Boeing F-15SE Silent Eagle to be Seoul’s Next Generation Fighter

I think it is a good choice. There is a lot we do not know about the F-35. It is very expensive and does SK need those capabilities?

I don’t think any country that is not a front line airforce needs the F-35. I don’t know why Canada bought into it, because something less would have met its needs.

I don’t think any country that is not a front line airforce needs the F-35. I don’t know why Canada bought into it, because something less would have met its needs.

South Korea is a front line airforce. When compared against the USAF it may not seem to be, but what country can really compare to the USAF on their best day? South Korea has a front line airforce, and they have the most advanced F-15s (the K version) in operational service anywhere in the world (including the USAF and Israeli versions), and they have exceptionally good training and tactics.

The problem with the F-35 in my opinion (which I listed in an unfortunately long post a month and half ago) can be distilled as follows:

i) Too expensive, with a cost trajectory that seems to be defying gravity. The price offered, by itself, more or less doomed the F-35. The only way it could survive is by showing (absolutely) overwhelming capability over cheaper options.

ii) Too much insistence on cutting edge technologies that are either

(a) upgradeable onto enhanced versions of current aircraft, for instance the F-35's electro-optical distributed aperture system, which enables a pilot to have a 360 view around the plane, among other nifty things, can be upgraded into current aircraft once the technology stabilizes. Also;

(b) reliance on technologies that are facing significant obsolesence pressure. A good example here is the recent announcement that US Navy is working on increasing the range of the Sidewinder missile by 60%. Why? Because 'the need for that added flexibility arises from the proliferation of advanced digital radio frequency memory (DRFM) jammers that many potential adversaries are adding to their fighter fleets. DRFM jammers have the potential to blind the AMRAAM's onboard radar, which makes the AIM-9X's passive imaging infra-red guidance system a useful alternative means to defeat those threats.' That is something that had been mentioned before, but always poohpooed as crap by various people, including some on FR. Someone once said way back that I was full of crap saying that future development of DRFM jammers, and general ECM development, would make certain types of BVR shots ineffective. This was a couple years back when the USAF faced off against the Indian airforce, and while the big story was the performance of the SU-30 the real story should have been the performance of the Indian MiG-21s coupled with Israeli jammers. Those modernized Fishbeds were said to be difficult to 'kill' before they got to WVR range, and at/near the merge even an obsolete plane with a good WVR IIR missile can kill the most advanced plane. Yet I was allegedly full of crap. Well, it seems it wasn't that crappy after all. Now, when it comes to raw performance, an upgraded F-15 carrying its weapons internally (the SE) simply has better numbers than what is known about the F-35. I don't know that, but the South Koreans were given that information, and on aggregate went F-15SE.

iii) The South Koreans already use F-15s ...the aforementioned F-15Ks. More influence from a cost perspective, and lots of logic from a logistics perspective.

iv) And finally the dirty secret. Just how stealthy is the F-35 offered to the South Koreans? This was the main litmus test in my opinion. Lockheed Martin states that the F-35 has a RCS of 0.001m2, which is very very small. However, Boeing said something VERY interesting ...that in the frontal hemisphere the F-15SE would have similar RCS to the F-35 export countries would receive. Now, the F-15 in its normal form is a rather unstealthy aircraft. The main changes made to the SE is canting the vertical stabilizers, putting blockers in the inlets, internal weapons carriage, and RAM coating. That does a lot to make it smaller, especially against Xband radar from directly forward, but makes it have an RCS at best of around 0.5m2 to 1.0 m2 (big improvement from white source numbers of 15m2 to 20m2). Now, how is that comparable to the F-35's 0.001m2?????

Three possibilities exist: (a) Lockheed Martin is lying and the F-35 does not have a RCS of 0.001m2; (b) Boeing is lying and the SE doesn't have an RCS comparable to that of the F-35; or (c) none of them is lying.

The truth is (c). None are lying. The truth is that the export version of the F-35 is simply not as stealthy as the F-35A used by the USAF. This is something that the British and Israelis were pushing back on, and I think their versions may be far stealthier than those sold to other 'lower' partner nations like Turkey and that offered to South Korea.

The decision to go with the F-15SE shows a combination of (probable) reasons. Obviously there is cost, and risk of cost increases. There is logistics, and South Korea's use of the Eagle. There is the fact that the Eagle is already quite advanced to face whatever North Korea would have, and China and/or Russia will not be selling Pyongyang the J-20 or J-31 stealth fighters (China) or the T-50 (Russia) ...at least not for a very long time. Additionally, with upgrades such as the SE, the huge advantage given by the K version simply gets juiced up.

FINALLY ...there is the stealth question. Since it appears that the F-35 offered to Seoul doesn't have the RCS figure of 0.001m2 offered, then it made no sense for Seoul to invest in an expensive and risky (from an increasing cost and technology perspective) project if they would not get the very best out of it. I believe had the South Koreans found a significant/overwhelming difference in RCS between the F-35 they were offered and the F-15SE they would have gone for the F-35 ...even if it meant buying fewer planes.

They most probably did not see an overwhelming difference.

The South Koreans would have jumped at the chance to buy some F-22’s I bet, before Obama cancelled it.

Very good post.
You sound like an engineer :-)

Didn’t Israel play a big part developing this?

It is only stealth from the front, not the sides and back.

Good call on Korea’s part. I can’t believe anybody would call the ROK AF anything less than a front-line force, and they most definitely need to be.

TC

That is true. The F-15SE only has lowered RCS from the frontal hemisphere as mentioned, while the F-35 was designed from the very start as a stealthy airframe (although not as stealthy as the F-22). However, my point is that Boeing was claiming that the frontal hemisphere RCS of the SE is comparable to that of the F-35. Hence the three possibilities - either Lockheed is lying about the 0.001m2, or Boeing is lying about the SE being comparable to the 35 in the frontal hemisphere, or finally, both are saying the truth but then it sucks to be an export partner for the F-35 project since it seems the export version simply is not that stealthy.

Especially as modern aircraft used by other nations start to employ more and more AESA type radars. And especially with continued development of AESA technology.

Stealth has never been the magic bullet some think it is ...for instance a stealth mission normally includes a lot of jamming from other assets in the area to confude the defending IADS even more. However, even with that said, developments in air to air radars are pushing RCS requirements for 'true' stealth lower. As for ground to air radars, and ship to air radars, already the level of stealth required is exceedingly high. Some European ship borne AESA radars are powerful enough to detect stealthy missiles ....

It’s a shame that Grumman was never allowed to developed the Super Tomcat 21, which had similar modifications to reduce RCS and significant enhancements in capability overall.

I worry about an overdependence on stealth. Stealth is extremely expensive and makes for small procurement quantities.

But worst of all, no aircraft is stealthy with external stores and/or external fuel tanks and in the real world the F-35 will have to use both. Even the F-22 does to a lesser extent.

Even without external stores and fuel tanks in the early stages of a conflict, there are other problems. They will be dependent on tanker support. Tankers aren’t stealthy, thus this creates a detection vulnerability. Carrier-based stealth aircraft like the F-35 will require aircraft carriers approach closer to targets as well.

I’d like to see a mix of Silent Eagles and Super Tomcat 21s to make up for the lack of numbers and vulnerabilities necessitated by stealth.

(And don’t come back with anything about the Super Hornet. The only thing the Super Hornet has is great avionics, which could just as easily have been installed in the 15 or the 14, both of which can fly faster, farther, longer and fight better than the Super Bug.)

True to a point, but in reality, for an Air Superiority role, that's fine: They knock down all in front of them before the opposition can see them.

Are SAMS an issue? Probably, unless the sites are known a priori, then the SE’s can remove them using a K as a decoy.

While it may suck to be the K pilot, that's the job.

The RCS being similar may be a stretch, or they may be considering probability of detection at standoff weapon range. If I can approach a ground based radar site close enough to fire on it with my weapons and at that range it has a low probability of detecting me, that is stealthy enough. Ditto with air targets. Paying tremendous amounts of money to drive RCS much lower generally doesn’t make much sense, nor significantly alter the chance for mission success. The SE marketing types may have latched onto that idea as a way to promote “similar stealth characteristics” of being stealthy enough to get most missions done.

The thing is, without access to actual numbers one is either left with mindless speculation or logical speculation. Both are speculation, but logical speculation is probably the best tools we can work with. Hence, there are a couple of things we can say is fact. One is that the difference between 0.001m2 (Lockheed's statement on the RCS of a F-35A frontal hemisphere) and 0.5m2 (white paper source of the SE) is not a stretch. There are several magnitudes of difference between the two. For instance, taking a normal F-15 RCS of somewhat under 20m2 to around 0.5m2 to 1.0m2 (a dBsm of 0), is very different from something stated to have an RCS of 0.001m2 (a dBsm of -ve 30). Those are several magnitudes of difference. Same thing comparing what is stated about the F-35 versus what is stated about the F-22. The F-35 would have a dBsm of around -30, while the F-22, with an RCS of (allegedly) 0.0001m2 in the frontal hemisphere, has a dBsm of -40. Again, between the two stated figures is a whole magnitude of difference. Thus my saying that there are three options ...Lockheed is lying, Boeing is lying, or it boils down if you are getting the USAF secret sauce version of the F-35, or you are getting the export-flavored version of the F-35. However, no way the two are similar and no way it is a simple stretch.

I do fully agree with you on the other point. Stealth is more of a functional attribute. It is not about becoming invisible, but rather whether or not it will enable the pilot to accomplish the mission. Additionally, there are a number of advanced aircraft that solely rely on stand-off weapons - some of which, like the European stealthy cruise missiles, can be quite advanced - to attack well defended IADS. For instance, a Rafale or Typhoon using a Scalp or Stormshadow. There are many ways to skin a cat ...totally agree with you on that.

However, there have been some questions raised on the actual stealthiness of export F-35s for some time - in media, blogs, as well as some governments (the UK comes to mind). However, this is one case where it does seem, using logical speculation (and I emphasize speculation), that the export variant F-35 is nowhere as stealthy as the USAF version. It was always known they would not be at the same level (for instance, there is a reason the F-22 is simply not for sale, and it is not avionics since the F-35 does have snazzy stuff), but it does seem that the difference is bigger than was hoped for.

That would also explain Boeing's marketing material to the 't'.

A lot of folks don’t realize that other countries have more advanced versions of the same jets that make up most of our air force. Israel, Turkey, UAE, for example all have newer models of the F-16. As you mentioned several countries have more modern F-15s