WWII question: why "half-tracks"?

Hi Folks,

I was watching a truly awful movie last night about the Battle of the Bulge (it was on Prime, and it was appallingly bad --"Winter War").  But it did feature half-tracks, and I wondered what  the advantages of that configuration were?  Obviously the traction of the tracks?  But what advantage dd the front wheels offer?

What else do you know about those things? 

I'm guessing simplicity and reduced costs had a lot to do with it. A halftrack wouldn't require differential steering via the tracks, which would simplify the running gear a lot. Heavy truck front axle components were likely used in at least some models. They were much lighter vehicles than tanks, so the ground pressure would have been considerably less, meaning smaller track surface would still be sufficient (in theory) to provide good off-road mobility.

Lower ground pressure so they are less likely to get stuck on soft terrain.

Simple truck steering setup, unlike a full tracked vehicle that requires multiple clutches and brakes. 

Any idiot with a driver's license can drive them with zero training. 

If I had to guess they were mainly just simpler to build. With a full tracked vehicle you need a drivetrain where you can control each track to steer the vehicle. With a half track I would imagine the drivetrain is no different then a truck it was most likely based on. I'd imagine normally the differential would be unlocked in the back with a way to lock it for when things get soft and sloppy.

I'd guess these would also end up being lighter and faster than a full track vehicle as well.

Now lets see how far off I am when someone who actually knows shows up.

Pretty good article here:

https://military.wikia.org/wiki/Half-track

People use the same principle for vehicles on low-friction terrain even today:

In reply to Beer Baron :

I live in Canada.  I would never have considered that a "half track".  And now you've rocked my world :)

In reply to Beer Baron :

Our drive thru windows are lower in Canada so you can take your sled to Timmys.

In reply to ZOO (Forum Supporter) :

Do halftracks have a regular diff? Are they beam axles or IRS? Do they have limited slip diffs? Can you do a one wheel(track) peel in a halftrack?

I have so many questions.

Remember the member Celica-halftrack? I think he was onto something. 

Toyman01 + Sized and said:

Any idiot with a driver's license can drive them with zero training. 

I think this was the key reason militaries used them in WW2, increased mobility with almost no additional training required.

Not really totally on topic, but interesting.

Guy who can't pronounce "Citroen"

I don't know about all tanks, but some German tanks could only turn in 16 discrete turning radii.  They had multiple fixed differential ratios and steered by shifting the diff. (Imagine engineering THAT sucker)

For a truck?  I'll take a steer axle for the simplicity and greater maneuverability.  Could you imagine having a tank commander tell the driver to stop, shift into whatever left turn radius to go around a building, find an impassable obstacle most of the way around, get hit by an anti-tank shell because the opposing force knew you couldn't make that turn...

Pete. (l33t FS) said:

I don't know about all tanks, but some German tanks could only turn in 16 discrete turning radii.  They had multiple fixed differential ratios and steered by shifting the diff. (Imagine engineering THAT sucker)

I can 100% imagine a German engineer coming up with that solution to that problem.

I think even the little halftracks still had differential steering for real turns. The "regular" steering doesn't work great, but it allows for easy small adjustments like following a road and maintaining lane position. Modern steering has good enough control that halftrack no longer buys anything.

Beer Baron said:

Pete. (l33t FS) said:

I don't know about all tanks, but some German tanks could only turn in 16 discrete turning radii.  They had multiple fixed differential ratios and steered by shifting the diff. (Imagine engineering THAT sucker)

I can 100% imagine a German engineer coming up with that overly complex, easily, and often broken solution to that problem.

History fixored.

In reply to Beer Baron :

The discreet steering radii is the simple solution. Differential braking is nicer in theory than practice. The discreet radii came from having a differential right of the engine and a transmission on each output shaft. It helps solve the problem of finding a strong enough transmission and you can replace an entire steering system with another shift lever.

A tank is presumably a full-track. So what is this?

A double-track?

In reply to ZOO (Forum Supporter) :

I've seen Motel Ts with a bolt on floating rear axle & tracks similar to the big car above, unbolt it in the spring.  MacGuyver something similar for that RWD POS out behind the barn.

pinchvalve (Forum Supporter) said:

A tank is presumably a full-track. So what is this?

A double-track?

Quadra-track!

pinchvalve (Forum Supporter) said:

A tank is presumably a full-track. So what is this?

A double-track?

yes, double track. bigger than full. There's also queen track, king track (size of two fulls), and california king (longer and leaner than king) track. 

In reply to secretariata (Forum Supporter) :

Taken

In reply to bearmtnmartin (Forum Supporter) :

I know. I was trying to alter the memory by attaching the name to something else... 

Another advantage that I can think of is resistance to small-arms and rifle fire.  Tires deflate pretty easily, but a half-track will keep propelling even if the fronts get shot out.