[BUG] Bombing in the wind - ED Forums
 


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Old 07-18-2019, 07:27 AM   #1
Adrian858
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Default [BUG] Bombing in the wind

Alright folks, for the last couple of days, I've been trying to figure out the best way to hit targets in somewhat windy conditions with Dumb Bombs, primarily MK-82's.


Below is a rundown of the mission in particular.



12c
Snow (Cloud Density 9)
Windspeed:
-12kts at 33ft
-25kts at 1600ft
-0kts higher than 6600ft
Direction bearing 120
Turbulence 2
Fog Visibility 4000ft
Fog Thickness 1200



First target area elevation 430ft


I'm finding the bomb fall line has a tendency to shift right when the wind is coming in from the left (which is normal), but makes getting the bomb pipper difficult to get on target as a result. Bombs are landing about 100 meters away when putting the pipper directly on the target. Bombing into the wind seems to help a little bit, but still not the accuracy I'm looking to achieve with dumb bombs in such weather. I doubt that the HUD can be caged or uncaged similar to the F/A-18C, but is there a way to correct the bomb fall line based on wind?


Any helpful advice is appreciated!

Last edited by IronMike; 07-19-2019 at 03:57 AM.
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Old 07-18-2019, 10:53 AM   #2
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The RIO can enter and readout wind data, which iirc is used for example if the pilot uses ground track with the AP (or for backup navigation), but I have to ask how it affects the bomb fall line.

However we discovered an issue (it has been reported in another thread), where different wind settings in different layers seem to cause inaccuracy (that is higher than expected), which we are currently investigating.


Finally the bomb fall line will be displaced according to the wind in the current layer in which you are flying, which can result in an inaccurate drop if the difference of wind speed and/or direction between layers is large, as in your mission. So it is not necessarily related to the issue I mentioned above as we discovered that one under specific wind speed settings only. So your issue could also be due to the high difference of wind settings between layers.

If you like you can test this yourself: Set all layers to 25kts for example, and see if it makes a difference.


EDIT: Just talked to Supergrover, so a couple things to add: In INS mode the RIO cannot really edit the wind, it is automatic (and hence the bomb fall line is calculated according to the wind setting of the INS of the layer you are in). In IMU/AM and AHRS/AM, means backup navigation, he can alter the wind setting, but those modes are not meant for A/G really.

Another thing Supergrover pointed out is your starting altitude - which I did not consider. Assuming it is airstart and you have 0 kts at 6600 feet, and most starting altitudes are around that altitude, your INS calculated wind will be close to 0, too. So this will cause a huge displacement of course. (If this is the case, starting altitude and wind settings are chosen unluckily. In general it is preferable to drop laser guided muntions in high wind scenarios.)

Lastly there is a chance that your INS is broken (say if you pulled too hard or damaged it otherwise).
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Last edited by IronMike; 07-18-2019 at 11:16 AM.
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Old 07-18-2019, 08:10 PM   #3
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Hmm, very interesting indeed!

I knew that the wind would affect the bomb fall line, but thought there might be a way to set it manually adjusting for wind.

Also, played the mission a few times with the same results, always taking off from the Carrier, and I started to wonder if that may have had anything to do with it.

I think you're right though, considering that the F-14 (as amazing as she is) didn't stick around long enough for JDAM's that would have been better suited to adverse weather. Laser guided it is!




Thanks for the response!
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Old 07-18-2019, 09:26 PM   #4
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Quote:
Originally Posted by Adrian858 View Post
Hmm, very interesting indeed!

I knew that the wind would affect the bomb fall line, but thought there might be a way to set it manually adjusting for wind.

Also, played the mission a few times with the same results, always taking off from the Carrier, and I started to wonder if that may have had anything to do with it.

I think you're right though, considering that the F-14 (as amazing as she is) didn't stick around long enough for JDAM's that would have been better suited to adverse weather. Laser guided it is!




Thanks for the response!

My pleasure. Could you do me a favour though, please? Could you try airstart in the mission and see if you get the same results? Thank you.
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Old 07-19-2019, 12:48 AM   #5
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Alright, gave it a go with airstart. Surprisingly more accurate results compared to taking off from the Carrier, then flying over to the Objective... The bomb fall line shifted minimally on run ins. I also noticed that the INS was far more accurate.

I previously noticed that MK-20's were still fairly accurate despite the Mk-20's before I tested the mission in an airstarted F-14B, not sure if that matters much, but forgot to include it in the OP.

When taking off from the Carrier, letting Jester do all the necessary starting in the back until he's ready to taxi, then flying 86nm to target, I found halfway there, without pulling any hard G's, that Waypoint 1 would show 10nm away or so when I'm flying right over it. The bombs were missing as posted originally, except the MK-20's which were almost spot on.

When airstarting at 10,000ft, INS accurately showed that I was flying over WP1, and the bomb line actually seemed to be adjusting better, allowing me to hit targets with decent precision. Felt like the bomb line was trying stay centered, attempting to match the wind when I started to drop bombs below 6,000ft where it's windy. Then I tried pulling some hard G's on a few runs with no real change. INS and bombs dropping still seemed sufficient.

In comparing the two, the INS seemed to degrade a bit faster when cold started on the Carrier, then flying 86nm to target at around 12,000ft. It's as if the bomb line hugged the HUD opposite of the wind direction.

Air start above 10,000ft then descending into the wind seemed to impact the INS, and bomb line, but nowhere near from when I launched from the boat.


If you'd like, I can send you the Mission to test out, maybe you'll have different results?

Last edited by Adrian858; 07-19-2019 at 01:02 AM.
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Old 07-19-2019, 01:12 AM   #6
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Quote:
Originally Posted by Adrian858 View Post
Alright, gave it a go with airstart. Surprisingly more accurate results compared to taking off from the Carrier, then flying over to the Objective... The bomb fall line shifted minimally on run ins. I also noticed that the INS was far more accurate.

I previously noticed that MK-20's were still fairly accurate despite the Mk-20's before I tested the mission in an airstarted F-14B, not sure if that matters much, but forgot to include it in the OP.

When taking off from the Carrier, letting Jester do all the necessary starting in the back until he's ready to taxi, then flying 86nm to target, I found halfway there, without pulling any hard G's, that Waypoint 1 would show 10nm away or so when I'm flying right over it. The bombs were missing as posted originally, except the MK-20's which were almost spot on.

When airstarting at 10,000ft, INS accurately showed that I was flying over WP1, and the bomb line actually seemed to be adjusting better, allowing me to hit targets with decent precision. Felt like the bomb line was trying stay centered, attempting to match the wind when I started to drop bombs below 6,000ft where it's windy. Then I tried pulling some hard G's on a few runs with no real change. INS and bombs dropping still seemed sufficient.

In comparing the two, the INS seemed to degrade a bit faster when cold started on the Carrier, then flying 86nm to target at around 12,000ft. It's as if the bomb line hugged the HUD opposite of the wind direction.

Air start above 10,000ft then descending into the wind seemed to impact the INS, and bomb line, but nowhere near from when I launched from the boat.


If you'd like, I can send you the Mission to test out, maybe you'll have different results?

Yes please, having the mission would be great. I'll show you this little vid I made with different wind setting with airstart, as you can see the bombs are all spot on. (for some reason the sound is off every time I bomb the EWR, but release was always pipper on target). As you can see, with a functioning INS, no matter the wind, the bombs hit very accurately every time.

It thus has me thinking that maybe something might be related to carrier startup. Which is what I am testing tonight. Would you do me another favour and try a third variant on your side, please? Coul you hotspawn on the carrier, please, and see if you get different results? Thank you for all your input, it is really helpful!

As for the Mk-20s, that is unfortunately ED side, they have been off for a while, both in accuracy a bit and in strength, too.


(again mind you when I edited it quickly the sound got pulled fwd for some reason, which is why it looks as if I drop infront of the EWRs, the store release button was pressed with pipper on target)
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Old 07-19-2019, 02:02 AM   #7
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Yeah, that looks to be about the same results I was having when I airstarted.



That actually just jogged my memory too. I've made / played a few missions in the past (more than a month ago) where wind was also a factor, but manageable. It was only this last update where I noticed it as I incorporated more wind than I usually do.

I'll pop in to DCS and take a look at a Hoststart from the boat, the mission I'm currently on has been attached.
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File Type: miz Operation Winter Harvest TEST.miz (71.3 KB, 3 views)
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Old 07-19-2019, 03:56 AM   #8
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Quote:
Originally Posted by Adrian858 View Post
Yeah, that looks to be about the same results I was having when I airstarted.



That actually just jogged my memory too. I've made / played a few missions in the past (more than a month ago) where wind was also a factor, but manageable. It was only this last update where I noticed it as I incorporated more wind than I usually do.

I'll pop in to DCS and take a look at a Hoststart from the boat, the mission I'm currently on has been attached.



Thank you. I think I was able to narrow it down further, imo it is related to stored heading align (which you also use in your mission - hence you'd get the same bad results both from ground and carrier imo). If you do a normal cold start with a CAINS alignment or GND align, everything should be ok. You can observe how with AHS in the HSD the wind indication does not match the set wind layers in the mission. With a normal alignment however it does. Thank you again for your input, I've tracked it as a bug now and hopefully we can fix it soon.


PS: Moved thread to bug section.
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Old 07-19-2019, 04:10 AM   #9
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No problem, and here I was thinking I'm all of the sudden bad at bombing in a 12nm wind!

I just finished testing it from Hot Start on the Carrier, same results and worked as intended, glad I could help though!
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