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I've been following this for a while:

 

http://www.dtic.mil/ndia/2002gun/kathe.pdf

 

http://www.dtic.mil/ndia/2007gun_missile/GMTueAM2/MinerPresentation.pdf

 

http://www.dtic.mil/ndia/2009gunmissile/katheEmertechtuesday.pdf

 

It's a remarkably good idea.

 

RAVEN a drastically improved design for a recoilless rifle.  In a traditional recoilless rifle, at the moment of ignition gas is free to exit the rear of the gun out of a De Laval nozzle:

 

 

US_Special_Forces_soldier_fires_a_Carl_G

 

 

If the thrust of gas going through the nozzle is close enough to the momentum of the gas and projectile exiting the muzzle, the weapon is recoilless or close enough to.  The problem is that this is hideously inefficient; most of the propellant mass is used to counteract projectile momentum instead of pushing the projectile.

 

In the RAVEN, the breech is closed to gas flow at the moment of firing:

 

3xELPGD.png?1

 

But it is opened shortly afterward, while the projectile is still in-bore.  The wave cause by the sudden drop in pressure due to the breech vents opening cannot catch up with the projectile in time to affect it, so there is no velocity loss and the recoil reduction is essentially free.

 

Timing of the opening of the breech is most easily achieved by a blowback breech, IMO.  The acceleration of a delay mass should be extremely repeatable, and could easily give consistent timing.  The vent holes and nozzle will likely be consumable items, just as they are in traditional recoilless rifles.

 

Unlike traditional recoilless rifles, which are limited to low-to-medium velocities due to their inefficiency, RAVEN works better with high velocities, since the projectile will be moving a higher percentage of the speed of sound of the propellant gas, and so venting can occur earlier.  Furthermore, in high velocity weapons the momentum of the gas at the muzzle is a higher percentage of total recoil, so the percentage reduction of recoil will be higher.

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If the pressure release timing is correct, there is zero efficiency loss, so you could make, say, a recoilless version of an M256 if you were so inclined (or at least one with less recoil).

The problem you'll run into is dealing with the backblast.

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I think there is something missing, there should be some sort of small nuance that ruin this weapon system, which is a reason why nobody bothers to actually produce those. I think there is some sort of technical limitation that make this weapon not fit for service.

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I think there is something missing, there should be some sort of small nuance that ruin this weapon system, which is a reason why nobody bothers to actually produce those. I think there is some sort of technical limitation that make this weapon not fit for service.

 

The clear problem is that it wasn't designed by superior teutonic engineers.

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I think there is something missing, there should be some sort of small nuance that ruin this weapon system, which is a reason why nobody bothers to actually produce those. I think there is some sort of technical limitation that make this weapon not fit for service.

There is.

 

Here's part of it-

YLVyxb3.jpg

 

The pictured gun would launch a 28 pound HESH round to ~1500 FPS. Note the size of the fireball out it's ports.

 

Now, think of something producing ~3X higher velocites, and a corresponding puff out the backside.  That's a BIIG "danger zone" to deal with.

Dealing with port erosion I suspect is another limiting factor, unless the ports are incorporated into the shell somehow and hence "consumable"..

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The De Laval nozzles on big RRs are already consumable, so the vent ports on a big RAVEN would likely be as well.

 

And yes, while it improves over an RR in thermodynamic efficiency, a RAVEN does not do anything to make the backblast smaller.

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The gun on a stick in the first link is one of the greatest things I've ever seen. Integrating it on an autocannon looks quite doable given the trend towards unmanned turrets, and their swinging breech looks a lot like the CTA 40 breech. Not that IFV's care about recoil or long term sustained fire with the limited ammo load of a large calibre IFV, but I'm sure they could find something that would appreciate it.

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The De Laval nozzles on big RRs are already consumable, so the vent ports on a big RAVEN would likely be as well.

 

 

Kind of. if this higher velocity system works the way I imagine you'll be replacing them every shot, instead of say every fifty shots.

The odd little 20mm Lahti rifle did this by making the wear prone components a part of the shell base.

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Come to think of it, you'd want the wear component of the vent to be on the case anyhow, because you'd need to have different strength burst valves or whatever on different cartridges to achieve different timing.  Optimal timing for APFSDS will be different than optimal timing for HE-FRAG.

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There is.

 

Here's part of it-

YLVyxb3.jpg

 

The pictured gun would launch a 28 pound HESH round to ~1500 FPS. Note the size of the fireball out it's ports.

 

Now, think of something producing ~3X higher velocites, and a corresponding puff out the backside.  That's a BIIG "danger zone" to deal with.

Dealing with port erosion I suspect is another limiting factor, unless the ports are incorporated into the shell somehow and hence "consumable"..

Simple solution: simply turn it around for close range flamethrowing action!

 

"Close range flamethrowing action!" is a trademark of the stupid ideas corporation. Warning: flamethrowing has been shown to result in a number of medical issues including: first degree burns, second degree burns, third degree burns, hair loss, skin loss, ignition of subcutaneous fat, asphyxia, uncontrolled bowel movements, cataracts and death. Flamethrowing should only be done in a carefully controlled environment and under adult supervision. Use at own risk.

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Come to think of it, you'd want the wear component of the vent to be on the case anyhow, because you'd need to have different strength burst valves or whatever on different cartridges to achieve different timing.  Optimal timing for APFSDS will be different than optimal timing for HE-FRAG.

 

We must move more wear components into the case! Bring on the single shot preloaded barrels!

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We must move more wear components into the case! Bring on the single shot preloaded barrels!

"And thus did the cycle begin anew".

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So I had a bunch more links on RAVEN, these don't seem to have been posted, so I'm posting them.   Dr Eric Kathe is a prolific guy: 

 

http://www.dtic.mil/dtic/tr/fulltext/u2/a435128.pdf <-  this one is a 317 page thesis by Dr Kathe on RAVEN in relation to other recoilless concepts

 

http://www.dtic.mil/get-tr-doc/pdf?AD=ADA398942 <-  pdf download if you click on the link.   

 

Google cache link here:http://webcache.googleusercontent.com/search?q=cache:6eBVulAzScsJ:www.dtic.mil/get-tr-doc/pdf%3FAD%3DADA398942+&cd=5&hl=en&ct=clnk&gl=us

 

It's another technical paper by Dr Kathe in the same vein as the above, but with fewer pages.

 

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2015/armament/wedKathe.pdf < - powerpoint along the lines of what you posted a few years back, but with some other differences (I think) which analyzed alternatives

 

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2015/armament/MondayKathe_Tutorial.pdf <- another powerpoint.  With the monday/wednesday thing  I think it wsa part of a larger seminar in 2015.  you posted one of those originally (the Tuesday one) 

 

Some technical reports on RAVEN and the tech demonstrator

http://www.dtic.mil/dtic/tr/fulltext/u2/a597442.pdf

http://www.dtic.mil/dtic/tr/fulltext/u2/a591200.pdf

http://www.dtic.mil/dtic/tr/fulltext/u2/a504316.pdf

 

And another powerpoint:

 

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2010/armament/WednesdayLandmarkAMikeBixler.pdf

 

I'm also fascinated by RAVEN and it has many nifty implications regarding 'light weight without losing performance'  as far as recoilless technologies go.  One was for improving man portable firepower (mentioned in the first pdf Collimatrix posted   in the original post.

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