Mk 82 and Snakeye depression tables

Hi everyone,

Due to the rather incomplete data provided to us by Belsimtek, I looked through my archives and found this gem.

Attached is an 83-page pdf of depression tables from the Australian Mirage IIIO Weapons Delivery manual for the Mk 82 and Mk 82 Snakeye. They're hopefully accurate for the F-5 as well, but I've had no time to test it unfortunately.

For anyone that wants the Mirage IIIO flight, performance and weapons delivery manuals, I'll upload them

https://drive.google.com/file/d/0B7VYEhWAnBfbMnFib2UyUHZ6VDA/view

Peace and love and happy bombing xx

Time to bust out Tacview...

Hi everyone,

Due to the rather incomplete data provided to us by Belsimtek, I looked through my archives and found this gem.

Attached is an 83-page pdf of depression tables from the Australian Mirage IIIO Weapons Delivery manual for the Mk 82 and Mk 82 Snakeye. They're hopefully accurate for the F-5 as well, but I've had no time to test it unfortunately.

For anyone that wants the Mirage IIIO flight, performance and weapons delivery manuals, I'll upload them

 

https://drive.google.com/file/d/0B7VYEhWAnBfbMnFib2UyUHZ6VDA/view

 

Peace and love and happy bombing xx

They wont be exact as ejection rack velocities from the PM3 and RPK10 on the Mirage will differ from those on the F5E. F5E Ballistic tables are floating around the net as an F5E/F weapon delivery manual

After doing some experimenting with 300ft level bombing with Snakeyes, they appear to be quite accurate. Keeping in mind slight adjustments to your release point IRT slight errors in your speed and altitude, it's certainly pretty good. With practice, you can become fairly accurate

I have an F5E/F Weapons manual happy to upload to the "User files" section of the DCS site if I could figure out how to do it !

Edit

Figured out trying now to upload it. .... just says sending request but not sure if its actually going up ... not much seems to happen !

Is it the same: http://www.digitalcombatsimulator.com/en/files/1946809/ ?

They wont be exact as ejection rack velocities from the PM3 and RPK10 on the Mirage will differ from those on the F5E. F5E Ballistic tables are floating around the net as an F5E/F weapon delivery manual

Tried usin that, but they seem to be completely off. At least some of them. For example one level delivery profile listed the depression at 17 mills while the results were closer to 90 mills!!! I don't know what causes such a large difference.

17 mils in level bombing ??? Impossible, I think you took the "impact angle" instead of "sight depression from flight path mils" column.

But anyway after several hours of reading and tests it seems there some issues... at least with Mk-82LDGP (I didn't have tested other bombs yet).

According to this manual ("Aircrew Nonnuclear Weapons Delivery Manual" T.O. 1F-5E-34-1-1 for the F-5E") and his "mission planning form" (start reading from p.264):

Sight depression setting = Sight Depression from Flight Path + Rangewind Correction + ZSL Angle of Attack

_Sight Depression from Flight Path: From bomb tables.

_Rangewind Correction: I did my tests in no wind condition so I don't use this value actually.

_ZSL (zero sight line) Angle of Attack: From angle of attack chart. ZSL AoA = FRL AoA (A+B+C) - 35 Mils ; I don't use Flaps so "C"=0.

I did my tests with 2x Mk82, a CL external fuel tank of 275Gal. and a Gross WT of 16000lbs at my airstart/attack position (obviously).

=> Dive Angle 30°; Release Altitude 2000ft; Release Speed 440Kt; I start my dive from 6000ft 350kt as per Belsimtek manual.

_With Weapon Delivery Manual, I found a sight depression of 102 mils = Bombs fall far too long...

_With Belsimtek Manual, it says 79 mils = Bombs fall too long...

To have the good parameters in dive is not really easy so I tested in level bombing too:

=> Leveled flight; Release Altitude 500ft; Release Speed 440Kt; same payload.

_With Weapon Delivery Manual, I found a sight depression of 144 mils = Bombs fall far too long... (Even with only bomb table and no ZSL AoA it give 131 mils and bombs fall too far too).

So:

_ I am a bad pilot who can't respect parameters (but I don't think so) ?

_ or I am wrong with tables/charts calculations ?

_ or there is an issue with Belsimtek F-5E ?

_ or there is an issue with Eagle Dynamics Mk82 flight model ?

_ or a mix of the above ?

:book: :joystick: :book: :joystick:

The only bombing I've tried is the training mission, and I got a direct hit first time by following the instructions. Not sure if that'll help!

Is it the same: http://www.digitalcombatsimulator.com/en/files/1946809/ ?

Yep ok no need to upload :)

I did some quick and dirty Calcs from the WEAP manual for a 45 Degree MK82LD release 500KTAS/7000ft release which is a pretty standard attack to keep out of the Small arms envelope (Vietnam era). Allowing for AOA (Flaps Auto) etc came up with 126Mills. Though Bomb impacts were reasonable all were over the top.

For this type of delivery a Bomb inside 100ft of the aim point is quite a reasonable bomb.

For Low Angle HD deliveries depression is going to be a lot more.

I guess it just depends on how accurate the Ballistics of the bombs in DCS are to Real world ... and of course FM AOA etc.

The delivery profiles suggested in the manual (20°/1500 ft and 30°/2000 ft) are unsafe. Both bottom out at about 700 ft over the target, in the middle of the frag envelope of your bombs. You get away with it in DCS only because it does such a bad job with fragmentation damage. Still I would suggest to add more realistic profiles in the manual.

If you're dropping to 700ft I don't think you're pulling 4Gs like you're supposed to. Just going from memory but I think I was bottoming out at about 1000' plus the horizontal range from bomb impact.

Sent from my iPhone using Tapatalk

I have to correct myself. After checking the real Weapons Manual, both profiles in the DCS manual are actual safe for the Mk-82 (but not for the Mk-83/84). The reason I have an unsafe pullout altitude seems to be exessive altimeter lag.

Release at 1460ft in a 20 dive, slightly fast with 426 kts.

Compare the altimeter in the cockpit at 1750 ft with a lag of 300 ft. If you go according to the altimeter, you will drop 300 ft low.

According to the manual, lag should only be 50 ft.

Minimum altitude at pullout is 930 ft, corresponding to 500 ft altitude lost, which is in line with the weapons manual. Though the weapons manual specifies a 4G pull within 2 seconds, I did a 5.5G pull (might be due to the higher speed).

Position at bomb impact.

Been out there Practicing 45Deg High Angle Low drag all morning. Getting consistent hits with 100mils dep. This for 45 Deg 500TAS/7000ft Release. Roll in 14000ft 300Kias. Calcs from the weap manual shown below give dep of 141mils

Off to try again.

Err yes dumb error on my part will aim for slower release IAS (450) to achieve 500TAS at 7000ft

Ok went back using 450KCAS as the release Air speed (to achieve 500KTAS) also decided to drop right on 7000ft ignoring the calculated Altimeter Lag (figuring maybe the Sim doesn't really have any) Still using 141mills.

Much better bombs. Used the old airstrip on the coast just north of Batumi using the runway intersection as the aimpoint to get some yardstick.

Got consistent bombs 1 runway width over the top. So roughly 50feet 12 O'clock bombs..... pretty good for 45deg 7000ft release. also pre trimmed nose heavy before the roll in. If I didnt do this the trim couldn't keep up with the change required going down the dive requiring forward stick to control the reticle drift up to the target. therefore in a slight bunt .... which would also tend to throw the bombs over the top.

So WEAP manual ballistic tables seem ok to use in the SIM. Though I don't think Altimeter lag needs to be allowed for.

Did the numbers on 10 Deg High Drag pass Again pretty much all bombs hit around 100ft long. No allowance for Altimeter lag

Same with 20Deg LD 2500ft release. Using calculated depression values all bombs hit around 100ft long. No allowance for altimeter lag.

Taking around 20mills off the calculated figure results in consistently good bombs. Interestingly that is close to the AOA correction in the calculations.

Did the numbers on 10 Deg High Drag pass Again pretty much all bombs hit around 100ft long. No allowance for Altimeter lag

 

Same with 20Deg LD 2500ft release. Using calculated depression values all bombs hit around 100ft long. No allowance for altimeter lag.

 

Taking around 20mills off the calculated figure results in consistently good bombs. Interestingly that is close to the AOA correction in the calculations.

IvanK, I assume you mean you dropped on hitting the release alt on the altimeter. May I ask you to compare this to your actual altitude according to the external view status bar and report back?

IvanK, I assume you mean you dropped on hitting the release alt on the altimeter. May I ask you to compare this to your actual altitude according to the external view status bar and report back?

Yes MBOT on the cockpit Altimeter. Will record a Track to see what that is on the status bar.

Noodle Ref Pilot errors. Thanks for the table ... Yep I am sure there are some in there (Been 30 years since I last dropped a manual bomb .... but it floods back :). Anyway I think I am getting pretty close to the planned release parameters I planned on. Bombs are all going pretty much in the same hole around 100ft over the top. if they were all over the place I would think it was me.

Mbot Cockpit Altimeter 7000ft. Status Bar in external view 6585ft. So a diff of 415ft. Looking at Noodles error chart that would imply a Bomb around 100ft long.

So in a 45 Deg dive it would seem the Alt lag is around 400ft. Weap manual gives 110ft Altimeter lag. That confirms your finding and also in my eye explains the impact points.

Off to try releasing at 7400ft Alt :)

Mbot Cockpit Altimeter 7000ft. Status Bar in external view 6585ft. So a diff of 415ft. Looking at Noodles error chart that would imply a Bomb around 100ft long.

 

So in a 45 Deg dive it would seem the Alt lag is around 400ft. Weap manual gives 110ft Altimeter lag. That confirms your finding and also in my eye explains the impact points.

 

Off to try releasing at 7400ft Alt :)

Thanks for the confirmation. This evening I will make a documented report about the altimeter lag in the forums's bug section.

What about the CBUs? Do they follow different release parameters? I dropped them like the Mk 82s but the warheads won't engage armored targets.

I dropped them like the Mk 82s but the warheads won't engage armored targets.

"The CBU-52В/В is loaded with 220 BLU-61А/B anti-material, anti-personnel submunitions."

Not suited for medium/heavy armored targets. What kind of armored target do you used ?

What kind of armored target do you used ?

Some BTRs and some Trucks but the CBU didn't engage any of them. I looked back and couldn't see the dispersion of the submunitions.

CBU-52 need 4 seconds after release to open and launch submunitions. If you release your CBU at too low altitude they may never open.

And CBU-52 submunitions dispertion in game is actualy very small... I don't know for real one.