Halftracks (M3, Sdkfz.251, and others) Questions and What-if Ideas?

[dy031101]

The 105mm howitzer was too much recoil for the vehicle.  The T19 was not a wonderful setup and was very much a stopgap.  This could be done, but there are a couple configurations that may be more practical.  I think that you need to stick with the pedestal mount setup that is natural to the D-30, but go with an unarmored mount due to weight and gun operation.  The recoil would still be too much for the chassis but that's solved with some simple outriggers or recoil spades at the rear of the vehicle.

I do not think you could honestly go with an armored D-30 122mm mount on an M3 series halftrack in real life and hope to operate it.

Would modern 105mm howitzers (LG1, L118, M119, and the likes) be a bit easier on the recoil factor?

I wanted to see how far I can go with at least some crew protection......

[Logan Hartke]

Honestly, probably not for the most part.  Most of them are firing the same ammunition at even longer ranges.  While part of that is because of a longer barrel, a lot of that is due to better charges, too, which equates to greater recoil when you're talking about a fixed vehicle mount.  Now, there is one post-WWII 105mm howitzer that would work just fine, even in a semi-armored mount and that's the OTO Melara Mod 56.  Another neat choice for post-war guns (and another Soviet one, too) is the 82mm 2B9 Vasilek.  You could probably even do turreted mounts for those.

Logan Hartke

[dy031101]

Honestly, probably not for the most part.  Most of them are firing the same ammunition at even longer ranges.  While part of that is because of a longer barrel, a lot of that is due to better charges, too, which equates to greater recoil when you're talking about a fixed vehicle mount.

Would fitting a better muzzle brake help or am I truly doomed to be stuck with pack howitzers and mortars? 

[Logan Hartke]

Well, it's whiffery, so you can do what you want.  Also, you could make the 105mm howitzer work if you restrict it to a direct-fire, fixed forward mount, like the M3 75mm GMC.  You kill the suspension and even warp the vehicle, though, when you rely on it to take the recoil for high-angle mounts.  That why they had trouble with the 105mm howitzer, the 106mm mortar, and 40mm Bofors on the halftrack.  It's really a pretty light vehicle, about like a deuce-and-a-half.  Rapid fire mounts are fine, as are most direct-fire, but larger calibers firing up are usually bad for the chassis.

Why not take a standard Israeli-style M3...



...take the 105mm howitzer from an M37 HMC (same style as on an M4 105mm-no recuperator to mess with)..



...and stick it where the ball mount on the Zahlan is, Stummel-style...



...then give it overhead protection...



...and you've got yourself a cheap bunker-busting halftrack.

Logan Hartke

[dy031101]

Well I've been under the impression that muzzle brakes can help controlling the recoil.  How much does that statement still apply for howitzers?

Also, you could make the 105mm howitzer work if you restrict it to a direct-fire, fixed forward mount, like the M3 75mm GMC.  You kill the suspension and even warp the vehicle, though, when you rely on it to take the recoil for high-angle mounts.  That why they had trouble with the 105mm howitzer, the 106mm mortar, and 40mm Bofors on the halftrack.  It's really a pretty light vehicle, about like a deuce-and-a-half.  Rapid fire mounts are fine, as are most direct-fire, but larger calibers firing up are usually bad for the chassis.

Some sources claim that the mobility of the T19 HMC led to some user units employing the halftracks in a more aggressive manner (like they would assault guns, judging from the examples given)- is it safe to assume that this is in "direct fire" mode as you described?  Is M37 HMC also operated in the same way (more like a direct fire vehicle than a traditional self-propelled howitzer)?

To further elabourate on what you said, if the halftrack is to be capable fo both direct and indirect fire and has recoil spades at the rear, does it have to use the spades whenever it fires, or can it engage in direct fire mode without the use of the spades (and without the risk of killing its suspension or warping its chassis)?

[Logan Hartke]

Well I've been under the impression that muzzle brakes can help controlling the recoil.  How much does that statement still apply for howitzers?

It certainly still applies, but it doesn't do an absolute ton.  It's typically worth it, but just.  It helps by pushing the gas sideways and not forward (which would push the barrel back--recoil).  The lower velocity weapons (howitzers, mortars) are affected less, though.  Modern howitzers would actually be considered guns if they entered service 70 years ago--or at least gun-howitzers (in Soviet nomenclature).

Some sources claim that the mobility of the T19 HMC led to some user units employing the halftracks in a more aggressive manner (like they would assault guns, judging from the examples given)- is it safe to assume that this is in "direct fire" mode as you described?  Is M37 HMC also operated in the same way (more like a direct fire vehicle than a traditional self-propelled howitzer)?

To further elabourate on what you said, if the halftrack is to be capable fo both direct and indirect fire and has recoil spades at the rear, does it have to use the spades whenever it fires, or can it engage in direct fire mode without the use of the spades (and without the risk of killing its suspension or warping its chassis)?

The T19 was used as a direct-fire weapon also because there weren't a great deal of good HE throwers up front at the time.  In North Africa, for example the US still had a lot of M3 Stuarts as the main tanks for a lot of units.  Even some tank destroyer units still had the M6 GMC.  They had plenty of good artillery at the time, however, so the T19s weren't absolutely needed there.

Once more Sherman 75s got up front, you didn't see that anymore.  The M37 HMC was not employed that way, but the M4 Sheman 105mm assault guns used the same basic gun and were used for both.

As far as the direct and indirect fire question goes, it depends on what you put on it.  With indirect, put something more powerful than the M2A1/M101 105mm on it and you'll definitely need something.  You could easily do something as big as a Cockerill 90mm or US 76mm before you'd needs something for direct-fire.  You're very safe that way.

Logan Hartke

[GTX]

How about a half track variant of something like the Caesar 155mm Self-Propelled Artillery System:



Regards,

Greg

[dy031101]

How about a half track variant of something like the Caesar 155mm Self-Propelled Artillery System...

Now that I think about it, that's a great idea, too! 

With indirect, put something more powerful than the M2A1/M101 105mm on it and you'll definitely need something.

Judging from your description of T19 as a direct fire weapon vehicle, is it safe to assume that the spades are only needed when the vehicle is used in indirect fire mode?

You could easily do something as big as a Cockerill 90mm or US 76mm before you'd needs something for direct-fire.  You're very safe that way.

What of a full-power 90mm like the one below?

[GTX]

Some different, though real world never-the-less half tracks:




Regards,

Greg

[dy031101]

Umm...... halftrack jeep...... 

[GTX]

Umm...... halftrack jeep...... 

Go on - do it!!!

Regards,

Greg

[dy031101]

You kill the suspension and even warp the vehicle, though, when you rely on it to take the recoil for high-angle mounts.  That why they had trouble with the 105mm howitzer, the 106mm mortar, and 40mm Bofors on the halftrack.  It's really a pretty light vehicle, about like a deuce-and-a-half.  Rapid fire mounts are fine, as are most direct-fire, but larger calibers firing up are usually bad for the chassis.

Going back to this quote, you recommended OTO Melara Mod 56 before this...... the official pdf spec. states this one can use the same ammunitions as the M101.

(Hum...... if LG1 can't do, the Mod 56 sounds good, too, except for range......)

Do you mean that its recoil would be okay for use with the semi-armoured arrangement in indirect fire mode as well?

Also, according to the Wikipedia, New Zealanders found their examples unsuitable for sustained fire support missions and replaced their guns with the M101 during the Vietnam War.  What exactly happened to those guns as the result of the fire missions?

[Weaver]

It certainly still applies, but it doesn't do an absolute ton.  It's typically worth it, but just.  It helps by pushing the gas sideways and not forward (which would push the barrel back--recoil).  The lower velocity weapons (howitzers, mortars) are affected less, though.  Modern howitzers would actually be considered guns if they entered service 70 years ago--or at least gun-howitzers (in Soviet nomenclature).

A well designed muzzle brake can make a hell of a difference, but a lot of the ones in actual service are pretty pants. A good muzzle brake actually deflects gas sideway and backwards between expanding surfaces that function like a rocket nozzle, containing the expansion of the gas and converting it into forward thrust (on the barrel) that counteracts the recoil. Like a lot of other ordenace issues, muzlle brake design is mired in a web of patents.....

[Weaver]

Heres a couple of relatively simple half-track ideas:

1. Take an Sdkfz-231 6x4 armoured car and drop it onto the chassis of the Hanomag,

2. Take a Greyhound armoured car and fit it with the half-track system of the White M3.

[Logan Hartke]

Going back to this quote, you recommended OTO Melara Mod 56 before this...... the official pdf spec. states this one can use the same ammunitions as the M101.

Ammunition, yes.  Charges, I don't think so.  It's about the powder you're putting behind the round and I don't think the Mod 56 can use nearly as many as the M101.

Do you mean that its recoil would be okay for use with the semi-armoured arrangement in indirect fire mode as well?

By my estimation, absolutely.  I'm no expert.

Also, according to the Wikipedia, New Zealanders found their examples unsuitable for sustained fire support missions and replaced their guns with the M101 during the Vietnam War.  What exactly happened to those guns as the result of the fire missions?

What did they do with them after they got rid of them?  I don't know.  Or do you mean why were they unsuitable?  Probably because of their light construction, lower durability, and shorter range.

As far as the 90mm goes, your guess is as good as mine.  I don't think I'd want to be in the crew compartment when you tried it, but I'd not be surprised if you told me it worked fine.  The weight in an armored configuration might be a bit much.   I know that the M18 Hellcat was light enough to have a time with the recoil, but could handle it.  Likewise, so could the M56 Scorpion, and it was light.  Again, though, the recoil was violent and neither had much at all in the way of protection and certainly no overhead protection.

Logan Hartke