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Thread: Future naval gunfire support concept.

  1. #1 Future naval gunfire support concept. 
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    So my idea is a modified ship-based MLRS based on the GMLRS-ER missile to provide cheap long range precision fires fired in large masses to provide Naval gunfire support to troops ashore. It would require some expensive initial development, but would lower the cost per missile to be cheaper than cruise missile and longer ranged with bigger warhead than conventional artillery becoming a compromise between the two. It would be essentially a smallish short ranged ballistic missile designed to strike tactical targets deep inland with precision incorporating semi-experimental technologies that could possibly be implemented with low production cost.

    The GMLRS-ER is a missile developed by lockheed martin and is the longer range evolution of the M30/M31 GMLRS designed to be fired from the M270 and HIMARS launch systems, that is around 227mm diameter and 3.9 meters long carrying a 90kg DPICM or unitary HE warhead. It has a range out to 120km flying at around mach 2 and uses GPS/INS precision guidance to hit targets within a CEP of 50m. It costs around 100,000-200,000 dollars per unit and is a cost effective solution for precision firepower.

    However, I have a few small proposals and modifications, that could possibly improve the performance of the system to possibly partially supplant the role of cruise missiles and carrier aircraft for long range precision strike at lower cost. These modifications would increase the cost to closer to $ 300,000 per unit (really rough estimate) and would require a great deal of development work, however this could benefit all the service branches as the rocket is also compatible with Army and Marine corp launch platforms. However this would still be cheaper than our current strike solutions as a single tomahawk cruise missile costs around a million dollars and carries a smaller warhead and flies slower, but does reach farther, and according to some articles I read a single airstrike costs an average of 2.5million dollars factoring in the fuel, munitions cost, maitenance cost, etc. So it is much cheaper than our current strike solutions for the navy by many orders of magnitude.

    So heres a list of what mods I plan to make:

    Rocket motor: I would add a ram-effect air intake behind the nozzle of the rocket turning it into an air-augmented rocket motor, what it does is as the rocket is flying it compresses air and forces it out the back of the rocket as it's flying using the rocket's exhaust, which allows the use of the air as extra reaction mass doubling the specific impulse of the propellant and increasing the thrust by a wide margin. The ramjet within the intake would also combust the unburnt fuel from the rocket making better use of the propellant with less waste. This would possibly more than double the range of the rocket to around 320km giving it the range of the ATACMS and maybe increasing the velocity of the warhead to around mach 3. I'm not an engineer so I havent run the calculations, but the principle does work and is used in the MBDA meteor air to air missile. Now, I know ramjets like this require expensive materials, but since this missile is a disposable munition the enegine only has to last for around an hour or so, possibly less, so it can be built of cheaper material. Also since the rocket exhibits a ballistic trajectory, so even after the fuel has run out and it begins to fall towards the target, the ram intake continues to compress air as it falls allowing it to keep gaining velocity hitting the target at high speed and shredding it with not just the explosive blast of the warhead, but the immense kinetic energy of the rocket.

    Guidance system: The current GPS/INS system is nice, but it can be jammed and spoofed which in wartime is very unaccepatble, and also the satellite network can go down quick. The rocket would keep the inertial guidance hardware, but it would use a different system to gve it the updated positioning data. It would use a solid state three-axis magnetometer similar to the one in smart phones, but much more powerful. It would navigate by reading the anomalies in the earth's lithospheric crustal magnetic field and comparing it to a stored onboard magnetic map in a similar fashion to the TERCOM/DSMAC guidance in cruise missiles, except unlike those it doesn't need a huge camera, and doesn't need to lock onto landmarks and it works over water. Unlike GPS it can't be jammed or interfered with and doesn't require satellite infrastructure. It also isn't affected by the weather and works at all times because the crustal field is stable on geological timescales unlike the core magnetic field that fluctuates every five years. And since the magnetometer works on three axes it doesnt matter which way the device is oriented it will still get accurate readings. However to even more accurately fix targets it would use a radar altimeter to determine it's exact altitude.

    I envision this missile being able to be quadpacked into VLS cells since it has similar dimensions to the ESSMs. However it could also be sixpacked into MLRS pods.

    So any thoughts?


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  3. #2  
    Genius Duck Moderator Dywyddyr's Avatar
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    Quote Originally Posted by ASPIS View Post
    So heres a list of what mods I plan to make:
    Rocket motor: I would add a ram-effect air intake behind the nozzle of the rocket turning it into an air-augmented rocket motor
    Which would involve modifications to the rocket body and very probably modification/ replacement of the motor itself. That puts paid to it being "also compatible with Army and Marine corp launch platforms".
    This would possibly more than double the range of the rocket... maybe increasing the velocity of the warhead to around mach 3
    I haven't looked at the calculations for this but I doubt that simply making it an air-breathing rocket would double the range AND give a 50% increase in speed.
    I know ramjets like this require expensive materials, but since this missile is a disposable munition the enegine only has to last for around an hour or so, possibly less, so it can be built of cheaper material.
    It doesn't work like that.
    The materials are expensive because they have to stand up to high temperatures/ pressure. If you use cheaper materials then components need to be thicker/ larger, adding weight )which adds cost) and reducing performance.
    Also since the rocket exhibits a ballistic trajectory
    If it's powered it's not ballistic.
    the ram intake continues to compress air as it falls allowing it to keep gaining velocity
    No. If the fuel has run out then there's no propulsion. Plus ramming air into the intakes would cause drag: slowing the projectile.
    It would use a solid state three-axis magnetometer similar to the one in smart phones, but much more powerful.
    That "much more powerful" is correct. Ergo, considerably more expensive.
    It would navigate by reading the anomalies in the earth's lithospheric crustal magnetic field and comparing it to a stored onboard magnetic map in a similar fashion to the TERCOM/DSMAC guidance in cruise missiles, except unlike those it doesn't need a huge camera, and doesn't need to lock onto landmarks and it works over water.
    And would need very precise mapping beforehand. That adds cost...
    a radar altimeter to determine it's exact altitude.
    More cost.
    I envision this missile being able to be quadpacked into VLS cells since it has similar dimensions to the ESSMs. However it could also be sixpacked into MLRS pods.
    So you're using a quad or sextuple pack to replace however many dumb artillery rounds are carried on a ship?
    Even with reloads I'm not sure that you'd get a viable number.
    Even in such a short conflict as the Falklands War 17,500 rounds of 4.5" (114mm) rounds were fired1.


    1 Source: Under Fire: The Falklands War and the Revival of Naval Gunfire Support, Steven Paget, War in History, 24:2, 2017, pp.217-235.


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  4. #3  
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by ASPIS View Post
    So heres a list of what mods I plan to make:
    Rocket motor: I would add a ram-effect air intake behind the nozzle of the rocket turning it into an air-augmented rocket motor
    Which would involve modifications to the rocket body and very probably modification/ replacement of the motor itself. That puts paid to it being "also compatible with Army and Marine corp launch platforms".
    This would possibly more than double the range of the rocket... maybe increasing the velocity of the warhead to around mach 3
    I haven't looked at the calculations for this but I doubt that simply making it an air-breathing rocket would double the range AND give a 50% increase in speed.
    I know ramjets like this require expensive materials, but since this missile is a disposable munition the enegine only has to last for around an hour or so, possibly less, so it can be built of cheaper material.
    It doesn't work like that.
    The materials are expensive because they have to stand up to high temperatures/ pressure. If you use cheaper materials then components need to be thicker/ larger, adding weight )which adds cost) and reducing performance.
    Also since the rocket exhibits a ballistic trajectory
    If it's powered it's not ballistic.
    the ram intake continues to compress air as it falls allowing it to keep gaining velocity
    No. If the fuel has run out then there's no propulsion. Plus ramming air into the intakes would cause drag: slowing the projectile.
    It would use a solid state three-axis magnetometer similar to the one in smart phones, but much more powerful.
    That "much more powerful" is correct. Ergo, considerably more expensive.
    It would navigate by reading the anomalies in the earth's lithospheric crustal magnetic field and comparing it to a stored onboard magnetic map in a similar fashion to the TERCOM/DSMAC guidance in cruise missiles, except unlike those it doesn't need a huge camera, and doesn't need to lock onto landmarks and it works over water.
    And would need very precise mapping beforehand. That adds cost...
    a radar altimeter to determine it's exact altitude.
    More cost.
    I envision this missile being able to be quadpacked into VLS cells since it has similar dimensions to the ESSMs. However it could also be sixpacked into MLRS pods.
    So you're using a quad or sextuple pack to replace however many dumb artillery rounds are carried on a ship?
    Even with reloads I'm not sure that you'd get a viable number.
    Even in such a short conflict as the Falklands War 17,500 rounds of 4.5" (114mm) rounds were fired1.


    1 Source: Under Fire: The Falklands War and the Revival of Naval Gunfire Support, Steven Paget, War in History, 24:2, 2017, pp.217-235.
    Thanks for the input, it did help me study up on some of the design flaws:

    1. Well, making it an air augmented rocket wouldn't make it incompatible with army launchers since all that would need to be done is slight modification of the launch canisters that hold the missiles to be loaded into the MLRS, like the israelis did to fire BM-21 grad rockets from the M270 MLRS.

    2. The velocity increase I am talking about is only by about 20% or slightly less, according to https://www.globalsecurity.org/milit...itions/m31.htm it says the approach velocity of the M31 GMLRS rocket is mach 2.5. So it could be achievable especially in the terminal stage.

    3. Doubling the range in my estimation comes from the fact listed in this article Gnom that the gnom air augmented rocket stage had twice the specific impulse of a conventional chemical rocket at around 550s which in my opinion is achievable with this missile platform which would most likely double the range due to more efficient utilization of propellant and greater overall thrust. Also the PR-90 russian test ballistic rocket achieved 100km with only 300kg of propellant on a 1,500kg rocket flying at close to mach 3, but this was in the 1960s with lower quality propellants and metallurgy and built with poor quality soviet engineering. And the Gnom rocket built around the same time would have achieved orbit with 56% less launch vehicle mass using this concept.

    4. The current unit cost of a GMLRS rocket is around 110,000 with a possible increase to around 200,000 for the later GMLRS-ER, I estimated the cost increase to around 300,000 something to compensate for the more advanced materials and guidance systems, however by cheaper materials I mean that the titanium and composites usually used in this role arent neccessary and maybe cheaper alloys like aluminum lithium which have been proven and used in many rocket platforms and as prop blades in jet engines.

    5. The rocket does exhibit a ballistic trajectory kind of like a short range ballistic missile, it flies upward until the rocket runs out of fuel and then descends toward the target from high altitude using fins for steering.

    6. You may be right about the ram intake slowing it down as it falls, so i'd have to think of something.

    7. The price of solid state magnetometers for commercial use fell under a dollar or so in 2009 according to the wiki article. https://en.wikipedia.org/wiki/Magnet...#Mobile_phones , so the military versions should not be super expensive, maybe a hundred dollars at most.

    8. It would not require much pre-mapping as very detailed maps by geologists and satellites already exist of the earth's magnetic fields including the crustal field. World Digital Magnetic Anomaly Map

    9. Radar altimeters aren't that expensive and are used in most cruise missiles already.

    10. The quad and sextuple packs are a interim solution until a better shipboard launcher with higher missile capacity can be developed, and can be fitted to existing vls pods aboard ships as a partial replacement for the crazy expensive tomahawks. Also compared to the 5inch guns they hold a much larger warhead by many orders of magnitude and are precision guided so fewer would need to be fired by far. They also reach farther so they can continue to support troops far inland, or be used for preemptive strike and suppression of enemy air defenses. They are no replacement for a dedicated NGFS gun, but they are an interim solution that would be easier to implement.
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  5. #4  
    Genius Duck Moderator Dywyddyr's Avatar
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    Quote Originally Posted by ASPIS View Post
    1. Well, making it an air augmented rocket wouldn't make it incompatible with army launchers since all that would need to be done is slight modification of the launch canisters that hold the missiles to be loaded into the MLRS
    Not true. Here's a quote from Wiki: The intakes of high-speed engines are difficult to design, and they can't simply be located anywhere on the airframe whilst getting reasonable performance in general, the entire airframe needs to be built around the intake design.
    like the israelis did to fire BM-21 grad rockets from the M270 MLRS.
    Not come across that, link please.
    3. Doubling the range in my estimation...
    I was querying the doubling of range coupled with a 50% (on your original figures) speed increase.
    4. The current unit cost of a GMLRS rocket is around 110,000 with a possible increase to around 200,000 for the later GMLRS-ER, I estimated the cost increase to around 300,000 something to compensate for the more advanced materials and guidance systems, however by cheaper materials I mean that the titanium and composites usually used in this role arent neccessary and maybe cheaper alloys like aluminum lithium which have been proven and used in many rocket platforms and as prop blades in jet engines.
    Until you look at the specific engineering then your estimates (with regard to cost) are guesses.
    5. The rocket does exhibit a ballistic trajectory kind of like a short range ballistic missile, it flies upward until the rocket runs out of fuel and then descends toward the target from high altitude using fins for steering.
    By definition if it's powered it's not ballistic.
    7. The price of solid state magnetometers for commercial use fell under a dollar or so in 2009 according to the wiki article. https://en.wikipedia.org/wiki/Magnet...#Mobile_phones , so the military versions should not be super expensive, maybe a hundred dollars at most.
    One more time. The magnetometer in a mobile phone is considerably less sophisticated/ sensitive than what you're looking at (those in a mobile sense up/ down only essentially).
    [quote8. It would not require much pre-mapping as very detailed maps by geologists and satellites already exist of the earth's magnetic fields including the crustal field. World Digital Magnetic Anomaly Map[/quote]
    Except that that data is for 5 km altitude, not "low down" where the missile would be. Nor does that data appear to be of sufficient resolution for the targeting accuracy required.
    9. Radar altimeters aren't that expensive and are used in most cruise missiles already.
    But it would still have to find room in the missile, displacing existing equipment/ payload and be integrated with the rest of the electronics.
    Also compared to the 5inch guns they hold a much larger warhead by many orders of magnitude and are precision guided so fewer would need to be fired by far.
    They are precision-guided but they're also area weapons.
    Thus the type of support offered is not equivalent to that of NGFS.
    Artillery fire is (generally) about sustained bombardment. Your MLRS isn't such a weapon.
    They also reach farther so they can continue to support troops far inland
    Is there a requirement for this?
    but they are an interim solution
    To a problem that hasn't been voiced?
    that would be easier to implement.
    Not easier at all. Ships with guns already exist.
    Your weapon doesn't, nor do the ships to use it.
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