View Full Version : Ramjet PGM Artillery
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https://aviationweek.com/defense-space/missile-defense-weapons/ramjet-powered-artillery-moves-beyond-experimental-status
Ramjet-Powered Artillery Moves Beyond Experimental Status
A Nammo-designed solid-fuel ramjet inserted into a 155mm artillery shell ignited upon release from a U.S. artillery cannon in December 2019, proving for the first time the feasibility of an indirect fires system with extreme range.
Although it was a major technical breakthrough for ramjet propulsion, the newly revealed, two-year-old test by the Boeing/Nammo partnership still stops short of a graduation event for transforming 106-lb. artillery shells into supersonic pseudo-cruise missiles.
That milestone comes next May. The U.S.-Norwegian industry team plans to demonstrate ignition and maximum range of the cannon-fired weapon they simply call the “155mm ramjet.” The desired distance is not being released, but U.S. Army officials have previously estimated ranges of up to 150-200 km (90-125 mi.).
“That’s when we show the Army that this is real,” Dan Palmeter, a capture team leader for the Boeing Phantom Works Advanced Weapons Product Line, told Aviation Week at the Association of the U.S. Army (AUSA) annual convention.
If the test is successful, the goal is to transition the solid-fuel ramjet into the Army’s Extended-Range Cannon Artillery (ERCA) system, which modifies the BAE Systems M109A7 Paladin self-propelled howitzer with a 58-caliber, 30-ft. gun barrel replacing the 39-caliber, 20-ft. barrel. The ramjet-powered projectile also would be modified with small, deployable fins, mini-canard wings and a precision guidance kit.….
At the same time, the artillery system is only the first of a series of potential applications for Nammo’s decade-old investment in solid-fuel ramjet technology. Nammo and Boeing also have partnered on the Tactical High-Speed Offensive Ramjet for Extended Range, a U.S. Navy-funded program to demonstrate prototypes of a new air-launched missile.
Nammo announced during AUSA that more than 300 tests have been completed using solid-fuel ramjet propulsion systems.
“We believe ramjets have the potential to revolutionize artillery, combining exceptional range increases with precision never before seen in artillery,” said Morten Brandtzaeg, Nammo’s CEO. “We also see a potential for huge range increases on the missile side.”…..
trim it out
27th Oct 2021, 11:06
Sounds like an expensive party popper.
Tactical Offensive Ramjet - TOSSER?
Ninthace
27th Oct 2021, 12:46
Whizz.................................bang?
EEngr
27th Oct 2021, 15:35
To be fair, with a 155mm caliber, they have a chance of incorporating some active avionics rather than having to deal with the subject's poor balistics.
Salute!
I can see it now....
F-35 or stealth drone gets the laser code and a firebase or even a ship fires the bullet.
Tgt is lased, projectile hits. Too neat, and no serious collateral damage.
War must be ugly, lest we have more of them.
Gums sends...
tdracer
27th Oct 2021, 18:33
Must admit I'm rather curious about how a 'solid fuel ramjet' would function. The big advantage of a ramjet vs. a conventional rocket motor is that you get the oxidizer from the air rather than having to carry it - so you can get more range from the same weight of propellant (and ramjets can have very impressive specific impulse numbers). But metering a solid fuel is going to be, um, interesting. I wonder if they are doing something with having the fuel be part of the combustion chamber wall?
If anyone has links to additional information I'd love to see it.
Ninthace
27th Oct 2021, 18:44
General Melchett will need to find a chateau even further behind the lines.
https://www.researchgate.net/figure/Schematic-of-artillery-shell-with-ramjet-in-fuel-rich-mode_fig1_341187474
https://en.wikipedia.org/wiki/Ramjet#Integral_rocket_ramjet/ducted_rocket
Ascend Charlie
27th Oct 2021, 19:25
With a ramjet engine and fuel inside the skin, how much room is left for a *bang* at the other end?
Bengo
27th Oct 2021, 19:53
With a ramjet engine and fuel inside the skin, how much room is left for a *bang* at the other end?
If it arrives accurately, at Mach 3 or so, is it important that there is a 'bang'? Get the head shape and the material right and it will turn into something suited to ruining the day of several sorts of folks.
N
To which I presume the answer, having been modified to carry a PGM kit to reduce the CEP, is “enough”.
tdracer
27th Oct 2021, 20:32
Thanks ORAC - so basically a solid rocket motor with a highly fuel rich mixture - with the rocket exhaust feeding the fuel to the ramjet. Interesting...
trim it out
27th Oct 2021, 21:42
To which I presume the answer, having been modified to carry a PGM kit to reduce the CEP, is “enough”.
Exactor hasn't exactly been revolutionary, which is basically what this is but this has more range. It's competing in quite a congested battle space against numerous other PGMs both surface to surface and air delivered, the 'so what' to that being what does it actually bring to the party that isn't already covered inside someone else's arc?
Dread to think how long it would take to get the goal posts hot too.
I would thing what it will be bring is 24/7 availability. The artillery be behind the front line on call regardless of time or weather. If there is a fight it will be between the army and Air Force on the provision and control of suitable UAV assets providing similar 24/7 coverage of the target airspace.
trim it out
27th Oct 2021, 22:35
I would thing what it will be bring is 24/7 availability. The artillery be behind the front line on call regardless of time or weather. If there is a fight it will be between the army and Air Force on the provision and control of suitable UAV assets providing similar 24/7 coverage of the target airspace.
There already is 24/7 artillery with decent reach...GMLRS.
155mm is good at suppression, typically dismounted infantry. Why you would want or need to suppress dismounts with such accuracy from 150-200km as quoted is, I think, a solution to a problem that doesn't really exist.
If the SPGs are that far away from the FLET then you lose all of its flexibility that it's other ammunition natures bring to the party.
Basically, I think it would be a tough sell to a ground commander to use this shiny new shell. Hopefully they develop tech that can benefit other industries like rocket science or similar perhaps.
MAINJAFAD
27th Oct 2021, 23:30
Thanks ORAC - so basically a solid rocket motor with a highly fuel rich mixture - with the rocket exhaust feeding the fuel to the ramjet. Interesting...
Been around for ages. Augmenter Tube on a Jetex Model in the 1950 somewhat works the same way. NACA did studies into such motors in the late 1940s. Such motors are used on the SA-6 SAM and Meteor AAM.
Mr N Nimrod
28th Oct 2021, 09:35
Been around for ages. Augmenter Tube on a Jetex Model in the 1950 somewhat works the same way. NACA did studies into such motors in the late 1940s. Such motors are used on the SA-6 SAM and Meteor AAM.
Hmmm, just a little disingenuous. The solid fuelled, throttlable ramjet was viewed as a very high risk part of the BVRAAM programme!
tdracer
28th Oct 2021, 18:19
Been around for ages. Augmenter Tube on a Jetex Model in the 1950 somewhat works the same way. NACA did studies into such motors in the late 1940s. Such motors are used on the SA-6 SAM and Meteor AAM.
From what I understand (admittedly limited), those are not the same as a ramjet. Augmenters use the 'ejector' effect to draw air in from the front to augment the thrust of the rocket motor to improve overall efficiency - there is no secondary combustion of the incoming air as there is with a ramjet.
Many decades ago, we played with augmenters as a way to improve performance of model rockets.
t43562
29th Oct 2021, 04:59
From what I understand (admittedly limited), those are not the same as a ramjet. Augmenters use the 'ejector' effect to draw air in from the front to augment the thrust of the rocket motor to improve overall efficiency - there is no secondary combustion of the incoming air as there is with a ramjet.
Many decades ago, we played with augmenters as a way to improve performance of model rockets.
Might as well look at their own explanation and diagrams:
https://www.youtube.com/watch?v=0vIPNElDkns
Salute!
My unnerstaning is the "ramjet" does not augment anything, but acts to sustain a high velocity by its basic nature of compressing the air and using fuel to produce thrust to maintain the velocity. I think of Bomarc... maybe SA-6...
So you can use simple fuel... hell, a candle of paraffin down the middle should work..The shell is already up at mach 3 within milliseconds and the motor starts and keeps the round going for seconds or minutes versus pure ballistic .
The thing I do not see is the warhead... the explosive stuff. Ditto for a terminal seeker. At the ranges they are discusing, GPS or pure INS ain't gonna hack it with a small projectile.
Oh well... interesting stuff
Gums sends...
etudiant
29th Oct 2021, 22:47
Salute!
My unnerstaning is the "ramjet" does not augment anything, but acts to sustain a high velocity by its basic nature of compressing the air and using fuel to produce thrust to maintain the velocity. I think of Bomarc... maybe SA-6...
So you can use simple fuel... hell, a candle of paraffin down the middle should work..The shell is already up at mach 3 within milliseconds and the motor starts and keeps the round going for seconds or minutes versus pure ballistic .
The thing I do not see is the warhead... the explosive stuff. Ditto for a terminal seeker. At the ranges they are discusing, GPS or pure INS ain't gonna hack it with a small projectile.
Oh well... interesting stuff
Gums sends...
You raise a couple of interesting points.
Alternative 1 had been a round with just enough propulsion to offset air drag, which simplifies the targeting calculations and gives a decent boost in range for a basically conventional shell..
Alternative 2 was that the shell would be an air vehicle with ramjet propulsion, which obviously greatly extends the range potential, but is as noted an entirely different beast, mandating entirely new standards for targeting accuracy and speed.
Stuffing the needed capabilities into a 155mm round seems like a budget buster. Afaik, the US Navy gave up on Excalibur, essentially an alternative 1 design, because the costs were close to $1MM per round.
Is the Army ready to pay that much or much more?
trim it out
30th Oct 2021, 18:32
Afaik, the US Navy gave up on Excalibur, essentially an alternative 1 design, because the costs were close to $1MM per round.
$70k per Excalibur round according to the USNI (https://news.usni.org/2016/12/13/raytheon-excalibur-round-set-replace-lrlap-zumwalts).
Still not convinced you need such an expensive suppression weapon, with a range that far.
tdracer
30th Oct 2021, 19:42
Solid rocket motors are relatively cheap to manufacture - especially in bulk, so once you have the development costs handled there is no reason why the per-round costs would be excessive.
That being said, with that sort of range, it's going to need some sort of precision guidance system to be overly useful.
Doing some digging they e been working on the PGM side for a while, a GPS chip combined with a millimetric seeker head for terminal guidance for moving targets. Speed should mean the targets won’t have moved much after firing.
One of the main touted advantages is that it exceeds the range of the enemy counter-battery fire conferring a major advantage.
Salute!
Somehow I cannot see using an expensive round for "barrage", but maybe for a precision HVT strike. The new GPS/INS chips are very rugged and fairly cheap, so maybe could use them for the more "conventional" use of arty.
The HVT employment could use a ground designator or maybe a drone to help get the 3 meter accuracy. Seems the ISIS or other bad outfit lost an important leader last year, huh?
Gums sends...
trim it out
30th Oct 2021, 20:10
Doing some digging they e been working on the PGM side for a while, a GPS chip combined with a millimetric seeker head for terminal guidance for moving targets. Speed should mean the targets won’t have moved much after firing. Really? What's the time of flight likely to be for a round that has to travel 100km+? We try and avoid artillery for moving targets as it is, increasing the range just makes targeting harder. Take Exactor for example, plenty of cold shifts had to be executed due to targets moving, same for Hellfire.
One of the main touted advantages is that it exceeds the range of the enemy counter-battery fire conferring a major advantage.
The Holy Grail of Gunnery.
etudiant
30th Oct 2021, 20:23
$70k per Excalibur round according to the USNI (https://news.usni.org/2016/12/13/raytheon-excalibur-round-set-replace-lrlap-zumwalts).
Still not convinced you need such an expensive suppression weapon, with a range that far.
You are quite right, I was conflating Excalibur (half the range at a tenth the price) with the prior LRLAP, which as the article notes was projected to cost as much as $2B for 2000 projectiles, a cool $million per shell, albeit one with 100km range.
Your larger point about the operational utility of such 'silver bullets' has not been addressed anywhere afaik.
Yet the US Army is talking about the 1000 mile range cannon, presumably using an LRLAP++, without thus far addressing any of the targeting issues that throws up.
trim it out
30th Oct 2021, 20:38
Your larger point about the operational utility of such 'silver bullets' has not been addressed anywhere afaik.
Yet the US Army is talking about the 1000 mile range cannon, presumably using an LRLAP++, without thus far addressing any of the targeting issues that throws up.
I mean, it wouldn't be the first time a Gunner has gone for a land grab opportunity to justify their existence on the battlefield :E
Watchkeeper
tdracer
30th Oct 2021, 21:13
Really? What's the time of flight likely to be for a round that has to travel 100km+? We try and avoid artillery for moving targets as it is, increasing the range just makes targeting harder. Take Exactor for example, plenty of cold shifts had to be executed due to targets moving, same for Hellfire.
GPS guidance would have obvious limitations for a moving (or likely to move) target, but a lot of high value targets are not likely to move. If nothing else, the inability to safely stockpile supplies and weapons within 100 miles of the lines would be a game changer.
For actual moving targets, something like laser guided would be more suitable.
trim it out
30th Oct 2021, 21:34
GPS guidance would have obvious limitations for a moving (or likely to move) target, but a lot of high value targets are not likely to move. If nothing else, the inability to safely stockpile supplies and weapons within 100 miles of the lines would be a game changer.
For actual moving targets, something like laser guided would be more suitable.
Purely Devil's advocate here...
Protection of ammunition is quite simple, dig it in and give it some OHP (see HESCO HABs that were used in the last 20 years, easily knocked up in a morning by a section of Sappers). Plus, it's 155mm HE, hardly bunker busting weapon of choice.
Who's going to lase it? A few years ago I was a targeteer involved in a serial (on exercise) where they intended to use GR4 to destroy a C2 node some 40km behind the FLET. All was going as per the set piece script until I asked who was going to lase the target as we have no friendlies anywhere near it and a 200' ovc cloud base. End of serial. May have made a few staff officers feel a bit silly but they should have asked the SMEs in the HQ for their tuppence before crafting an elaborate plan for the 1* ;)
I'm sure there's a staff officer in a HQ somewhere coming up with answers to all these questions, these are just my initial thoughts and "so whats". Weapon development is generally always a positive step and tightening the accuracy of "dumb" ordnance will always be favoured over non precision direct or indirect options in many environments we are likely to operate in short of peer on peer conventional warfare. See JDAM for an example.
tdracer
31st Oct 2021, 01:12
Purely Devil's advocate here...
Protection of ammunition is quite simple, dig it in and give it some OHP (see HESCO HABs that were used in the last 20 years, easily knocked up in a morning by a section of Sappers). Plus, it's 155mm HE, hardly bunker busting weapon of choice.
But that takes time and materials, and useless if the front line is not static. And it's going to take a heck of a bunker to shelter a battalions worth of equipment and supplies.
Who's going to lase it? A few years ago I was a targeteer involved in a serial (on exercise) where they intended to use GR4 to destroy a C2 node some 40km behind the FLET. All was going as per the set piece script until I asked who was going to lase the target as we have no friendlies anywhere near it and a 200' ovc cloud base. End of serial. May have made a few staff officers feel a bit silly but they should have asked the SMEs in the HQ for their tuppence before crafting an elaborate plan for the 1* ;)
Drones are perfect for this task, and we've had the technology to 'look through' clouds for decades.
trim it out
31st Oct 2021, 12:00
But that takes time and materials, and useless if the front line is not static. And it's going to take a heck of a bunker to shelter a battalions worth of equipment and supplies.
There is always likely to be static installations, BFIs, APODs, engineering ech etc, some harassing fire from 155mm could be useful in that scenario.
Drones are perfect for this task, and we've had the technology to 'look through' clouds for decades.
I've been out of the CAS game for a few years now, can we now lase through clouds for terminal control? The use of drones is assuming we have air superiority that deep in the battle space. AD will probably be taken quite seriously in a PvP scrap. Could mensurate the grids via satellite I suppose, thus negating the requirement for a laser seeker in the nose.
Reference army required range and seeker heads….
https://breakingdefense.com/2021/04/can-army-triple-prsm-missile-range/
https://breakingdefense.com/2020/06/army-tests-prsm-seeker-to-hunt-ships-sams/
Salute!
I knew about the 70mm rocket and then looked up other BAE systems. Walla! A whole family of precision arty systems. So I wonder what the U.S. Army is looking for.....
https://www.baesystems.com/en-us/productfamily/precision-guided-munitions
Gums sends...
https://insidedefense.com/daily-news/army-test-cannon-1180-mile-range-fy-24
Army to test cannon with 1,180-mile range in FY-24
The Army plans to shoot artillery rounds 1,180 miles over the Pacific Ocean in fiscal years 2024 and 2025 to test a next-generation cannon, according to a recently filed environmental notice. The service will test-fire 77 non-explosive projectiles from the Extended Range Cannon Artillery II at Vandenberg Space Force Base, CA, over those two years, mostly in FY-24, according to the notice ……
https://twitter.com/thedewline/status/1479212460695556097?s=21
petit plateau
7th Jan 2022, 11:12
At mach 3 the 100km range is a 1.6 minute time of flight. A 40mph target could move 1 mile in that time.
At mach 3 the 1900km range (1180 mile) is a 31 minute time of flight. A 40mph target could move 21 mile in that time.
At mach 3 the 100km range is a 1.6 minute time of flight. A 40mph target could move 1 mile in that time.
At mach 3 the 1900km range (1180 mile) is a 31 minute time of flight. A 40mph target could move 21 mile in that time.
It's possible to imagine scenarios where a weapon with 1900km range that can only hit fixed targets would be more useful than a weapon with 30km range that can hit moving targets.
Ninthace
7th Jan 2022, 11:31
It's possible to imagine scenarios where a weapon with 1900km range that can only hit fixed targets would be more useful than a weapon with 30km range that can hit moving targets.
It is also possible to envisage a projectile with a guidance system to seek out its target. In fact, I would expect a long range projectile to have one if only to allow to correct for variations in the ballistic path
I would assume a datalink with the round having a PGM module allowing UAV and/or satellite terminal guidance.
etudiant
7th Jan 2022, 12:00
At mach 3 the 100km range is a 1.6 minute time of flight. A 40mph target could move 1 mile in that time.
At mach 3 the 1900km range (1180 mile) is a 31 minute time of flight. A 40mph target could move 21 mile in that time.
Packaging a ramjet plus fuel for a thousand miles into a 155mm shell does not leave much room for ta warhead or terminal guidance.
Can someone articulate a rationale for this effort?
Can someone articulate a rationale for this effort?
https://armadainternational.com/2021/02/breaking-a2d2-with-long-range-fires/
Enhancing the delivery of long range precision fires (LRPF) is being driven largely as a potential response to the increasing presence of A2/AD (anti-access area denial) defences on the battlefield.….
Ninthace
7th Jan 2022, 13:27
Packaging a ramjet plus fuel for a thousand miles into a 155mm shell does not leave much room for ta warhead or terminal guidance.
Can someone articulate a rationale for this effort?
Would you need a warhead?
petit plateau
7th Jan 2022, 13:31
Packaging a ramjet plus fuel for a thousand miles into a 155mm shell does not leave much room for ta warhead or terminal guidance.
Can someone articulate a rationale for this effort?
A 155mm artillery shell is generally fired from something with a much deeper magazine than a typical aircraft. And unlike a missile an artillery piece has almost no arms control treaty limitations. And the cost per unit might well be favourable.
The 100km range and 1.6-min time of flight could probably manage with just an onboard target seeker. It only needs to look at a 1-mile radius patch of ground. The 1.6-mins is sufficient for use against any shoot-n-scoot type targets, especially counter-battery use.
The 1900km range and 31-min time of flight would likely need datalink and/or terminal guidance for use against a lot of targets. Though some might be capable of being addressed from (only) an onboard seeker. Whilst a 40mph vehicle could be in a 21-mile radius patch of ground which would be a challenge, in comparison a 12-knot group of ships would be in a much smaller patch of sea. The magazine depth of the artillery piece would be enough to deal with most anti-missile/anti-aircraft point or area defence systems, and would also have very favourable cost of exchange metrics.
Such a system opens up a lot of possibilities and should not just be thought as being in competition with aviation, but complementary to aviation. It would be a brave S-400 operator who wanted to be within range of one of these (proposed) artillery pieces.
I wonder what the Indo-Pacific looks like if you draw 1000-mile circles on every island.
etc.