investigating Blowing myself up with MK 82 Snake Eyes in multiplayer with my F-5 ... any hint?

[Frag]

Hi guys, I had a session with two friends of mine tonight and we did not stop having this issue. I never had this issue in Single Player.

 

While approaching a convoy with a load of MK82 SnakeEyes (speed 450 knots, altitude 400 feet), 50% of the time, my F5 was exploding as soon as I was releasing the bomb. All of us got the issue. But it was working from time to to time. One of the player has a weak network with some latency issue ... could it be some kind of latency issue with the position of the bombs and the aircraft? Anyone ever got that issue?

 

I have to say that it is quite a buzz killer to fly 25 minutes away, to explode mid air while releasing the bombs. I really wish that I am missing something! I would appreciate if you have any hints. Here are my bombing parameters if needed:

 

- Interval 0.6

- Store RIPL

- Fuse: Nose & Tail

- All pylon selected (9 bombs)

- Pip Mode "MAN"

- Depress 90

 

Thanks!

Edited January 15, 2021 by Frag

[lmp]

Latency issue sounds plausible but let's rule out two simple mistakes.

 

Was anybody at less than 1G when releasing? Could be a case of flying into your own bombs.

 

Was it really 400ft AGL? Maybe you got the terrain altitude wrong?

 

I pressume there's no track or Tacview record?

[Baaz]

Believe this is going to be a bug.  

I've provided several tracks below to show that I met your flight requirements (or very closely).

After watching the TacView files, I noticed an issue with the bombs coming off the center rack in which bomb #3 and #4 were colliding.  This appears to be a timing issue with the bomb release.  Further testing would also show that the faster the F-5 was going, the more likely the bombs would collide.  Slowing down to less than 450 knots negated the issue altogether.

F-5_SnakeEye_test.trk F-5_SnakeEye_test_2.trk F-5_SnakeEye_test_3.trk

[Baaz]

Some additional information from the F-5 Weapons Delivery Manual to show that there should be no issue with dropping Snakeyes at 450 knots, and 400' AGL

[Lawn*Dart]

This is a bug that my wingman and I have been experiencing recently, even when flying perfectly straight and level al 10,000 ft AGL.  We didn't have this problem at all the last time we flew the F-5 six months or so ago. It only seemed to happen when rippling the centerline rack of 5 and, while it occurred with all ripple and fuzing combos, it seemed to happen less often with longer ripple delay selected.  This is definitely in need of a fix, as it cripples the F-5's already-limited ground attack capabilities.

[baboeska]

I have heard the theory that wind may be causing the bombs to touch mid-air.
Here's a screen-shot of the Tacview when the bug happens.

[Machalot]

4 hours ago, baboeska said:

I have heard the theory that wind may be causing the bombs to touch mid-air.

I wonder if that is affected by the "headwind/tailwind" bug in which the wind seems to be missing from the aircraft's flight model and it uses ground velocity to determine engine performance, etc.  Normally an aircraft flies on the moving airmass, but if it's modeled incorrectly and missing the wind, then the instant the bombs are released they would be blasted with a huge wind shear. Hopefully the next patch will fix this!

[Lawn*Dart]

14 hours ago, Machalot said:

I wonder if that is affected by the "headwind/tailwind" bug in which the wind seems to be missing from the aircraft's flight model and it uses ground velocity to determine engine performance, etc.  Normally an aircraft flies on the moving airmass, but if it's modeled incorrectly and missing the wind, then the instant the bombs are released they would be blasted with a huge wind shear. Hopefully the next patch will fix this!

I don't think this is the case, as this bug did not seem to exist until somewhat recently.  Six months to a year ago I was able to ripple snakeyes in the F-5 without ever having a mid-air detonation, now it happens constantly.  Unless the headwind/tailwind bug is itself recent?

[Lucas_From_Hell]

The problem here is not on the F-5, it's a DCS bug in general. The Mk 82 Snakeye fuses are arming instantly instead of the pre-set delay there specifically to make sure they get enough time in the air to clear the fuselage and other bombs.

[Machalot]

8 minutes ago, Lucas_From_Hell said:

The problem here is not on the F-5, it's a DCS bug in general. The Mk 82 Snakeye fuses are arming instantly instead of the pre-set delay there specifically to make sure they get enough time in the air to clear the fuselage and other bombs.

There is also the issue of safe separation from the aircraft. The bombs world not likely be certified for employment in this manner if there was a risk of collision, fused or not. 

[RustBelt]

Keep in mind also, weirdness happens when a weapon leaves a pylon in DCS. It gets swapped from the airplane model to the world model and looks like it may not have the right inertia when it switches to the world model. So it may be a problem inherent in the F5, but not actually an F5 problem, but a weapon problem on the world side. 

[Machalot]

1 hour ago, RustBelt said:

Keep in mind also, weirdness happens when a weapon leaves a pylon in DCS. It gets swapped from the airplane model to the world model and looks like it may not have the right inertia when it switches to the world model. So it may be a problem inherent in the F5, but not actually an F5 problem, but a weapon problem on the world side. 

Are you referring to the moments of inertia? 

[Shadow KT]

Just tested this, it seems to be an issues. I've done such passes in the past and they worked fine. Now with 450 knots, 300 feet AGL, 99 depression bombs collide with each other

F-5 SnakeEye .trk

[RustBelt]

21 hours ago, Machalot said:

Are you referring to the moments of inertia? 

No like ACTUAL inertia. They aren't respawning in the world model with the correct energy and velocities. Or something very much like that. The handover has always been....shakey. Especially in MP. 

[Machalot]

1 hour ago, RustBelt said:

No like ACTUAL inertia. They aren't respawning in the world model with the correct energy and velocities. Or something very much like that. The handover has always been....shakey. Especially in MP. 

Haha, sorry, engineer brain does not comprehend normal human speech inputs.  I understand you now.

 

I have created a simulation of this type of problem before for work -- start with one moving body that detaches part of itself to spawn a second body.  Reinitializing both bodies with the physically correct states of motion can be tricky, because you have to make sure the motion states before and after separation follow all the laws of conservation (momentum, angular momentum, kinetic energy) while applying any interaction forces and torques to both bodies, across a discontinuity in the position of each body's center of mass.

 

Wouldn't be surprised if you're right about this.

[Shadow KT]

I would recoomend you report this in the Weapon Issues part of the General Bugs forum, as it is more likely to get attention. 

Something is up, bombs seem to be dropping short as well

Edited January 29, 2021 by Shadow KT

[NineLine]

Checking, thanks guys.

[NineLine]

I checked the most recent track and I am not seeing anything, are people still experiencing this issue?

[Frederf]

I ran the track on the current build (60966) and the F-5 is destroyed by at least one of the bombs within a second after release.

[NineLine]

Interesting, I will keep trying. I first tried in our internal build so perhaps something has been fixed. Thanks.

[Iridul]

It might be unrelated, but I have had a similar issue dropping the racks of 4 x FAB100 from the Su25A. They seem to crash into each other immediately after release and blow me up. This may be a broader 'multiple bombs releasing from a single rack' issue. Though this does not happen everytime.

Edited February 9, 2021 by Iridul
Edited for clarity

[Inf]

This might be very unrelated, but I've experienced this in the Viggen. Done low level high-drag bombing till the cows come home in single player without problem, then every time I've tried it online I've suddenly exploded, as if I collided with my bombs. I know this is the F5 forum, but could be related.

[Machalot]

2 hours ago, Inf said:

This might be very unrelated, but I've experienced this in the Viggen. Done low level high-drag bombing till the cows come home in single player without problem, then every time I've tried it online I've suddenly exploded, as if I collided with my bombs. I know this is the F5 forum, but could be related.

That's strange. I've never had a problem like that in the Viggen. I pay almost exclusively online and mainly fly the Viggen. 

[Frederf]

It looks like DCS explodes any bomb which collides with another bomb even when it is not armed.

[NineLine]

As long as this has been an issue, we are making improvements to this with the fusing options, etc. Arming times and such will be better honored properly, we will also look at proper collision models for bombs as well.