Long-Range (1000 Mile Range) Strategic Cannon Program Update or New Details?

[riggerrob]

All this talk of increasing artillery ranges reminds me of a tour of Dr. Gerald Bull’s High Altitude Research Project at Highwater, Quebec back in 1967. Dr. Bull bragged that he could fire a shell all the way to Moscow!
HARP started with souped-up 5” US Navy surplus barrels. Dr. Bull welded a pair of 5” gun barrels end-to-end to improve muzzle velocity. He touted HARP as an inexpensive way to launch satellites into low earth orbit.
Sadly, the US Army pulled Bull’s funding in 1967.
Bull went on to develop base-bleed shells to extend ranges.
He up-graded artillery for the South African and Indian Armies.Rumor has it that Bull was assassinated (1990) by the Israeli Mossad when he designed a super-gun for Iraqi dictator Saran Hussein. Hussein wanted to shell Israel from Iraq.
Bull was a brilliant engineer who fell afoul of Cold War politics.

 

[Scott Kenny]

All this talk of increasing artillery ranges reminds me of a tour of Dr. Gerald Bull’s High Altitude Research Project at Highwater, Quebec back in 1967. Dr. Bull bragged that he could fire a shell all the way to Moscow!
HARP started with souped-up 5” US Navy surplus barrels. Dr. Bull welded a pair of 5” gun barrels end-to-end to improve muzzle velocity. He touted HARP as an inexpensive way to launch satellites into low earth orbit.
Sadly, the US Army pulled Bull’s funding in 1967.
Bull went on to develop base-bleed shells to extend ranges.
He up-graded artillery for the South African and Indian Armies.Rumor has it that Bull was assassinated (1990) by the Israeli Mossad when he designed a super-gun for Iraqi dictator Saran Hussein. Hussein wanted to shell Israel from Iraq.
Bull was a brilliant engineer who fell afoul of Cold War politics.

Bull also developed the Extended Range Full Bore, ERFB, projectile shape.

 

[publiusr]

There is a new rock-boring machine called Petra that uses gas flames to bore holes in even the toughest rock. Line with barrels.

I could see Petra drilling holes of many lengths/angles for different targets... preferably with an organ keyboard arrangement so you could play your bombardment Dr. Phibes style.

Kabul gets the D-flat.

 

[A_Random_Guy]

But they too found it not workable due to the imprecision of the machines, basically for pipes you need .XX precision, for guns you need .XXXX precision. And the metals that modern guns use will destroy the machines since the devil details are THAT different. The Baylon Gun managed it by trading mobility, any accuracy, and barrel life to use the pipe sections, and even that barely worked.

Given it would be using a guided round, this isn’t that much of a dealbreaker. It’s just replacing to propellant stage for what’s probably a boost glide weapon, with the DoD recently noting that propulsion was one of the major drivers of cost for hypersonic weapons.

If it can take the pressure combined with using a smoothbore and a propellant scheme like a CLG gun, barrel wear can be reduced significantly.

 

[Scott Kenny]

Given it would be using a guided round, this isn’t that much of a dealbreaker. It’s just replacing to propellant stage for what’s probably a boost glide weapon, with the DoD recently noting that propulsion was one of the major drivers of cost for hypersonic weapons.

If it can take the pressure combined with using a smoothbore and a propellant scheme like a CLG gun, barrel wear can be reduced significantly.

I have severe doubts about the combat durability of a light-gas gun...

And conventional gunpowder maxes out at 1700m/s muzzle velocity, right around mach 5. You'd really need a sustainer scramjet for a 1000mile cannon.

 

[A_Random_Guy]

I have severe doubts about the combat durability of a light-gas gun...

And conventional gunpowder maxes out at 1700m/s muzzle velocity, right around mach 5. You'd really need a sustainer scramjet for a 1000mile cannon.

I’m talking about a Combustion Light Gas Gun, not a Light Gas Gun. They operate under very different principles. A CLGG uses a mixture of O2, H2, and a buffer gas like Helium as a substitute for the normal propellant. A LGG uses an explosive to drive a piston which forces air (and the projectile) through the barrel.

https://apps.dtic.mil/sti/tr/pdf/ADA462130.pdf

As for barrel wear, flame temperatures are lower in a CLGG, leading to less erosion.

Depending on arrangement, 2500 meters per second is not unreasonable for such a weapon with possibly more achievable.

 

[Scott Kenny]

I’m talking about a Combustion Light Gas Gun, not a Light Gas Gun. They operate under very different principles. A CLGG uses a mixture of O2, H2, and a buffer gas like Helium as a substitute for the normal propellant. A LGG uses an explosive to drive a piston which forces air (and the projectile) through the barrel.

https://apps.dtic.mil/sti/tr/pdf/ADA462130.pdf

As for barrel wear, flame temperatures are lower in a CLGG, leading to less erosion.

Depending on arrangement, 2500 meters per second is not unreasonable for such a weapon with possibly more achievable.

Must be the buffer gas reducing temps, H2+O2 is usually a painfully hot flame (one of the preferred gas welding combos, in fact).

 

[A_Random_Guy]

Must be the buffer gas reducing temps, H2+O2 is usually a painfully hot flame (one of the preferred gas welding combos, in fact).

Modern propellants run a flame temperature between 2500 and 3500 Kelvin with most in the 3,000 Kelvin range and the particularly high energy formulations typically running well above that.

Military Propellants

Depending on arrangement they found a flame temp between 2500 and 2700 Kelvin.

 

[Scott Kenny]

Depending on arrangement they found a flame temp between 2500 and 2700 Kelvin. View attachment 727833

Hrm... That bottom option with the lowest flame temps implies a fairly large muzzle blast as the (hot) excess hydrogen mixes with air and then detonates...

But that's a separate issue.

Are we talking the "booster gun" types where there are additional propellant injectors up the barrel? Because I have severe doubts about that system being sufficiently rugged for field use.

 

[A_Random_Guy]

Hrm... That bottom option with the lowest flame temps implies a fairly large muzzle blast as the (hot) excess hydrogen mixes with air and then detonates...

Possibly but it’s going to be pointing at a high angle so it’s probably not too much of a practical issue.

Are we talking the "booster gun" types where there are additional propellant injectors up the barrel? Because I have severe doubts about that system being sufficiently rugged for field use.

There doesn’t seem to be any boosting. It’s just the propellants are higher energy and have a different speed of sound, thus providing a far higher muzzle velocity.

 

[MihoshiK]

Modern propellants run a flame temperature between 2500 and 3500 Kelvin with most in the 3,000 Kelvin range and the particularly high energy formulations typically running well above that.

Military Propellants

Depending on arrangement they found a flame temp between 2500 and 2700 Kelvin. View attachment 727833

Isn't this part of the same thing why hydrogen is so interesting as propellant for turbine engines? No soot particles = no radiative heating of parts, and thus your engine (or barrel) can run cooler while being more energetic?

 

[Scott Kenny]

Isn't this part of the same thing why hydrogen is so interesting as propellant for turbine engines? No soot particles = no radiative heating of parts, and thus your engine (or barrel) can run cooler while being more energetic?

No, regular H2 combustion is really hot, 3000K or so. (6000degF)

Most engineers like hydrogen due to energy per KG, until they see how much storage volume you need for 1kg of hydrogen...

 

[MihoshiK]

No, regular H2 combustion is really hot, 3000K or so. (6000degF)

Most engineers like hydrogen due to energy per KG, until they see how much storage volume you need for 1kg of hydrogen...

I know it's really hot, but how much of that transfers due to contact, and how much due to the gas being incandescent?

 

[Scott Kenny]

I know it's really hot, but how much of that transfers due to contact, and how much due to the gas being incandescent?

That depends on the materials in contact...

 

[publiusr]

Line it with Borazon?

Liquid metal has allowed diamond deposition with lower pressures, after all

Liquid metal synthesis of diamonds achieved at atmospheric pressure

Combining nickel, iron and silicon with gallium enabled diamond film synthesis from methane

www.chemistryworld.com

For a shock absorber

Programmable liquid hints at widespread applications

A 'metafluid' formed from collapsible elastic shells suspended in oil exhibits very different properties at different pressures

www.chemistryworld.com

 

[Prophet141]

I wonder if that diamond film deposition could be used to deposit graphene liners for other applications as well?

 

[Scott Kenny]

Interesting thoughts from the Paris Gun thread: Take your standard 35cm Naval gun, but give it a 20cm shell in a sabot, 1500m/s MV at 530MPa/52,000psi chamber pressures. Instant 100km range from WW1 tech.

We now have extremely low drag shell shapes, like that of the 155mm LRLAP (which also happens to be rocket boosted, but that's a different discussion). LRLAP is 220cm long, 155mm diameter, and weighs 102kg. ELD bullets are usually good for +50% range in small arms, and they get better as they get bigger due to better ballistic coefficients. I'd be surprised if a 155mm ELD shape wouldn't give you +100% range. Now we're talking about 200km or more before we count the rocket booster. LRLAP had a big enough rocket booster to count for at least 50% of the range, so now it's 400+km for a 155mm shell. Still not 1000km, but we're getting there. Admittedly with a stupid expensive shell, but I don't see any way around that.

Build a similar gun for modern day artillery, maybe you can get away with a 20-25cm bore ~55-60 calibers long using a 155mm shell diameter. Composite sabot design more or less copied from the tank guns, though figuring out a driving band interface will be "interesting". Doing that also gives you the option of full bore diameter shells for really dropping the hurt on someone.

 

[Firefinder]

Admittedly with a stupid expensive shell, but I don't see any way around that.

Oh thats easy.

Buy more then 150 of the things.

Cause that was the issue.

Just like their ships the Zumwalts, the number ordered drop for cost cutting balloon the cost. Cause in stead of sharing the RD cost between oh...

500,000 shells.

You now have get the same money from 150.

You can see the issue.

We can see that in the Excalibur. That shell does everything the LRLAP Shell does expect having a 4 foot long rocket motor, instead it has a 6 inch long one. The current going price for it is...

100k for the newest marks to the LRLAP 800k to a Million.

And the Newest Marks actually do more with a laser seeker and Home on Jam System. And what I can find was built to s higher Standard, both precision, toughness, and EMCOM. With them working on a millimeters seeker for it so it can be shot and drop on moving targets.

And the newest shells like the XM1155 SC and the Ramjet 155 have both shatter the LRLAP shell ranges using a shorter barrel, ERCA L58 to the AGS L64, reach out to 110 and 150km respectively in tests last year.

 

[Ravinoff]

There is a new rock-boring machine called Petra that uses gas flames to bore holes in even the toughest rock. Line with barrels.

I could see Petra drilling holes of many lengths/angles for different targets... preferably with an organ keyboard arrangement so you could play your bombardment Dr. Phibes style.

Kabul gets the D-flat.

Hah, great image. And you just discovered a concept that's been knocking around hard scifi (and possibly some demented military engineer's minds) for a while now called a Thunderwell. Idea is derived from the infamous Pascal-B nuclear test during Operation Plumbbob that fired off a very small (300 tons TNT equivalent) warhead at the bottom of a shaft 500 feet deep, capped with a two-ton steel plate. The idea was trying to find a way to carry out underground tests safely after the Pascal-A shot detonated at 50,000 times its intended yield and blew out the concrete stopper in the test shaft.

Yeah, turns out a two-ton armor steel plate doesn't fare much better. In fact, no trace of it was ever found...but that's where the fun part starts. Some calculations before the test suggested the blast might accelerate the cap plate to "interesting" velocities, and the researchers pointed a camera filming one frame per millisecond at it before the shot. It caught a single frame of the plate "going like a bat out of hell" to quote one engineer. It more than likely vaporized from compression heating before getting very far, but napkin math suggests it might have been doing about six times Earth's escape velocity when it broke loose.

Thunderwells take that result and weaponize it. Drill a hole and drop a low-yield nuke into it (I've heard it suggested that filling the shaft with water would make it work even better), but replace the steel plate with an aerodynamic heat-shielded ballistic slug. Voila, a dirt-cheap hypervelocity orbital kinetic kill weapon. Guidance is...problematic, and aim is more or less fixed, but with that much velocity who cares?

 

[Scott Kenny]

Oh thats easy.

Buy more then 150 of the things.

Cause that was the issue.

Just like their ships the Zumwalts, the number ordered drop for cost cutting balloon the cost. Cause in stead of sharing the RD cost between oh...

500,000 shells.

You now have get the same money from 150.

You can see the issue.

We can see that in the Excalibur. That shell does everything the LRLAP Shell does expect having a 4 foot long rocket motor, instead it has a 6 inch long one. The current going price for it is...

100k for the newest marks to the LRLAP 800k to a Million.

We're still talking 200k or more per shell (due to bigger rocket). Which ain't cheap.

 

[A_Random_Guy]

We're still talking 200k or more per shell (due to bigger rocket). Which ain't cheap.

Keep in mind it isn't a replacement for Excalibur or even Tomahawk, it's a replacement or suplement for other boost-glide systems like OP-FIRES and IRCPS.

National Academies of Sciences, Engineering, and Medicine. 2022. Assessing the Feasibility of the Strategic Long Range Cannon: Unclassified Summary. Washington, DC: The National Academies Press. https://doi.org/10.17226/26129.

Although the total life-cycle cost to integrate and sustain the SLRC program within the force structure is not yet known, differing cost estimates have been provided for the hypersonic-glide projectile. Initial round investments will also be high. LTG Thurgood, RCCTO Commanding General, estimated the initial SLRC round cost is greater than $8 million each; then $800,000 per round after 1,000 are purchased;31 the OUSD estimate was $85,000 per round at 10,000 rounds.32

Initial investment is expensive which tends to give congress plapatations.

 

[Scott Kenny]

Keep in mind it isn't a replacement for Excalibur or even Tomahawk, it's a replacement or suplement for other boost-glide systems like OP-FIRES and IRCPS.

Except the Army is buying Tomahawks for the 1000+nmi strike role. And SM6 Blk1bs for the ~500nmi strikes.

Which of course makes me wonder if the Patriot radar systems can talk to an SM6 in flight.

Initial investment is expensive which tends to give congress plapatations.

Always an issue.

 

[Firefinder]

Which of course makes me wonder if the Patriot radar systems can talk to an SM6 in flight.

That was done like a Decade ago in 2015 irc.

Basically had Patriot guided both a SM2 and SM6 and the Aegis the Pac2/6.