I am pretty sure that in ww2, most german armour had tracks that would sag. My question is do tank tracks sag when the tank is in motion? I am planning on building a diorama and its a flammpanzer 3, the tank will be moving (slowly as its getting ready to attack) and I was wondering should I put some or any track sag on the tank?

It would depend upon whether the sprocket is in the front or the rear. Normally, when a front sprocket is pulling on the track, it'll be tight, except if the tank is decelerating. Motorcycle chains are act the same way. Sag on the back side can be taken up with a chain tensioner.

Andrew:

That's one of those fun questions indeed!

Robert's answer is, in general, correct, albeit the devils are, as some say, in the details

There are some variables to entertain you here...

1) What actually was the tension on that track? While we modelers love to "sag" our dead-link, dry-pin panzer tracks, in reality, as seen in the period photos, real panzers exhibited a wide range of apparent track-tension - and many "at rest" panzers III and IV (which wore the same actual track link sets) were apparently pretty tight and had almost no evident sag, whereas others looked pretty loose and droopy. So this goes into your answer - what is your assumption about the general state of the tracks?

(PS: there was a tensioner provided, and crew were trained to keep the tracks fairly tight, as a loose track could easily jump the idler or a road-wheel and shed the track under way... Balanced against this, a looser track actually rolls around the gear easier and so is less wearing on the track pins - but this is a fine balance...)

2) Robert is spot-on about the front sprocket applying tension - to the upper run. So that run should be snug and "sagless" when accelerating. On the other hand, the turning sprocket is "pushing" links down in front of the leading road-wheel. So, an accelerating tank, or one going even modestly "uphill" will "pile track" below the sprocket - if that track is the looser set, it will have some evident sag below the sprocket - but will be "straight" between sprocket and return rollers, between rollers, between roller and idler, and between idler and last road-wheel. Think of pulling a string - it will be straight (under tension) throughout all the pulled lengths- but as a closed loop, the length just below the sprocket will be loose.

3) And combining 1 and 2... those tanks with already-tight tracks would exhibit little evident sag either at rest or in motion. Those with looser tracks would exhibit varying degrees of "piling" beneath the sprocket (or, if backing up, piling between the sprocket top and the first return roller, and sag between rollers, but straight (tight) between idler and last roadie, etc. And once a tank is up to even speed on a level hard surface... pretty much a loose track will sag some - a bit like at rest, but to lesser degree. It will assume a dynamic catenary curve form.

4) All of the above is more true for smaller tanks with lighter track-sets. The very heavy tanks - Panthers, Tigers I and II - had very heavy large link tracks which probably sagged at all times accept under greatest acceleration (watch videos of restored Panther and Tiger tanks under way and see this sag-in-motion effect). And, just for added fun - those small-but-heavy Pz 1 F and Pz II J "rolling pill-box" tanks with wide, heavy tracks also probably sagged under way!

So... IF in your dio you are, say, depicting your tank creeping up a slight slope or over an obstacle, tighten-up the upper run and sag beneath the sprocket to show motion!

Bob

Sometimes the track sags as the vehicle is moving and sometimes it pulls tight under the load - it really just depends on a lot of variables. Generally, tanks with a good deal of sag in the track while at rest seem to have a fair amount of sag while in motion, even up or down hill. However, there are many exceptions.

You can go to Youtube.com and search for "German World War II Tanks" and find literally hours of film of tanks in motion.

Here's a quick 2 minute sample that shows several variations, but this is just a couple of minutes of footage. You can even see examples in this clip of tanks in motion where in one moment the tracks are sagging and in the next, they're pulled fairly tight. Watch a few more clips, and you'll get a feel for the subject.

You Tube::WW2 German Tank Footage

HTH,

Cheers guys

and any kind of turning will make the track and sag move about too ;-)

Hi Andrew,

Nothing to add to Bob's (professional?) comments.
Just this: any tracked vehicle commander would try to avoid too much slack tracks since the risk that the might jump of the return rollers or of the road wheels is very high and could lead to a halted vehicle. And thus an easy prey.
I can recall moments of great frustration as one of our AMX Artillery vehicles took turn up a slope and easily lost a track due too much allowance in track tension. So, just don't overdo it in your model.
Though, MiniArt has a crew which is busy with a broken track! ( model 35011)

Modern day but here is a

Jadgpanther

Panzer IV

both from the german Panzer-Collections at Koblenz and Munster

Thanks again people, you have helped me a lot