US Halftracks

[volgaG68]

I wonder why so many US halftracks have Red MP? I don't see anything in individual Vehicle Notes or in the collective subscript information explaining why so many have it. Poor design? Is the reason officially stated somewhere that I overlooked?

Thanks (just curious)!

 

[clubby]

Weren't they all Dodges? That probably explains it.

 

[volgaG68]

Weren't they all Dodges? That probably explains it.

I will accept this answer as both funny and likely correct!

 

[Paul M. Weir]

The tracks. The M2/M3/M5/M9 halftracks used a variant of the Kégresse track system. Basically it was moulded in rubber in one piece with embedded steel cables and small plates unlike most tracks which are assembled with individual links/plates joined by track pins. So basically a giant (slightly reinforced) rubber band.

Maintenance:
So while in a conventional track bad links and pins could be replaced when seen to be worn, with the US h/t it was a case of replacing all or nothing. So you can imagine that in normal use that was put off longer than equivalent individual track replacement regimes.

Materials:
Nearly all tracks have a steel basis. Most German h/t used cast plates with rubber pads for their tracks. So if the rubber wore down there was still LOTS of steel holding the thing together. With the US it was mainly rubber with a few steel cables, so imagine which outlasts heavy wear better.

Vehicular design:
One of the attractions of the Kégresse system is that it was designed to allow the replacement of a truck's rear wheels with Kégresse track boogies, turning a truck into a h/t. That was the root of the US h/t line. A truck fitted was with a Kégresse boogie to become the T9 unarmoured h/t, the idea copied with a M3 SC to become the T7 that eventually emerged as the M2 h/t. The Germans started from scratch with their h/t suspensions and vehicular designs, indeed they might be better described as 3/4 rather than 1/2 tracks. The result is that though their front (steering) wheels were unpowered, unlike the US designs, they had roughly twice the length of track in contact with the ground, thus reducing the wear per inch length of track.

So the German designs had better flotation overall but were at a disadvantage with unpowered front wheels (IE muddy field better, small ditch worse) and had tracks that were both easier to maintain and had were more durable. Due to the US's material wealth that would not be a problem at the strategic level, but could be nasty at the tactical, sharp end.

I hope that gives an idea of the what might have been in the designer's mind. I don't know whether they really got it right, but the choice seems very plausible to me.

 

[volgaG68]

I hope that gives an idea of the what might have been in the designer's mind. I don't know whether they really got it right, but the choice seems very plausible to me.

Thank you. It makes perfectly plausible sense now.

 

[Paul M. Weir]

Well, that's my best guess. It's an interesting question and I am surprised it has not cropped up before. US combat vehicles in general were from 5 to 10 years ahead of everyone in terms of mechanical reliability, so the h/t sort of stick out.

One thing that struck me after posting is the comparison between the suspension on German and US h/t. The Germans, in the main, used torsion bar suspension. So hitting a rock or a hard landing coming down from an obstacle might be enough to break 1 or 2 torsion bars and make a wheel or two 'lame', but do the same in a US h/t and you might loose or warp the whole side unit. The US unit looks really, really flimsy to me.

Bonus Extras:
In ASL the M5/M9 variants are slightly slower (came with WoA/FKaC). The M5/M9 series was produced by IHC to make up for existing M2/M3 manufacturing limitations. It was produced using homogeneous armour, slightly thicker 5/16" than the M2/M3 1/4" face hardened armour. While that could be rolled, hence the rounded rear corners, it was slightly inferior in protection, though given the M2/M3 thin armour, that's not saying much. The extra armour thickness and construction details added up to an extra 700 kg or so of weight and combined with a fractionally weaker engine (142 vs 148 HP) meant a slightly lower HP/weight thus 19 MP vs 20.

While in ASL the M2 and M3 series are pretty much the same, in real world design they had very different rears. The M2 had side ammo bins that opened to the outside and a shorter rear hull than the M3 though both the chassis and everything from the driver position and forward were identical. The M2 was designed as a prime mover and recon vehicle while the M3 was designed as an infantry taxi. The M5 (M3 equivalent) and M9 (M2) had the exact same bodies, only internal fittings and arrangements to suit the disparate purposes differed.

 

[aneil1234]

It was explained fairly well in the SL days when GI-Anvil came out

The "Purple Heart Boxes" chewed up their tracks like no bodies business. Nasty tendency to leave them behind if you turned left or right

 

[jrv]

The Osprey series on the M3 halftrack says:

The M2 and M3 half-tracks were used in the autumn 1941 Tennessee and Louisiana wargames. Their combat debut came months later in the Philippines with the Provisional Tank Group, which had 46 half-tracks. These were used mainly in command and general utility roles, and were much preferred to the Bren carriers otherwise used by the unit.

The Philippines fighting uncovered many technical shortcomings in the half-track, especially in the suspension, and these were reported to the Ordnance Department by radio before the fall of Bataan. The Provisional Tank Group officers were critical not only of the fragility of the suspension, but of the lack of thick armour and overhead armour cover. Although the Ordnance Department initiated immediate modification programmes to correct the suspension difficulties, the lack of overhead armour was to remain a controversial feature of the M2 and M3 half-track. Prototypes of half-tracks with overhead cover were built and tested, but Ordnance felt that the added weight excessively degraded the automotive performance of the vehicle.

The Army later did a comparison with the SPW 251. They liked the M3 better because it had the roller up front and powered front wheels, making it more mobile. They also wrote that the complicated interleaving of the rear road wheels on the SPW 251 led it to picking up dirt and muck, and between that and the tank-style tracks, it was prone to throw tracks in rough terrain.

JR

 

[KhandidGamera]

Just happened to see this today, going to some segments of the board I don't normally go.

Paul's explanation very helpful and credible.

What I find interesting though is the consistent feed back from 2nd Armored Division folks in "United States verses German Equipment". The 2nd Armored people really had good things to say about their half-tracks, and used, but didn't generally like the captured German ones they used-didn't like the lack of front wheel drive especially, but did like sloped armor. It came across that the German ones they used didn't last serviceable long. Don't remember any bad feedback on the US Half-track system. So did that mean it worked well or it broke and it was easy to fix, or the support was good enough to get it fixed - that it doesn't emerge as a complaint about equipment?

Reading about the 251 tracks my impression was "complexity" that wouldn't stand up well in the field - separate and before reading Paul's detailed comparison above.

Paul, I'm interested to know if you are familiar with "United States verse German Equipment" and if so your thoughts. Seemed to me credible as by definition its a document closer in time and space to the events - a formal first-hand combat report, from a cross section of troops, officer and enlisted. Been meaning to post about it for a while, but lacked the time. There is a lot of ASL relevant stuff in there.

Also, I have the Osprey on German 251, but looking on Amazon, available material on German half tracks seems very thin.
For the American M2/M3 I didn't give in to buying the two volume ~$100 set out there.

I