Release interval distance - How accurate is it?

[sirrah]

I was playing around a bit with the release interval distance and I noticed the distance I set on the mfd, didn't at all match the distance at which my bombs impacted.

 

Just flew the instant action take-off mission at PG and went to the shooting range. I set my BDU-33 release interval distance to 425ft (which pretty much matched the 0.07nm distance from the first to the last truck).

 

I flew in straight at approx. -15deg doing 320kts and hit the pickle button when the pipper went over the first truck. I watched my first bomb go short (might have been me hitting that pickle button to early), but the last bomb dropped ±600 to 800ft from the first one.

 

So, is this normal? Did I overlook something, or is the interval distance just not that accurate?

 

 

(sorry for the lack of a track file. I was sure I saved it after the mission, but I can't find it in my tracks folder.. I probably hit the "save debriefing" button instead :doh:)

[Frederf]

CCRP BDU-33 isn't accurate in general for single bombs. You can try 200, 300, 400, 500 kt releases on a known target and find this. The faster the farther beyond the aimpoint impact turns out.

 

Level release pattern can be evaluated regardless. Tried a 999' RP2 level release, bombs landed about 700' apart. I tried a 999' RP12 level release, bombs landed 11,000' apart total. It's whacky. They seem to be either good spacing or oddly compressed and I don't know why.

 

You don't mention how many bombs you released so it's hard to judge.

[sirrah]

You don't mention how many bombs you released so it's hard to judge.

 

I dropped 6

 

Just to make sure.. with RP>2...

Does the release interval set the individual bomb release interval? Or does it mean all bombs will drop within the set distance (so if I set 600', will the distance between each bomb will be 600', or will the first and last bomb be separated 600'?

 

 

Oh and btw, all the above was done in ccip, not ccrp

[Pantera93]

There are some platforms were I experienced this behaviour too and found out that both CCIP and CCRP reticles should be pointed "in the middle" of your bombing run when you set repetitions and separation. I believe Viper is one of those, along with the Hog and the Hornet, while instead the Tomcat points in CCIP at the first bomb impact point.

It's quite tricky to understand, but you can practice with runway bombing and see what i mean. If you place your pipper at the beginning of the runway, with large separation (e.g. 12 82s with 600 feet) and high number of repetitions, half of your bombs will drop short.

IDK if this behaviour has been fixed or if it is correct as it is, but it is what I spent a whole evening trying to figure it out.

 

BTW, interval is separation between bombs, not bombing run lenght.

 

Inviato dal mio SM-G950F utilizzando Tapatalk

 

 

[sirrah]

and found out that both CCIP and CCRP reticles should be pointed "in the middle" of your bombing run when you set repetitions and separation.

 

Although I believe you when you say you tested it, this would mean that the pipper would move, depending on the RP. Is that correct? (not at my pc now, so I can't test myself)

 

E.g., if we use the CCIP runway attack as an example:

Imagine you active pause when you have the pipper at the start of the runway. You then set RP from 1 to anything more than 1, if your statement is true, that should result in the pipper automatically move up.

 

I mean, initially at RP1, the bomb would drop exactly on the pipper point (strart of the runway).

When setting RP to more than 1, the first bomb would still fall at the start of the runway (just the dumb bomb falling curve). However, the pipper should then indicate the center between all bombs. Hence the pipper should move up. Does it?

 

 

 

(this would explain btw, why my first bomb went short)

[Pantera93]

 

 

 

Although I believe you when you say you tested it, this would mean that the pipper would move, depending on the RP.

It will.

 

And in even repetitions, no bomb will follow the pipper (if distance is 600 ft, the pipper will be 300 ft apart from the middle bombs).

 

I stand to be corrected

 

 

Inviato dal mio SM-G950F utilizzando Tapatalk

 

 

[Frederf]

CCIP and CCRP only differ on the method of aim, the result is the same. Yes spacing is between each release event (pairs or singles) and not the total length. I'm trying to reserve the words spacing for distance and interval for time. There is a manual bombing mode where the pilot enters release time interval directly. Aim point is "middle of stick" as Pantera says with equal numbers of bombs before and after the DMPI. DMPI is desired mean point of impact with 'mean' indicating average. That's all proper behavior. With PROF1 and PROF2 set up with different patterns and active pause you can verify for yourself by jumping back and forth how the pipper/cue jumps ahead/behind with a single button.

 

And DCS does all this to a reasonable degree. There are some ballistic calculation errors especially at high speed, the Hornet does it too and who knows how many other modules. But the aimpoint = middle of pattern concept applies. The spacing shouldn't shrink based on dive angle (i.e. time between release should get longer when not level) which seems like DCS is doing wrongly. For example 6 bombs at 425' should be (6-1)x425=2,125' total length. ~700' is not even close.

[Scrape]

The SMS is calculating milliseconds between release pulses. That how it understands separation. If you change the angle the number of milliseconds will not change, and thus the spacing will change. To achieve a desired result, the pilot must fly to a specific delivery point and speed or the result changes. The SMS doesn't try and predict what the pilot wants to achieve and will not 2nd guess what's happening. A level .8mach release at 10k with 400ms will have a wider spacing than a 45degree dive at .8mach at 10k with 400ms spacing.

[Dragon1-1]

Actually, in the Viper at least, IIRC the CCIP aimpoint is where the first bomb will impact (or in the middle of the first pair of bombs), while CCRP is the middle of the stick.

[Frederf]

Both of the above statements are not true. CCRP calculates separation based on actual flight conditions. If 100' spacing is entered the time interval of release will vary based on ground speed, dive angle, etc. in order to achieve the desired impact spacing. For manual bombing, sure, the pilot enters the interval directly but not for computed bombing.

 

And CCIP, DTOS, LADD, CCRP are all center of aimpoint = center of bomb pattern. CCIP pipper position represents projected center of impact pattern.

[Bailey]

Actually, in the Viper at least, IIRC the CCIP aimpoint is where the first bomb will impact (or in the middle of the first pair of bombs), while CCRP is the middle of the stick.

 

In DCS I found this statement to be true through my independent testing a few minutes ago.

 

Edit: Nevermind. See below.

[Bailey]

Whoops. Pressed "Send" too early. I found that statement to be true both in actual drops, and also represented via the drop cue data. To replicate:
1. Load a F16 with 6 mark 82s.
2. Target a point on the ground.
3. Fly to 20 seconds prior to the release point and Active Pause.
4. Set Ripple to 6 and impact spacing to 999. Take note of the time to drop cue value.
5. Set Ripple to 99 and impact spacing to 999. Take note of the time to drop cue value.
6. If you are in CCIP, the time to drop cue values in step 4 and 5 will be the same.
7. If you are in CCRP, the time to drop cue values in step 4 and 5 will not be the same and you have likely missed your cue.

 

What I said is incorrect. CCIP does, in fact represent the center of your intended bombing area.

[Bailey]

Here is a CCIP drop at approximately level flight from about 6000ft. Right to left. The Containers are placed at 500ft intervals.

Ripple to 6. Impact spacing to 500. The red arro points where I tried to aim with the CCIP piper. As you can see, the 500ft interval looks ok.