M270 MLRS and M142 HIMARS Developments

Posted over on the Asramm/Taildog/SRAAM thread...

MBDA have renamed the proposed Future Land Indirect Fires proposal to Land Precision Strike and have added M270 (and therefore HiMARS) launch capability for the proposed CAMM/Brimstone hybrid missile.


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Out of curiosity, why is the diameter of the MLRS rocket 227mm? I mean, it is 8.937inch, why not round it to 9.0inch (since the Americans still frequently uses Imperial units) or 228.6mm?

Or is it a NATO thingy so that it "encouraged" more NATO states to get onboard?
 
Out of curiosity, why is the diameter of the MLRS rocket 227mm? I mean, it is 8.937inch, why not round it to 9.0inch (since the Americans still frequently uses Imperial units) or 228.6mm?

Or is it a NATO thingy so that it "encouraged" more NATO states to get onboard?
Don't know, they have a thing for odd sized rockets and artillery, the new MLRS rockets will be 274mm and howitzers are 155mm, neither of which is an integer number of inches. Strangely Russia uses the metric system but its howitzers are 152mm and 203mm, which are exactly 6 inches and 8 inches respectively.
 
Out of curiosity, why is the diameter of the MLRS rocket 227mm? I mean, it is 8.937inch, why not round it to 9.0inch (since the Americans still frequently uses Imperial units) or 228.6mm?

Or is it a NATO thingy so that it "encouraged" more NATO states to get onboard?

I think the tubes are actually closer to 230mm, with a small allowance for the rifling rails. And the newer guided rockets are not spun, so they may have moved up to 230mm nominal (that's the number KMW uses for MARS II, for example.)
 
I think the tubes are actually closer to 230mm, with a small allowance for the rifling rails. And the newer guided rockets are not spun, so they may have moved up to 230mm nominal (that's the number KMW uses for MARS II, for example.)
Spun?
 
I think the tubes are actually closer to 230mm, with a small allowance for the rifling rails. And the newer guided rockets are not spun, so they may have moved up to 230mm nominal (that's the number KMW uses for MARS II, for example.)
Spun?

MLRS has rifling.

Interesting; I’d always assumed the fins handled the spin up. I assume spin stabilization is a throwback to when this caliber/system used unguided rockets? I think GMLRS-ER switches from spin stabilized nose fin guidance to fully fin stabilization and guidance on the rear of the rockets.
 
I believe all "traditional" tube launch rockets are spin stabilized. Only the later, "guided" versions are not as there is active control, and knowing the attitudes are important.
 
MLRS tubes are arranged in 3-by-2 tubes configuration. From the FM6-60 MLRS operator manual, the launch pod measures 3 feet 5 inch (41 inch) wide and 2 feet 4 inch (28 inch) high.

41 inch divided by 3 = 13.7 inch
28 inch divided by 2 = 14.0 inch

ATACMS diameter given as 24 inch, so the launch pod can only hold one ATACM.

So, PrSM diameter should not exceed 41 inch divided by 2 = 20.5 inch. This tallies within with the given value of 17 inch in open source.

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Are Himars/MLRS rocket pods typically reloaded or is a single use disposable canister? If the former, how many launches can the tube rifling support?
 
Are Himars/MLRS rocket pods typically reloaded or is a single use disposable canister? If the former, how many launches can the tube rifling support?

I'd say that they are reloaded after being inspected for any post-firing damage however the fibre-glass tubes will have a finite life-span and are no doubt replaced after a number of firings.
 
I believe all "traditional" tube launch rockets are spin stabilized. Only the later, "guided" versions are not as there is active control, and knowing the attitudes are important.

It's odd. Seems like the M30 at least are spun at launch, but the canards are essentially de-coupled from the spinning tail section, and then the whole missile stops spinning very early in flight.


The GMLRS is supported by spiral rails inside the launch tube during the launch sequence. It uses sabots similar to those used on other MLRS munitions to position the rocket in the tube to avoid damage to the canards and fins during launch. It is guided by the guidance set in the guidance and control section and controlled by canard surfaces mounted on the Control Actuation Section (CAS) of the rocket. It has a spinning tail section mounted on bearings to avoid interference from the wake of the forward canard control surfaces. It rotates up to three times and then stabilises, flying with the Guidance Positioning System (GPS) antenna.
 
Out of curiosity, why is the diameter of the MLRS rocket 227mm?

To accommodate the German AT2 mine.

Out of curiosity, why is the diameter of the MLRS rocket 227mm? I mean, it is 8.937inch, why not round it to 9.0inch (since the Americans still frequently uses Imperial units) or 228.6mm?

Or is it a NATO thingy so that it "encouraged" more NATO states to get onboard?

I think the tubes are actually closer to 230mm, with a small allowance for the rifling rails. And the newer guided rockets are not spun, so they may have moved up to 230mm nominal (that's the number KMW uses for MARS II, for example.)

The rails are pretty sizeable, tbf. There's about an inch or so difference in diameter between GMLRS and GMLRS-ER IIRC.
 
To accommodate the German AT2 mine.
The AT2 round is actually slightly fatter than the MLRS submunition rounds. See post #53 in this thread -- the AT2 rounds have a fairing that bumps out slightly from the propulsion section, while the MLRS and MLRS-ER rounds are straight-sided. Which explains why you need slightly different software to fire them.

The rails are pretty sizeable, tbf. There's about an inch or so difference in diameter between GMLRS and GMLRS-ER IIRC.

Yeah, deeper than I realized. Interestingly, DesignationSystems.net reports that the nomenclature for the MLRS pod is "Rocket Pod, 298 mm." Which suggests a LOT of windage.
 
The rails are pretty sizeable, tbf. There's about an inch or so difference in diameter between GMLRS and GMLRS-ER IIRC.
The -ER is 274mm.

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Uh, that's referring to the unguided M26A1/A2 MLRS-ER, which has a rocket motor that is 274-mm (10.8-inch) longer than the original M26 MLRS, and thus has less length available for submunitions (only 518 compared to 644). Note that the brief dates to 2007, while ER-GMLRS is from around 2020. Also, ER-GMLRS has a unitary warhead.
 
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Uh, that's referring to the unguided M26A1/A2 MLRS-ER, which has a rocket motor that is 274-mm (10.8-inch) longer than the original M26 MLRS, and thus has less length available for submunitions (only 518 compared to 644). Note that the brief dates to 2007, while ER-GMLRS is from around 2020. Also, ER-GMLRS has a unitary warhead.
Right you are, sorry. This suggests the new pod will accommodate rockets up to 10".

 
And confirmation that they used all of that is here:



The original GMLRS featured small canard wings on the front cone, being thus a front controlled actuated rocket, the LM representative explains, while in the new rocket, the GMLRS-ER, for Extended Range, control surfaces have been moved at the back, making it a tail-driven rocket, which according to Mr. Harrison considerably reduces the drag while increasing manoeuvrability. “We also increased the rocket motor diameter, from 9 to 10-inch [228 to 254 mm], but the important thing is that we are still able to maintain six rockets in each pod,” he explained. In the GMLRS-ER Lockheed Martin engineers managed to free some room in the nose cone, that allows for future growths. “We can put different sensors in it,” Harrison said, “carrying out incremental upgrades in the future, we can put more data links, and we made a modular nose where we can insert various warheads that will be developed in the future.”
 
I'm not surprised about the SALH seeker however what I had in mind was something like an IIR terminal seeker (Perhaps based on the Javelin's seeker) or an MMW active-radar seeker (Perhaps based on the Brimstone's seeker).

Edit: Perhaps a terminal homing multi-mode seeker like the one for the JAGM.
 
This is a Brimstone seeker, slightly smaller diameter than the missile itself, which is 180mm, so should fit in a 230mm rocket comfortably.

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I also had the idea of a rocket that can launch a drone out to the target area to select targets.
 
I also had the idea of a rocket that can launch a drone out to the target area to select targets.
What about an M26 (The US has hundreds of thousands of surplus M26 rocket-motors in storage) rocket used as a booster to launch a SPEAR 3?

On YouTube Defence Updates has just uploaded a video about the M30A rocket on the M142:

 
What seems to be missing from the HIMARS ammo suite provided to Ukraine to date is a round specifically engineered to destroy modern Class 1 steel bridges with reinforced concrete decks...even though bridges are a key target category.

Certainly we've seen plenty of HIMARS bridge hits resulting in holes punched in decks, but I'm not aware of instances where one hit has caused failure of the underlying structure of a Class 1 bridge. Holes in decks can be patched quickly for light- or medium-weight traffic.

How much more effective would the ATACMS warhead be for that target category?

Perhaps what's needed by users in conflicts similar to the Ukrainian conflict, subject to the same deployment limitations as currently apply in that conflict, is an 80km-range version of ATACMS.
 

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