Smoke

[Nemesis Lead]

Has anyone ever done any tests of how long you get smoke for various types of ammunition (e.g., US 81mm smoke ammo generates smoke for 120 seconds)?

[Soddball]

I don't believe such tests have been done. It's definitely the case that smoke from mortars lasts less time than smoke from equivalent artillery shells, and the larger the mortar/shell, the longer the smoke lasts. It could be linked to the 'blast' value of the round but, as I said, I don't believe definitive tests have done.

Of course, smoke is also affected by wind strength.

For a good, long smoke barrage 120 rounds of 25pdr should do the trick.

[securityguard]

I also think ground affects smoke shells as well. Opponent of mine shot a 75mm smoke shell through snow and strong wind (no idea why) and smoke didn't even appear. However on dry, windy conditions I saw a 81mm mortar smoke last a little while.

It also seems like it takes multiple shots to get an effect. If you fire one small caliber smoke round it usually doesn't have any effect.

[leakyD]

I have (or had) an old CMBO arty spreadsheet that I got off some website. It had a bunch of arty data in it.

I kinda remember something along the following:

Small caliber smoke (under 100mm): 60-90 seconds duration

Medium caliber smoke(100-149mm): 90-120 seconds

Heavy caliber smoke(150mm+): 120-180 seconds

I don't think any single smoke shell of any caliber will last more than 3 minutes.

I have no idea where this spreadsheet is. Maybe I'll find it someday. If so, I'll post a link to it here, or start a new thread.

Again, this was CMBO data, so I don't know how the current modeling may effect smoke duration now.

As a general rule, I try to stick to the above numbers. It usually/kinda/sorta works.

Mostly.

[Dook]

Below is the part of what may be the table referred to above that is relevant to smoke. Note that it is from CMBO. This was stashed on my hard drive long ago - I forget who did it and have never tested it for accuracy.

Enjoy.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">

Axis

Caliber Smoke dur.*

75 1:10

81 0:50

105 1:45

120 mor n/a

150 2:30

150 roc 2:30

170 n/a

210 n/a

210 roc n/a

240 n/a

300 roc n/a

US

Caliber Smoke dur.*

75 1:15

81 mor 1:10

105 1:30

105 VT 1:30

4.2 mor n/a

4.5 inch n/a

155 2:30

155 VT 2:30

8 in gun n/a

8 in how n/a

240 n/a

14 inch n/a

British

Caliber Smoke dur.*

3.5 mor 1:00

4.2 mor 1:30

25 pdr 1:30

25 pdr VT 1:30

4.5 inch n/a

5.5 inch n/a

5.5 VT n/a

7.2 inch n/a

14 inch** n/a

*Smoke duration is the average time a smoke shell puts out smoke, in minutes and seconds. In practice, the smoke duration is the upper time limit for a useful smoke screen</pre>

[Nemesis Lead]

That is awesome Dook---thank you.

[The Colonel]

I've noted that it takes 40 seconds from shell impact to the start of the smoke plume regardless of shell size. And remember what Soddball said, the wind strength definitely plays a role in how long the plume hangs around. One of my favorite tricks for making an instant and long-lasting smoke screen is to blow up an intervening building in the area if one's available. I've seen smoke from building collapse last over 5 minutes.

[Zalgiris 1410]

Originally posted by The Colonel:

I've noted that it takes 40 seconds from shell impact to the start of the smoke plume regardless of shell size.

I fully concur that it always takes 40 seconds and for each individual shell AFAIK!