Schweres Wurfrahmen 40 Revisited--Surprising New Data

[Jeff Duquette]

Ok John I’ll bite After going through some of the data that Mathias sent, it still impresses me that Schwerer Wurfrahmen was very inaccurate. From the previous example for a US ARMY 155mm. Dispersion relative to range is was follows:

Example: 155mm-AM-2 firing M107 HE using 4G charge, 50% zones:

<UL TYPE=SQUARE>

Range______Range_________Deflection

2,000m_________16m_____________2m

3,000m_________22m_____________4m

4,000m_________28m_____________6m

5,000m_________36m_____________8m

6,000m_________46m_____________10m

7,000m_________56m_____________12m

With rocket artillery, at least based upon review of two sets of firing table data that Mathias was kind enough to email to me, it looks like range probable error decreases with an increasing range. Deflection probable error on the other hand does seem to do what one would expects (i.e. dispersion zone increases with increasing range).

Example: German WWII era 28 cm Rocket, Schwerer Wurfrahmen, 50% Zones:

<UL TYPE=SQUARE>

Range______Range Error_____Deflec. Error

700m___________160m____________20m

1,000m_________150m____________30m

1,200m_________150m____________40m

1,300m_________140m____________40m

1,400m_________130m____________60m

1,500m_________120m____________60m

1,600m_________110m____________60m

1,700m__________90m____________70m

1,800m__________80m____________80m

1,900m__________80m____________90m

German 32cm rocket for Schwerer Wurfrahmen appears to exhibit a similar pattern\trend of decreasing range probable error with an increasing range.

The difference in dispersion between conventional artillery and rocket artillery is considerable. For example, Range Probable Error for the 280cm rocket. On the basis of the 100 percent dispersion rectangle, 50 percent of the rounds will impact within 120 meters (over and short) of the mean range line. 82 percent will impact within 240 meters, 96 percent will impact within 360 meters (over and short), and 100 percent will impact within 480 meters (over and short).

Dispersion from range probable error of the 155mm at 2000 meters is: 50 percent of the rounds will impact within 16 meters of the mean range line. 82 percent will impact within 32 meters, 96 percent will impact within 48 meters, and 100 percent will impact within 56 meters.

You can go through the same exercise for deflection probable error to get the width of the potential target area. The 100% rectangle for the 280cm Rocket @ 1500 meters is therefore 480m long by 240 meters wide.

My biggest gripe with the inclusion of Wurfrahmen in Close Combat III & IV was:

1)The uncanny accuracy of Wurfrahmen. By the above dispersion figures it is apparent that the Wurfrahmen is anything but accurate relative to more conventional artillery.

2)The small map sizes of CC relative the large dispersion zones for Wurfrahmen.

As far as their inclusion in Combat Mission, I don’t see why they couldn’t be included, with the stipulation that their relatively large dispersion zone is modeled, and the rarity issues which Hofbaur has elaborated on are seriously considered.

[This message has been edited by Jeff Duquette (edited 02-24-2001).]

[M Hofbauer]

I am about to offer a possible explanation to the "range error decreasing with range" which seems to be a paradoxon.

Maybe, just maybe...

We all know that a certain amount of propellant will make for a certain range. However, severe difficulties were encountered by the germans in letting the rockets burn their propellant at the same constant usage rate (fact). So at half the range some rockets would have burnt a little more already and others a little less (educated guess), meaning that the range difference between these two would be considerable (deduction). Now, at the total range, both would have eventually burnt their total propellant and therefore achieve a more comparable range (speculation). In other words, the longer the range the more the problem of uneaven solid fuel usage would even out (speculation).

Just a specualation of mine, and probably not the only contributing cause to the effect we are seeing here.

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"Me tank is still alive me churchill's crew must be laughing there heads off." (GAZ_NZ)

[This message has been edited by M Hofbauer (edited 02-23-2001).]

[Jeff Duquette]

Interesting. Certainly seems like a plausible explanation. I have some feelers out in other areas and hopefully I will get some responses soon. I’ll post anything I get here.