Tank Length to Width ratio....

[Peter Cairns]

I read an article a few years back that stated that there was an optimum ratio for length and width of tracked vehicles, which I think was something like 3 to 5.

At more than 3 to 5, long narrow tanks tended to have poor turning circles and manouverability, though good traction.

wide short tanks on the other hand turned better, but tended to slither at speed, particularly on wet roads, where they could skid on corners.

I was wondering is this simulated in CM at the moment or could it be something that could be incorporated into the next CM.

It might be done by forcing fast tanks like Hellcats to slow do more when approaching corners on roads, or making Churchhills, less likely to bog down when moving forward or back, but more likely when they turn.

Just an idea, what do people think.

Peter.

[Michael Emrys]

I think some of the effects you describe may exist, but I doubt that the l/w ratio is really all that critical. What is critical is that tanks not be too wide to use existing roads or transportation, but there's even a little wiggle room there if you want to go to the trouble. As for length, a longer track (not necessarily hull) means a larger area in contact with the ground, therefore lower ground pressure, therefore better flotation. But it also means harder to turn and more likely to break a track in turning I should think due to to the higher lateral forces. But I admit I may be mistaken on that latter point. A key thing would be that a tank that is either wider or longer or worst of all both would have been more difficult to maneuver in the narrow confines of European and Middle Eastern cities. And believe me, regardless of what your doctrine might say, sooner or later you'd have to.

Michael

[dieseltaylor]

I understand that the TigerI was actually quite a manouvreable tank. Tending to the square shape 8:4.8 and with broad tracks. MkIV was 8:3.8

[tar]

Well, having the tanks too wide would certainly hamper strategic mobility, since railroad clearances are much harder to do anything about than road clearances. Having great tanks that aren't where you need them isn't all that handy in wartime.

Certain design features of weapons were dictated by the need to ship the products around. IIRC, the Me-109's narrow landing gear (undercarriage for Brits) track was due to a desire to be able to remove the wings for rail shipping while still letting the fuselage be supported by the main wheels.

Tanks certainly had to be able to be transported by other vehicles. Even today, long road marches with armored vehicles are made using trucks or rail rather than driving the tanks under their own power. Tracks are somewhat (a lot?) less reliable than wheels for motive power, so you don't really want to increase the chances of breakdowns unnecessarily.

[Merkin Muffley]

I seem to recall (no doubt incorrectly) that the Stuart didn't have the ability to turn on the spot (tracks going different ways) and therefore would describe a tight arc when doing 180 degree turns rather than a pivot.

If so, that would be nice to see.

[gibsonm]

Originally posted by tar:

Tanks certainly had to be able to be transported by other vehicles. Even today, long road marches with armored vehicles are made using trucks or rail rather than driving the tanks under their own power. Tracks are somewhat (a lot?) less reliable than wheels for motive power, so you don't really want to increase the chances of breakdowns unnecessarily.

Tracked vehicles now (and no doubt 60 years ago) are good for long distant tactical driving and if required long road runs (e.g. after the Normandy breakout to Belgium, the deployment from Saudi Arabia into Iraq in 1991 or the drive to Baghdad in 2003). However running a vehicle on its tracks will generate a considerable amount of wear and tear (as track stretches, running gear wears, etc.).

The problem is that at the end of such a road run normally extensive maintenance is required and crews are exhausted.

Rail / Road travel alllows an armoured unit to move long distances far more quickly than on its own tracks and at the end of the trip, the unit is operational (no crew fatique, no wear and tear on the vehicles).

[Michael Emrys]

Originally posted by gibsonm:

Tracked vehicles now (and no doubt 60 years ago) are good for long distant tactical driving and if required long road runs...

I believe the Sherman was probably the first tank to be able achieve long drives without a high probability of a track failure. Most tanks required daily maintainence of the tracks and still had frequent breaks. Going only on anecdotal evidence, the British tanks circa 1940 would break a track if you even looked at them cross-eyed. I don't know about the Soviet tanks. They generally enjoy a better reputation for robustness, but I doubt that was so true of the early war models. The Germans fell somewhere in between, being better off than the Brits but not so reliable as the Sherman, or the Stuart for that matter. The later Brit designs were greatly improved in that regard, but I don't think ever quite matched the best.

Michael

[gibsonm]

Originally posted by Michael Emrys:

</font><blockquote>quote:</font><hr />Originally posted by gibsonm:

Tracked vehicles now (and no doubt 60 years ago) are good for long distant tactical driving and if required long road runs...

Going only on anecdotal evidence, the British tanks circa 1940 would break a track if you even looked at them cross-eyed.</font>

[JonS]

Originally posted by Michael Emrys:

As for length, a longer track (not necessarily hull) means a larger area in contact with the ground, therefore lower ground pressure, therefore better flotation.

Floatation is substantially more complex than a simple "veh weight" / ("track length" x "track width") equation (aka Nominal Ground Pressure, NGP). IIRC, two of the key factors is the pitch of the track segments and the spacing between the road wheels. This is is why the Churchill, and most German tanks, were so good in this regard. And also why the early Shermans were so bad. Sherman track area in contact with ground ~ PzIV, IIRC, yet they had very different 'floatation'.

[Michael Emrys]

Originally posted by JonS:

</font><blockquote>quote:</font><hr />Originally posted by Michael Emrys:

As for length, a longer track (not necessarily hull) means a larger area in contact with the ground, therefore lower ground pressure, therefore better flotation.

Floatation is substantially more complex than a simple "veh weight" / ("track length" x "track width") equation (aka Nominal Ground Pressure, NGP). IIRC, two of the key factors is the pitch of the track segments and the spacing between the road wheels. This is is why the Churchill, and most German tanks, were so good in this regard. And also why the early Shermans were so bad. Sherman track area in contact with ground ~ PzIV, IIRC, yet they had very different 'floatation'. </font>