US light tanks & derivatives: how would you do it?
WW2 GeneralDiscuss US light tanks & derivatives: how would you do it? in the World War II - General forums; Since M3 medium, followed by M4 were to be 'proper' tanks, you can change/develop M3 light tank to be better ...
US light tanks & derivatives: how would you do it?
Since M3 medium, followed by M4 were to be 'proper' tanks, you can change/develop M3 light tank to be better suited for WW2 battlefield. Starting point can be US entrance in war; M3 is already in combat in N. Africa, using both US and UK/Commonwealth products for improvement. The 1st usage of new tanks/derivatives circa late summer of 1943 (invasion of Italian 'boot').
No Cold War guns, thankyou
By they time they got done they hit 25 tons light and 29 tons and used some of the same engines as the M4 medium. It was finally canceled when it was decided it offered no advantages over the Sherman.
Best "aid the Allied cause" would been to have developed a successor to the Sherman faster and skipped fooling around with light tanks. Yes they are useful for reconnaissance but the US made almost 9,000 M5 light tanks. That is a lot of recon vehicles.
Now are you looking for a "better" recon vehicle? 3 man crew instead of 4, lower height, faster, quieter, lower ground pressure for crossing muddy ground/snow?
Or are you looking for something better suited to slugging it out with MK IV German tanks and Stugs? Bigger gun, thicker armor?
Something around APC, US Vespe, US Marder... US indeed produced AFVs that worked very well in these roles, but those were not available all places M3/M5 went. Sure enough, US Army wouldn't decline those, too
For inspiration, historical Stuart Pak.
Ingreadients are Stuart V supplied by UK for Yugoslav partisans (for their 1st Armored brigade, IIRC), captured 7,5cm Pak, work was done in late 1944 in shipyard in Šibenik, Croatia (60 km away from my town).
Stuart Flak also existed (quadruple 20mm Flak), and 15cm SiG was bolted on too.
Last edited by tomo pauk; 04-02-2011 at 03:28 PM.
Reason: Stuart V, not III
Workshop conversions of small quantities (1-12) are one thing. Quantities like the US usually produced are another. The US probably tested most likely combinations:
Thanks for the links; the site is great & well known.
After looking at what was tried, we still lack APC and SP ATG (3in).
The SP 105mm was designed in 1944 - too late to use production examples in combat; M7 Priest & Sexton are available by then; it uses M3 howitzer that has lower MV than M2, M2 howitzer is in full production by the time M3 starts production (spring of 1943).
The placement of combat compartment hampers all 3 'versions'. Therefore, we copy Germans.
The Pz-II, Pz-38(t) and Pz-IV have had similar propulsion layout as US tanks - engine back, transmission on front. In converting tank hulls to 'geschützwagen', Germans have relocated engine in center of the hull, leaving the back of the hull free for guns, ammo and crew (minus the driver, of course). We will also extend the hull by 1ft, maybe 1.5ft, arriving at AFV as long as Wespe, or Marder III, but wider some 20cm.
The M-3 was too small to make a useful APC. See the Recce modifications with turret removed. needed 3 vehicles to transport a single squad isn't going to work. The other thing about Americans building some of these other versions is that they had halftracks out the wazoo.
Many of the functions could be done by halftrack conversions and done better. Half tracks provided the SP AA mounts, SP mortar mounts, SP 75 howitzer mounts, SP 105 howitzer and 75mm AT gun mounts.
In most cases they gave the guns crews more room to work and carried more ammo.
The Germans did a lot of those conversions because they had to. Lack of production capacity+ short development time. No or little MK III/IV production capacity to spare. When you get to the 105 Howitzers (Wespe) the use of too small a chassis starts to show. It carried 32 rounds of ammunition. Four every 4 gun armed vehicles there was a 5th without a gun that acted as an ammo carrier and spare chassis that a gun could be swapped into. The American M7 carried 69 rounds.
If you are talking about a "what if" in which the Americans had some bizarre reason only the M3 light chassis to work with then some of the vehicles make sense. With the M3/M4 chassis and the halftrack chassis available they don't.
The M-3 was too small to make a useful APC. See the Recce modifications with turret removed. needed 3 vehicles to transport a single squad isn't going to work. The other thing about Americans building some of these other versions is that they had halftracks out the wazoo.
Asking from turret-less M3 to perform as proper APC is asking too much; asking from halftrack to be Armoured (the A from APC abbrewiation) is asking too much, too, as shown with usage of Cangaroos. Half-tracks, while better than trucks, can't compete with off-road capabilities of 90% of tanks.
Many of the functions could be done by halftrack conversions and done better. Half tracks provided the SP AA mounts, SP mortar mounts, SP 75 howitzer mounts, SP 105 howitzer and 75mm AT gun mounts.
In most cases they gave the guns crews more room to work and carried more ammo.
The half-tracks gave sterling job as platform for AAA, mortars, 75mm artillery. I did not ask from a M3 derivative to double in those roles, though.
The US half-tracks were not outfitted with 3in gun ( difference vs. 75mm is substantial in AT capabilities), while T-19 was judged to light for 105mm recoil, so 105mm was stripped from them eventually.
Again I'll admit, hull of M3 makes a lousy platform for 'proper' guns.
The Germans did a lot of those conversions because they had to. Lack of production capacity+ short development time. No or little MK III/IV production capacity to spare. When you get to the 105 Howitzers (Wespe) the use of too small a chassis starts to show. It carried 32 rounds of ammunition. Four every 4 gun armed vehicles there was a 5th without a gun that acted as an ammo carrier and spare chassis that a gun could be swapped into. The American M7 carried 69 rounds.
Since US produced whooping 25K + of M3 & M5 combined, think we can spare some to act as ammo carriers
The M3 starts as 10% wider vehicle, and, earlier, I've suggested lengthening the hull.
If you are talking about a "what if" in which the Americans had some bizarre reason only the M3 light chassis to work with then some of the vehicles make sense. With the M3/M4 chassis and the halftrack chassis available they don't.
US issued many 3in towed AT guns - instead being loathed from GIs, better thing is to mount them to 'my' M3 chassis.
M7 Priest was not ever shipped to the Russians, leaving them with SU-76 to act as indirect mobile fire support. Sending 700 M3/105mm (not only) there makes more sense than another 1000 of light tanks. Ditto for M3/3in.
Sure enough, acquiring of another, say, 3000 of SP artillery 'stead of towed pieces makes Allied forces more mobile, faster to deploy/fire/redeploy, cuts on manpower...
My proposal:
-hull elongated between main wheels
-engine in center, simple gearbox couples engine with transmission 'stead of prop shaft
-muffler on lower hull, exhaust under returning part of tracks
-hull extended back, vertical rear
Now that is some 'geschützwagen' - note the much bigger combat compartment, unobstructed by prop shaft, compared with turretless M3 hull (1st pic).
The M5 offers itself for a neat conversion.
Deleting of a turret & one of engines cuts weight to, perhaps, 12 tons. That leaves us with 148HP, power-to-weight ratio 12,3 HP/ton - almost equal to M4s with Chrysler, or GM engines. That would be the APC; even with no mid-hull stretching the number of troops carried can be as previous M3 conversion, because the engine can go in place previously occupied by radio-man.
The fully-fledged, stretched variant mounts both engines mid-hull. Usable as platform for 3in, 105mm, or better armored APC.
The red boxes depict the new location of engine & transmission, blue depicts place for infantry.
im not convinced that light tanks are a waste, mostly because the concept continued after the war. but i would concede its changed considerably since the war. The one that comes to mind are the m-41 Bulldogs and AMX-13s at the heavy end of the spectrum. at the light end you have the LAV-25, and the russian BTR90 and the various turretted versions of the m-113 such as the ARVN ACAV and the australian turetted variant of this concept . The brits developed the scorpian striker and spartans, along with a wide range of other light tanks.
often the line between AC and Light tank is blurred with these vehicles, and a particular role is not envisaged for the type as a whole. they fulfil a wide range of functions, including amphibious tanks, Light and heavy recon, Infantry support, policing, AT and a whole range of other specialised functions.
If you want to draw some arbitrary distinction by calling a light tank a tracked vehicle, and a wheeled vehicle an armoured car, the only difference that might arise from that distinction is that tracked vehicles have traditionally been seen as somewhat more mobile under certain conditions, and can generally deliver more firepower. This however seems a largely academic or theoretical distinction as wheeled vehicles can in fact be faster and still fairly mobile ove rough terrain, and can be fitted with quite heavy armament.
if you wanted to restrict the functions of light tanks in the WWII context to recon (which is not the only function, but we are going to go nuts otherwise), then there is this constant battle between survivability and expendability. You dont want your recons destroyed by Infantry weilding AT rifles, by the same token you dont want to spend so much of your military capital making your Recon vehicles invulnerable, but at excessive cost.
I think like everything it has to be a combination of the two ....having some firepower to deal with some threats, but also enough mobility to out of trouble if need be, and to be done at a cost that is not prohibitive.
Light tanks are also useful in certain specialised roles, like armoured suport in the jungle, amphibious tanks, or in exceptionally rough terrain. As a dangerous generalization Light tanks tend to be less maintenance hungrary than regulsr tanks, because they put less strain on their drive systems
Fr President Clemenceau’s speech to the AIF 7th July 1918: “ we expected a great deal of (Australians)… We knew that you would fight a real fight, but we did not know that from the beginning you would astonish the whole continent. I shall go back and say to my countrymen “I have seen the Australians, I have looked in their faces …I know that they will fight alongside of us again until the cause for which we are all fighting is safe for us and for our children”.
On a related issue, too bad the 105 M3 was not tried at US halftracks. While offering a much heavier punch than 75mm, it was substantially less powerful (lower MV) than the M2, so the recoil wouldn't be such an issue?
Or just bolt the muzzle brake on M2, for same (better?) effect.
And, how about this combo: Vickers light tank Mk. VI + 18pdr, later + 25pdr. Another reliable vehicle married with reliable gun.
Before you start laughing, Germans were using those hulls as platforms for 10,5cm M.1916 howitzers, and were satisfied according to Jentz.
im not convinced that light tanks are a waste, mostly because the concept continued after the war. but i would concede its changed considerably since the war. The one that comes to mind are the m-41 Bulldogs and AMX-13s at the heavy end of the spectrum. at the light end you have the LAV-25, and the russian BTR90 and the various turretted versions of the m-113 such as the ARVN ACAV and the australian turetted variant of this concept . The brits developed the scorpian striker and spartans, along with a wide range of other light tanks.
We may get mired in semantics here, between wheeled tanks (original name for the British Diamler?), tracked armored cars and stretched mission requirements. M-41 bulldog use late/post war technology to pack the firepower of a 76mm Sherman into a very fast chassis, weight of 23.5 tons kind of puts it in the MK IV medium class but with less protection in places. AMX-13 was an air transportable (barely)tank destroyer. It had some rather strange limits as a "tank".
you have left out the most famous fiasco, the M-551 Sheridan. The original "it sings, it dances, it tells jokes, it even washes your dishes and does windows" tank.
The more successful tanks, light and other wise, usually had a clearly defined mission requirement and a reasonable performance requirement. The broader the area that was tried to be covered and the more extreme the requirements the less likely the design was to succeed.
There were (are) two different schools of thought on recon vehicles, one is to try to gather information by stealth and/or bypassing strong points. The other is to "fight" for information, recon troops should be able to blast their way through all but the most determined/well equipped opposition.
Obviously the school in power at a given time influenced a nations purchase of vehicles and the standards for stealth and fighting power changed over time.
WW II and the 50s also brought in the air deliverable and air transportable light tank. A new requirement not exactly inline with the old light tank requirements but overlapping in many ways.
In the early part of WW II light tanks filled out numbers (sometimes at great cost to the crews, British, Italian, Russian and even German MK I and MK II crews), performed recon duties or provided armored support against even less well equipped opponents.
Japanese light tanks worked perfectly well against the Chinese, They were total death traps against US M-3 light tanks which in turn were death traps against German 20-25 ton tanks with High velocity guns.
Light tanks had a place and they still have a place, as long as that place is recognized and it's limits are recognized.
Sticking a wacking big gun on a light vehicle turns it into a self-propelled gun, that is a gun than can propel itself from one firing site to another. It does not always mean that it has turned into a tank destroyer or assault gun let alone a "tank". And unless you have the communications network, the maps and survey crews, and the needed logistics and supply self-propelled guns might not actually be self-propelled artillery.
Originally Posted by Shortround6
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