Accuracy of Nebelwerfer Strikes?

[GoofyStance]

Last night, I played as the Germans vs. the American AI in a home-made scenario in Italy, October 1943. It was midday, weather was clear with a light breeze blowing across the battlefield. There was a church on a hill on the German side of the line, with an excellent view of the battlefield. On the first level of this church, I had a crack SS company HQ squad (+1 or 2 on all attributes), and on the second level, under the HQ's C&C, I had a crack FO directing a battery of 214mm Nebelwerfers. The FO had a direct, unobstructed LOS to four TRPs on the battlefield. During the fighting, I directed the FO's placement of a Nebelwerfer strike on a TRP about 350 meters away in front of the church. The rockets landed generally in the area of the TRP, but one landed 10 meters in front of the church, rattling the occupants, and another landed 75 meters to the right of the church, demolishing a small building and taking out half the Pzgr. squad that was inside.

Now, I know that Nebelwerfers were rather inaccurate, but being off target by some 340 meters seemed rather extreme. The FO had unobstructed vision to the TRP from the time of the artillery call to the time the rockets started landing (about 70 seconds, IIRC), and the Americans had not yet spotted any German presence in the church. Were Nebelwerfers really that inaccurate during the war, or is the modelling a bit off (no pun intended)?

[Kingfish]

Sounds about right. Nebs, and rocket artillery in general, were mainly used for deep strikes, such as counter battery, while tube arty worked closer to the front line.

Targeting a neb barrage 350 meters away from your troops is asking for trouble, and to be honest you are very lucky only two landed close to your guys.

[MikeyD]

Nebelwerfers were not that inaccurate... they were more-so! Watching wartime footage of those things being ripple-fired you inevitably catch a glimpse of one of the rounds shooting off at some crazy angle. I think I read somewhere that the Russian Katyusha fin-stablilized rail-fired rockets were notably more accurate than the spin-stabilized Nebelwerfers. Basically, you probably wouldn't want to be anywhere within a normal CM-size map when those rockets started falling... just like in the game!

[Londoner]

You don't need LOS to a TRP Goofy. Thats half their usefulness!

[GoofyStance]

I had the impression that having an unobstructed LOS to a TRP allowed for a quicker response to an artillery call? In addition to greater accuracy of the artillery strike?

The hit on the occupied building also reminded me of another question I had: Does the damage caused by a direct hit of an artillery shell vary within a range, or is the damage a fixed amount? For example, if an artillery shell directly hits a building, does it cause X amount of damage, which automatically results in the reduction of the building to rubble (if the amount of damage is great enough), or can the amount vary, which results in the building possibly still standing afterwards?

[John D Salt]

Originally posted by GoofyStance:

Were Nebelwerfers really that inaccurate during the war, or is the modelling a bit off (no pun intended)?

PRO document WO 291/2317, "German use of the multi-barrelled rocket projector", dated 07 Jan 1944, has a couple of things to say on this question.

It gives safety zones from several sources. A German circular dated March 1942 gives safety zones for own troops for 15cm rockets as 500m in range and 300m in line from each edge of the target area, and says that concentration of own troops should be avoided for 3000 metres short of the target. Other reports give safety zones of 500 yards and 600 metres.

It also gives the results of three firing trials with captured rockets:

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">15cm Nebel trial in North Africa

Rounds QE Mean range (m) m.d. dispersion in range (m)

10 6° 3' 2710 252

5 30° 7018 130

5 45° 7723 115

15cm HE trial in North Africa

Rounds QE Range (yds) m.d. range (yds) m.d. line (yds)

10 6° 3' 2954 247 77

4 30° 7675 142 37

5 30° 8446 127 34

Trial in England, 15cm HE and smoke

Type Rounds QE Range (yds) m.d. range m.d. line time of flight (secs)

HE 22 15° 4565 107 42 17.73

Smoke 15 15° 3509 117 33 13.60</pre>

[Mr. Tittles]

Does that data show that they have less deviation at longer range?

These rockets were spin stabilized?

In Tigers in the Mud, the author gets caught under friendly nebel fire. Hes in a Tiger but his supporting infantry is demolished. He said it was an almost perfect hit on the jump off point. Perhaps the rocket guys mixed up coordinates.

[John D Salt]

Originally posted by Mr. Tittles:

Does that data show that they have less deviation at longer range?

These rockets were spin stabilized?

Yes, and yes.

To enlarge upon the second point a bit -- it makes perfect sense if you consider the dispersion pattern of the rockets to be described as a cone, but a cone that has been given a Daliesque droop by the influence of gravity. Evidently, the area over which this droopy cone of dispersion intersects the place of the ground will be an ellipse. The finer the angle of intersection, the longer the ellipse, and this effect appears to dominate the effect of the cone getting wider as the range increases.

Note that this sort of reasoning also helps to explain why howitzers are preferred to guns for most field artillery work, and why LV or MV guns are better than LV guns as direct HE-chuckers.

All the best,

John.

[flamingknives]

You mean LV or MV are better than HV for HE chucking?

[Mr. Tittles]

At 8000+ yards, a single 6 rocket nebelwerfer can place them onto a football field? Considering the heavy payload and the range, thats pretty good chucking. I dont think the larger rockets were as accurate though.

The soviets katyushas were not that accurate if they were fin stabilized. They would be very susceptible to crosswinds also.

[John D Salt]

Originally posted by flamingknives:

You mean LV or MV are better than HV for HE chucking?

That's what I mean, it's just not what I typed.

All the best,

John.

[John D Salt]

Originally posted by Mr. Tittles:

At 8000+ yards, a single 6 rocket nebelwerfer can place them onto a football field? Considering the heavy payload and the range, thats pretty good chucking.

If I'm reading the figures correctly, and if a football field is about 100m long, then it means that it would put half of them within a football field's length of the MPI -- in other words, the 50% zone would be two football fields long.

Whether the MPI is accurately adjusted onto the target is another question, and as the point of MRLs is surprise fire I would expect the registration process to be less accurate for NbWs than tube artillery because of the practice of using silent or offset registration to preserve surprise.

All the best,

John.

[JonS]

Originally posted by John D Salt:

... it makes perfect sense if you consider the dispersion pattern of the rockets to be described as a cone, but a cone that has been given a Daliesque droop by the influence of gravity. Evidently, the area over which this droopy cone of dispersion intersects the place of the ground will be an ellipse. The finer the angle of intersection, the longer the ellipse, and this effect appears to dominate the effect of the cone getting wider as the range increases.

Note that this sort of reasoning also helps to explain why howitzers are preferred to guns for most field artillery work, and why LV or MV guns are better than HV guns as direct HE-chuckers.

Not surprisingly, the beaten zone of MG fire shows exactly the same effect.

[GoofyStance]

John, thanks for posting that body of data - it's very interesting to see the range of dispersion. We should note, however, that only the trials in England can be treated with any level of statistical meaning; the data from North Africa is drawn from too small a sample to make statistically significant inferences. Still, taken as a whole, along with the German guidance, it's plain to see that Nebelwerfers were best used, as Kingfish and MikeyD said, for blanketing distant targets.

In my defense, I was up against three platoons of M10s and Shermans and an assortment of Rangers and rifle squads, and my lone PaK 38 and Mk IVH had been knocked out. I didn't have anything else in my arsenal to take out the American armor, except for 30m Panzerfausts. Fat lot of good the Nebelwerfers did me though; after it was all over, only one M10 had been immobilized and two rifle squads sent packing. Needless to say, I got creamed in that scenario :mad:

[Big Jim]

Of course, if one were a Bayesian statistician, the data from the North Africa tests could be taken as a prior belief and so give a posterior set of beliefs when combined with the data from the more statistically significant test in England.

How much difference (in weight, accuracy, etc.) is there between HE and smoke shells?

[Michael Emrys]

By way of comparison, in one game of CMBB about a year ago, I had five batteries of 132mm Katyushas set in a pre-planned bombardment to come in on about the second or third turn, the time that my attacking troops would be breaking cover. I had set the impact points fairly close together in order to saturate the most likely area where I suspected German troops would be located that could bring fire on my troops as they advanced.

The time came and the rockets fell for 10-15 seconds, I think. The impact points for the individual rockets were randomly distributed, but weighted toward the center of the pattern. Nevertheless, they covered an area somewhat less than half a square kilometer, IIRC.

Oh yes, one more thing. It was pretty awesome while it was happening.

Michael

[Mr. Tittles]

I imagine the nebels could send one 6 rocket launcher to a deserted firing area, and fire all 6 rockets, one at a time. The strike could then be observed for a center of effect. The launcher would immediately skidattle but this site could be used later.

The effect on the recieving end could sow panic if rounds impacted. The fear being that they would get a larger concentration soon.

It would make little sense to fire one rocket and then try to adjust in the next one. They are not accurate enough (not repeatable really) to bother. The accuracy of a sample of 6 or so WOULD show the beaten area and THAT could be dialed in.

Once a barrage was selected, ammo could be delivered first, the launchers arrive second and given the pre-determined co-ords, a mass fire launched and the nebels could scatter afterwards.

Fire into towns with tall buildings would catch the longs (due to the height of the building) and the shorts could hit mines and wire. Its ellipse is then shortened by the buildings height.

It really is a blast weapon and its destructive effects and secondary missiles are its main feature. They were not much of a fragmentation weapon. Against dug in troops in an infantry line, it is more a terror weapon. Direct hits being needed and its longs and shorts would be very wasteful.

[ May 22, 2004, 07:49 PM: Message edited by: Mr. Tittles ]

[Richie]

"why won't my nebelwerfer's kill somfink"...

Oh dear

Hope for the best Tiger!

[Panzer_M]

Nebelwerfers were a effect weapon,

My grandfather loved them, had a model of a 15cmNbwfr41 on his mantel.

The noise was the best thing as a barrage from a battery did more effect than a small battery of 10cm FH and could keep the enemy shocked long enough for an assault to work.

[von Paulus]

I suddenly realize that I had luck with my last 300m Katyushka fire ...

I had troops at 400 meters of the TAP but the nearest landed at 200m of my guys. Anyway some of the rockets landed in other directions at 500m of the TAP or even more.

[Michael Emrys]

W. Churchill after the battles of El Alamein :

"It's not the beginning of the end, but it's the end of the beginning"

I thought he said that after the capture of Tunis.

:confused:

Michael

[Michael Dorosh]

Originally posted by Michael Emrys:

</font><blockquote>quote:</font><hr />W. Churchill after the battles of El Alamein :

"It's not the beginning of the end, but it's the end of the beginning"

I thought he said that after the capture of Tunis.

:confused:

Michael </font>

[Kitty]

Dorosh is right. =|

Kitty

[von Paulus]

Damn, I'll have to change that

[Michael Dorosh]

Originally posted by Von Paulus:

Damn, I'll have to change that

Why? Tripoli did fall after the battles of El Alamein....just several months later.

Although, if you watch the World at War series, you do hear his voice in English, and on at least one occasion, he said (as near as I can remember....)

"This is not the end. This is not even the beginning of the end. It is, perhaps, the end of the beginning."

Immediately after he says "I must tell you that your fame...the fame of the desert army...has spread throughout the world."

And then an immediate segue into my favourite part of the entire series; the massed Pipes and Drums of the 51st Highland Division marching something like 15 abreast through what is presumably Tripoli, playing "Leaving Port Askaig."

[ May 23, 2004, 10:42 AM: Message edited by: Michael Dorosh ]