# BVR Combat: Today's F-15C vs. F/A-18E



## Sgt. Pappy (Oct 25, 2010)

It was only recently when the F-15 was finally fitted with the newest of AESA radar systems the U.S. has to offer - the APG-63(V)3. 

From what I've managed to gather, there's virtually no information on this version of the -63 which I could find. 

My question is how it stacks up against similar radar systems around the world, and more specifically, how an F-15 fitted with said radar would stack up against something like a Rafale, Typhoon or Super Hornet.

The Super Hornet itself is easiest to compare as I've found more info on its APG-79; a system that is probably not as good as the -63(V)3 (pure speculation, given that the -63(V)3 is apparently an F-15 radar system with APG-79 tech). The Super Hornet is claimed to have a small RCS inthe magnitude of around 0.1 sq.m while the F-15 has a gigantic 15-25 sq. m RCS. These are clean figures, however, and when the two aircraft carry missiles, their RCS is to go up dramatically. Still though, it's likely that the Super Hornet would still have a tiny RCS compared to the Eagle. Thus, I've come to question whether the F-15's impressive new radar system is offset by its humongous RCS. 

Would an F-15 fitted with the APG-63(V)3 be able to take down an F/A-18E with an APG-79? Would the two aircraft be able to track each other far before within firing range? Or would an F-15 simply not know what hit it?







From this chart I've found, the -63(V)2 is similar in performance to the -79. Given the Hornet's small RCS, it looks like the Hornet has the advantage until the -63(V)3 was installed. The diagram simply states 'Detection/Tracking Range'. I'm not sure as to what mode the radar systems were assumed to be in when the graph was plotted.


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## krieghund (Oct 25, 2010)

The APG-63(v3) is an entirely new critter when compared to the APG-63 Mechanical Scanned Array (MSA).

The APG-63(v1) replaced all the LRUs in the radar package except the antenna. It got a face lift in the means of a new cable wrap assembly in the antenna which was to increase its MTBF greatly. The old APG-63 was good for about 65 hours if you were lucky. My experience was in the low 20's.

The APG-70 is an improved -63 with some refinements for MTBF and adding Synthetic Aperture modes for enhanced sky to dirt operations.

The APG-63(v2) was a kluge lash up with prototype (v1) LRUs and a square array AESA. It was fitted to 18 F-15C or the Alaskan Air Command especially modified a new IFF, Link16 and other avionics refinements. They performed extremely well I'm told and were used to further refine the AESA systems.

The APG-63(v3) is basically a (v1) less some bits required for the MSA and a new antenna array mounted. It essentially makes the Eagle a new bird (kind of like a poor man's F-22)

The APG-82 is the (v3) with further refinements but essentially the same. The USAF kept the -63 designation thinking congress would approve money to upgrade instead of buying a new system.

To answer your question of the F-15SG vs the F-18E we have to consider a few items of the radar.

It is reported that the APG-63(v3) and APG-79 have a common ancestry and I assume the processing capabilities to be similar (same manufacturer). 

So all other things being equal the main differences which could affect their respective capabilities are the number and type of T/R modules and the array aperture size. Since the F-15's antenna array is larger it also has more T/R modules increasing its range detection capability.

I assume that both aircraft are equipped with the same air to air missiles. That being said the F-15 has a much larger RCS and I think that would offset the narrow range advantage it has over the F-18. The only way the F-15 could win repeatedly is if it were sitting perch. (a F-22 tactic)

I have included here the APG-79 picture and drawing of the APG-63(v3) [APG-82] and a clip out of an article of AW&ST a few years back about the latest AESA systems indicating range in nm against a 1m2 target. I also included a drawing or comparative ASEA radar aperture sizes.

Hope this answers your questions


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## Sgt. Pappy (Oct 25, 2010)

Thanks for the info, Krieghund. That is some useful stuff and those pictures are pretty epic. If I didn't know better, I'd bet you're a Raytheon's forum rep  AFAIK the -63(V)3 is built by Raytheon just like the -79.

Though, I'm wondering what you mean exactly by sitting perch. Does that mean using one's performance to stay BVR, along with a kinematic advantage for a better firing position? If that's so, I'd assume neither a Raptor or F-15SG or F-15C (with v3 AESA) would have little trouble getting into a better position. 

That is assuming, of course, that _both_ planes are carrying AIM-120's, which would allow the F-15C/SG to track the F/A-18E/F before the Hornet gets within firing range.


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## krieghund (Oct 25, 2010)

No I'm not with Raytheon. My career has offered me the chance to work on a wide variety of equipment. In fact the transmitters of the APG-63 (the 011) I worked on still had Hughes part number labels on them.

Yes sitting perch is a tactic were a section of F-22s climbs to maximum attainable altitude then cruises and observes the battlefield with the help of the E-3. They then dive on their unsuspecting target building up kinetic energy enabling the missile to have more energy at launch.

In this way the same type of missile will have a longer f-pole (max range marker) then the same missile trying to shoot up at a slower initial launch speed. 

The F-22 scores the kill before the target knows he is there and the F-22 zoom climbs back to the perch reducing any possibility of retaliation if he we detected.

The F-15SG, F-15K and now F-15SA are all equipped with the GE129 engine which is more capable than the PW229 or in the case of the F-15C the PW220. (affectionately known as *P*uff *W*heeze) 

It allows the so equipped aircraft to cruise more efficiently and possesses greater SEP (Specific Excess Power)


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## Sgt. Pappy (Oct 26, 2010)

The perching tactic is reminiscent of 'boom and zoom' utilized by pilots of WWII and earlier - but now with missiles. Thanks, Krieghund, your information has been a big help. 

It is interesting that the U.S. would invest in building more efficient Eagles for other nations, but choose not to spend copious amounts of cash on upgrading their own Eagles with said power plants. Sure it's expensive but when you're got no F-22's, might as well upgrade the best right? Not only would an F-15C with 2x F110-GE-129s be more fuel efficient, they'd perform far better than the F-15E/SA/SG/K. I think in the long run, the U.S. would get the most of its F-15's if it just upgraded them with the new engines. I bet it's a political thing.

That being said, I'd assume that an armed F-15C as it is now has enough performance to maintain a perch/kinematic advantage over any missile-carrying Hornet, regardless of who detects who first.


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## davparlr (Oct 26, 2010)

As a point of interest, as netting of battlefield information increases, frontal cross sectional RCS becomes less important. Aircraft can be tracked off center by supporting aircraft, and/or ground sites, including aircraft in the shooters flight. The data is relayed to the shooter and he in turn attacks the target never detecting or tracking the target with on-board sensors. Of course the next step would be for UCAVs with AA missiles providing the the shooter functions. I suspect the air battle in 10 to 20 years will be completely different from that up to now.


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## Sgt. Pappy (Oct 26, 2010)

Integrated avionics does change the battlefield quite an amount. 

Perhaps once all the Cold War designs phase out and stealth takes over, WVR combat may be a dominant form of air-to-air fighting. Though, with all the insane missiles being built, WVR combat will be about luck, and will likely be a massacre. Maybe countermeasures and radar will develop quickly enough to offset stealth advantages. 

It will be an interesting future seeing stealth UAVs being directed by manned aircraft, safely hundreds of miles away.


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