reported CCRP fall line impossible to follow with (limited) wind on mission

[Sharpe_95]

Hi guys,

I have been building a mission and was experimenting with CBUs in a map with (very limited) wind (2knts @ 310).

 

However, I would like to draw your attention to the following two tracks for scrutiny.

 

The first track shows me executing a loft attack from low altitude with CBU-97s with no wind. As you can see, I am able to follow the bomb fall line/cue fairly easily.

 

The second track shows exactly the same situation, but with 2knts of wind. As you can see, it is impossible to follow the fall line as it keeps 'flicking' (cant think of a better descriptive term) from one side to another - impossible to follow.

 

I dont know if this is an issue with the F16s code (I suspect it is) or DCS code in general - but I am not aware of other aircraft with this issue so I suspect it is F16 related? Either way I dont believe there is a reason why such limited wind (or any strength of wind) should have such a dramatic and variable impact on the CCRP fall line?

 

-S

CBU Bomb fall line impossible to track bug(no wind).trk

CBU Bomb fall line impossible to track bug.trk

Edited May 18, 2020 by Sharpe_95

[Bonzo0181]

edit: not quite the same as OP describes, or at least not the only issue

 

 

 

It took me a while to figure it out, but it's user error. ish*...

 

 

Your ingress is below burst altitude, so the bomblets will be dispersed as soon as the canister leaves the pylon. For the CBU-97, this means the bomblets have to be released right over the target. Now, if you pop-up and reach an altitude above the burst altitude, it works just like an iron bomb. This does mean, however, that the bombs should be dropped way before the target area.

 

 

What's happening:

-You fly in low, and pop-up before the target area, as expected for a loft delivery. (position 1)

-Here, the aircraft tells you to fly to position 2 to release the bombs, since they will burst immediately.

-You are unaware of this mechanic and keep climbing, through burst altitude.

-As soon as you reach burst altitude, the aircraft tells you to go towards position 3, since the canisters will now loft as expected.

 

 

 

 

 

Now, as for the wind:

Wind has en effect on your munitions, I assume you already know that, of course. The CCRP line is correcting for that. The further up you are, the more correction is needed. Thus, when climbing, the needed correction increases and the aircraft tells you to fly to the right. Now you pass burst altitude, with the target left of your nose. This means the new release point is somewhere on your 7-o'clock: the line shifts abruptly towards the left.

 

 

 

 

I hope it made sense, if not: please tell me where to clarify.

 

 

*This assumes the CBU will always burst below BA, instead of when passing BA while descending. That might be a bug, but I really don't know.

Edited May 18, 2020 by Bonzo0181

[Sharpe_95]

Thanks for taking the time to respond with such detail, but while I understand the principle of the point you are trying to make, I believe this is not user error nor merely a case of the wind conditions, but one of a coding issue within the F16.

 

Think of the parameters: wind 130/2 knots, the wind is very weak, is one direction only and is not intersecting the flight path at 90 degrees. The sudden and dramatic variance is so great that the wind would have to be MUCH stronger and in different directions over a spacing of a couple of thousand feet to have the impact you are talking about.

 

Further, I do not have this issue in other sims or other modules in this sim (inc A10 and FA18 ) and in much more testing conditions.

 

Also, the computer is continuously computing these factors and should be calculating a smooth release point not a violently variable one based on 'unpredictable/unknown' wind-age as it encounters it - this is not how the CCRP system works - if it was it would never be used as it would be to unpredictable and thus impossible to fly.

 

Finally, see attached track showing me flying the same mission but with 6knt wind at 130 (three times more than the original track), as you can clearly see, the bomb fall line is much easier to follow.

 

I can only surmise that this is not user error, nor an issue regarding how CBUs work/dont work in wind but rather a factor linked to the F16s coding and not pilot error or wind-age.

 

-S

PS: Sorry to all you FA18 drivers out there - I haven't flown it in over a year and had to quickly google how to do a 'CCRP' (Auto) loft, but I am sure I make a mess up of the set up etc - but it was only to demonstrate how the CCRP/Auto free fall line should behave even with wind.

CBU Bomb fall line impossible to track bug(FA18).trk

Edited May 18, 2020 by Sharpe_95

[Bonzo0181]

I see what you mean and I agree. The computer is indeed over-correcting for wind a few miles out of the target, making you have to correct back to the target when you are approaching it (think sine wave with the target at 1/2f). This effect is greatly exaggerated below BA. This is why you see the sudden jump in your track, which happens at 1500ft.

 

 

Basically, if you the flip the x-axis jump from my previous drawing to the z-axis, that's what happens.

 

 

Only happens with -97s, all other munitions I'm able to test work fine. The only other aircraft with -97s that I own is the A-10A, but I can't be arsed to figure out CCRP in that.

Edited May 18, 2020 by Bonzo0181

[Sharpe_95]

I see what you mean and I agree. The computer is indeed over-correcting for wind a few miles out of the target, making you have to correct back to the target when you are approaching it (think sine wave with the target at 1/2f). This effect is greatly exaggerated below BA. This is why you see the sudden jump in your track, which happens at 1500ft.

 

 

Basically, if you the flip the x-axis jump from my previous drawing to the z-axis, that's what happens.

 

 

Only happens with -97s, all other munitions I'm able to test work fine. The only other aircraft with -97s that I own is the A-10A, but I can't be arsed to figure out CCRP in that.

 

Thanks for your help confirming this issue Bonzo. As you have probably already noticed I only tested 97s on the F16 and rockeyes on the Hornet. I didnt even consider it could be just one specific munition on the F16.

 

-S

[BIGNEWY]

Reported to the team, I will let you know what they say.

 

thanks

[Carbon715]

Made a quick track to demonstrate what I mean...discovered the other day while playing wild weasel with some sam sites. Designate tgt with tgp and go extremely low. CCRP line deviates extremely left or right with little to no wind. As i go for a pop up the line scans left and right very rapidly then shoots to a side. Makes popping up not even possible to loft and hit the deck for sam avoidance. I have tried all kinds of alignments...be it cold and dark with both stored/norm alignment, warm start, in flight start, runway start. Result is always the same so it is not alignment. I don't remember ever having these problems when i was playing with the 16 last April. I created this quick mission to make a track to show what is going on with a group of bmps, not that it matters what the target is. Made in vr so adjust camera view as necessary. I even went to the training section for cbu's and it seemed ok there, the only difference is there is no tgp in that training...

ccrpBUGGED.trk

[Carbon715]

eh on second I think this behavior might be correct, however...the steering line going bonkers seems...off.

Edited March 8, 2021 by sdirmitt
rephrase

[BIGNEWY]

Already reported thank you, I have merged the threads. 

 

thank you