PJungnitsch Posted November 10, 2002 Share Posted November 10, 2002 How is tank ground pressure worked out in CMBB? Is it simply total weight divided by area of track? 0 Quote Link to comment Share on other sites More sharing options...
Wretch Posted November 10, 2002 Share Posted November 10, 2002 Judging from context in the vehicle description screens, that would seem to be the most logical assumption. 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 11, 2002 Author Share Posted November 11, 2002 Just wondering as I found a couple papers by a D. Rowland that deal with ground pressure and bogging. He has found that bogging has much more to do with something called mean maximum pressure, which takes into account chain pitch (length of the rigid portions of the track), and amount, diameter and width of the bogie wheels, as well as track size and vehicle weight. Little things like chain pitch seem to make a huge difference to how well a vehicle copes with soft ground. I've got them scanned and I'll send them on to BTS. 0 Quote Link to comment Share on other sites More sharing options...
Redwolf Posted November 11, 2002 Share Posted November 11, 2002 Hear hear. Just assuming that the track is evenly loaded is not very useful. Big wheels are better than small wheels, more whells are better than fewer, not to speak of the nature of the suspension. This one of the big reasons why, in CM, the StuG III is so much lamer than the StuG IV although I have never seen any historical remark that the IV would be better in mixed terrain or in difficult ground conditions than the IV. Apparently they performned pretty much the same in real life. 0 Quote Link to comment Share on other sites More sharing options...
karch Posted November 11, 2002 Share Posted November 11, 2002 I really have a feeling that tanks getting bogged/imobilized is not a calculation as detailed as you are hoping. The ground itself is an abstraction, I'd guess that there are some calculations that happen each second for each vehicle and based on the ground, ground condition, vehicle ground pressure and any modifiers, you either bog or not. I just think it's more abstracted than it seems you are expecting. If I'm wrong, I apologize. S 0 Quote Link to comment Share on other sites More sharing options...
Redwolf Posted November 11, 2002 Share Posted November 11, 2002 I'm not talking about bogging. Just raw speed in open ground. 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 11, 2002 Author Share Posted November 11, 2002 Some interesting things... One example he gives is the Elephant having only 12% heavier nomimal ground pressure (NGP, weight per track area) than a King Tiger, but having a mean maximum ground pressure (MMP) approx double, at 370 compared to 184. They more or less have the same weight and track area, but the suspension designs are quite different. Another is that Christies original suspension/track design gave good floatation partly due to very long-pitch track, which the Soviets mostly stuck with, but which is hard on track pins and very noisy. (Jives with what I've heard about T-34's) The British designers halved the track pitch in their cruiser tanks which got away from this, not realizing that it halved the floatation also. His conclusions are (I quote): 1)tracked vehicles with MMP over 300 are scarce and short-lived. 2)Tracked vehicles with MMP substantially above 200 have been substantially affected by bogging, while vehicles below this are little troubled. 3)Vehicles below 170 MMP are noted for good mobility. Some examples: Churchill VII 182-223 (low speed suspension) Cromwell IV 352 (track pitch .097) Sherman VVSS M4 282 Sherman HVSS M4 205 T-34/76 174-186 (track pitch .171) T-34/85 196 JS-II 245 Panzer III 220-232 Panzer IV 184-191 Panther 150-155 (wide, overlapping) Tiger I 185-192 Tiger II 184 Elephant 370 Explains one reason why the Germans were so keen on putting everything on difficult to work on overlapping suspension systems. They got a high speed suspension with excellent floatation. An M60 has an MGP of only 221-236, but I guess fighting in the mud of the undeveloped Soviet Union of the 1940's was not a big worry. He goes on about trucks, half-tracks, armoured cars, etc as well. 0 Quote Link to comment Share on other sites More sharing options...
Soddball Posted November 11, 2002 Share Posted November 11, 2002 Wow! I'm really surprised by the figure for the Cromwell! I always found that it floated like a happy flower across the muddiest battlefields. Very interesting info. 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted November 11, 2002 Share Posted November 11, 2002 This confirms what I had always felt intuitively including the bit about the interleaved wheels of the Panzer V-VI. Where can Rowland's work be found? Alternatively, how big a download are the files you have? Michael 0 Quote Link to comment Share on other sites More sharing options...
mike the wino2 Posted November 11, 2002 Share Posted November 11, 2002 Panther bogging and Churchie VII still moving? Not according to these numbers. BTS, please fix or do somefink! 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 11, 2002 Author Share Posted November 11, 2002 The papers are found in the proceedings of the 4th International Conference of the International Society for Terrain-Vehicle Systems (ISTVS), held in 1972 in Stockholm, the second is from the 5th International Conference, held in 1975 in Detroit. I am going to university at the moment, and the engineering library has them on file, so I just photocopied them. ISTVS has the proceedings for sale at their website here, but they are very expensive. I shrunk the files to 2.5 and 4 MB, but still found e-mailing them a tedious process on my hotmail. Let's see what Matt thinks of them. 0 Quote Link to comment Share on other sites More sharing options...
Andreas Posted November 11, 2002 Share Posted November 11, 2002 Originally posted by redwolf: his one of the big reasons why, in CM, the StuG III is so much lamer than the StuG IV although I have never seen any historical remark that the IV would be better in mixed terrain or in difficult ground conditions than the IV. Apparently they performned pretty much the same in real life.Hmm, according to those figures the IV should be quite a bit better than the III, not? Unless you meant it the other way round (which one is the typo in the second sentence?). Good thread Paul! 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 12, 2002 Author Share Posted November 12, 2002 Not quite done the post [ November 11, 2002, 11:00 PM: Message edited by: Paul Jungnitsch ] 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 12, 2002 Author Share Posted November 12, 2002 Here we go.... Was doing this out of interest, thought I may as well post it. A more complete list, in order of best to worst of ability to traverse soft ground. Panther 150-155 M-24 Chaffee 175 BT-5 175 T-34/76 174-186 Churchill M IV 177 (11 roadwheel) Tiger II 184 Tiger I 185-192 Churchill VII 182-223 Churchill Mk IV 217 (9 roadwheel) Panzer IV 184-191 T-34/85 196 Sherman HVSS 205 M3 Stuart 216 Panzer III 220-232 BT-7 240 JS-II 245 Universal Carrier 253 Sherman VVSS 282 E-100 290 Cromwell VII 300 Cromwell IV 352 M3 Halftrack 363 US 2 1/2 ton 367 (6X6) Elephant 370 SD KFZ 231 (8 rad) 415 M8 Greyhound 460 Maus 470 Opel Blitz 525 (4X4) Opel Blitz 700 (4X2) For comparison M29c Weasel 27 Caterpillar D7 32.5 (widepad) Caterpillar D7 80 (regular) Leopard II 201 M-60 221-236 T-62 242 M-47 246 AMX-30 249 0 Quote Link to comment Share on other sites More sharing options...
Grisha Posted November 12, 2002 Share Posted November 12, 2002 Good stuff, Paul! Thanks for the research. 0 Quote Link to comment Share on other sites More sharing options...
Andreas Posted November 12, 2002 Share Posted November 12, 2002 Paul, two questions: 1) does he compare the flotation with Ostketten and without Ostketten? 2) Does he have figures on the Panzer II? 0 Quote Link to comment Share on other sites More sharing options...
Soddball Posted November 12, 2002 Share Posted November 12, 2002 Interesting how the Panther is at the top of the list. That must have made it even more of a killer than it was - low bogging chance, fairly reliable, great armour, great gun and great optics. 0 Quote Link to comment Share on other sites More sharing options...
JonS Posted November 12, 2002 Share Posted November 12, 2002 Originally posted by Soddball: Interesting how the Panther is at the top of the list. That must have made it even more of a killer than it was - low bogging chance, fairly reliable, great armour, great gun and great optics.That is borne out by the comments in the March 1945 report to Eisenhower comparing US and German equipment. It's available on the web, but I can only find this link at the moment. 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 12, 2002 Author Share Posted November 12, 2002 1) does he compare the flotation with Ostketten and without Ostketten? 2) Does he have figures on the Panzer II?He doesn't show how he got the PZIV figure, other than giving a variation of (184-191). He does give his figures for the highest floatation of the PZIII (220), in which he used the narrowest track (360mm) but a fairly light weight (19). Tiger I is given with battle tracks (185-192), and transport tracks (230-240) He doesn't have figures on the Panzer I or II other than mentioning that that they use similar roadwheels and a similar but double pitch track to the Universal carrier, which is not particularly good at 250. 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 12, 2002 Author Share Posted November 12, 2002 Oh and the Eisenhower report is here. 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 13, 2002 Author Share Posted November 13, 2002 First report (mostly where the formula is worked out) is posted here. Click on the other interests link down and to the left on this Africa page to get to the report. [ November 12, 2002, 10:57 PM: Message edited by: Paul Jungnitsch ] 0 Quote Link to comment Share on other sites More sharing options...
Tarquelne Posted November 13, 2002 Share Posted November 13, 2002 Originally posted by Paul Jungnitsch: First report (mostly where the formula is worked out) is posted. here. Click on the other interests link to get to the report.Are the URL references correct for the article? Pointing to your hard drive, maybe?("file:///C:/Data/Words...") The Properties trick that ususally allows the viewing of pictures on the forum isn't working, at least. Nice site, though! And thanks for bringing this up. I'm always fascinated by the significant often-easy-to-overlook details of how weapons are used and wars are fought. 0 Quote Link to comment Share on other sites More sharing options...
PJungnitsch Posted November 13, 2002 Author Share Posted November 13, 2002 Thanks for pointing that out. Just checked it on a buddy's computer and sure enough, the first 4 scans were linked wrong. Seems all ok now. It is a big page though, and may take a while to load. Switching back and forth helps. 0 Quote Link to comment Share on other sites More sharing options...
JonS Posted November 13, 2002 Share Posted November 13, 2002 LOL - now you're blowing your bandwidth limit 0 Quote Link to comment Share on other sites More sharing options...
Tripps Posted November 13, 2002 Share Posted November 13, 2002 Originally posted by JonS: </font><blockquote>quote:</font><hr />Originally posted by Soddball: Interesting how the Panther is at the top of the list. That must have made it even more of a killer than it was - low bogging chance, fairly reliable, great armour, great gun and great optics.That is borne out by the comments in the March 1945 report to Eisenhower comparing US and German equipment. It's available on the web, but I can only find this link at the moment.</font> 0 Quote Link to comment Share on other sites More sharing options...
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