) but that got shut down once (brain dead) Biden got into the office. The KF-21 could be a step towards 5th gen capability for UAE, Qatar, and Suadi Arabia albeit the KF-21 i would consider more of a semi-5th gen aircraft.

But that isn't the real problem. The real problem is the fact it's not a VLO aircraft, though its often positioned as such. In fact "reduced RCS" is the term I've seen used to describe the Block I and II, with only the Block III promised to have a meaningful RCS reduction. And not everyone is convinced Block III gets built. It may, but its hard to see who's going to order it. If they manage a RCS something on the order of a clean SH, I think that's a big win for S. Korea. How much capability that buys you on the battlefield of tomorrow though, is questionable IMO.

But hey let's focus on the positives. It looks really, really sharp and the S. Koreans will no doubt have cutting edge avionics in it. As a stated F-4/F-5 replacement, it should be far superior (if not exponentially more expensive). Short production run, questionable Indonesian backing and lack of a big export customer will see to that...

Im willing to bet this aircraft in its first operational iteration will be significantly more stealthy than a Super Hornet RCS wise. Though you cant eye ball an aircraft and determine exactly how stealthy an aircraft is, however you can atleast draw some reasonable conclusions based on publicly available data. For it appears that this aircraft has a very stealthy looking outer mold/shape design. Hell it looks like a smaller version of F-22. The Super Hornet on the other hand took the legacy Hornet design made it bigger and and put some RCS reducing measures (redesigned panels, RAM on leading edges, and redesigned intake). Even when it carries external weapons/payload I am willing to bet that the KF-21 would look smaller on a screen than a Super Hornet with similar load out.
For whatever reason South Korea didnt go full hog into VLO the first time around is anyone's guess when they have plenty of info on how (they do operate and i think they build the F-35 after all).

Potential customers is anyones guess. Will Indonesia fulfill its part of the program? who knows at this point. One potential partner or customer could be Taiwan. If I remember correctly Taiwan is not getting the F-35 despite its pleads to the US Government. Even though the KF-21 is not an F-35, this would be a decent alternative. The KF-21 already seems to be ahead of European stealth attempts as this one is now starting its live testing.
Philippines is another potential customer, though not an economic powerhouse we are seeing the Philippine military take decent strides to modernize. Already the PAF use the KAI's F/A-50. I dont know where the Philippine government is concerning their decision between Gripens and Vipers. Having a small number of these aircraft would give the PAF substantial boost for its tiny Air Force.
Middles east is a potential market. So far the US is not going to send any F-35s to any ME countries. From my understanding the UAE was offered the F-35 during the last administration (Trump) but that got shut down once (brain dead) Biden got into the office. The KF-21 could be a step towards 5th gen capability for UAE, Qatar, and Suadi Arabia albeit the KF-21 i would consider more of a semi-5th gen aircraft.

I mentioned before in another KF-21 thread that I have a native speaking Korean friend who follows the KF-21 with a lot of interest. He did mention that the version you see now will eventually evolve to include internal weapons bays. It is considered stealthier than current 4th Gen aircraft, but said when loaded with external weapons and pods, it looses the stealth, which is expected. He said performance should be good and will be a good baseline for KAI to learn and improve upon in future variants. He said reports from Korean media said the ground testing is going fine with only minor issues and first flight is expected soon.

To me, it looks good. Of course, it has a certain DNA in it.