investigating GBU-24 still drops short and TTI is still off

[Furiz]

Altho it is labeled as fixed in the latest changelog GBU-24 timer is off. And it still drops way short.

 

Shouldn't it correct for sooner or later release since it has large drop zone.

It acts like a dumb bomb atm, if you drop a dumb bomb before or after the release cue hits the FPM it will fall short or long, same with GBU24 which has different drop envelope.

 

gbu24 TTI timer .trk

Edited September 21, 2022 by Furiz

[Lord Vader]

Hello @Furiz

I've tested your track and noticed you were within proper altitude and speed to release the bomb. 

However, I noticed you didn't touch the release angle. I assumed control of your track and set the release angle to 15º and was able to hit the target. 

At 18000ft you are pressing to release at max range with your setup of 8nm in the cue ring. At 30º angle the bomb is gliding to that path all the time and only at 12 seconds to impact does the bomb track, and it's too late. 

With my 15º the bomb tracks and glides to target. I also prefer a 15/17 seconds laser to allow a slightly earlier guidance.

What do you think? Let me know. 

[Furiz]

Hey @Lord Vader

I repeated my test and did a few more, I figured out that if I laser the target 20ish seconds before impact it will fly to it, but my concern is about the CCRP release it self, with NO Laser, it drops way short, I assume it is because of the large DLZ, while dumb bombs and gbu12 do not have DLZ and without laser designation, they hit nearby the target but GBU24 hits way short, about a mile I'd say,

I think that GBU24 should correct for that even with no Laser designating, I am not saying it should hit spot on, as it does with help of the laser designation, but it should hit somewhere near the target as well. CCRP is just another release method, altho it is not as accurate as laser guided or GPS or even CCIP while diving, it shouldn't miss for a whole mile.

I assume its cause of the large DLZ that we have on our HUD which enables us to drop sooner or later, but the game still looks at gbu24 as a dumb bomb which just drops to the target and that's it. While GBU24 can correct for release inside the DLZ, the one in DCS can't do that.

 

>>I'm talking here about CCRP release with NO LASER designating, just to be clear.<<

 

I released GBU24 inside the DLZ with no laser designation:

30 angle - gbu24 hitting way off - CCRP - NO LASER .trk

0 angle - gbu24 hitting way off- 0 angle - CCRP - NO LASER .trk

15 angle - gbu24 hitting way off- 15 angle - CCRP - NO LASER .trk

 

Now GBU12 with no laser in CCRP:

gbu12 no release under 300kts.trk

 

Dumb bomb CCRP:

dumbbomb - CCRP - NO LASER .trk

 

Made sure I'm lined up as best as I could,

and as you can see GBU24 is dropping short way too much even when dropped inside the DLZ. While GBU12 and dumb bomb drop near the target.

 

P.S. Thanks for being polite and patient with us! 

 

 

[BIGNEWY]

Hi, 

they are designed to be guided by laser to target not free fall. 

[falcon_120]

Couldn't it be that ccrp for gbu 24 (if no laser is detected) is designed to enter the laser basket, not hit the target?

It makes sense to me that way, so the bomb during the last part of the path If no laser is detected, is aimed to the center of the basket which should be a bit before the target itself... meaning that if no laser is detected it will hit a bit short

Don't know if I made myself clear...

Enviado desde mi ELE-L29 mediante Tapatalk

[Furiz]

2 hours ago, BIGNEWY said:

Hi, 

they are designed to be guided by laser to target not free fall. 

Hey,

 

Yea off course they are designed to be guided by laser,

I'm not saying it should hit the target spot on without guidance, but it should at least fall in the general area of the target, they are now dropping half a mile or a mile short (didn't measure the distance),

From what I can find online the GBU24 can correct for relatively large deviations from planned release parameters in the primary delivery mode.

Now again I'm not saying that it should hit the target, I'm saying that it should not drop short almost a mile away from the SPI - target.

CCRP stands for Continuously Computed Release Point so shouldn't it be computed for GBU24 to hit in the general area of the target? Without laser designation and released withing release parameters,

What do your SMEs say on this matter, does it correct or it just drops like a dumb bomb?

[Deano87]

What @BIGNEWYis saying is that the GBU-24 is designed to be laser guided continuously from release to impact. It has a totally different seeker to earlier Paveway units. Fire the laser the whole time during the bomb fall. It is not meant to be lased in the last 10-15 seconds like the more primitive PW1-2 series weapons.

[AlexCaboose]

1 hour ago, Deano87 said:

What @BIGNEWYis saying is that the GBU-24 is designed to be laser guided continuously from release to impact. It has a totally different seeker to earlier Paveway units. Fire the laser the whole time during the bomb fall. It is not meant to be lased in the last 10-15 seconds like the more primitive PW1-2 series weapons.

Adding on to this, the PW2 uses “bang-bang” guidance, which is basically a bunch of full deflections, which is probably why there is no DLZ. It’s inefficient and leads to a lot of overshooting on the way down. PW3 behaves more like a JDAM and should be continuously lased.

[Moonshine]

I think there was also something with the limited laser range, as its only about 11nm. Hence if you drop at max range in the DLC and start lazing, the end of the laser beam is somewhere floating mid air, throwing off any guidance either way

[Frederf]

PWIII if released and never guided by laser it will fly according to its autopilot having a trajectory very different than a ballistic "rock".

[Fromthedeep]

1 hour ago, Frederf said:

PWIII if released and never guided by laser it will fly according to its autopilot having a trajectory very different than a ballistic "rock".

Mode 1 above 15000 feet follows a ballistic midcourse.

 

On 9/22/2022 at 4:37 PM, AlexCaboose said:

Adding on to this, the PW2 uses “bang-bang” guidance, which is basically a bunch of full deflections, which is probably why there is no DLZ. It’s inefficient and leads to a lot of overshooting on the way down. PW3 behaves more like a JDAM and should be continuously lased.

PW2s today at least are almost always dropped at the ballistic release point. If for whatever reason, an optimal release point is desired, you can add an along track modifier based on mission planning data. There's no point in having a LAR bucket like you'd see with a weapon that can actually glide a significant way.

 

 

[tdk]

We were using GBU-24 in F-16s, and we found something weird, the bomb went straightly towards to the ground after release.

Then we tested it several times, it came out that if I release at 13k ft, it correctly glided, and if we released at 18k or like 25k, it went straightly towards to the ground. I don't know if it depends on the release altitude or something else, we just assumed the altitude to be the variable.

I was using pre mode and other settings remained default. I was not lasing during all tests, I just released it and watched its behavior, I know it won't hit the target without laser, but some behaviors were just way too strange ,you can easily saw it turning to the ground early instead of gliding.

 

1-20230119-014326.trk

Edited January 18, 2023 by tdk

[Furiz]

Paveway III can glide more than standard Paveway II, so it can be released further away from the target, but if you don't lase early it will just drop like a regular bomb, the late lase will make it go off boresight of the bombs so it won't catch it and its wasted, so you have to adjust your laser time according to the altitude and range to target,

anyway you don't have to start lasing as soon as it releases, but sooner then with paveway II. Practice with it to figure out when to lase etc.

 

btw, I know it does feel strange when falling I think thats been reported and they are still investigating.

 

Edited January 18, 2023 by Furiz

[BIGNEWY]

I'm sorry but I am not seeing any problem here, if the GBU-24 is released correctly and within parameters there is no issue. 

 

[tdk]

18小时前，BIGNEWY说：

I'm sorry but I am not seeing any problem here, if the GBU-24 is released correctly and within parameters there is no issue. 

 

According to Furiz, The issue is you need to start lasing immediately after releasing the bomb, the bomb will just turn to the ground instead of gliding further if you don't.

If it's correct as is, i.e. you need to start lasing as early as possible, then no problem.

But according to Frederf, it should fly according to its autopilot, which may mean that it should be trying to glide to get to the spi, but it doesn't behave like that in my tests, that's what confusing me.

 

 

 

Edited January 20, 2023 by tdk

[tdk]

2023/1/19 AM5点36分，Furiz说：

Paveway III can glide more than standard Paveway II, so it can be released further away from the target, but if you don't lase early it will just drop like a regular bomb, the late lase will make it go off boresight of the bombs so it won't catch it and its wasted, so you have to adjust your laser time according to the altitude and range to target,

anyway you don't have to start lasing as soon as it releases, but sooner then with paveway II. Practice with it to figure out when to lase etc.

 

btw, I know it does feel strange when falling I think thats been reported and they are still investigating.

 

 

It indeed made me feel strange. And what made it even stranger was that it sometimes glided correctly even without laser, and sometimes didn't

[BIGNEWY]

I will keep the thread investigating for now and revisit soon. 

thanks 

[WHOGX5]

6 hours ago, tdk said:

According to Furiz, The issue is you need to start lasing immediately after releasing the bomb, the bomb will just turn to the ground instead of gliding further if you don't.

If it's correct as is, i.e. you need to start lasing as early as possible, then no problem.

But according to Frederf, it should fly according to its autopilot, which may mean that it should be trying to glide to get to the spi, but it doesn't behave like that in my tests, that's what confusing me.

 

 

 

 

Frederf is completely right. The GBU-24 has an autopilot (in real life) with mid-course guidance and different modes, extending the range more than just having bigger fins would. The GBU-24 doesn't have an INS nor GPS guidance so it will not be accurate at all without laser guidance in the terminal phase, but it will be able to get close enough to capture the laser. In DCS you literally can't even drop the GBU-24 at its maximum range according to the DLZ. The target will be beyond the max range of your laser designator and therefore the GBU-24 will just fall ballistically and impact way short of the target. I was really stoked for the GBU-24 but it is literally useless compared to the GBU-10 with it's current implementation so don't even bother. You get a slight increase in maximum range in exchange for not knowing what the actual maximum range is since the DLZ seems to be correctly modeled but the bomb itself isn't.