Russian Nuclear Submarine Force: Discussion

lancelot wrote:Hypergolic fueled SLBMs are quite a dangerous thing to put in a submarine. It is a disaster waiting to happen. The fuel ignites in contact with water in case you did not know about it. Any leak in the missile propellant tanks can prove to be fatal to a submarine. This is one of the reasons why the submarines equipped with R-29 have to go.

Hmmm... given that there have literally been many 100s of missiles/silos on Soviet/Russian SSBNs for a period stretching over 6 decades and yet AFAIK there has only been one known example of a missile tube fire (K-219 in 1986), I would have to say that sort of undermines your contention?

A lot of people dont know that even bulava has a hyperbolic fuel third stage. They can be stored on subs safely. The delfin class is an amazing lineage of boats.

Hypergolic rockets are dangerous. Period.

Solid rocket fuel is just as dangerous.

The fuel just by itself is corrosive, its fumes when it evaporates are corrosive and toxic, and the fuel ignites in contact with water. What else do you need to know really?

But if you are hungry solid rocket fuel makes a nice treat...

The K-219 incident is not the only case of accidents with hypergolic rockets. The USSR also lost K-129 that way.

An Akula class sub had a fire loading an SS-N-20 solid fuelled rocket so it is not like they are safe and liquid fuelled rockets are not.

On the other hand, the land forces are developing a new Sarmat for liquid fuel. Thanks to this, the missile has amazing parameters and is ahead of everything the West has by decades.

Even with improvements in solid rocket fuels, liquid fuels are generally more powerful... and in this day and age with the potential for scramjets to reach and exceed rocket performance the potential is even more in favour of liquid fuels.

lancelot wrote:The K-219 incident is not the only case of accidents with hypergolic rockets. The USSR also lost K-129 that way.

Thats a theory only, certainly not confirmed.  Damage observed around the missile tubes could easily have been caused by missiles being damaged by hydrostatic overpressure as the boat sank below crush depth. Sitting at nearly 5km depth, the water pressure is nearly 500 atmospheres, more than enough to crush the missile tanks and release the propellents to ignite on contact.

AFAIK the hulls break point was well forward of the tower, so not consistent with a missile explosion  A fire in the torpedo room and subsequent warhead cook-off is a more likely cause, but we will probably never know for sure.

Yes, hypergolics are dangerous propellents, but so is solid fuel, as is kerolox and cryogenics for space launchers. Risk is determined not just by likelihood and consequence, but by safeguards employed. Russians are masters of hypergolic propulsion and no-one does it better. Liquid fuels have significantly more energy than solids, and the higher ISP of the motors means more payload delivered for a given mass of missile. I agree that solids are a natural progression for submarines, and eventually Russia will retire the Sineva and Layner missiles in favour of Bulava and future variants, but lets not exaggerate the risk. It is managable, and Soviet/Russian service experience proves liquid-fuelled SLBMs are safe to an acceptable degree.

A lot of people dont know that even bulava has a hyperbolic fuel third stage. They can be stored on subs safely. The delfin class is an amazing lineage of boats.

The thing about the third stage of most long range missiles is that this is the stage running mostly in space and it is needed to put the missile on the correct trajectory to hit the target so it needs to be rather precise.

Having liquid fuelled rockets for that stage makes sense because solid rockets can't be shut down or throttled... once you start them up they burn till they burn out.

Funny that many people thinking liquid fuels are backward and bad also think they have to load the fuels onboard the missile just before launch so they take a day before they can be launched so they can be properly fuelled up before launch.

The Soviets mastered storable liquid propellents with their first genuine ICBM... the R-7.

Interestingly before they had ballistic missiles with strategic ranges they were developing high speed cruise missiles with thousands of kms of range, which were dropped when their ICBM ballistic missiles started taking off literally.

Now they have scramjet technology it would be rather well worth looking at that sort of thing again because it makes the weapons rather smaller and lighter... and liquid fuelled...

You are correct, my mistake... it was missiles just after the R-7 that had storable liquid propellants.

Solid rocket fuels had issues too, they are very expensive and not really as powerful as the liquid fuel models and of course once they are started you cannot shut them down and they are not able to be throttled or shut down and started up again.

Solid or liquid fuels are immensely dangerous.