Titan Missile Museum: Starting the Stage-1 Engine

Hey everybody. I just wanted to take a
minute or two to explain how the engine for Titan to get started. So the engine
is started with what amounts to a, like a solid fuel 4th of July sky rocket. And
it’s attached to a flange right here. It’s called the start cartridge, and when
the start cartridge ignites, the exhaust from that is blown into a turbine, right
here. And when the turbine starts turning, it’s attached with a set of gears to two
pumps. This is one of them right here. There’s a pump for the fuel and one for the oxidizer. And when the pumps begin turning, a little bit of fuel and
oxidizer gets bled off into a gas generator right here. So the fuel and the
oxidizer meet inside the gas generator, where they ignite spontaneously. And that
creates a high-pressure flow of gas, and that gas gets fed through this pipe back
up into the turbine. So it’s a bootstrap operation. The start cartridge gets it
going and the gas generator keeps it going. So once things are in motion, fuel and oxidizer are pumped through a series of
pipes to this point right here. And when the pressure behind these valves gets to
be something like (don’t quote me, but) something like 300 pounds per
per square inch [2068 kPa], then the pressure sequencer, right here,
opens these valves and fuel can then flow into the combustion chamber right
here. Now, the oxidizer is pumped directly into the thrust chamber, but the fuel
takes a detour. The fuel goes down these pipes here. It goes down one pipe and
back the next, and then back down and then into the combustion chamber. And the reason for that is, they discovered they were designing these engines that,
if they mixed the fuel and the oxidizer simultaneously in the thrust chamber,
then the initial explosion was big enough to tear the engine apart. But if
they flooded the oxidizer in the chamber first, and then added the fuel like a
second later, that would dampen the initial explosion enough to get it going
steady state. And so that was very important. Then the other thing that that
does, is that the fuel is then actually used to cool the bells here so they
don’t melt down. So if you look inside you can see that there, this is the end,
what’s called the injector plate. And there are pairs of holes, and some of the
holes are larger and some are smaller. The large holes are for the oxidizer and the small holes are for the fuel. And so they meet here in front of the injector plate.
They will all burst into flame spontaneously, and Bob’s your uncle. So
take a look at this video of a test firing of a Stage-1 Titan II engine,
and you can see what’s going on here. And this all happens very, very quickly. So
pay close attention. Watch right between the thrust chambers. When the start
cartridge fires, you can see the black smoke come out of the turbine exhaust
pipe. So you can see that the start cartridge fires, only for like a second,
and doesn’t take very long for the turbo pump to spin up for the pressure to rise.
For the fuel and oxidizer to flow into the engine, all that happens almost
instantaneously – it only takes three seconds for the engine to come up to
100% power very quickly. So there you go. Thanks for watching.

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