China Ballistic Missiles and Nuclear Arms Thread

[Temstar]

Some digging work on possible propellant for third stage engine:

Patent filed by CASC 42 Institute says that it developed a GAP/CL-20/AlH3 propellant, theoretical Isp 2790.40 Ns/kg, density 1.80g/cm3
To give you an idea how insanely powerful it is, it means Isp 271s at sea level in reality and Isp >311s in the vacuum, an Isp on par with liquid pbv used by US and Soviet.

In comparison with hypergolic engine:
RD-270, the most powerful hypergolic ever built, has an Isp 322s in the vacuum.
RD-869, MIRV bus used by R36M, has an Isp around 311s-313s in the vacuum.

View attachment 101356

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However, it is too expensive and sophisticated to produce, its annual production is around 10t/a and a price tag of 60,000RMB/kg. CL-20 production is not high either, only around 27t/a. The real production rate of such propellant is around 50-60t/a with consideration of two important ingredient in mind, so it will be enough for 10 DF-41 or 5 DF-45 per year.


Too expensive and unnecessary for other purposes. Ofc you can use AlH3 for solid battery if you want to pay for 60,000RMB/kg for a car battery product. One 10t/a AlH3 production line costs 278 million RMB to build, no one is going to waste that money on it without clear prospect.

AFAIK, another company is currently auctioning for AlH3 production line, 10t/a in initial investment and another 30t/a in the future. It will increase AlH3 production for 4 times, to 25 DF-45s/50 DF-41s in total per yer. It could be higher if there is other undisclosed production expansion on the way.

HOLY MOLY, a solid fuel that's 51% CL-20?!
For those not aware, here's a skeletal formula of CL-20, aka hexanitrohexaazaisowurtzitane

Do you see just how many nitrogen is inside this baby? Every single one of them is just dying to break out of that molecule that by all account shouldn't exist and combine with another single nitrogen into tripled bonded red hot nitrogen gas molecule.

The ability to beat the crap out of a molecule to add that many nitro group to it, at a industrial scale and handle it so it's stable enough for use in rockets all without blowing yourself up is tremendous technological achievement.

 

[FairAndUnbiased]

HOLY MOLY, a solid fuel that's 51% CL-20?!
For those not aware, here's a skeletal formula of CL-20, aka hexanitrohexaazaisowurtzitane
View attachment 101394
Do you see just how many nitrogen is inside this baby? Every single one of them is just dying to break out of that molecule that by all account shouldn't exist and combine with another single nitrogen into tripled bonded red hot nitrogen gas molecule.

The ability to beat the crap out of a molecule to add that many nitro group to it, at a industrial scale and handle it so it's stable enough for use in rockets all without blowing yourself up is tremendous technological achievement.

when I see that many NO2s on a molecule I know it's trouble. Holy crap. Also the N-NO2 bond... Wtf...

 

[sunnymaxi]

when I see that many NO2s on a molecule I know it's trouble. Holy crap. Also the N-NO2 bond... Wtf...

very serious information it seems. can you explain little more.

CASC building most powerful engines. does it means in near future we can see super heavy ICBM and SLBM ?

 

[FairAndUnbiased]

very serious information it seems. can you explain little more.

CASC building most powerful engines. does it means in near future we can see super heavy ICBM and SLBM ?

NO2 groups are extremely energetic upon combustion due to the high bond enthalpy of the N-N triple bond formed during combustion of nitrogen containing groups that produce nitrogen gas. When you bond NO2 to N, the bond is even weaker than a C-N bond due to equal electronegativity. So you have a molecule that is barely hanging on to stability and can burn with any small input. To have something that's this unstable yet with 51% weight fraction is insane.

 

[luosifen]

NO2 groups are extremely energetic upon combustion due to the high bond enthalpy of the N-N triple bond formed during combustion of nitrogen containing groups that produce nitrogen gas. When you bond NO2 to N, the bond is even weaker than a C-N bond due to equal electronegativity. So you have a molecule that is barely hanging on to stability and can burn with any small input. To have something that's this unstable yet with 51% weight fraction is insane.

How far do you think the chemists in China will push that % to? 100?

 

[FairAndUnbiased]

How far do you think the chemists in China will push that % to? 100?

Still need binder for mechanical properties and to avoid detonation.

 

[Kalec]

very serious information it seems. can you explain little more.

CASC building most powerful engines. does it means in near future we can see super heavy ICBM and SLBM ?

There are two kinds of Isp, which are Isp and density Isp.
Isp is the efficiency indicator on how many thrusts the propellant is able to generate per mass.
Density Isp is how many thrusts the propellant is able to generate per volume.

Broadly speaking, not strictly applying to reality, a good rocket designer should use cheap high-density-Isp propellant in first and second stages, expensive high-Isp propellant in the third stage.

How far do you think the chemists in China will push that % to? 100?

Typical advanced propellant like NEPE-75 used by Trident D5, as its name suggests, is made of 25% binding agent and 75% solid fuel and you need oxidizer to burn the fuel.

Long time short, solid propellant is made of mainly binding agent + metal fuel + explosive.
Binding agent: HTPB, NEPE, GAP
Metal fuel: Al, AlH3
Explosive: RDX, HMX, CL-20
Oxidizer: AP, ADN

 

[Temstar]

I think CL-20 is considered the oxidiser component, as when the nitro groups decompose they release oxygen. Beijing Institute of Technology wrote about it in a news 6 years ago:

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在固体推进领域，学校研制的含能材料CL-20，作为我国在研的能量最高的固体推进剂的主氧化剂，直接实现了我国固体火箭推进能力大幅提升，成为对航天动力研究领域的耀眼贡献。

"In the field of solid fuel propulsion, our institute studied energetic material CL-20. It is the most energetic primary oxidiser being studied for solid fuel rockets across China, and has allow great improvements in performance for our nation's solid fuel rockets, becoming an outstanding contribution to the field of aerospace propulsion research"

 

[Kalec]

I think CL-20 is considered the oxidiser component, as when the nitro groups decompose they release oxygen. Beijing Institute of Technology wrote about it in a news 6 years ago:

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"In the field of solid fuel propulsion, our institute studied energetic material CL-20. It is the most energetic primary oxidiser being studied for solid fuel rockets across China, and has allow great improvements in performance for our nation's solid fuel rockets, becoming an outstanding contribution to the field of aerospace propulsion research"

Nah Cl-20 is not a oxidizer but it does consume less oxygen than HMX.

	Oxygen Balance	Production Rate
AP	+34.04%	>40,000t/a
CL-20	-10.95%	~30t/a
HMX	-21.6%	~2000t/a
ADN	+25.8%	N/A
TKX-50	-27.1%	N/A

IMO China would use GAP/HMX/AP/Al in the first and second stage and GAP/CL-20/AP/AlH3 in the third stage due to availability of CL-20 and AlH3. Basically old NEPE formula with a new binder and new advanced energetic formula in the third stage.

 

[sunnymaxi]

if i m not wrong. this is first time someone from CMC gave this kind of statement. damn

https://twitter.com/i/web/status/1591068925604859909

Xu Qiliang, outgoing vice chair of China's Central Military Commission, stated that China "will insist on prioritizing the development of capabilities that the enemies fear most, and will strengthen strategic capabilities," demonstrating China's strong & persistent commitment to building up its nuclear forces (and other strategic military capabilities) and the lack of interest in restraining such developments. That said, he also said China "will insist on asymmetric balancing" and selective development (有所为有所不为). To me, this adds to credibility of the argument that China has not decided to achieve nuclear parity with the US. China likely is keeping its nuclear buildup an open-ended process: taking a step-by-step approach by evaluating result & new situation after each step and readjusting the goal before taking the next..