Weapons depression Settings ??

[IvanK]

Just had a look through the Depression tables published, The huge depression values looked way over the top to me so went to calculate some.

I took the example given in the IFE Manual for 45 deg Dive MK82 Slick, 5000' release Alt , 400KTas .. it calls for depression of 850mills !!

(The sight allows up to 999mills to be selected .....a crazy amount imo !)

So Took the worked example in the MB339A Weapons manual (which includes wind corrections) and re worked it to the same values in the India foxtrot Echo manual. The red numbers mine.  The ballistic figures for the MK82 taken from standard ballistic tables, the remainder from the 339A Weapons manual. The resultant Nil wind depression is just 140mills

So something is not right in the depression settings provided in the manual. By inspection they all look way to excessive to me. The Level release at 500' has the same depression as 45 Deg release at 5000' ??

 

Edited December 20, 2022 by IvanK

[IvanK]

Trying to resolve this (to me) huge disparity in depression settings real world calculation to quoted value in game documentation; I went into FMB and tested some calculations I made for level bombing using my settings. The result weapon impacts nowhere near the the pipper. So checked actual bomb range achieved (used a runway to get accurate length).. bomb range was very very close to the book numbers so ballistics are good.

So what is the issue ? I wondered if there was something wrong with the Mill values used in the depression setting and or an issue with the mill dimension of the reticle. Using the references in the manual conducted a test to see what gives.

Sitting on the Runway with Zero depression (Left image) the Top of the pipper is tangential to the red Runway lights. I then wound in the depression to set the top of the vertical bar to be tangential to the red runway lights (right image). This required in a game a depression setting of 70mills.

I then went to the reticle dimension diagram in the manual to measure the same angular value in the sight the answer was 9 mills ! .... a difference of 61mills. So either the depression relationship in the FIE MB339 is in error or the reticle sizes are in error. More testing to come to try and figure out whats what ... I suspect its the depression value scaling.

[IvanK]

And if we use the Mills diagram we can see that only about 100mills worth of depression should be usable.... which then begs the question is the Zero mill datum correct or the sight reticle size in mills correct ?

Next checking Reticle Mills versus Known object size. Placed an IL76 with wingspan of 50.5m a distance of 1000m away from MB339. So Reticle should subtend wingspan. Results below.

What you see in the sight .. something does not look right here.

My head now officially hurts so off to fly and enjoy the wonderful thing the MB339 is .

Edited December 20, 2022 by IvanK

[IvanK]

So in dealing with the displayed reticle size. I took the IL76 image and the  Reticle sizes stated in the MB339 manual. Then using the image worked out what 50mills in Pixels should subtend (between the Yellow arrows) that came to 276pixels.  I then compared the FIE representation of 50 mills (White arrows) that came to 426 pixels.

I conclude that he IFE MB339 Reticle is 1.54 times to big.

The second error is that the Mills depression scaling is also wrong. This is a little harder to determine but I think its in the order of 6 times to big. i.e. a supposed current entry of 850 mills should more reasonably be 140mills to provide a realistic real world sight line.

Tied in with all of this is the exact Zero Sight Line position in the combining glass AND its relationship to the 3D model  and the flight model AOA to IAS relationship.

A complex problem, but at present these errors prevent accurate/realistic weapons delivery calculation and or sight setting.

Edited December 23, 2022 by IvanK

[Torbernite]

2022/12/24 AM7点28分，IvanK说：

So in dealing with the displayed reticle size. I took the IL76 image and the  Reticle sizes stated in the MB339 manual. Then using the image worked out what 50mills in Pixels should subtend (between the Yellow arrows) that came to 276pixels.  I then compared the FIE representation of 50 mills (White arrows) that came to 426 pixels.

I conclude that he IFE MB339 Reticle is 1.54 times to big.

The second error is that the Mills depression scaling is also wrong. This is a little harder to determine but I think its in the order of 6 times to big. i.e. a supposed current entry of 850 mills should more reasonably be 140mills to provide a realistic real world sight line.

Tied in with all of this is the exact Zero Sight Line position in the combining glass AND its relationship to the 3D model  and the flight model AOA to IAS relationship.

A complex problem, but at present these errors prevent accurate/realistic weapons delivery calculation and or sight setting.

 

I checked with a 14m long Su-25T from 185m away. It should be about 75.5 mil or around 1.5 times of the sight length, and it is with C-101 sight of same size, but it fills the exact length in MB-339. Correspond with your result.

However, it seems that most of us don't think it's a serious problem.

[Lookiss]

What works for me is 800 mils, 45 deg dive, 2000-3000ft release. I tried doing the same at 140-150 and even 200,  but I was unable to get the same results.

No idea if it's real-world accurate, but it does work for me.

[TheSkipjack95]

@IvanK I also noticed that wildly differing depression settings (off-hand, 70 and 200) place the pipper pretty much in the same spot, which obviously can't be.

[IvanK]

On 4/21/2023 at 1:58 AM, Lookiss said:

What works for me is 800 mils, 45 deg dive, 2000-3000ft release. I tried doing the same at 140-150 and even 200,  but I was unable to get the same results.

No idea if it's real-world accurate, but it does work for me.

800 mills in a 45 deg dive is nowhere near Real world .... for any aeroplane !!!

A worked example in the 339 Weapons delivery manual for a MK82 40 deg Dive 3000' release at 300kts provides a total depression of 183mills

Edited June 5, 2023 by IvanK

[Lookiss]

18 hours ago, IvanK said:

800 mills in a 45 deg dive is nowhere near Real world .... for any aeroplane !!!

A worked example in the 339 Weapons delivery manual for a MK82 40 deg Dive 3000' release at 300kts provides a total depression of 183mills

 

Good to know, thanks.  So something is off then :-)

[Gianky]

On 4/9/2023 at 4:57 AM, Torbernite said:

However, it seems that most of us don't think it's a serious problem.

I didn't say anything because I don't have the real world -34 and I didn't have anything to add to what IvanK already wrote, but I do care and I'd like to see this and other bugs (chiefly, the randomly occurring damage/explosion during taxi, due to inexplicable accelerations on the airframe). And, by now, I do think this module has been put aside by the devs: and I do hope they'll prove me wrong, very soon hopefully.

[buur]

Am 19.12.2022 um 03:20 schrieb IvanK:

Just had a look through the Depression tables published, The huge depression values looked way over the top to me so went to calculate some.

I took the example given in the IFE Manual for 45 deg Dive MK82 Slick, 5000' release Alt , 400KTas .. it calls for depression of 850mills !!

(The sight allows up to 999mills to be selected .....a crazy amount imo !)

So Took the worked example in the MB339A Weapons manual (which includes wind corrections) and re worked it to the same values in the India foxtrot Echo manual. The red numbers mine.  The ballistic figures for the MK82 taken from standard ballistic tables, the remainder from the 339A Weapons manual. The resultant Nil wind depression is just 140mills

So something is not right in the depression settings provided in the manual. By inspection they all look way to excessive to me. The Level release at 500' has the same depression as 45 Deg release at 5000' ??

 

 

Hi, thanks for this valid report. Do you know where I can find the 339A Weapons manual?

[PawlaczGMD]

I don't have the module, but the order of magnitude of these depression values is completely unreasonable.

FYI 850 milliradians is almost 50 degrees. This depression setting would be well outside the HUD, somewhere inside the stick. Hard to imagine any sight would be able to display more than 200 mills. 

Maybe the sight scale has hidden decimals, so 999=99.9 mils? 

[BJ55]

You're right regard max mils :

 

And no, there are no decimals (this is not a Hensoldt ZF 6-24x56).

[6S.Duke]

Hi Guys, we have this in our to do list and will be Fixed shortly.
We are now focused to release the Flight Director, after this we will work on this issue.
Thanks for your patience.

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[6S.Duke]

Gunsight depression settings fixed internally. It will be available with the next patch

[BJ55]

I've noticed that after the last update 9 clicks are needed in the hundreds rotary to go from 0 to 1 and the reticle moves at every click, also with more than 3 clicks+9+9 the reticle goes out of sight.

As you can see from the image with 0 click+9+9 (99 mils) the reticle is lower than with 9 click+0+0 (100 mils).

[6S.Duke]

I've noticed that after the last update 9 clicks are needed in the hundreds rotary to go from 0 to 1 and the reticle moves at every click, also with more than 3 clicks+9+9 the reticle goes out of sight.

As you can see from the image with 0 click+9+9 (99 mils) the reticle is lower than with 9 click+0+0 (100 mils).

Thanks for reporting, we will check and fix to the next update.


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[thebeloved]

On 11/4/2024 at 8:44 PM, 6S.Duke said:

Thanks for reporting, we will check and fix to the next update.


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Could you also check the size of the reticle please? It looks way smaller than it was in the previous version. Thanks!

[6S.Duke]

Could you also check the size of the reticle please? It looks way smaller than it was in the previous version. Thanks!

Now the size is correct as per flight manual

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[IvanK]

On 11/5/2024 at 2:44 AM, 6S.Duke said:

Thanks for reporting, we will check and fix to the next update.


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Should be 1 click per digit for each tumbler. The diff between 99mils and 100mills as illustrated is significant, its about 9 mills when there should only be a 1 mill difference.

[6S.Duke]

Should be 1 click per digit for each tumbler. The diff between 99mils and 100mills as illustrated is significant, its about 9 mills when there should only be a 1 mill difference.

Yes, definetely that was a bug. We will fix with the next update

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[IvanK]

some more info. The error between 100miils and 99mills is in the order of 13mills and in the wrong sense as well

Edited November 13, 2024 by IvanK

[IvanK]

Some depression settings calculated from the MB339 Weapon delivery manual. No allowance made for PEC or Altimeter lag as I don't know how these are modeled in DCS.

MK82LD, Fuze 4secs, 30Deg Dive Angle, 400Ktas, Rel at 3000'AGL, Wt 4300Kg

Bomb range 3874', TOF 6.79secs, Aim Off Angle 137mill, ZSL AOA 6.5Mil

Tot Depression on sight 144mills

------------------------------------------

MK82LD, Fuze 4secs, 45Deg Dive Angle, 400Ktas, Rel at 5000'AGL, Wt 4300Kg

Bomb range 3823', TOF 8.31secs, Aim Off Angle 134mill, ZSL AOA 6Mil

Tot Depression on sight 140mills

------------------------------------------

MK82HD Snakeye, Fuze 4secs, Level Release, 400Ktas, Rel at 250'AGL, Wt 4300Kg

Bomb range 2050', TOF 4.51secs, Aim Off Angle 125mill, ZSL AOA 9Mil

Tot Depression on sight 134mills

------------------------------------------

MK82HD Snakeye, Fuze 4secs, 10Deg Dive Angle, 400Ktas, Rel at 450'AGL, Wt 4300Kg

Bomb range 2005', TOF 4.8secs, Aim Off Angle 119mill, ZSL AOA 8Mil

Tot Depression on sight 127mills

------------------------------------------

Seems we are limited to MK904/905 fuses with minimum 4Sec setting. A dedicated HD fuse with settings down to 2.5secs or so is needed for in your face Snakeye delivery's.

Edited November 13, 2024 by IvanK

[Bashibazouk]

I'm getting the same issue where the left most tumbler is not displaying the numbers as I'd expect. The tutorial for rockets requires 800 mils depression, if I click 8 times, the tutorial moves on (I assume internally it is indeed moving the pipper for 800mils). But it's barely displaying a one for the number, it's just shy as if it's actually displaying a tenth of a movement of the tumbler for each actual step. I hope this explanation isn't too confusing, I can use the sight as long as I count up to the number I need for each click. 

I don't know anything about the accuracy, I'm not experienced enough with the plane yet.

[6S.Duke]

I'm getting the same issue where the left most tumbler is not displaying the numbers as I'd expect. The tutorial for rockets requires 800 mils depression, if I click 8 times, the tutorial moves on (I assume internally it is indeed moving the pipper for 800mils). But it's barely displaying a one for the number, it's just shy as if it's actually displaying a tenth of a movement of the tumbler for each actual step. I hope this explanation isn't too confusing, I can use the sight as long as I count up to the number I need for each click. 
I don't know anything about the accuracy, I'm not experienced enough with the plane yet.

Tutorials are based to the old settings.
We are working to fix them.
We will release the corrected mission with the first patch of 2025.

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