The Army cancels the M10 Booker, a ‘light tank’ that was too heavy

[M.Becker]

Not enough.

The 105mm gun is too big for the desired weight. The amount of armor is too much for the desired weight. The extra crew person probably only accounts for around 500 lbs at most, and an autoloader would weight at least that much.

What they needed to do is scale the gun down to something in the 50mm to 76mm size, drop the armor thickness by a bit, and keep the same powerplant.

The 105mm L7 is effective against anything except the frontal/turret armour of modern tanks. So what would suffice to penetrate older tank from the front and modern ones from the side? Preferably some already existing AVF gun.

[Nik_SpeakerToCats]

Move fast.
Shoot hard.
Have useful armour.
Air-droppable ( More than once !!)

Pick any three...
Snark:
As was said of ever-growing weight of Hermes EU mini-shuttle:
Even without French wine-cellar, had negative payload capacity...
/
Um, I think they need a better heavy-lift / short field aircraft...

Hmm: Could a 'Pegasus' engine be crossed with turbo-prop ??

[Calder]

Make a s-tank but made of titanium.

Actually this sort of the question I can in here to ask. How much weight could be saved if we dropped the turret and used an autoloader with only a 2-3 man crew? Which now that I think about it is basically an S-Tank.

Not enough.

The 105mm gun is too big for the desired weight. The amount of armor is too much for the desired weight. The extra crew person probably only accounts for around 500 lbs at most, and an autoloader would weight at least that much.

What they needed to do is scale the gun down to something in the 50mm to 76mm size, drop the armor thickness by a bit, and keep the same powerplant.

Weight for an armoured vehicle scales at approximately the cube of the overall size. Your going to save a hell of a lot more than 500 pounds if you size the vehicle for only 2 or 3 crewmen. Just add 1-2 additional people to the HQ section for each assault gun to help with the maintenance. (Previous studies have shown that 2-3 people is not enough to keep up with the maintenance of requirements.)

Besides, if you remove the turret, the Army can fire all of the publists they hired to keep telling everyone it is not a tank it is an assault gun over and over again.

[Nathan45]

Honestly a unmanned afv seems likely in the near future, if we can deal with jamming and ew. (Just make the armored hunter killer machines autonomous...)

[kdahm]

Not enough.

The 105mm gun is too big for the desired weight. The amount of armor is too much for the desired weight. The extra crew person probably only accounts for around 500 lbs at most, and an autoloader would weight at least that much.

What they needed to do is scale the gun down to something in the 50mm to 76mm size, drop the armor thickness by a bit, and keep the same powerplant.

Weight for an armoured vehicle scales at approximately the cube of the overall size. Your going to save a hell of a lot more than 500 pounds if you size the vehicle for only 2 or 3 crewmen. Just add 1-2 additional people to the HQ section for each assault gun to help with the maintenance. (Previous studies have shown that 2-3 people is not enough to keep up with the maintenance of requirements.)

Besides, if you remove the turret, the Army can fire all of the publists they hired to keep telling everyone it is not a tank it is an assault gun over and over again.

Crew size does not significantly affect the size of the vehicle between 3 crewmen and 4 crewmen. Sure, there's a range between rattling around and sticking their butts in each other face when shifting, but dropping a crew won't do that much for the volume. There are 4 men armored vehicles anywhere from 10 tons to 70 tons. Going down, there are 3 crew very light tanks and tankettes down to 5 tons. A Type 95 Ha-Go has a 37mm gun, three crew, and is 7.4 tons, for example. Going up, a M3 Grant is 30 tons with a four man crew and enough room inside for them not to smell each other's farts.

Plus, that autoloader and magazine arrangement would need to take some volume itself, and estimating should be about the requirement for that crewmen and their space.

The biggest question determining the weight is the size of the gun, the number of shots carried, the armor protecting the thing, and the propulsion plant needed to get to the desired speed. Crew size has only a small impact.

[kdahm]

Honestly a unmanned afv seems likely in the near future, if we can deal with jamming and ew. (Just make the armored hunter killer machines autonomous...)

Something like this:

But with a different payload?

[Calder]

Not enough.

The 105mm gun is too big for the desired weight. The amount of armor is too much for the desired weight. The extra crew person probably only accounts for around 500 lbs at most, and an autoloader would weight at least that much.

What they needed to do is scale the gun down to something in the 50mm to 76mm size, drop the armor thickness by a bit, and keep the same powerplant.

Weight for an armoured vehicle scales at approximately the cube of the overall size. Your going to save a hell of a lot more than 500 pounds if you size the vehicle for only 2 or 3 crewmen. Just add 1-2 additional people to the HQ section for each assault gun to help with the maintenance. (Previous studies have shown that 2-3 people is not enough to keep up with the maintenance of requirements.)

Besides, if you remove the turret, the Army can fire all of the publists they hired to keep telling everyone it is not a tank it is an assault gun over and over again.

Crew size does not significantly affect the size of the vehicle between 3 crewmen and 4 crewmen. Sure, there's a range between rattling around and sticking their butts in each other face when shifting, but dropping a crew won't do that much for the volume.

I know that isn't true. One of the primary tenets of Soviet tank design from WWII onwards was to reduce the size of the tank to make armoring it cheaper and lighter. Now, there are obviously costs in ergonomics and Soviet tank crewmen having to be under a certain size.

[jemhouston]

Honestly a unmanned afv seems likely in the near future, if we can deal with jamming and ew. (Just make the armored hunter killer machines autonomous...)

Mandatory Terminator reference

[kdahm]

I know that isn't true. One of the primary tenets of Soviet tank design from WWII onwards was to reduce the size of the tank to make armoring it cheaper and lighter. Now, there are obviously costs in ergonomics and Soviet tank crewmen having to be under a certain size.

It doesn't work out that way. The turret volume gets smaller in the Russian tanks by having ammo stowage in the hull and an autoloader, but it also puts the ammo in the bottom of the hull and keeps them from using blowout panels.

Lets look at some for data, mostly for medium tanks:
Leopard 1: 42.2 tons, 105mm, 19.3 hp/ton, 4 crew, 7.1mx3.4mx2.4m
T-62: 37 tons, 115mm, 14.5 hp/ton, 4 crew, 6.6mx3.3mx2.4m
T-72 (T-64 similar): 41 tons, 125mm, 19 hp/ton, 3 crew, 6.7mx3.5mx2.2m
T-80: 42.5 tons, 125mm, 23-27 hp/ton, 3 crew, 7.4mx3.4mx2.2m
M60: 50.2 tons, 105mm, 15.1 hp/ton, 4 crew, 6.9mx3.6mx3.2m
M1: 54 tons, 105mm, 24-27 hp/ton, 4 crew, 7.9mx3.7mx2.4m
Chieftain: 55 tons, 120mm, 13.6 hp/ton, 4 crew, 7.5mx3.7mx2.9m

M10 Booker: 38 tons, 105mm, 21 hp/ton, 4 crew, 6.8mx3.6mx2.4m (Listed dimensions are 2.4m wide and 3.6m high. I believe they are switched.)

Of note, the T-62 to the T-72 dropped a crew member, added 4 tons, added 4.5 hp/ton, and kept about the same dimensions.

One crew member weighs about 200-225 lbs, plus another 200 lbs of gear and occupies 1.0 to 1.7 cu. m. of volume (https://www.sciencedirect.com/science/a ... 4713000597). Therefore, a three man crew would take up between 3 and 5.1 cubic meters, and a four man crew would take up 4 to 6.8 cubic meters.

In particular, getting from 38 tons down to 25 tons would require a lot more than simply dropping one crew member.

[Johnnie Lyle]

See the Chieftain’s video on why the Booker is NOT a tank.

The main AT weapon of Airborne and air-mobile forces are the infantry anti-tank missiles (or the helos and zoomies supporting them).

This thing’s an assault gun, more like an SU-76, or a souped-up Bradley or Stryker with a bigger gun. They wanted the 105 for much the same reasons that an AC-130 gunship or the Stryker variant carry one: a big HE shell. It’s more intended to fix the problems of minimal direct fire weapons to blast things like bunkers, machine-gun emplacements, etc. The two big needs are strategic mobility in platoon strength and the carrying biggest practicable boom.

As is, it may be able to kill light vehicles and older tanks, but it can’t be armored to the degree necessary to resist tank gunfire and still have more than one in a given aircraft. So they’re in a sour spot of enough armor to not be deployable in sufficient mass, but not enough armor to ensure the crew survives incoming heavy tank or missile fire.

So, if you want to give the Airborne direct fire support, you have to go with less armor. We’ve already made that decision with IFVs, which are not armored to resist beyond the 20-35 mm family, and so probably have to make the same decision here.

Otherwise you might as well just airlift in an Abrams.

[kdahm]

It's the Alaska class of armored vehicles.

And a M1 is air droppable. Once.

[Johnnie Lyle]

It's the Alaska class of armored vehicles.

And a M1 is air droppable. Once.

I don’t think the M10 is intended to be air dropped by parachute, even if theoretically capable of it. I think the plan is to have the paratroopers secure an airhead and then fly these things in to expand the perimeter. So if you can fly in an Abrams, you might as well if the choice is 1 M1 or 1 M10 per plane.

[Nightwatch2]

It's the Alaska class of armored vehicles.

And a M1 is air droppable. Once.

I don’t think the M10 is intended to be air dropped by parachute, even if theoretically capable of it. I think the plan is to have the paratroopers secure an airhead and then fly these things in to expand the perimeter. So if you can fly in an Abrams, you might as well if the choice is 1 M1 or 1 M10 per plane.

I thought it was 1 Abrams or 2 M10's per plane?

that's the only advantage that I see. Other than that it doesn't look like a good option and the reprioritization of funding is a good decision, I think.

[kdahm]

It's the Alaska class of armored vehicles.

And a M1 is air droppable. Once.

I don’t think the M10 is intended to be air dropped by parachute, even if theoretically capable of it. I think the plan is to have the paratroopers secure an airhead and then fly these things in to expand the perimeter. So if you can fly in an Abrams, you might as well if the choice is 1 M1 or 1 M10 per plane.

The initial design requirement was for a vehicle that could be air-dropped. It was in the RFP, and I think was still around during the competition and selection in 2021. I'm not sure when air drop requirement was papered over.

The selling point for the M10 was that it could be packed two in a C17 or C5, instead of one M1. Still, I'd rather have one M1 than two M10.