Wait what? Why would a howitzer require liquid nitrogen?
The War in the Ukraine
- Thread starter SampanViking
- Start date
increased support cost, require additional engineering resources from the manufacturer.
Icnrease the long term income generating capability of the weapon system for the manufacturer .
Good investment, slightly increase the system cost, but generating stable income stream .
Obivous the advantage of a liquid nitrogen system in an howitzer.
Without it they found themselves in the same situation like the manufacturers of the Soviet howitzer systems, without stable long term engineering and maintanance income stream for the produced guns.
the support is the real driver of the profit, on the long term support contract the manufacturer can make 50% profit easly, on the sale of the gun in good case they can make 20%.
So, we could experience the inclusion of liquid nitrogen, helium ,expiring components in every USA made weapon systems.
I bet it is lost in translation. You do need nitrogen in hydraulic.
My question is, what part of a howitzer would actually liquid nitrogen to operate?
Black Shark
Junior Member
Are you one of the western Snake Oil sellers?
You sound so proud of it. It is a burden to any military and has performed mediocre at best. Such liability to a military and logistics is doing more damage to your own than to your enemies. You convinced me, sell moa!
Interesting tactics and a bad day for those who just got bombed
Perhaps , the NATO 155 howitzer systems (M77 , CAESAR, PzH 2000) in Ukraine are being supplied with precision guided shells .
So, the liquid nitrogen might be used to cool the infrared sensors of those munitions?
Even if such a shell had an uncooled bolometer, nitrogen would be inappropriate as its boiling point is too high.
The only thing I can think of is dampeners using nitrogen gas.
Discussions about M777 observed on the Moon of Alabama :
"Per this article describing the M777 "The Elevating Mass comprises an open-structured Cradle pivoted from the saddle and a 155mm Cannon mounted in the cradle. The Cradle consists of four large thick-walled tubes with lightweight perforated side frames, and linked together by yokes. The four cradle tubes perform a useful secondary role as nitrogen gas and hydraulic fluid pressure vessels for the recoil systems and the ‘ equilibrators’ or balancing gear."
So nitrogen and hydraulic fluid are part of the recoil absorbing mechanism of the howitzer. I remember discussions by experienced military veterans after the M777s were being sent to Ukraine that the M777 was very lightweight and would not stand up to heavy usage which seems to be what is happening. Hearing this is happening to other NATO gear as well. Maybe the simple, solid, sturdy designs of Russian equipment are better suited for prolonged conflict...."
"
wrt liquid nitrogen for M777 howitzers perhaps I can help. In the old days we used compressed air to charge the accumulators and such on aircraft. The accumulator is a vessel (also found in your home heating system if you have hot water heat) that cushions shocks. When the gun is fired the barrel moves back forcing hydraulic fluid into this vessel. The air inside is compressed which makes the resistance increase as travel increases. When the lateral motion has been absorbed, the high pressure air in the vessel pushes the gun barrel back to its firing position so it can be loaded and fired again.
though I am not an artilleryman I sat next to a former one for many years and he related that on the mobile artillery he worked with, the air pressure would sometimes leak out and there would not be enough oomph to make the barrel return, so troops would push it back to where it belongs. this was only a temp fix and as air pressure was lost it became harder and harder to do so and the firing became much more violent as there was no longer a cushion of air to absorb the force of firing the gun. any time you have hydraulic cylinders there is always the possibility of leakage. happens all the time. it can be repaired.
as for liquid nitrogen, the gun does not use liquid nitrogen but does use high pressure nitrogen gas in those accumulators or expansion vessels. The reason for using nitrogen is that it is non flammable, the atoms are fairly big, the gas is dry which helps control corrosion of the metal parts. In the old days we used high pressure air compressors to do this with the associated gasoline or diesel engines to run them. Now Liquid Nitrogen (LIN) carts are used that are filled with liquid nitrogen but are able to provide high pressure gas for use as required. the boiling of the liquid nitrogen provides enough pressure to charge to 3000 psi (more than 200 bar) or more."
I am not an expert but it doesn't surprise me that the N2 and hydraulic fluids would need replacement. Keep in mind that the M777 was intended to be used in rapid deployment, air-lifted or paratrooper operations. Lots of engineering trade-offs were made in favor of cutting weight. This means that the carriage must be lightweight and thus cannot be expected to disperse much of the gun's recoil. Next the recoil mechanism itself will have to be lightweight. In absorbing the gun's recoil much of the energy of that recoil gets entropied into? Yep, heat.
Experiment: Rapidly open and close your trunk lid several times forcing it to open and close much faster than normal, then place your hand on the struts. Ouch!
The M777 can apparently be reloaded and fired again faster than the lightweight recoil mechanism on it can shed the heat from the previous shot, and they don't have the thermal mass to absorb more than a few shots worth of heat. Overheating the recoil mechanism will cause the seals to break down and then your gun turns into a hot oil fountain on the next shot.
This is all just guesswork based upon the knowledge that the gun's design was steeply biased towards being lightweight. You never get features like that for free in engineering.
Recoil mechanisms are generally some type of hydraulic or pneumatic compressor. As the M777 is intended to be light, it seems pneumatic is likely.
And in turn, keeping the pneumatic cylinder filled is non-trivial especially if you want to do things like maintenance or repair damage. I can see liquid nitrogen being used to fill the cylinders after repair/maintenance and resealing; the subsequent regasification would fill the pneumatic cylinder to desired pressure.
You wouldn't want to use oxygen or any other flammable gas, for example, as that could be explosive if the recoil mechanism is ruptured.
- no way to repair weapons on the spot due to the lack of spares and specialists - everything is sent to Poland
This, for example, was specifically said about M777 fire control units, which allegedly proved very vulnerable to debris and shards.
* * * * *
B asked if 777 is bad quality weapon. To me it more looks a narrow niche instrument abused. It is like using air rangers to stop tank army, their performance would be awful. And 777 was made to be air ranger of howitzers. Everything was sacrificed for weight. 777 had to be jetissonned or airlifted at best, so the ranger could have heavy fire for their first hours when creating a new bridgehead. They were not supposed to last long or pledge "general war". Now they are being abused for roke they were not created for and of course they fit badly. It was all just about PR...
And here's a long answer:
"Per this article describing the M777 "The Elevating Mass comprises an open-structured Cradle pivoted from the saddle and a 155mm Cannon mounted in the cradle. The Cradle consists of four large thick-walled tubes with lightweight perforated side frames, and linked together by yokes. The four cradle tubes perform a useful secondary role as nitrogen gas and hydraulic fluid pressure vessels for the recoil systems and the ‘ equilibrators’ or balancing gear."
So nitrogen and hydraulic fluid are part of the recoil absorbing mechanism of the howitzer. I remember discussions by experienced military veterans after the M777s were being sent to Ukraine that the M777 was very lightweight and would not stand up to heavy usage which seems to be what is happening. Hearing this is happening to other NATO gear as well. Maybe the simple, solid, sturdy designs of Russian equipment are better suited for prolonged conflict...."
"
wrt liquid nitrogen for M777 howitzers perhaps I can help. In the old days we used compressed air to charge the accumulators and such on aircraft. The accumulator is a vessel (also found in your home heating system if you have hot water heat) that cushions shocks. When the gun is fired the barrel moves back forcing hydraulic fluid into this vessel. The air inside is compressed which makes the resistance increase as travel increases. When the lateral motion has been absorbed, the high pressure air in the vessel pushes the gun barrel back to its firing position so it can be loaded and fired again.
though I am not an artilleryman I sat next to a former one for many years and he related that on the mobile artillery he worked with, the air pressure would sometimes leak out and there would not be enough oomph to make the barrel return, so troops would push it back to where it belongs. this was only a temp fix and as air pressure was lost it became harder and harder to do so and the firing became much more violent as there was no longer a cushion of air to absorb the force of firing the gun. any time you have hydraulic cylinders there is always the possibility of leakage. happens all the time. it can be repaired.
as for liquid nitrogen, the gun does not use liquid nitrogen but does use high pressure nitrogen gas in those accumulators or expansion vessels. The reason for using nitrogen is that it is non flammable, the atoms are fairly big, the gas is dry which helps control corrosion of the metal parts. In the old days we used high pressure air compressors to do this with the associated gasoline or diesel engines to run them. Now Liquid Nitrogen (LIN) carts are used that are filled with liquid nitrogen but are able to provide high pressure gas for use as required. the boiling of the liquid nitrogen provides enough pressure to charge to 3000 psi (more than 200 bar) or more."
I am not an expert but it doesn't surprise me that the N2 and hydraulic fluids would need replacement. Keep in mind that the M777 was intended to be used in rapid deployment, air-lifted or paratrooper operations. Lots of engineering trade-offs were made in favor of cutting weight. This means that the carriage must be lightweight and thus cannot be expected to disperse much of the gun's recoil. Next the recoil mechanism itself will have to be lightweight. In absorbing the gun's recoil much of the energy of that recoil gets entropied into? Yep, heat.
Experiment: Rapidly open and close your trunk lid several times forcing it to open and close much faster than normal, then place your hand on the struts. Ouch!
The M777 can apparently be reloaded and fired again faster than the lightweight recoil mechanism on it can shed the heat from the previous shot, and they don't have the thermal mass to absorb more than a few shots worth of heat. Overheating the recoil mechanism will cause the seals to break down and then your gun turns into a hot oil fountain on the next shot.
This is all just guesswork based upon the knowledge that the gun's design was steeply biased towards being lightweight. You never get features like that for free in engineering.
Recoil mechanisms are generally some type of hydraulic or pneumatic compressor. As the M777 is intended to be light, it seems pneumatic is likely.
And in turn, keeping the pneumatic cylinder filled is non-trivial especially if you want to do things like maintenance or repair damage. I can see liquid nitrogen being used to fill the cylinders after repair/maintenance and resealing; the subsequent regasification would fill the pneumatic cylinder to desired pressure.
You wouldn't want to use oxygen or any other flammable gas, for example, as that could be explosive if the recoil mechanism is ruptured.
- no way to repair weapons on the spot due to the lack of spares and specialists - everything is sent to Poland
This, for example, was specifically said about M777 fire control units, which allegedly proved very vulnerable to debris and shards.
* * * * *
B asked if 777 is bad quality weapon. To me it more looks a narrow niche instrument abused. It is like using air rangers to stop tank army, their performance would be awful. And 777 was made to be air ranger of howitzers. Everything was sacrificed for weight. 777 had to be jetissonned or airlifted at best, so the ranger could have heavy fire for their first hours when creating a new bridgehead. They were not supposed to last long or pledge "general war". Now they are being abused for roke they were not created for and of course they fit badly. It was all just about PR...
And here's a long answer: