Jump to content

AIM-120 Missing Contrails


Cmptohocah
 Share

Recommended Posts

AMRAAM is smokeless yes, but according to this live AIM-120 shot, it should produce contrails when conditions are right.
In the video the shooting platform (F-35A) is not con-trailing, but the missile is, so I guess in DCS it should leave a contrail when ever the launching platform is con-trailing.
 

 

  • Like 2

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

Posted (edited)

Here's another one:
in this one one can clearly see that the AIM-120 produces no vapor initially only to leave a thick contrail second or two latter, once it entered the clouds.

[timestamp 01:06]

One also at 01:26 of the same video.
 

 


Edited by Cmptohocah
  • Like 1

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

On 8/23/2021 at 9:53 AM, DCSoping said:

Have not tested myself but i do not think any DCS missiles have contrails ?

Yes they do and to the big effect in both RL and DCS.

 

Since the players can zoom in DCS (something you can see very often in popular youtube channels, especially if you are using large 4K TV screen), this can be observable from large distances. It helps you detect and defeat the missile, since you know about the missile bearing and possible distance if you correlate with radar/DL.

 

Obviously having a non-smoking/non-contrailing missile is a large advantage.

 

In this case it appears @Cmptohocah has found very solid evidences that RL AIM-120B/C(and possibly even D, since raptor was also involved) produce lots of smoke/condensation.


Edited by okopanja
Link to comment
Share on other sites

Posted (edited)
18 hours ago, okopanja said:

Yes they do and to the big effect in both RL and DCS.

AIM-120 does not contrail in DCS as can be seen by the following screenshots. There is just a faint smoke trail without any contrail being present. Second image is there as a reference.

above_contrail_height.png

below_contrail_height.png


Edited by Cmptohocah
Dcreased size of the images

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

2 hours ago, Cmptohocah said:

AIM-120 does not contrail in DCS as can be seen by the following screenshots. There is just a faint smoke trail without any contrail being present. Second image is there as a reference.

🙂 Sorry I was imprecise, what I actually meant is that for some other missiles in DCS, these effects are much more visible in DCS compared to AIM-120s. Also I would expect that contrailing behaves similarly as for the airplanes. The first image is well into the area where the condensation effects are quote pronounced as seen behind the Hornet, yet not condensation trail from AIM-120. The second one seems to be right on the edge height were you can expect contrailing. I gather that this is what you meant.

 

So if I got you right expected behavior for AIM-120s is:

- on first image there should be a very pronounced contrail (along smoke)

- on second image only the smoke should be visible

 

Link to comment
Share on other sites

Posted (edited)
2 hours ago, okopanja said:

So if I got you right expected behavior for AIM-120s is:

- on first image there should be a very pronounced contrail (along smoke)

- on second image only the smoke should be visible

 

That is correct.

There is a contrail missing at altitude at which the airplane is already contrailing - so much for physics.

In the YT videos the launching platforms are not contrailing but the AMRAAMS are, but I guess this would be then open to debate, so the Slammer in DCS should contrail at least once the airplane starts doing so. Maybe even sooner, but I have no data to show when this would actually happen. Maybe at 80% of the altitude the airplane contrails?


Edited by Cmptohocah

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

4 hours ago, Cmptohocah said:

Maybe at 80% of the altitude the airplane contrails?

Not sure, the operating principle of motors for airplane and the rocket are quite different. Since I am not a rocker scientist I googled and found this estimation of AIM-120c performance (oddly, by persons who actually references DCS in introduction!):

http://www.zaretto.com/sites/zaretto.com/files/missile-aerodynamic-data/AIM120C5-Performance-Assessment-rev2.pdf

 

Apparently someone really did put an effort into estimating performance, but smoke effects were not of primary concern.

 

On page 6 it states, they cover the fuel type and state that it is "reduced smoke XXX". I gather they figured out the rough composition of the fuel being used. The smoke at least should be visible but reduced by unknown factor.

 

Now the videos you found clearly show high levels of smoke/contrail (note F-22 can not carry older version due to the dimensions, so the ones you found are at least C versions) so we have several options to consider:

 

1. same/similar reduced smoke fuel is still used in C, but something stays behind the engine that condenses sooner than the exhaust of the aircraft on the same altitude.

2. A&B versions were using reduced smoke fuel, but as the AMRAAM evolved and requirement for range has been increasing, it is quite possible that "reduced smoke" requirement was removed/modified and fuel type has been changed, resulting in more smoke at the end for C version.

3. "reduced smoke" is nothing more than a Raytheon corporate marketing being creative.

 

Bottom line: it should show way more smoke/contrail at least under some conditions in DCS if not always.

Btw: Disclaimer on page 44 is priceless.

Link to comment
Share on other sites

5 hours ago, okopanja said:

2. A&B versions were using reduced smoke fuel, but as the AMRAAM evolved and requirement for range has been increasing, it is quite possible that "reduced smoke" requirement was removed/modified and fuel type has been changed, resulting in more smoke at the end for C version.

3. "reduced smoke" is nothing more than a Raytheon corporate marketing being creative.


Smoke is not the issue here and in my opinion it's modeled correctly. The issue is with contrails: for some reason it just does not contrail even when the launching platform does and this is in total contrast to what's happening in reality.


From the videos, one can see that AMRAAM contrails even before the aircraft does, but in DCS it doesn't - even when aircraft does. Since there is no way to determine what altitude those airplanes in the videos were, it's safe to deduct that the Slammer should contrail in DCS at leaast once the airplanes start to contrail.

 

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

  • 4 weeks later...
1 hour ago, Cmptohocah said:

I feel like a crazy person. Is it me? 😄

Would you be able to provide a track @okopanja?

I don't have access at the moment to DCS

No it is not just you, although drag calculation borders it...

 

😆 I think we need focus on simple things and pass the 1st line support, you know just follow the rules and demonstate the issue in reproducable way:

1. Enter cockpit (F-15)

2. Turn on electric installation

3. Turn on enigine 1

4. Wait for 40%

5. Turn on 2

6. ...

X. Some time later, fire 120 on unsuspectig Su-27 drone...

 

Anyway the issue bumped to the top if anyone visits the section...

Link to comment
Share on other sites

The title of the thread is simply wrong.   'Missiles don't have contrails' is what it should be.

[sIGPIC][/sIGPIC]

Reminder: SAM = Speed Bump :D

I used to play flight sims like you, but then I took a slammer to the knee - Yoda

Link to comment
Share on other sites

1 hour ago, GGTharos said:

The title of the thread is simply wrong.   'Missiles don't have contrails' is what it should be.

 

I couldn't find any AIM-9X launches that are leaving contarils behind and from what I know only smokeless A2A we can fire are the AMRAAM and the 9X, but technically yes all of them are missing contrails.

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

5 minutes ago, Cmptohocah said:

I couldn't find any AIM-9X launches that are leaving contarils behind and from what I know only smokeless A2A we can fire are the AMRAAM and the 9X, but technically yes all of them are missing contrails.

 

There may be some motor formulations that don't leave contrails but I don't recall any 'smokeless' motor being in use, but 'reduced smoke' instead all of which should cause some form of condensation under the right circumstances.   This includes all the really smokey rockets, it's just sort of moot because they're already smokey.

  • Like 1

[sIGPIC][/sIGPIC]

Reminder: SAM = Speed Bump :D

I used to play flight sims like you, but then I took a slammer to the knee - Yoda

Link to comment
Share on other sites

12 hours ago, GGTharos said:

This includes all the really smokey rockets, it's just sort of moot because they're already smokey.

In case of AIM-120, it is reduced smoke, true but obviously creates very visible contrails under right conditions. This would make them visible on the sunny blue sky once they get launched.

 

Regarding smokey, I gather you meant the R family, but for AIM-120 it looks like contrail effect should be way more visible than smoke itself (even when compared to smokey).

 

Link to comment
Share on other sites

I mean any smokey missile, be it R-27 or AIM-7/54 etc.  In-game, those are plenty smokey, no real need for contrails which is why I say that this is moot for them.

[sIGPIC][/sIGPIC]

Reminder: SAM = Speed Bump :D

I used to play flight sims like you, but then I took a slammer to the knee - Yoda

Link to comment
Share on other sites

5 hours ago, GGTharos said:

I mean any smokey missile, be it R-27 or AIM-7/54 etc.  In-game, those are plenty smokey, no real need for contrails which is why I say that this is moot for them.

 

One could argue that the contrails linger for longer than the smoke, so I guess it's also important for the "smokey" missiles also.

  • Like 1

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

Just a thought, but could it be that these motors where intentional smoking to be easily observable during testing? They seem to produce an awful lot of smoke right at launch, where as the launching platform is not.

[sIGPIC][/sIGPIC]

Win10 64, Asus Maximus VIII Formula, i5 6600K, Geforce 980 GTX Ti, 32 GB Ram, Samsung EVO SSD.

Link to comment
Share on other sites

It's the contrail.  Jet engines and rocket motors will create contrails in different conditions.  Theoretically ED could take this into account but the whole contrail thing is already pretty simplified.

[sIGPIC][/sIGPIC]

Reminder: SAM = Speed Bump :D

I used to play flight sims like you, but then I took a slammer to the knee - Yoda

Link to comment
Share on other sites

4 minutes ago, Svend_Dellepude said:

Just a thought, but could it be that these motors where intentional smoking to be easily observable during testing? They seem to produce an awful lot of smoke right at launch, where as the launching platform is not.

Nope, you can see that one launched off of a Hornet had no contrails at all until it pierced through the cloud: video #2

Anyway a RL Fulcrum pilot that was fired on with live AMRAAMS in '99, reported contrails also and this is what led him and his wingman to take evasive maneuvers.
On that day atmospheric conditions were such that the Slammers were leaving contrails between FL240 and FL270.


Edited by Cmptohocah
Added example.

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

1 minute ago, Svend_Dellepude said:

Yes, i see that one. But the one from the F-35 cons, while the F-35 doesn't. But as i wrote, just a thought.

In RL it depends on the atmosphere mostly, so you can have one day no contrails and have them the other at same altitude.

Cmptohocah=CMPTOHOCAH 😉

Link to comment
Share on other sites

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...