SgtPappy

I was flying as RIO with a buddy versus other friends in a practice session when I realized that pulse locks did not seem to be broken once range was within, say 15 nm or so. We were looking down from ~12000 ft over flat land on the Caucasus map with the target being a Hornet right on the deck, cold, beaming, S-turning, pumping chaff. We tried a few more times and another friend also could not break pulse lock in look down conditions at ~ 10 nm in the Viper. I'm not sure if this is a bug, but the intent of this post is to ask if others have had similar experiences and if this is an accurate scenario. Is the resolution cell of the AWG-9 at 10 nm so tight that a pulse lock can be maintained? I did so prelim calculations and at that distance, the angular resolution cell length is around 2200 ft (2.1 deg. beamwidth for 3 cm wavelength and AWG-9 array diameter ~= 0.91 m). Assuming chaff takes 1/2 a second to bloom to a large RCS (~30 dBsm or so) and the defending target is beaming at 400 kn, you'd have a bunch of fully-bloomed chaff in the res cell for over a second - and a constant stream should throw off a pulse track of the RCS centroid. Obviously, there's more to it than this but if it's realistic, that's awesome! But I have a sneaking suspicion it might not be unless there's something special about the AWG-9 pulse modes in tracking I'm missing. If people want to see tracks/tacview, I'll setup an experiments with my buddies this week. Thoughts?

Indeed, and Bio, who we all love, has specifically quoted the same mistake in OP's video stating that the detune from 20,000 lbf in the enthusiast books to 17,000 lbf in the NATOPS was a "big hit" to engine thrust. These guys obviously know what they're talking about, but engineering-level mistakes like this that don't actually concern the crew are made even by the best pilots/RIOs. After all, they're more concerned about turn rates, speeds, climb profiles, TSFC etc. and the engine thrust curve is just extra trivia since that value is unseen and is baked into the performance parameters that actually matter to them.

Yea, I believe the -412A was that mod and then came the -414 sometime in 1977 and the -414A in 1984 which was reportedly much better but still not up to the standards of the late 80's digital EEC-equipped engines. AFAIK they all were trimmed at the same levels by the time the -414 was widespread in the F-14 fleet. I've heard some pilots (there's a video on youtube of an airshow Tomcat crew in 1997) even state that the engine was detuned to ~17,000 lbf thrust because they're quoting the installed thrust value from the manual and comparing it to the brochure uninstalled static thrust (the ~20,800 lbf value). Pretty confusing.

@Noctrach @Naquaii, I also noticed something similar (maybe the same) when testing vs both AI and humans... Even at ~5nm, a Phoenix can be spoofed by chaff with the cold (human) bandit doing hard S-turns while in burner (doesn't look like the angle is enough to notch). Against the AI, it's even easier as I see Pheonixes pass by me harmlessly while I was cold and turning side to side when launched by AI. I'll work on getting a few tracks when my friends and I have the time. I thought this was also the MLC and Doppler filters kicking in but then I realized, the AIM-54 is closing ~300+ kn to the target and only the AWG-9 would be vulnerable to this +/-100 kn closure speed. Do I misunderstand something? Would like your thoughts.

Wow, this is wild stuff! Super excited to hear something like this in the F-14A. Thanks for the link. Good stuff to study.

This is epic! It actually makes me even more excited for the old school stuff coming out on the earlier F-14A's. How the heck did you find/come up with this audio? In other discussions, we've heard that you needed off-the-shelf fuzz busters to get the SA-6 launch signal as the ALR-45/50 either couldn't give launch warning or would give spurious false alarms and so was often in filtered mode which removed the ability to hear/see the SA-6 launch. Some crews even mentioned the system was useless. If in filtered mode, I guess you'd have to pay attention to the track signal and then look in that direction for a launch?

It looks like there's good news on the horizon! See Chizh's reply on implementing the correct APG-63 ranges:

This would be awesome to have, as many of my lost targets are right there, near the merge when I've seen cold bandits basically just turn around and instantly break lock during the 0.5 seconds they're in the notch. At such close ranges, the range gating and small res cell should prevent this but anyone who flies the F-15 knows that any bandit can break lock at any range without chaff just by being 90 deg. aspect momentarily. No chaff needed, just turn around. I've died a couple times this way as my boresight has been just a bit off. This tactic should be suicide for a bandit at this range, but it ends up as very deadly (at least against my flying which needs improvement). As mentioned I've noticed at longer ranges (> 5nm or something), the radar will try to extrapolate the target's heading via MEM and if the target comes out of the notch enough, it will reacquire but at short ranges, I've never seen this happen. The high level of automation necessary to make the Eagle a deadly WVR is missing from FC3 and though I understand that it's not a FF aircraft, it would be good to use existing architecture to have some of these function in the background perhaps.

So excited! Can't wait. The latest patch too was a lot of fun - being able to use the AIM-54 and AIM-7 online for a bit was great. Too bad the TF30 won't make it in Oct since everyone knows the A is the real star heheh but very glad that it will be worked on with quality in mind over schedule. Keep it up! And of course thank you!

We did a few more tests and it appears that the AIM-7MH and R-27R are roughly equivalent in being spoofed by these gimbals + loads of chaff maneuvers and the AIM-7M is much more easily spoofed. However all three - AIM-7M, MH and R-27R are spoofable and it seems only when they are above the target and there's a lot of chaff in their FoV. We clocked closure rates in excess of 900 kn so this is just further evidence that something is amiss. Keeping my fingers crossed that this can be addressed

@NineLine @BIGNEWY, any idea if this is something that can be looked at? It's fairly influencial to the outcome of a lot of the Fox 1 fights and I would assume it may have some effect on more modern missile encounters as well.

I fly the Su-27 all the time. I never said the R-27R was phenomenal.. both the AIM-7M and R-27R chaff resistance suck, but the R-27R just sucks slightly less. Note that I'm not using the AIM-7MH which might have slightly better chaff resistance than the AIM-7M because you can't control its loft in the F-15. I assume you haven't done the above experiments that I've been doing. Try it with a friend (like with me ). I simply found that I couldn't get the R-27R to bite the chaff in this "gimbal spoof" experiment as often. That's all.

These seem like really good ways to make ECM more realistic with the resources available today! Thanks for suggesting them. Just to add to the evidence, I also have a few more clips of the Su-27 and F-15 dodging AIM-7M's by just spamming chaff while at gimbals. I thought I had a good one of the R-27R being spoofed but evidently, I'll have to make more attempts at that. The R-27R is a lot harder to spoof but not impossible (I probably just need to spam more chaff). See below for clips where I maintain lock at gimbals but still defeat several AIM-7Ms launched in MP by my friends: https://streamable.com/ifslnz https://streamable.com/wl1gfq And here's one of a Mirage, barely maneuvering managing to do the same thing once again while I had lock the whole time: https://streamable.com/lkt8v8

I wonder if there's something that can be done in the meantime.. I mean you can't do this versus an AIM-120 and you cant do it directly facing the shooter while flying at 300 kn and spamming chaff even vs an AIM-7 (or maybe you can?) so perhaps there is a bit more to it than just closure speed. And even then, the guy's closure speed was showing up in excess of 700 kn on the VSD with no indication of my radar losing track (blinking TD box when target is at low closure speed). Maybe there's someone who can share more on the actual requirements of spoofing these missiles because what's then stopping me from just diving under you and popping all my chaff at once ? An extreme case, but I feel that whats happening now isn't far from that.

I have noticed a few instances of a player managing to spoof my AIM-7's in the 80's Blue Flag server while at gimbal limits (i.e. 60 deg. aspect or so). They dive under me, put their radar at gimbals and spam chaff and somehow, the AIM-7 goes stupid even if the target is at Mach 1.2 at gimbals - all the while they are guiding their own missiles. It can't be seen in the tacview, but I never lose lock in these situations. So I tried to do it myself vs AI. I know AI has different chaff and flare rejection characteristics, but it appears that since you can do this stunt at all vs AI means that it would simply take more chaff to do it vs a human player. I do not believe that this should be possible or practical and it seems to be a limitation of DCS. It makes notching an unnecessary tactic at least at these ranges (~10 nm) and also highlights the lack of proper range gating in lookdown situations (i.e. if my target is at 15000 feet, my missiles probably shouldn't be super spoofable if I'm at 17000 feet. - spoofing AIM-7 vs AI: https://streamable.com/qmn3bf - spoofing R-27R vs AI: https://streamable.com/qmn3bf - human spoofing AIM-7: https://streamable.com/hgm3c3 and associated track (sorry I couldn't compress it any more): https://ufile.io/nvufw2zo and associated tacview: https://ufile.io/mvm1xb9w. Another example: https://streamable.com/4qua18 Is my understanding correct? Chaff should be easily rejected at these geometries/ closure speeds but I wonder if I am missing something and this is by design.

Haha at this point I think we're just quoting each other because we spend so much time on these kinds of threads I think I'd be a bit too lazy if I asked that. Thanks!

It's a good paper. If anyone is interested, the paper is here: https://apps.dtic.mil/dtic/tr/fulltext/u2/a151928.pdf Just being nitpicky but fig. 24 shows that the probability of break lock is ~2% for a hot target (table parameters for this simulation shows hot target and the paragraph above that states that the filter easily filters chaff due to the intercept geometry). Fig. 25 shows the the probability of break lock as a function of aspect and it's basically 2% until around 85 deg. aspect and then it shoots almost asymptotically to 100% at 90 deg. This is consistent with old pulse radar. To add to the above, the newer missiles also have multiple medium PRFs to try and find the target in some clutter clear returns, not to mention the use of Ku rather than X-band for finer resolution. Nice! Just because I'm super lazy, do you know which one it is that talks about the AMRAAM? I get a page of several episodes form this link

That's awesome, thank you for the help!

Why so hostile... I don't read the discussion as being overly obtuse. It just seems like a whole bunch of nerdy people discussing our nerdy passion - aircraft. It's a bit par for the course for people to point out details and how they understood an article/other source of info. If the language triggers you and nothing wrong or unfair was actually stated, you need to identify why it triggers you or talk to the other person without insulting them - after all this is a forum designed for us to discuss these exact topics with scrutiny. You and your wife probably didn't go into that line to talk to a stranger about the colour of the sky, but when you come here, you are more or less signing up to discussion and opinions of others on aircraft/simulation. I've heard that we might not be able to remove the CFT's which would make it a bit tough then to fight competitive BFM. But at this point, it's too early to speculate what features really will show up. I can see people removing them online in general and using the F-15E as an F-15C - something I might do a lot until a holy grail FF F-15C exists anywhere but in my dreams

Luckily there's a brightness control that I find works very well and if you turn it down as needed for the given light condition, the big blurb of green goes away without sacrificing any HUD info detail or readability.

Another point in the case for the F-4E: Israelis had at least nine aces in the F-4E during the 1973 Yom Kippur war - they shot down some 116 planes with the F-4E (slatted, hard-wing, TISEO-equipped, weird versions with different combinations of the aforementioned features) between 1969 and 1973. This even fits the Syria map real well. If we could have both, I'd like any slatted F-4E and the F-4J - both Vietnam variants that would work decently well in DCS mid-Cold War servers. The original ARN-101-equipped version that Belsimtek was doing would have been great too.. just a dream for now I suppose!

Very interesting, thanks so much Naquaii for clarifying that! That last bit about CW illumination was my second question but it all makes sense now, that it's only used for Sparrow illumination and not for tracking.

Ah understood, thanks! I understand that the hardware limitations of the time prevented the heterodyning of a low doppler signal to show up.. after all you can only fit so much non-digital hardware into a 60s processor. But I could've sworn I saw a series of DDD images which had the rejection doppler "tuned" such that you could keep the target tracked as its radial speed decreased at the cost of rejecting fewer things like trees moving in the wind. I could be mistaken, but I can't for the life of me find the image right now. EDIT: Just read in my handy Hughes Radar Handbook that the blind speeds are a strong function of the PRF, which, in the Tomcat's case is not very variable, only having low or high PRF and no medium PRF waveforms. However, I believe since its CW illumination is chirped (i.e. varying frequency) in order to determine range while locking. I am curious if its HPRF waveform is chirped as well or can be modulated in any way by the RIO?

Just out of curiousity - is the real F-14 blind speed tuneable with a knob? I know we have some gain knobs and the like that have no function in DCS due to game engine limitations and that this function might be one of them.

Thanks StuntPuppy! So in theory, I could take the T-45 mod and mess with it to give it, S530s and Magics to simulate a Mirage and practice with that? If so I'll have to dig into this procedure.