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Restartable solid rocket motor

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shrox

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I have thought that injecting a gas like nitrogen might throttle a solid rocket motor.
 

aerostadt

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Quite often called a pintle nozzle. Put several pintle nozzle motors around the airframe connected to a solid propellant gas generator and you have an attitude control system. Hook it up to a guidance system and you have an important application that is widely in the industry used.

Bob
 

The EGE

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I recall seeing a design, I think in a fictional book, with small pellets of propellant being continuously injected. Somewhat like a liquid-propellant motor, only with solid grains. I'd be hard to make it small enough for us though - and ridiculously expensive.
 

JDcluster

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Even if it were possible, it would extremely difficult to do. You would need an ignition source for each time you wanted to restart the motor. Provided that you don't kill it on the first point of ignition....



JD
 

Orionblamblam

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Even if it were possible, it would extremely difficult to do. You would need an ignition source for each time you wanted to restart the motor.
A motor of this kind would actually be remarkably simple, though the thrust to weight ratio would be at best poor.


1: Replace the regular bullets with blanks.
2: Replace the gunpowder blanks with blanks using granulated solid rocket propellant.
3: Replace the brass cartriges with a caseless cartrige.
4: Replace the magazine with a consumable belt feed, a conveyor belt, or some other form of feed system.
5: Replace the barrel witha shorter, non-rifled tube and a proper nozzle. If the propellant can be made to actually detonate, then a convergent throat wll not be needed.

Cyclic rate can be adjusted.

I proposed this idea some years back as an alternative astronaut manuevering system. Isp would be substantially higher than cold-gas nitrogen, along with density impulse.
 

Orionblamblam

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Well, not really. It might be okay for one concentrated burst of high thrust, but due to the difficulty of reloading it, firing time would be very limited. And if you're going to have a single high-thrust pulse, you might as well use a conventional rocket... lighter weight, higher Isp. The advantage of using the guts of a small machine pistol is that if you have a good ammo feed mechanism, you can in principle fire it for as long or as short as you like.
 
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