[DCS BUG] AIM-7 massive guidance difference F-14 vs F-15

So doing tests on the AIM-7 I've discovered an egregious difference between the sensitivity to chaff on this module compared to the F-15C.

It appears ED's implementation of AIM-7F guidance is leagues ahead of the implementation in use with the F-14's AIM-7M in terms of chaff and notch resistance.

I know guidance is out of your hands, but I can't help but wonder if there's something going on with the AWG-9 or PAL mode because the difference is rather extreme.

Setup: Altitude 15000 ft, 400 knots on both jets, head on aspect, 10 miles separation against a MiG-23MLA Excellent AI in the mission editor, NTTR standard day.

Diving to the deck while firing to maintain look-up all the way.

AIM-7M's, fired in sets of 4 at 10 miles with the F-14 in PAL (P-STT).

• 33 out of 40 missiles were chaffed. Target was never less than 3000 feet above shooter, missiles even got chaffed on head-on aspect. Lock was never broken. None of the missiles ever reacquired.
  

AIM-7M's, fired in sets of 4 at 10 miles with the F-14 in PD-STT, Jester auto-switch to P-STT turned off).

• 35 out of 40 missiles were chaffed. However, 2 of the chaffed missiles reacquired a couple seconds later. Lock was maintained all the way in look-up. If the target dipped below 3-5 degrees look-up while notching, the lock broke as expected. These results were not counted in the total.
  

AIM-7F's, fired in sets of 4 at 10 miles with the F-15 in STT medium PRF.

• 0 out of 40 missiles were chaffed. Including 12 shots in look-down with a target passing through the notch (flashing lock indicating radar memory mode). Missiles reacquired immediately when the target left the notch. One missile even scored a look-down kill after a 2 second notch. Every single missile tracked until impact or kinematically defeated.
  

AIM-7M's, fired in sets of 4 at 10 miles with the F-15 in STT medium PRF.

• 0 out of 40 missiles were chaffed. 12 shots in look-down also did not get chaffed, despite the target manoeuvring into the notch for a second or two, guidance was maintained. Five of these even ended up directly hitting the target.
  

The reason I've also used the AIM-7F in these tests is because it does not exhibit the same loft profile as the M/MH outside of 3 miles and therefore has a higher similarity to the modeling used in the F-14. The AIM-7F should also be more vulnerable to chaff than the later models.

I'd understand if your hands are tied but I felt it wouldn't hurt to make another post about this to really verify whether or not this is something to do with the module itself. Or at least see if the current AIM-7F guidance could be ported to the F-14 as it begs the question why the missiles for this module are so mindbogglingly much worse than their counterparts.

As it stands the Tomcat's Sparrow guidance is vulnerable to chaff to the point of uselessness.

Tacview Outtakes.zip

I wouldn't say that ED's implementation is ahead.

Interesting that there is a difference at all. Everything happened at below 13,000 feet. The missiles were all in a look down scenario.

Missiles fired by the F-14 seem to loose the target at around -5° in pitch. They also reacquire the target sometimes.

This might be a missing feature/bug on the F-15 not the F-14.

I wouldn't say that ED's implementation is ahead.

Interesting that there is a difference at all. Everything happened at below 13,000 feet. The missiles were all in a look down scenario.

 

Missiles fired by the F-14 seem to loose the target at around -5° in pitch. They also reacquire the target sometimes.

 

This might be a missing feature/bug on the F-15 not the F-14.

For SARH missile being look-down doesn't matter, since it just guides onto the "beacon" of reflected radar waves. It doesn't look at a doppler shift, but rather at a frequency band. It's like lighting up a butterfly with a flashlight in the dark, only when you move the light away can you not see the butterfly anymore.

F-15 as it stands is modeling this correctly, as long as the STT lock remains unbroken, the radar will continue flooding the target with guidance radiation.

This issue is known to us and we currently inquired with Eagle Dynamics as to what could be the reason, since the code of our aim7 matches the code of the aim7(m) the hornet uses 1:1

Please be aware that Eagly Dynamics is still working on their own missiles and guidance and any missile related fixes could be depending on that.

Alright. Thanks for the heads up, IronMike!

For SARH missile being look-down doesn't matter, since it just guides onto the "beacon" of reflected radar waves. It doesn't look at a doppler shift, but rather at a frequency band. It's like lighting up a butterfly with a flashlight in the dark, only when you move the light away can you not see the butterfly anymore.

 

 

F-15 as it stands is modeling this correctly, as long as the STT lock remains unbroken, the radar will continue flooding the target with guidance radiation.

Actually, @Noctrach, the missile does look for the doppler shift. In fact, the launching aircraft feeds a signal called PSEUDO to the front antenna of the missile just prior to the ejector cart kicking the AIM-7 off the station, or the missile coming off a rail. That PSEUDO signal is a simulated doppler shifted reflection from the target aircraft. The rear antenna on the missile is fed a reference of the launching aircraft's transmitted CW (illuminator) signal just prior to launch, as well. Once in flight, the missile's guidance system looks for the same doppler shifted signal from the target aircraft and uses CW from the launching aircraft to measure closure rate by comparing it to the doppler shifted CW reflected from the target.

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@IronMike it is due to the fact that you have not added the new missile code into the AIM7 in your entry.lua now it does have very similar values but quite a bit has changed missile code wise.

Your AIM7

ED's AIM7

Although when you do adjust the AIM7 if you could reduce the chaff chance as it is way to sensitive to it right now that'd be super sweet!

Thank you, we will take a look.

i love threads like this! proper feedback and proper reaction from devs

And here was i thinking it was me doing something wrong with the Sparrows :/

Although when you do adjust the AIM7 if you could reduce the chaff chance as it is way to sensitive to it right now that'd be super sweet!

I would argue for using EDs sparrow instead and have no inconsistencies. If you want a less sensitive sparrow fly your missile mod. Inconsistent versions of the same missile are not a good thing, as you have just demonstrated. :)

Fair, its just imo chaff is way to effective on PD missiles right now, but I guess consistency is more important than fixing the chaff resistivity.

IMHO a chaff fix should go beyond adjusting that one number - it's looks like there's almost no middle ground between no good and too good.

Agreed the way I view it is the code should effectivly draw a "box" around the target representing its radar return. It will then aim for this, when you dump out chaff it can drastically increase the size of this box increasing the missiles miss distance. With the tech level and if the missile is PD or not dictating how big of a return the chaff creates.

For example:

(please excuse my poor ms pain skills :P

Mike, any news on if this will be addressed/patched soon? Seems to me functional issues like this should be decently high priority. Especially if they are an easy fix.

Its not only the AIM7, its the radar guiding it.

Countermeasures are very easy to distract F14 Radar.

i even lock ships with PAL mode, @ PG Map.

This also happens with the AIM54. if you keep TWS after shot, the missle will miss more often than if you break away and missile guides by its own.

i even lock ships with PAL mode, @ PG Map.

That's how it should be. PAL is using Pule Search, which has no filtering at all and ships on the ocean stick out on the radar like a christmas tree. That's why the F-14 is a formidable naval recon asset, because the RIO can use Pule Search mode to locate ships at distances of 200nm and more. They show up on the radar screen (the DDD) like aircraft in a clear sky.

That's how it should be. PAL is using Pule Search, which has no filtering at all and ships on the ocean stick out on the radar like a christmas tree. That's why the F-14 is a formidable naval recon asset, because the RIO can use Pule Search mode to locate ships at distances of 200nm and more. They show up on the radar screen (the DDD) like aircraft in a clear sky.

hey thanks, didnt knew that.

i think that is not happening that much @ Caucasus tho.

hey thanks, didnt knew that.

i think that is not happening that much @ Caucasus tho.

Haven't really tried the radar on the static ships on the Caucasus map, but I think they're somewhat different to the static ships on the PG map. I have tested it with actual ship units on the Caucasus (as well as on the PG) map though and that worked as advertised. I was able to pick them up in Pulse Search mode just fine.

Anyways, this is a bit OT here :music_whistling: