Radar Tests: VERY VERY unusual results.

[USARStarkey]

So me and a friend of mine did some very extensive testing of the Su-27 and F-15 in BVR. Testing was done at 45,000feet and as close to equal speed as we could get. Radars were tested in modes.

 

Results

 

I was under the impression that F-15's radar is much better than the Su-27s. Everything I have read both from books, magazines, this forum etc. has backed that up. What we found was odd. at 45k, the F-15 detects the flanker only a few moments before the flanker picks it up. It obtains lock only a few moments before, and it gets launch authority for the 120 just a few moments before. All tests were conducted multiple times, and from a head on angle. Both planes locked on at about 55 miles. Detection at about 60-70

 

Anyone know what is going on?

[GGTharos]

All I can say for now is that detection range is not necessarily a measure of a better radar.

[FLANKERATOR]

AFAIK, both radars are very close in game when it comes to emitting power and that is the case since the early FC versions. One way to verify it (in-game) is to watch the LED's on the SPO, both fighters will fill same number of LED's from the same distance.

This is 'in game', RL may be different.

[Pilotasso]

At 45000 feet there isn't much to challenge both radars target discrimination capabilities.

[TAW_Blaze]

Better way of testing this would be set up notch or look down situations and see which one does better. Spotting a guy angels 40 cruising directly to you ain't no challenge, unless you're talking about a Raptor.

[104th_Maverick]

There is no bug or anything here.

 

55 miles is pretty standard, you will see larger aircraft at a longer range but for something the size of a fighter with its smaller RCS 55 miles is the max you'll be able to see.

 

This is all you need, yes at angels 40+ your going to get LA at some crazy range but these days your going to be wasting your ammo.

 

9/10 you will not hit anything fired on at rmax, if you do you have been lucky enough to come up against a pilot who does not know what he is doing.... likewise... if your getting killed from someone 25+ miles away... you have lots of catching up to do and should start learning more about BVR tactics.

 

Moral of the story... forget about long range shots at Rmax and getting caught up on who can fire on who first and start working on getting closer to bandits and delivering high energy ordnance to the fight and then extending away.

[OGREMAN]

Green Bloke Agrees!

 

;1998966']There is no bug or anything here.

 

55 miles is pretty standard, you will see larger aircraft at a longer range but for something the size of a fighter with its smaller RCS 55 miles is the max you'll be able to see.

 

This is all you need, yes at angels 40+ your going to get LA at some crazy range but these days your going to be wasting your ammo.

 

9/10 you will not hit anything fired on at rmax, if you do you have been lucky enough to come up against a pilot who does not know what he is doing.... likewise... if your getting killed from someone 25+ miles away... you have lots of catching up to do and should start learning more about BVR tactics.

 

Moral of the story... forget about long range shots at Rmax and getting caught up on who can fire on who first and start working on getting closer to bandits and delivering high energy ordnance to the fight and then extending away.

 

Well Said Mav! I agree

[Alfa]

So me and a friend of mine did some very extensive testing of the Su-27 and F-15 in BVR. Testing was done at 45,000feet and as close to equal speed as we could get. Radars were tested in modes.

 

Results

 

I was under the impression that F-15's radar is much better than the Su-27s. Everything I have read both from books, magazines, this forum etc. has backed that up. What we found was odd. at 45k, the F-15 detects the flanker only a few moments before the flanker picks it up. It obtains lock only a few moments before, and it gets launch authority for the 120 just a few moments before. All tests were conducted multiple times, and from a head on angle. Both planes locked on at about 55 miles. Detection at about 60-70

 

Anyone know what is going on?

 

What GG said.

 

But then your results actually points to the APG-63(F-15) being "better" than the N001(Su-27) in terms of range too.

 

Radar range is a factor of mainly three things - antenna size, emitter power versus target RCS. The RCS of the Su-27 and F-15 are likely quite similar(quite large) and AFAIK the radar emission power is something similar as well - something along the lines of 5Kw peak.

 

However, the the N001 has a larger antenna(some 1075 mm dia.) than the APG-63(some 900 mm dia.), so you would expect the Su-27 to have an edge in terms of pure range. But then the N001 has a cassegrain antenna, while the APG-63 has a slotted array antenna which is more efficient(losing less power through sidelobes).

[GGTharos]

Alfa, as a point of detail, I would actually not be surprised that the F-15 is getting better range on account of better electronics. The antenna sizes are closer than some other comparisons (ie. the MiG-29's antenna is much, much smaller) and IIRC part of the flanker's antenna is occluded, so it isn't using the full area. Like you stated, it's power vs. RCS, but if your electronics are less noisy, you can pick up a weaker signal and thus have superior range with a 'weaker' radar.

 

If you consider that by the time the Su-27S was in service the APG-63 had undergone several major revisions already, things start looking a bit different in terms of capability.

 

PS: So, I ran the math and did a bit of research. The F-15's antenna area is something like 70% that of the Su-27's, if you consider diameter exclusively. This means a significant difference in SNR capability must be present for the F-15's antenna to have equal/better detection ranges ... generally, the APG-63 is considered superior in this respect but, the proof? We don't have any.

 

So, look at this image:

 

This is the N001 antenna, and it's missing a huge chunk of area. This has the following effect: The theoretical resolution capability of this antenna is better than the APG-63's ... because in this case, it is the diameter that matters. However, the actual RF collecting area now appears to be similar, so their ranges would also be similar if we ignore differences in the two radar systems. Of course, this all changes when those radars acquire a planar MSA or ESA.

Edited February 19, 2014 by GGTharos

[Alfa]

Point taken in regards to the actual area not being as large as the difference in antenna diameter would suggest.

 

But even if it was I think the difference in antanna tech would still give the APG-63 the edge in range. Of course SNR and processing is a factor too, but as you said yourself, its the sort of thing thats difficult to compare since the information isn't there for the purpose.

 

If you consider that by the time the Su-27S was in service the APG-63 had undergone several major revisions already, things start looking a bit different in terms of capability.

 

Yes but then the N001 went though major revisions too - both before and after entering service :) .

[USARStarkey]

I did some more research on the the 2 radars in lieu of these tests. It was very hard to find data but I was finally able to get the following info, which is close to the game actually:

 

N001: 43-53nm against a 1 square meter rcs.

 

APG-63: 90km+ against a 1 square meter rcs. (which is 55 miles.)

 

So I guess there is our/my answer. The APG63 is slightly longer ranged.

[GGTharos]

Where did you get this data from? I get slightly longer ranges from some APG-63 sources ... but those are old.

[Frostie]

I did some more research on the the 2 radars in lieu of these tests. It was very hard to find data but I was finally able to get the following info, which is close to the game actually:

 

N001: 43-53nm against a 1 square meter rcs.

 

APG-63: 90km+ against a 1 square meter rcs. (which is 55 miles.)

 

So I guess there is our/my answer. The APG63 is slightly longer ranged.

90km = 48nm

Probably the original APG-63

FC3 use APG-63(1)

[GGTharos]

Original APG-63 is listed as having a range of 110mi for a 'typical target', no specification whether nm or just m or what a typical target is ... now having said that, I don't recall all these figures very well, but I do recall that it was impressively more than I expected.

 

I'll point out something else. The VSD has a 160nm display setting. There's a reason why that's there. If you imagine a 50sqm target can be seen at 120nm, a 3msq target is visible at half this distance - simple math, right (you need 1/16th the RCS to halve the range).

 

The F-15 has standard radar modes which are not available in FC3 that permit detection at longer ranges than we're used to.

 

PS: Found my source. Just shy of 80nm for a fighter-sized target for an 80's APG-63.

 

The same source lists the F-16 range as just shy of 30nm. I know that today, with MSA's, MLU F-16's pick 'small' things up at around 40nm. Think about a 90's APG-63.

Edited February 20, 2014 by GGTharos

[Frostie]

I think specified ranges will vary with no conclusive comparison, apparently the Russians tend to use their figures using 3-5 msq targets. A fighter sized target can vary from 1-15+msq, the F-16 APG-66 i've seen stated as 40nm head on against F-4 which I should imagine has quite a big RCS.

 

What should be used is power, antenna size etc. The APG-63 and N001 come out pretty equal on this I think. I've seen mentions of the APG-63 at 5.2kw compared to an F-14 at 9kw and the MiG29 at 6.5kw. The original N001 was expected to be comparable plus some to the APG-63 but it turned out originally to be not up expectations, but upgrades did ensue.

I'm not sure but I think the Russian twisted cassegrain affects performance, something along the lines of side lobe/wasted power.

 

There were 160+ F-15's upgraded to APG-63(1) then a further 18 upgraded to APG-63(2), so that left some 300+ F-15's carrying the original APG-63 without TWS and with extremely limited processing power for upgrades.

[Alfa]

I did some more research on the the 2 radars in lieu of these tests. It was very hard to find data but I was finally able to get the following info, which is close to the game actually:

 

N001: 43-53nm against a 1 square meter rcs.

 

APG-63: 90km+ against a 1 square meter rcs. (which is 55 miles.)

 

So I guess there is our/my answer. The APG63 is slightly longer ranged.

 

The figure for the N001 is not correct though - more along the lines of 90-100 km head-on detection range against target RCS of 3m2.

[GGTharos]

I think specified ranges will vary with no conclusive comparison, apparently the Russians tend to use their figures using 3-5 msq targets. A fighter sized target can vary from 1-15+msq, the F-16 APG-66 i've seen stated as 40nm head on against F-4 which I should imagine has quite a big RCS.

 

Against an EF-2000 for F-16MLUs as of last decade. 40nm.

 

What should be used is power, antenna size etc. The APG-63 and N001 come out pretty equal on this I think. I've seen mentions of the APG-63 at 5.2kw compared to an F-14 at 9kw and the MiG29 at 6.5kw. The original N001 was expected to be comparable plus some to the APG-63 but it turned out originally to be not up expectations, but upgrades did ensue.

I'm not sure but I think the Russian twisted cassegrain affects performance, something along the lines of side lobe/wasted power.

Right, but the idea is not play the guessing game too much unless we must when implementing, and there are ranges listed out there by reasonably reliable sources. Not always accessible, but not classified.

 

There were 160+ F-15's upgraded to APG-63(1) then a further 18 upgraded to APG-63(2), so that left some 300+ F-15's carrying the original APG-63 without TWS and with extremely limited processing power for upgrades.

Sorry but that isn't correct at all. APG-63's in service aircraft have constantly received upgrades piecemeal. The vX and MSIP1/2 programs were large standardization and upgrade efforts, but they were never the only thing happening and you won't find any F-15's in service without modern capability. The only recent thing that 'split the fleet', if that, is the golden eagle upgrade.

 

Going back to the v(1), there was a change in manufacturing methods /if/ I recall correctly, and that's mostly what the distinction with the v(1) kits is about, but it's not like other eagles didn't receive upgrade kits.

Edited February 20, 2014 by GGTharos

[GGTharos]

Which means you should be seeing a flanker or eagle a little further than that, about 1/8th more range is my guess.

 

The figure for the N001 is not correct though - more along the lines of 90-100 km head-on detection range against target RCS of 3m2.

[Alfa]

I think specified ranges will vary with no conclusive comparison, apparently the Russians tend to use their figures using 3-5 msq targets.

 

They do :)

 

What should be used is power, antenna size etc. The APG-63 and N001 come out pretty equal on this I think. I've seen mentions of the APG-63 at 5.2kw compared to an F-14 at 9kw

 

Thats what I heard too - mind you the AWG-9 also has a larger antenna some 980 mm IIRC.

 

and the MiG29 at 6.5kw.

 

Too high I think - the N019 and N001 have the same output - 1 Kw average, 5 Kw peak.

 

The original N001 was expected to be comparable plus some to the APG-63 but it turned out originally to be not up expectations, but upgrades did ensue.

I'm not sure but I think the Russian twisted cassegrain affects performance, something along the lines of side lobe/wasted power.

 

That was the point I was making earlier - that planar slotted arrays suffer less in this respect and phased arrays even less.

[Supersheep]

Hmm. I see the term "source" being used frequently. I find the lack of links disturbing, so I conclude that it's either a subscription to Jane's* or offline material/persons/contacts?

 

 

*Maybe I'm expecting too much from them? But anyways, looking at the price tag...

[GGTharos]

No, Jane's is expensive. Sometimes you can find interesting things on dtic.mil, at least that is free.

 

Some information does come from journals, but in that case people may or may not share since they've spent money on things.

 

Other info may come from FOIA action which can be either quite expensive, very difficult to find, or both.

 

And in certain cases it just plain takes huge amounts of digging.

 

In other cases, there are no internet sources.

 

Hmm. I see the term "source" being used frequently. I find the lack of links disturbing, so I conclude that it's either a subscription to Jane's* or offline material/persons/contacts?

[Alfa]

Which means you should be seeing a flanker or eagle a little further than that, about 1/8th more range is my guess.

 

Yup - AFAIK a Flanker(at least initial versions) have an RCS along the lines of 12 m2.

[GGTharos]

I've never been able to find reliable sources for RCS unfortunately, or at least, nothing that I could consider reliable, except for one mention, and sadly I can't recall where ... :P ... of 'typical targets' being in the 2-6msq range, and I would submit that this is a fairly typical variance of fighter RCS'.

 

Anything smaller is a cruise missile and anything bigger a bomber. Except for B-1B's, Tu-160s and B-2's :)

[Alfa]

I've never been able to find reliable sources for RCS unfortunately, or at least, nothing that I could consider reliable, except for one mention, and sadly I can't recall where ... :P ... of 'typical targets' being in the 2-6msq range, and I would submit that this is a fairly typical variance of fighter RCS'.

 

Anything smaller is a cruise missile and anything bigger a bomber. Except for B-1B's, Tu-160s and B-2's :)

 

The figures I have come by claim along the lines of 12m2 for the Su-27(and I would expect something similar for the F-15), 5m2 for something like a MiG-29/F-18 and 3m2 for an F-16 or MiG-21.

 

Sounds plausible, but how reliable it is ....well :) .

[AFAlinebacker42]

I find the lack of links disturbing