First salvo of GBU-10 doesn't track laser

[Top Jockey]

Hello,

 

I'll post this here, as I don't know if it's me doing something wrong or a possible bug.

 

Droping GBU-10s on enemy ship (ex. Molniya or Neutrashimi), from altitudes from 25.000ft to 30.000ft, the very first bomb(s) pitches down - not tracking the laser, but the next bombs do follow it perfectly hitting the target.

 

All the Stores and TGP pages parameters are well configured, so as the second or more salvo(s) of bombs sucessfully follow the laser, and effectivelly hit the ship.

Only thing is, I always select manual mode (not Auto, CCIP, etc.)

 

The first salvo can be of 1 or 2 bombs, depending on the quantity I chose:

 

- if I chose 1 bomb salvo; only the 1st one pitches down and fail;

( 2nd, 3rd and 4th bombs will guide sucessfully to the target )

 

- if I chose 2 bomb salvo; both 2 bombs of first salvo will pitch down and fail;

( both 2 bombs of the second salvo will guide sucessfully to the target )

 

I release the 2 (or more) salvos with 2 seconds interval, and I'm already firing the laser from a few seconds before releasing the bombs, until impact on target.

 

edit

 

- release distance:  ~  12 nm to target 

- release speed:  ~  Mach 0.95

- aircraft pitch / attitude: between 0 and -5 degrees (pitch down)

Edited April 5, 2021 by Top Jockey

[Harker]

In DCS, the laser has a max effective slant range of 8 NM. If you're dropping the bomb from 12 NM away and lasing immediately, it's either seeing nothing or it's seeing a point mid-air (the laser creates a "point" at the end of the 8 NM line, if it doesn't intersect the ground). It's probably the latter, which is messing with the first bomb.

I assume that subsequent bombs are released closer and thus you're close enough for the laser to actually hit the ship.

Try again, lasing only when you're closer to the ship. You'll need to drop in a manner that will ensure it's close enough, to the target when you start lasing. I'd advice you to do the drops in AUTO or CCIP, using the pitch to space them out and leave the laser to start automatically, at 10 TTI. Hold it down yourself after, until all bombs impact.

[Top Jockey]

Thank you Harker.

 

It can very well be something like that and I hope it is.

Indeed, when I return to that mission in the Hornet after some months later, something on the back of my head reminds me : things won't work if releasing the GBUs from much longer than those 12 NM i was used to, neither from very high altitudes also (ex. 35.000 ft +)

 

The possibility you mention can also be the reason why on other instances, the bombs also started to drift left related to the target (when in close proximity of him already)... coincidentally my aircraft was also doing a small bank left turn to avoid overflying the enemy ship, and thus I was probably moving the laser 'end point' away from the target.

 

Always used the Manual release mode because it looked simpler to me and lets me release the bombs at my will, but on the other hand it doesn't give TTI info.

I will try your advices latter today, and after see how it works I'll report here.

 

Thank you for your time.

[Top Jockey]

17 hours ago, Harker said:

In DCS, the laser has a max effective slant range of 8 NM. If you're dropping the bomb from 12 NM away and lasing immediately, it's either seeing nothing or it's seeing a point mid-air (the laser creates a "point" at the end of the 8 NM line, if it doesn't intersect the ground). It's probably the latter, which is messing with the first bomb.

I assume that subsequent bombs are released closer and thus you're close enough for the laser to actually hit the ship.

Try again, lasing only when you're closer to the ship. You'll need to drop in a manner that will ensure it's close enough, to the target when you start lasing. I'd advice you to do the drops in AUTO or CCIP, using the pitch to space them out and leave the laser to start automatically, at 10 TTI. Hold it down yourself after, until all bombs impact.

 

So, after some hours of experimenting I concluded it was probably my error, here's what I've found:

 

- using CCIP mode and releasing the bombs closer to the target, seems to diminish the possibility of GBUs fail to track the laser;

- didn't have much success with AUTO mode, as it seems to only allow bomb release when very close to the target already, causing the bombs to overshot the target;

 

After a considerable amount of tries, I'm convinced that my error was:

Not giving enough pitch down attitude, considering the 30.000ft altitude I tipically release the GBUs... so I suppose the GBUs laser seeker FOV was probably not pointed (pitched) down enough to acquire the laser's reflection from the enemy ship...

 

( Initially thought I was pitching down enough, roughly -5 degrees at the least; but looking carefully, many times it were only -2 degrees or so. )

 

After this, giving for example: near -10 pitch down, every single (and pair) GBU-10 release sucessfully tracked the laser, and I was able to release from 13 ~ 14 NM to target, even from 32.000ft altitude - even when the bombs fall short from target, they were at the least pointed at it.

In this case, I'm not understanding the laser 'end-point' of just 8 NM, or how it works.

 

[Machalot]

11 hours ago, Top Jockey said:

I'm not understanding the laser 'end-point' of just 8 NM, or how it works.

It's an artifact of how it's modeled. Imagine an 8 nmi long stick of laser beam originating from your TGP.  If the tip touches the ground, it shortens to fit the distance. Otherwise the end of the laser stick just flies through the air somewhere 8 nmi below and in front of the jet, and that end point is what the GBUs track. 

[Top Jockey]

12 minutes ago, Machalot said:

It's an artifact of how it's modeled. Imagine an 8 nmi long stick of laser beam originating from your TGP.  If the tip touches the ground, it shortens to fit the distance. Otherwise the end of the laser stick just flies through the air somewhere 8 nmi below and in front of the jet, and that end point is what the GBUs track. 

 

Hello,

 

Yes, that I understood when Harker explained.

 

What I don't get is, how do the GBUs manage to guide if I'm able to drop them from 13 NM at more than 30.000 ft, and the featured laser beam has only 8 NM lenght ?

Edited April 6, 2021 by Top Jockey

[Machalot]

32 minutes ago, Top Jockey said:

 

Hello,

 

Yes, that I understood when Harker explained.

 

What I don't get is, how do the GBUs manage to guide if I'm able to drop them from 13 NM at more than 30.000 ft, and the featured laser beam has only 8 NM lenght ?

 

What do you mean when you say manage to guide? They are guiding to the end of the 8 nmi laser.

 

Are you asking how any of them hit the target? Most likely you fly within 8 nmi slant range of the target before the bombs impact. 

 

If you're asking why they were pointed at the target even though the 8 nmi laser was short, remember that the laser is pointing directly toward the target along the of line of sight even if it doesn't reach. So GBUs will appear to guide toward the target even as the actually guide to a point on the line of sight. 

Edited April 6, 2021 by Machalot

[Top Jockey]

9 hours ago, Machalot said:

What do you mean when you say manage to guide? They are guiding to the end of the 8 nmi laser.

 

Are you asking how any of them hit the target? Most likely you fly within 8 nmi slant range of the target before the bombs impact. 

 

If you're asking why they were pointed at the target even though the 8 nmi laser was short, remember that the laser is pointing directly toward the target along the of line of sight even if it doesn't reach. So GBUs will appear to guide toward the target even as the actually guide to a point on the line of sight. 

 

 

You nailed it !

 

That was exactly my doubt, why they were pointed at the target even though the 8 nmi laser was short.

"Manage to guide", is when they go into almost completely nose down pitch attitude (roughly -60 degrees pitch) right after release, meaning they didn't even start tracking the laser beam.

 

My doubt is now clarified with the sentences in bold.

 

So this also explains why in a few instances, the bombs also started to drift left related to the target (when in close proximity of him already)... coincidentally my aircraft was also doing a small bank left turn to avoid overflying the enemy ship... I suppose I gained distance from target and the laser 'end-point' was pulled away from it.

 

Thank you.