Nervy pressurization method

I was reading the FAS page on Soviet ICBMs and came across this fairly
radical way of pressurizing the propellant tanks of a missile:

"The R-36M used a gas-dynamic method for the first and second stages
whereby special ports are opened through which the propellant tanks are
pressurized. This obviated the need for the use of pressurant gases from
tanks and the so-called chemical tanks pressurization (by injecting
small amounts of fuel in the oxidizer tank and oxidizer into the fuel
tank)."

Now, would starting a fire inside of the UDMH tank be a wise idea?
Doesn't that stuff act like a monopropellant when ignited?

Pat

Pat Flannery wrote:
I was reading the FAS page on Soviet ICBMs and came across this fairly
radical way of pressurizing the propellant tanks of a missile:

"The R-36M used a gas-dynamic method for the first and second stages
whereby special ports are opened through which the propellant tanks are
pressurized. This obviated the need for the use of pressurant gases from
tanks and the so-called chemical tanks pressurization (by injecting
small amounts of fuel in the oxidizer tank and oxidizer into the fuel
tank)."

Now, would starting a fire inside of the UDMH tank be a wise idea?
Doesn't that stuff act like a monopropellant when ignited?

Pat


It would have been fun to watch this rocket on the test stand during
development.

Rusty

Rusty wrote:


It would have been fun to watch this rocket on the test stand during
development.



Yeah, from inside a hermetically sealed bunker, as I get a sneaking
suspicion that they probably ruptured some propellant tanks while coming
up with this concept.

Pat

I'm thinking its better than dropping in a lit unfiltered cigarette.
Special cigarettes with circular rings along the length. Snip to circle
and light for specific level of pressurization, then drop into tank and
reseal... (then RUUUUUUN)...

Dave

David Spain wrote:

I'm thinking its better than dropping in a lit unfiltered cigarette.
Special cigarettes with circular rings along the length. Snip to circle
and light for specific level of pressurization, then drop into tank and
reseal... (then RUUUUUUN)...


They played around with emergency ballast tanks for subs that worked on
this principle also.
If the sub is sinking, you hit The Big Red Button, and pyrotechnic gas
generators inflated the ballast tanks with gas pronto.
Unfortunately, from what I've read, maybe a little too pronto, as it
sometimes caused them to explode if the water didn't vent fast enough,
and the pressure inside of them rose catastrophically.

Pat

In article ,
Pat Flannery wrote:
"...the so-called chemical tanks pressurization (by injecting
small amounts of fuel in the oxidizer tank and oxidizer into the fuel
tank)."

Now, would starting a fire inside of the UDMH tank be a wise idea?
Doesn't that stuff act like a monopropellant when ignited?

It can, yeah. The trick is not to ignite it. :-) Injecting small amounts
of oxidizer into a big tank of cool fuel is definitely not an easy way to
ignite it; the temperatures produced aren't that high, even locally.

"Main-tank injection", the usual name for this in the West (or sometimes
"direct injection"), has been done experimentally without disaster. Its
main problem is simply that nobody has ever been able to figure out how to
*scale* the test results -- apparently there is a lot of hidden complexity
there, despite the apparent simplicity, and neither theory nor empirical
curve-fitting has been able to yield workable predictions from small-scale
tests. People have trouble designing with a technique whose performance
can't be estimated in advance.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

On Wed, 15 Nov 2006 23:12:35 -0600, Pat Flannery
wrote:

I was reading the FAS page on Soviet ICBMs and came across this fairly
radical way of pressurizing the propellant tanks of a missile:

"The R-36M used a gas-dynamic method for the first and second stages
whereby special ports are opened through which the propellant tanks are
pressurized. This obviated the need for the use of pressurant gases from
tanks and the so-called chemical tanks pressurization (by injecting
small amounts of fuel in the oxidizer tank and oxidizer into the fuel
tank)."

Now, would starting a fire inside of the UDMH tank be a wise idea?
Doesn't that stuff act like a monopropellant when ignited?

Pat


First time I heard about it was in this book:

http://russianforces.org/


I remember thinking they were nuts. But then they also describe how
the Soviets use nukes to put out coal mine fires a couple times so...
Talk about "thinking outside the box".