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F-16C and GBU-10 Laser Guided Bomb release methods


Top Jockey

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I'd love for the podium effect to be modelled in DCS, would make using GBUs much more realistic and challenging.

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1 hour ago, Deano87 said:

14 degrees nose down compared the horizon correct?

 

Yes, at the bottom info bar in F2 outside view, the GBU-10 pitch tipically shows - 14º if I recal correctly, I'm yet to confirm.

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8 hours ago, Top Jockey said:

In the DCS Hornet, it is easily attainable for the GBU-10 in the following conditions:

- level flight at 25.000 ft or higher;

- speed roughly Mach 0.9 or above when release time;

- target (naval vessel) stationary - 0 kts speed.

 

I'd like to see a track of you doing this with a GBU-10 in the Hornet.  I've tried this multiple times just now with your parameters and get nowhere near the range that you claim you get.  At the range you say you're getting out of a GBU-10, the only thing that I am in range for is a GBU-38 at about 16 miles.  GBU-24 is max range at 9 miles, and GBU-10 and 12 command release at 5 miles and change.

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8 hours ago, Chain_1 said:

I'd like to see a track of you doing this with a GBU-10 in the Hornet.  I've tried this multiple times just now with your parameters and get nowhere near the range that you claim you get.  At the range you say you're getting out of a GBU-10, the only thing that I am in range for is a GBU-38 at about 16 miles.  GBU-24 is max range at 9 miles, and GBU-10 and 12 command release at 5 miles and change.

 

Hello @Chain_1,

Be my guest, I will gladly provide it.

As I'm surprised with which might have been the difficulties encountered ?

 

The only thing is it can be a long track as i've never saved one, and so I imagine it will be the complete mission.

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Remember that you need to be within 7-8nm to lase in DCS. A 13nm standoff goal might not be practical with paveway II.

The issue of continuous lase vs delayed lase is pretty complex and scenario dependant. There's not one "correct" way to employ. Delayed vs continuous combines with static vs moving target and level vs diving delivery and self vs buddy lase in a pretty intricate matrix.

If you want standoff with a paveway II, go high and fast, get into a slight dive to get faster, and then toss the bomb. Have someone on the ground with combined arms lase the bomb in for you. Unless you were tossing from very high, delayed lase is probably best. Last 10-15 seconds is probably best too, because there's a minimum time that the seeker needs to find the laser spot + corrections.

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@Chain_1, as promised:

Here is the mission track.

 

Droped 4 x GBU-10s with a 950 milisecond interval (didn't go too well)...

So maybe 2 of them colided between them and exploded, but the other 2 managed to hit the frigate and caused 47 % damage.

 

- this time released form under 13 nm, and somewhat at 28.000 ft... but they do get to the target.

F'A-18C vs Frigate (GBU-10).trk


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@Top Jockey

That's extremely interesting.  Your first two bombs never catch the laser and fall ballistically, as expected in an auto drop, and land about 7.5 miles short.  The other two do hit, and I can duplicate it now that I see how you do it.  I tried it at 25000, dropping one at 13 mi and a second at 12 mi (replicating your drop distances, using the same speed of 566 KTAS/.93M), and the first one runs out of energy and fall short, but the second connects.  I guess the parameters above were just a bit optimistic (that extra 4000' does help).  As others have pointed out, the GBU-10 should have the "bang-bang" flight controls, which one would think would bleed off the bomb's energy.  In any case, it's an interesting technique.  I never would have thought to use MAN mode like that.  We'll have to see what we can do with the Viper's MAN mode when it comes out.

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CCRP with the targeting pod should work for bombing ships. The TGP should have point track that's following the ship, and you should ideally attack from the bow or stern side of the ship. Depending on how fast the ship is moving one might be better than the other. You should be reasonably fast, around 400 knots or so, and some 6k to 20k ft above. Follow the cue line and hold WPN REL until the bomb is released, wait 3 seconds, then hold the trigger to lase the target. Also, make sure the laser is armed and the laser codes are set correctly, or the bomb would obviously not track. While lasing, steer the aircraft so that you keep the ship on the right side of your aircraft. Depending on your flight profile, you might want to continue left or circle right until the bomb impacts.

That's the procedure I have used very often, normally with GBU-10s, and it has worked very reliably for me so far.

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12 hours ago, Chain_1 said:

@Top Jockey

That's extremely interesting.  Your first two bombs never catch the laser and fall ballistically, as expected in an auto drop, and land about 7.5 miles short.  The other two do hit, and I can duplicate it now that I see how you do it.  I tried it at 25000, dropping one at 13 mi and a second at 12 mi (replicating your drop distances, using the same speed of 566 KTAS/.93M), and the first one runs out of energy and fall short, but the second connects.  I guess the parameters above were just a bit optimistic (that extra 4000' does help).  As others have pointed out, the GBU-10 should have the "bang-bang" flight controls, which one would think would bleed off the bomb's energy.  In any case, it's an interesting technique.  I never would have thought to use MAN mode like that.  We'll have to see what we can do with the Viper's MAN mode when it comes out.

 

Hahaaa ! So was that what happened !

I've done that mission in some hurry yesterday before leaving my PC, and in fact at some point in the F2 external view I've noticed 2 bombs disappeared after a while... so I imagined they could have collided between them or something.

 

Yes, I've noticed I should point the aircraft's nose down a few degrees prior bomb release moment, so that the GBUs seeker could catch the laser.

''Auto drop, don't understand it - I'm doing kind of a 'Manual drop'...

 

On the second bold, I'm mostly using this kind of attack profile, which although not a real scenario one, is merely a personal preference.

It's the one which allows for bomb release from altitude and at some distance; the MANUAL is merely the mode which gives the possibility to do the release in those conditions - without delay / release cues and count down timers.

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This behaviour seems highly unrealistic. 

From the seekers side:

1.) At a high enough slant range, the spot size increases considerably, its shape becomes oval and it will greatly reduce accuracy.

2.) The seeker itself has a nominal acquisition range assuming that its FOV isn't obsctructed. There are obviously upgraded seekers for more modern PW2s but it's still a limiting factor. Expecting it to pick up continuous laser energy at 15 nautical mile is not very realistic.

As for the guidance, obviously PW2s in theory are limited by lag, sag and energy loss and the 10 can be even more energy deficient, especially against movers. So this capability doesn't seem remotely realistic to me at all.

 

As for delay vs continuous lase, while it can be very complicated very quickly, in general common situations work like this:

Delay lase when:

-doing medium altitude deliveries

-low level loft

Continuous lase when:

-there are significant winds you're compensating for

-employing against movers

-buddy lazing

 

Medium altitude deliveries allow the bomb to have sufficient energy so lase timing has negligible impact on accuracy but it still affects terminal parameters. If the target has very stringent terminal parameter requirments, a PW3 with its programmable trajectory shaping and much better kinematic performance will make it a lot more likely to achieve DWE. Depending on the platform and the aircrew, delay lase in general was preferred unless the situation made it less optimal to employ. In the 90s, low level LGB lofts were the bread and butter of the F-16, F-15E and F-111 communities, and low level lofts absolutely, 100% require delay lase without exception. So to ensure better muscle memory and building proper habit patterns, aircrew often delay lased whenever it didn't have a negative impact on accuracy.

 

BRP and ORP was touched on, this was a pretty big point of contention in the Strike Eagle and F-111 communities. Simply put, BRP (ballistic release point) releases the PW2 at the computed ballistic trajectory, assuming a good enough release solution, the bomb should in theory hit the target even without lasing if all conditions are perfect. However, due to a quirk in the PW2 guidance, you could do an ORP (optimal release point), which is essentially an along track modifier that makes the aircraft release the bomb a tiny bit later, and this  takes into account the peculiarities of the PW2 guidance scheme and the guidance scheme slightly changes the energy profile of the bomb and the ORP makes it have a little bit more energy.

 

The issue with this is that 1.) it's mission planning intensive, 2.) it's really only useful for low altitude lofts with PW2s. It makes sense if the bomb is released in a low altitude/low terminal velocity situation but at medium altitudes, the bomb has more than enough energy, and the additional energy bucket provided by the ORP may even means that by the time the seeker FOV is pitched over and would pick up the laser spot, it will have flown too close to the target and the spot drifts outside its field of regard. And old PW2 seekers have pretty poor rearward FOVs.

 

This theory was pretty big in the 90s in the Strike Eagle and F-111 communities and caused a lot of contention, but today PW2 lofts from low level aren't really done anymore for tactically relevant scenarios even if we assume a near peer conflict, let alone mud hut bombing. PW2s retained a niche in medium altitude bombing and in that situation, current TTP is to never drop a bomb without any inertial guidance outside the calculated ballistic release point. BRP vs ORP does very little above a certain height over target anyway, so it would give no benefit in the slightest.

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From the deep -- that was an awesome explanation, thanks for that. Low altitude lofts are where it's at in DCS. Pretty satisfying to achieve, and definitely not something i would want to do in a single seat aircraft for real.

Thanks for taking the time to write out some of the factors for delayed vs continuous lase, that was more than I wanted to get into. I'd also throw on top of that, for people's planning purposes, the benefits of dropping PWII from a dive (medium altitude attacks) to help with that terminal energy state.

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On 4/15/2022 at 9:05 PM, Fromthedeep said:

This behaviour seems highly unrealistic. 

From the seekers side:

1.) At a high enough slant range, the spot size increases considerably, its shape becomes oval and it will greatly reduce accuracy.

2.) The seeker itself has a nominal acquisition range assuming that its FOV isn't obsctructed. There are obviously upgraded seekers for more modern PW2s but it's still a limiting factor. Expecting it to pick up continuous laser energy at 15 nautical mile is not very realistic.

As for the guidance, obviously PW2s in theory are limited by lag, sag and energy loss and the 10 can be even more energy deficient, especially against movers. So this capability doesn't seem remotely realistic to me at all.

...

 

They can lag and sag whatever they do, but this is physics; and with enought height nad speed, eventually they will travel a given distance.

 

Eitherway, my point is that (in DCS at the least) using GBUs seems more 'method restricted' and cumbersome in the Viper than in the Hornet.

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5 hours ago, Top Jockey said:

They can lag and sag whatever they do, but this is physics; and with enought height nad speed, eventually they will travel a given distance.

 

You can't just add infinite energy you know, they have a maximum release speed below the mach. As for altitude, there's no such thing as a free lunch. The higher you are, the more likely it is to have significant wind deviation that can influence the bomb during its TOF and every correction it makes for the wind bleeds the energy budget. Not to mention that it further increases the chance that some kind of weather limitation will also play a major role. PW2s wouldn't like even the puffy little Bob Ross clouds we have.  And the bigger the slant range, the less likely it is that you hit anywhere near the target. Even if we disregard seeker and laser limitations, if you lase for an excessive amount of time and try to impart a sort of long range glide trajectory on the bomb sagging will mean that it should very likely drop short of the target. It will bleed itself of energy and you'd never hit anything at those ridiculous ranges. When I said that at medium level deliveries it would have more than enough energy, I was talking about releasing at BRP, not at 15 miles.

 

Realistically speaking of course, we simply can't ignore laser and seeker limitations and it simply wouldn't work, too large spot size at shallow grazing angles means disaster for the expected accuracy and it would be well beyond the limit of the range at which the seeker can pick up the spot. There's a reason why PW2s are supposed to be dropped inside the laser basket and the LAR is either at the ballistic drop point or closer to the target.

 

DCS is a video game and the core interactions are way too simplified compared to real life, and if this works in the game absolutely make sure to use it. But understand that this would never work in real life, the weapon is not designed to do it, the TTPs are all designed around maximizing effectiveness and using some kind of wonky manual forced release mode as some kind of stand off release option in real life would be a great way to hit the dirt instead of the target.

It's a backup mode in case something fails in the computed calculation but it's not a magical way to utilize the weapon in a manner that means it would be absolutely wasted and achieve no results. The GBU-24 is the perfect weapon for what you're trying to achieve with its much more sophisticated guidance scheme, energy efficient flight profile and significantly increased range.

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Fromthedeep,

Can you explain generally what the laser basket is? Or maybe where we can go read about it at a generalized level? Does it apply to DCS? I'm guessing this impacts why medium altitude lofts aren't great for PWII, in the way that they can work for something like a JDAM.

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The basket is simply the range of acceptable delivery trajectories which can be steered onto target by terminal laser guidance. Naturally it applies to DCS as well.

PWII can be lofted but when the laser guidance happens is important. The bomb can't see the laser unless it is pointed at it with some angle, say 20 degrees. Until the arc of the trajectory has hit its maximum and starts to rotate down the laser is irrelevant.

If the laser is on target as the spot comes into view of the edge of the seeker and not the middle. PWII seeker only has two steering angles: 100% pitch down or 100% pitch up (left/right same thing). The seeker itself only has two sides per axis. It can't tell if laser is 0.1° off center or 19.9° off center.

The is also traveling relatively slowly at this point. The result is that the bomb steers toward the laser 100% effort until it is seen on the other half of the sensor. A large angular velocity develops during this initial turn and overshoot wildly. The bomb will take longer to settle around the LOS back and forth. Instead if the laser is delayed the bomb is already pointed more closely to the target and the oscillations are smaller producing less drag. Also any guidance produces drag and non-parabolic trajectory which are both energy reducing so the shorter the better.

Medium altitude toss (MAT) is the longest-range possible delivery kinematically be it Mk 82s or GBU-12s. The ballistic phase ends where terminal phase begins. PWII terminal phase is usually worse kinematically than ballistic so minimizing that phase improves overall energy. JDAM is an entirely different weapon because it flies like an airplane optimizing its glide range.


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On 4/17/2022 at 6:14 PM, Fromthedeep said:

You can't just add infinite energy you know, they have a maximum release speed below the mach.

...

 

Sure, I believe I also wrote we are talking about physics you know.

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On 4/14/2022 at 11:16 AM, TheBigTatanka said:

Remember that you need to be within 7-8nm to lase in DCS. A 13nm standoff goal might not be practical with paveway II.

The issue of continuous lase vs delayed lase is pretty complex and scenario dependant. There's not one "correct" way to employ. Delayed vs continuous combines with static vs moving target and level vs diving delivery and self vs buddy lase in a pretty intricate matrix.

If you want standoff with a paveway II, go high and fast, get into a slight dive to get faster, and then toss the bomb. Have someone on the ground with combined arms lase the bomb in for you. Unless you were tossing from very high, delayed lase is probably best. Last 10-15 seconds is probably best too, because there's a minimum time that the seeker needs to find the laser spot + corrections.

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Lasing the target should be done between  8 to 12 seconds before impact - check the HUD for the count down time (Time to Release):

image.png

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On 4/13/2022 at 6:16 PM, razo+r said:

CCIP in a dive or MAN when it's implemented.

 

Finally had a little bit of time to experiment it, and in CCIP mode the bombs indeed do release at pickle button press - no questions asked !

That's what I was looking for, now must try it with my "release profile" using the FLIR TPOD...


Edited by Top Jockey

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