A ground test of the Solid Fuel Ramjet engine being developed for the US Army

Northrop Grumman has carried out successful ground tests of a Solid Fuel RamJet (SFRJ) tactical engine that the company is developing for the US Army. Part of the Army’s XM1155 Extended-Range Artillery Projectile (ERAP) program, the engine is designed to boost the effective range of a 155 mm artillery shell to over 62 miles (100 km).

Even in an age of missile-firing drones and laser weapons, artillery is still the cornerstone of fire support for infantry and other ground forces. The problem is that artillery pieces have a relatively short effective range. Worse, the shells that they fire can only follow a ballistic trajectory, which means that once the projectile leaves the gun muzzle, there’s no way of altering its course, so it isn’t very effective against a target that’s actively avoiding the fall of shot.

There are a number of ways of overcoming this being explored and one of the more promising is the SFRJ. A ramjet is also known as a flying stovepipe because it is basically an empty tube into which fuel is sprayed. That may seem pointless, but when that tube is moving at high speed, especially in the supersonic range, its forward motion compresses the incoming air before burning the fuel, producing thrust without the need for moving parts.

Firing a SFRJ-equipped shell accelerates the engine to its operational velocity so it can ignite. Once it is running, it not only increases the range of the projectile, it also changes its flight characteristics because the engine keeps the shell from slowing down due to air resistance. In addition, it allows the shell to be steered in flight, making it more precise and capable of hitting a moving target.

The Phase One XM1155 ERAP ground tests included the firing of multiple rounds and determined that the SFRJ’s survivability and the performance met predictions. The eventual goal is to produce a shell that can be used against stationary and moving high-level targets in all weather conditions and any terrain.

https://newatlas.com/military/northrop-grumman-test-fires-solid-fuel-ramjet-engine-artillery/

Not sure if’s it right to admire our ingenuity in weapon making, quite inventive we are

PermeateFree said:

A ground test of the Solid Fuel Ramjet engine being developed for the US Army

Northrop Grumman has carried out successful ground tests of a Solid Fuel RamJet (SFRJ) tactical engine that the company is developing for the US Army. Part of the Army’s XM1155 Extended-Range Artillery Projectile (ERAP) program, the engine is designed to boost the effective range of a 155 mm artillery shell to over 62 miles (100 km).

Even in an age of missile-firing drones and laser weapons, artillery is still the cornerstone of fire support for infantry and other ground forces. The problem is that artillery pieces have a relatively short effective range. Worse, the shells that they fire can only follow a ballistic trajectory, which means that once the projectile leaves the gun muzzle, there’s no way of altering its course, so it isn’t very effective against a target that’s actively avoiding the fall of shot.

There are a number of ways of overcoming this being explored and one of the more promising is the SFRJ. A ramjet is also known as a flying stovepipe because it is basically an empty tube into which fuel is sprayed. That may seem pointless, but when that tube is moving at high speed, especially in the supersonic range, its forward motion compresses the incoming air before burning the fuel, producing thrust without the need for moving parts.

Firing a SFRJ-equipped shell accelerates the engine to its operational velocity so it can ignite. Once it is running, it not only increases the range of the projectile, it also changes its flight characteristics because the engine keeps the shell from slowing down due to air resistance. In addition, it allows the shell to be steered in flight, making it more precise and capable of hitting a moving target.

The Phase One XM1155 ERAP ground tests included the firing of multiple rounds and determined that the SFRJ’s survivability and the performance met predictions. The eventual goal is to produce a shell that can be used against stationary and moving high-level targets in all weather conditions and any terrain.

https://newatlas.com/military/northrop-grumman-test-fires-solid-fuel-ramjet-engine-artillery/

This is the shit, this sort of stuff. It is what Australia needs to be investing too. Especially a slight;y larger round with a range of 3-400 km, and fitted out as an anti-ship weapon. No bastard would be able to get a ship within 400 km of our coast without copping a pounding.

only for smooth bore cannons I gather..

transition said:

only for smooth bore cannons I gather..

Probably more of a mortar round even. If the thrust of the ramjet engine is sufficient to sustain it in flight then it would need less of a boost from the charge.

party_pants said:

PermeateFree said:

A ground test of the Solid Fuel Ramjet engine being developed for the US Army

Northrop Grumman has carried out successful ground tests of a Solid Fuel RamJet (SFRJ) tactical engine that the company is developing for the US Army. Part of the Army’s XM1155 Extended-Range Artillery Projectile (ERAP) program, the engine is designed to boost the effective range of a 155 mm artillery shell to over 62 miles (100 km).

Even in an age of missile-firing drones and laser weapons, artillery is still the cornerstone of fire support for infantry and other ground forces. The problem is that artillery pieces have a relatively short effective range. Worse, the shells that they fire can only follow a ballistic trajectory, which means that once the projectile leaves the gun muzzle, there’s no way of altering its course, so it isn’t very effective against a target that’s actively avoiding the fall of shot.

There are a number of ways of overcoming this being explored and one of the more promising is the SFRJ. A ramjet is also known as a flying stovepipe because it is basically an empty tube into which fuel is sprayed. That may seem pointless, but when that tube is moving at high speed, especially in the supersonic range, its forward motion compresses the incoming air before burning the fuel, producing thrust without the need for moving parts.

Firing a SFRJ-equipped shell accelerates the engine to its operational velocity so it can ignite. Once it is running, it not only increases the range of the projectile, it also changes its flight characteristics because the engine keeps the shell from slowing down due to air resistance. In addition, it allows the shell to be steered in flight, making it more precise and capable of hitting a moving target.

The Phase One XM1155 ERAP ground tests included the firing of multiple rounds and determined that the SFRJ’s survivability and the performance met predictions. The eventual goal is to produce a shell that can be used against stationary and moving high-level targets in all weather conditions and any terrain.

https://newatlas.com/military/northrop-grumman-test-fires-solid-fuel-ramjet-engine-artillery/

This is the shit, this sort of stuff. It is what Australia needs to be investing too. Especially a slight;y larger round with a range of 3-400 km, and fitted out as an anti-ship weapon. No bastard would be able to get a ship within 400 km of our coast without copping a pounding.

+1

“Solid fuel” ramjet? That’s not a ramjet, that’s a rocket.

I love ramjets, apart from the noise. They are the simplest and most effective way to get supersonic passenger planes to twice the speed of Concorde. Grollo Aerospace Australia makes ramjet engines.

mollwollfumble said:

“Solid fuel” ramjet? That’s not a ramjet, that’s a rocket.

I love ramjets, apart from the noise. They are the simplest and most effective way to get supersonic passenger planes to twice the speed of Concorde. Grollo Aerospace Australia makes ramjet engines.

Sure it’s a ramjet if it is getting it’s oxygen for combustion from the atmosphere; and instead of using a rotary compressor fan it uses its forward speed and a shaped intake to compress the air.

Counts as a ramjet to me.

party_pants said:

mollwollfumble said:

“Solid fuel” ramjet? That’s not a ramjet, that’s a rocket.

I love ramjets, apart from the noise. They are the simplest and most effective way to get supersonic passenger planes to twice the speed of Concorde. Grollo Aerospace Australia makes ramjet engines.

Sure it’s a ramjet if it is getting it’s oxygen for combustion from the atmosphere; and instead of using a rotary compressor fan it uses its forward speed and a shaped intake to compress the air.

Counts as a ramjet to me.

Roger.

Peak Warming Man said:

party_pants said:

mollwollfumble said:

“Solid fuel” ramjet? That’s not a ramjet, that’s a rocket.

I love ramjets, apart from the noise. They are the simplest and most effective way to get supersonic passenger planes to twice the speed of Concorde. Grollo Aerospace Australia makes ramjet engines.

Sure it’s a ramjet if it is getting it’s oxygen for combustion from the atmosphere; and instead of using a rotary compressor fan it uses its forward speed and a shaped intake to compress the air.

Counts as a ramjet to me.

Roger.

I call it a hybrid. Solid fuel plus gaseous source of oxygen counts as a hybrid rocket to me.
A ramjet is liquid fuel plus atmospheric oxygen. A “jet engine” never has solid fuel.

But I’m being pedantic.

I’d be more inclined to use this on those mobile missile launchers you see being used, you know the box on the back of a truck.

Id go for a three stage missile

Stage 1 missile is fired and after a short time gains gains height and distance using coasting trajectory. At top of curve..

Stage 2 : solid fuel slug fires to gain suitable height and speed for ramjet to operate.

Stage 3 ramjet fires and cruises to destination

wookiemeister said:

I’d be more inclined to use this on those mobile missile launchers you see being used, you know the box on the back of a truck.

Id go for a three stage missile

Stage 1 missile is fired and after a short time gains gains height and distance using coasting trajectory. At top of curve..

Stage 2 : solid fuel slug fires to gain suitable height and speed for ramjet to operate.

Stage 3 ramjet fires and cruises to destination

I go for:
stage 1 – mortar launch (smooth bore)
stage 2 – rocket assist and climb to high altitude
stage 3 – ramjet motor for high altitude level flight
stage 4 – as near as vertical descent and terminal phase

level flight phase so that even if the enemy picks it up on radar that can’t work out the launch point using a simple ballistic trajectory.

party_pants said:

wookiemeister said:

I’d be more inclined to use this on those mobile missile launchers you see being used, you know the box on the back of a truck.

Id go for a three stage missile

Stage 1 missile is fired and after a short time gains gains height and distance using coasting trajectory. At top of curve..

Stage 2 : solid fuel slug fires to gain suitable height and speed for ramjet to operate.

Stage 3 ramjet fires and cruises to destination

I go for:
stage 1 – mortar launch (smooth bore)
stage 2 – rocket assist and climb to high altitude
stage 3 – ramjet motor for high altitude level flight
stage 4 – as near as vertical descent and terminal phase

level flight phase so that even if the enemy picks it up on radar that can’t work out the launch point using a simple ballistic trajectory.

The third stage has tiny fins that allow control so the missile can change its height and direction so that if it comes under fire it can dodge.

Presumably the missile will be going just as fast as an artillery shell launched ramjet and they are confident that nothing can hit it / they don’t care if the enemy knows its coming.

A mobile truck mounted missile system would just shoot and scoot. By the time they fire back it will have gone.

Maybe the pointy bit is the explosive bit and the intake is slightly back and circular sat around the pointy bit. Maybe for drag considerations you DO have a fourth stage , the ramjet stage is dumped leaving only the shell to travel whilst using tiny vanes to guide it?

wookiemeister said:

party_pants said:

wookiemeister said:

I’d be more inclined to use this on those mobile missile launchers you see being used, you know the box on the back of a truck.

Id go for a three stage missile

Stage 1 missile is fired and after a short time gains gains height and distance using coasting trajectory. At top of curve..

Stage 2 : solid fuel slug fires to gain suitable height and speed for ramjet to operate.

Stage 3 ramjet fires and cruises to destination

I go for:
stage 1 – mortar launch (smooth bore)
stage 2 – rocket assist and climb to high altitude
stage 3 – ramjet motor for high altitude level flight
stage 4 – as near as vertical descent and terminal phase

level flight phase so that even if the enemy picks it up on radar that can’t work out the launch point using a simple ballistic trajectory.

The third stage has tiny fins that allow control so the missile can change its height and direction so that if it comes under fire it can dodge.

Presumably the missile will be going just as fast as an artillery shell launched ramjet and they are confident that nothing can hit it / they don’t care if the enemy knows its coming.

A mobile truck mounted missile system would just shoot and scoot. By the time they fire back it will have gone.

yeah pretty much. Ramjet speeds are around Mach 3 – Mach 5. Which would be around the same as a 155 mm NATO artillery shell.

wookiemeister said:

Maybe the pointy bit is the explosive bit and the intake is slightly back and circular sat around the pointy bit. Maybe for drag considerations you DO have a fourth stage , the ramjet stage is dumped leaving only the shell to travel whilst using tiny vanes to guide it?

Dunno. Whatever works best. Could also be a case of the casing being shaped to be both part of the ramjet and an armour-piercing body. Probably would need to have some sort of GPS and navigation computer included For an anti-ship version either an active radar, heat seeking or radar seeking (the ship’s radar) sensor system.

trying to imagine any advantage over what exists, a rocket basically shot out of a cannon

for starters the predictability in the (initial) arc of trajectory, or trajectory arc, seems potentially lost by any assist system, or made a lot more complex perhaps

biggest advantage may be the launch origin could be hard to determine, and the missile very difficult to detect because of its launch velocity

rocket powered missiles give their launch position away, either it can be seen, or can be roughly determined from the early trail, combustion products, heat trail, or heat signature

transition said:

trying to imagine any advantage over what exists, a rocket basically shot out of a cannon

for starters the predictability in the (initial) arc of trajectory, or trajectory arc, seems potentially lost by any assist system, or made a lot more complex perhaps

biggest advantage may be the launch origin could be hard to determine, and the missile very difficult to detect because of its launch velocity

rocket powered missiles give their launch position away, either it can be seen, or can be roughly determined from the early trail, combustion products, heat trail, or heat signature

But they launch fast and leave fast

wookiemeister said:

transition said:

trying to imagine any advantage over what exists, a rocket basically shot out of a cannon

for starters the predictability in the (initial) arc of trajectory, or trajectory arc, seems potentially lost by any assist system, or made a lot more complex perhaps

biggest advantage may be the launch origin could be hard to determine, and the missile very difficult to detect because of its launch velocity

rocket powered missiles give their launch position away, either it can be seen, or can be roughly determined from the early trail, combustion products, heat trail, or heat signature

But they launch fast and leave fast

think of as like avoiding using tracer ammunition in your machine gun, I mean it’s a great idea to see where your projectile is going, but the bad guys can use that trace to see where it’s coming from

transition said:

wookiemeister said:

transition said:

trying to imagine any advantage over what exists, a rocket basically shot out of a cannon

for starters the predictability in the (initial) arc of trajectory, or trajectory arc, seems potentially lost by any assist system, or made a lot more complex perhaps

biggest advantage may be the launch origin could be hard to determine, and the missile very difficult to detect because of its launch velocity

rocket powered missiles give their launch position away, either it can be seen, or can be roughly determined from the early trail, combustion products, heat trail, or heat signature

But they launch fast and leave fast

think of as like avoiding using tracer ammunition in your machine gun, I mean it’s a great idea to see where your projectile is going, but the bad guys can use that trace to see where it’s coming from

The missile will be able to move its position and trajectory through out its flight – no implied start point.

wookiemeister said:

transition said:

wookiemeister said:

But they launch fast and leave fast

think of as like avoiding using tracer ammunition in your machine gun, I mean it’s a great idea to see where your projectile is going, but the bad guys can use that trace to see where it’s coming from

The missile will be able to move its position and trajectory through out its flight – no implied start point.

yeah, and the big trouble of launching anything that can be seen from the starting point, or the starting point calculated, is it can be found, seen from a satellite or whatever, determined with pinpoint accuracy, tracked if moving, and destroyed

so you got to make it more difficult to find the launch position

similar thing applies of radio communications, radio emissions generally have an identifiable source, doesn’t matter that they are encrypted

transition said:

wookiemeister said:

transition said:

think of as like avoiding using tracer ammunition in your machine gun, I mean it’s a great idea to see where your projectile is going, but the bad guys can use that trace to see where it’s coming from

The missile will be able to move its position and trajectory through out its flight – no implied start point.

yeah, and the big trouble of launching anything that can be seen from the starting point, or the starting point calculated, is it can be found, seen from a satellite or whatever, determined with pinpoint accuracy, tracked if moving, and destroyed

so you got to make it more difficult to find the launch position

similar thing applies of radio communications, radio emissions generally have an identifiable source, doesn’t matter that they are encrypted

Yeah the whole thing of not knowing where its been fired from is obsolete now.

transition said:

wookiemeister said:

transition said:

think of as like avoiding using tracer ammunition in your machine gun, I mean it’s a great idea to see where your projectile is going, but the bad guys can use that trace to see where it’s coming from

The missile will be able to move its position and trajectory through out its flight – no implied start point.

yeah, and the big trouble of launching anything that can be seen from the starting point, or the starting point calculated, is it can be found, seen from a satellite or whatever, determined with pinpoint accuracy, tracked if moving, and destroyed

so you got to make it more difficult to find the launch position

similar thing applies of radio communications, radio emissions generally have an identifiable source, doesn’t matter that they are encrypted

This is why you want long range, so your weapon launch platform is a long way away behind the front line. Also if you have a non-ballistic trajectory which includes some level flight and some maneuver before terminal phase, it makes it hard to pin-point where the launch came from. if it is launch from 100 km away it is going to take some pretty sophisticated tracking equipment to figure out where the launch dite is, and some equally sophisticated long range weapon to indulge in counter-fire. By which time the launch vehicle might already have moved on.

>long way away behind the front line.

better still, don’t have a front line

I think that rather that the most important thing to winning a war is to prepare for it. The recent conflict with armenia shows that the Armenian military was curiously unprepared. Having suffered a holocaust at the hands of the turks they never prepared, never rearmed, never built defence systems and them wondered why they got their arses handed to them. Amusingly the Israelis were selling military tech to the other side.

wookiemeister said:

transition said:

wookiemeister said:

The missile will be able to move its position and trajectory through out its flight – no implied start point.

yeah, and the big trouble of launching anything that can be seen from the starting point, or the starting point calculated, is it can be found, seen from a satellite or whatever, determined with pinpoint accuracy, tracked if moving, and destroyed

so you got to make it more difficult to find the launch position

similar thing applies of radio communications, radio emissions generally have an identifiable source, doesn’t matter that they are encrypted

Yeah the whole thing of not knowing where its been fired from is obsolete now.

That means all field guns are too. Perhaps we should all go home.

PermeateFree said:

wookiemeister said:

transition said:

yeah, and the big trouble of launching anything that can be seen from the starting point, or the starting point calculated, is it can be found, seen from a satellite or whatever, determined with pinpoint accuracy, tracked if moving, and destroyed

so you got to make it more difficult to find the launch position

similar thing applies of radio communications, radio emissions generally have an identifiable source, doesn’t matter that they are encrypted

Yeah the whole thing of not knowing where its been fired from is obsolete now.

That means all field guns are too. Perhaps we should all go home.

The North Korean strategy is to just have thousands of artillery pieces.

In the event of war they fire them all

Dodge that