cannot reproduce and missing track file Why are my bombs falling short or behind the target?

[Silvera]

Hello everyone,

I apologize if this has been asked before but i couldn't find something similar to define my issue.

I am still learning the viper so please excuse my ignorance if i am doing something wrong, i have tried to read the manual as much as i could. I still cannot find what might be wrong.

Using CBU 97 or a similar loadout and i get the coordinates for attack. I just put my TGP on target. Bombs are ready and i release them on time. Then i see that bombs are ALWAYS falling short or behind that target. Most of the time behind target to the north and no hit unfortunately. 

At first i thought it is BA, so i set it lower to 1000 or 500ft. I got closer to the target somehow but still miss! (Could someone explain depending on what we are setting this BA? i can guess that if it's higher the bomb shells will spreat out to a wider area? i realized sometimes they don't even explode if i set it to 500 or lower.)

My second guess: WIND. I am checking it but there's no wind at all so they shouldn't be dragged by the wind. Then i tried something else and i slew my TGP before the target like 400-500ft to the south (considering i'm flying north) and then i hit the target. How is this possible when there's no wind at all? What do you think i am doing wrong?

I am going to reproduce it and upload a track as soon as possible but i thought someone could enlighten me.

 

Thanks!

Edited July 29, 2022 by Silvera

[RuskyV]

I’m going to take punt and ask if you have the barometric altitude set correctly, there is a switch on the standby altitude meter that should be switched to ELEC. this may not be the solution and in part it’s a question as well.

I ask this as i sometimes see this not being set correctly in some videos posted, so wonder if this is actually "a thing".

unfortunately I don’t have a solid answer 

[Silvera]

Thanks for reply RuskyV, and yes i always set it to ELEC and i make sure PNEU disappears. I also tried to release the bombs at 20000ft - 25000ft - 30000ft and the results are all the same.

[Frederf]

If you're genuinely getting a miss to the north then check by approaching from different directions. If the miss is always to north approaching from N E S W that points toba different issue than if it always short long left right.

Then compare against Mk82, CBU-87 to see if it's weapon dependent.

Then use different targeting sensors and different ground elevations. Something might be using the wrong height. For example the GM FCR doesn't do slant ranging in plain scan mode. Don't worry about elec/pneu for the round gauge tho. That just affects the round instrument.

[Fuggzy]

Try setting the bombs' Relative Release Angle from the usual default of 45 degrees to 0 degrees.  Or, leave the setting alone and actually dive bomb at 45 degrees -- see if now you hit 'em.  I think that the bombing angle setting matters quite a lot. 

[Silvera]

7 hours ago, Fuggzy said:

Try setting the bombs' Relative Release Angle from the usual default of 45 degrees to 0 degrees.  Or, leave the setting alone and actually dive bomb at 45 degrees -- see if now you hit 'em.  I think that the bombing angle setting matters quite a lot. 

Thanks for your suggestion Fuggzy, i was actually wondering if this might have an effect on why i miss. I am going to try this and report back. If i am dropping them with CCRP then it should be set to "0" as i will be flying level if i got it correct, right?

[Frederf]

10 hours ago, Fuggzy said:

Try setting the bombs' Relative Release Angle from the usual default of 45 degrees to 0 degrees.  Or, leave the setting alone and actually dive bomb at 45 degrees -- see if now you hit 'em.  I think that the bombing angle setting matters quite a lot. 

Are you talking about the REL ANG one the CNTL page? That will only change the toss anticipation cue circle.

[Silvera]

Here's my track file. Tried some different settings but mostly resulted in a miss. What do you think? There are so many variables that i cannot be sure of.

 

https://www.mediafire.com/file/aw9qkqa5xk5se1h/cbu97_miss.trk/file

[FusRoPotato]

I've been having the same problem, but only for CCRP. The only solution I've been able to come up with so far is to release with your centerline (not your VI) placed roughly 3 degrees below whatever you set the release angle at. That seems to drop them closest to the target. Otherwise, they always go over, regardless of speed, regardless of altitude, pressure, zero pitch rate, or whatever the rel angle is set to. It always lands about 50-100 feet behind.

If you're going to use dumb bombs, just use CCIP until they fix it.

[Fuggzy]

On 8/5/2022 at 7:38 AM, Frederf said:

Are you talking about the REL ANG one the CNTL page? That will only change the toss anticipation cue circle.

Hi Frederf,

Yes, that's the one.  Like OP's topic, when I think everything is right -- bombs hit short.   I started changing that to 0 at some point and it seemed I hit the targets sometimes.  But it was not real testing and I don't actually know what the hell it does.  In my practice I'm bombing pretty flat, minimal dive.  Is the release cue and toss anticipation cue the same thing, and is it having any effect or am I just riding placebo?

[Frederf]

REL ANG is just for HUD "clues" how to do the maneuver. The CCRP mechanization doesn't care about the setting; if you fly the right way the bomb releases the same no matter what.

Some clues are based on the max toss angle (45°) and some are based on the pilot entered angle (REL ANG). Circle cue and staple is 45, timer and pull up bar is REL ANG.

[void68]

I noticed exactly the same. What I did: The INS seems to get confused if you do a lot of turns and very short bomb runs. Also, use INS/AREA mode, not point track (TMS right). Then, when running in hot, fly a stable course for around 30s, just litte control inputs and it should work.

As this off-target-effect was really even worse when I do a low alt, pop up attack, also combined with a DTOS ("lob") manoeuver. So I fly a gentle course, do the pop up at around 20s from release point and climb with a very gentle pull at 20-30°, like giving the INS time to stabilize. When I run in, I also noticed that the vertical course line of the CCRP (forgot its name) was also initially way off the target (no wind!) but stabilizes the closer I got till it was perfectly over the target 5-10s before.

Just my observance.

[Coole28]

I can second what Void68 said, I would routinely have close misses with CCRP releases which turned out to be from INS/coordinate problems, but mine were caused by something different.  The two things I did that fixed this was

1.) on initial startup, making sure the plane is completely rearmed BEFORE starting the alignment process.  Rearming causes the plane to shift around, which during the alignment process causes slight errors in the INS system.  Wags mentions this in his official alignment tutorial.  
2.) The TPOD video feed by itself doesn’t give perfect coordinates, its more of an approximate location.  In order to get precise coordinates (and as such, a precise CCRP solution), you have to briefly shine the laser on the target to get proper ranging information.  Through mathematical magic the plane uses the ranging information provided by the laser and compares this to the INS/GPS coordinate of your own plane and the slant angle of the plane/TPOD to calculate the precise coordinate of the target.  You can visual confirm this is working as the coordinates displayed on the TPOD screen change after you briefly shine the laser.

Both of these steps are includes in the F-16 tutorials so in theory you should already be doing this, in which case all my typing was for naught.  But if you are a dumb*** like myself who relied entirely on prior experience flying the A-10 and F/A-18 rather than actual tutorials to operate the F-16, this might be your issue.

[Fuggzy]

I've been doing bombing practice and retract everything I said about REL ANG - had nothing to do with it, and I still dropped some measure of short every time.  What @void68 and @Coole28 just said here works. On my bombing test mission I was always re-arming after INS Align had started, by my own dumb checklist.  Correcting that got my bombs a whole lot closer right away.  But wow... lasing the target with the TGP early on in the run to help it get accurate range REALLY helps drop the bombs more accurately.  Much gratitude.

[Silvera]

Thanks for the answer Fuggzy i am definitely trying that! Can anyone also enlighten me about how to use BA appropriately? Depending on what i should set it? Sometimes 500ft works perfect and bombs hit the target with explosions, sometimes there's no explotion at all and bombs go dumb. Is this somehow related to Radar Alt? How can i know if it is set correctly? I know it affects spread area but why in some missions it works and for other it does not?

Edited August 30, 2022 by Silvera

[Moonshine]

not the answer to your last question but since the update, all CBU 97 fall short, using CCIP and CCRP. with other dumb bombs it seems to be fine.

 

[Silvera]

1 hour ago, Moonshine said:

not the answer to your last question but since the update, all CBU 97 fall short, using CCIP and CCRP. with other dumb bombs it seems to be fine.

 

Thanks for this!

Edited August 30, 2022 by Silvera

[Coole28]

2 hours ago, Silvera said:

Thanks for the answer Fuggzy i am definitely trying that! Can anyone also enlighten me about how to use BA appropriately? Depending on what i should set it? Sometimes 500ft works perfect and bombs hit the target with explosions, sometimes there's no explotion at all and bombs go dumb. Is this somehow related to Radar Alt? How can i know if it is set correctly? I know it affects spread area but why in some missions it works and for other it does not?

 

It depends on the vertical velocity of the bomb.  If the bomb is descending at too high of a speed at the time it reaches the set BA, all the dispersed bomblets will impact the ground before they have time to release their parachutes.  A higher BA will give the parachutes more time to deploy.  500 ft is fine for low level CCRP bombing, but if you do dive CCIP bombing or high level CCRP there is a good chance your bomb will be too fast by the time it releases its bomblets and they will dud into the ground.  I usually set the BA at 1,200 ft., I find it it be the minimum height that CCIP consistently works.  Default BA used to be 1,500 or so until a couple months ago, I don’t know why it got switched to a lower altitude.

[Silvera]

Beautiful explanation thanks a lot! I will try 1200 as default. I also noticed using 1200 was accurate. I was using 500 because of that bombs falling short issue. When set to 500ft my bombs were not drifted away from target and was getting better results.

[Moonshine]

I think it is back to 1500 again as the default BA (at least for the 97) not used the 87 since the patch

[silverdevil]

3 hours ago, Moonshine said:

I think it is back to 1500 again as the default BA (at least for the 97) not used the 87 since the patch

this is what i have been using. i did the a-10 for a while and i always used 1200 for cbu97s. go figure.

[Fuggzy]

I don't know what is going on, I can't hit anything with any type of bomb... they all fall short.

I've included a track file where I setup 5 missile launchers clustered together on a road.  In this track file, I'm starting airborne with 4 MK84 LD bombs, switching to AG, selecting Pair drop and ripple 2, and a little distance apart.  In this case I'm just trying for the simplest CCIP dummy drop, and my bombs fall short.  This happens every time for me now, in CCIP or CCRP, with any type of bomb.  Either I am doing something fundamentally boneheaded wrong, or it's like the computer always sees the ground lower than it really is in its calculations and it drops too soon.   I try with different run-in speeds, altitudes, it sure acts like the AGL is off in the weapon system.  On a hot airborne start, is INS jacked up?  Super frustrated, if anybody wouldn't mind to watch the track file and tell me what the crap I'm doing wrong I would send loving vibes.     

short_dumbombs.trk

[ASAP]

Try setting impact angle to 90. The steeper the bomb come in the less elevation errors will impact it. If all your misses are short/long and not left/right with a shallow impact angle it sounds like there is an elevation issue (I.e. the bomb/jet thinks it’s trying impact above or below the target so it misses). If the bomb is coming straight down that won’t matter