shutting down a solid rocket.

[LARRY A ROSA]

this is the problem i am working on........ shutting down a solid rocket after is has been started.

does anyone have any information on this subject, any past articles in magazines ect.

new member here .......

i do have some ideas i will be trying this year.

anyone else have an interest in this subject ?

 

[rharshberger]

The big solid motors like missles used had blow out panels on them to depressurize the motor and fuel combustion would cease. In the motors we use once lit they burn until fuel consumed.

 

[LARRY A ROSA]

what about water injectors to inject water gallons into the solid rocket

 

[LARRY A ROSA]

with X number of water high volume nozzels it would seem that that would work...... i am going to try that this summer.....

 

[SDramstad]

Our typical motors burn for less then 2 seconds. By the time you decide to shut them down they are done anyway.

 

[LARRY A ROSA]

the reason i am interested in this subject of a solid rocket shutdown procedure is that i want to put these light weight veriable solid rockets in cars...... LAND SPEED CARS.

 

[rharshberger]

the reason i am interested in this subject of a solid rocket shutdown procedure is that i want to put these light weight veriable solid rockets in cars...... LAND SPEED CARS.

Wrong type of forum for that stuff, we are almost entirely devoted to hobby rocketry.

 

[Charles_McG]

Wrong type of forum for that stuff, we are almost entirely devoted to hobby rocketry.

Second that.

Also please consider:
- solid rocket motors aren't 'light'. They are high thrust, but actually quite heavy for the amount of impulse they provide.
- most propellant burn rates are -very- sensitive to chamber pressure. See post 2. Jettisoning the nozzle would kill the thrust even if the motor doesn't stop burning.
- anything you try to inject into the motor will be against that chamber pressure, and increase it, maybe over the burst rating.
- Hybrid rocket motors have a solid fuel and controllable oxidizer. I think Scaled Composited only killed one person developing the motor for SpaceShip One.

 

[Steve Shannon]

the reason i am interested in this subject of a solid rocket shutdown procedure is that i want to put these light weight veriable solid rockets in cars...... LAND SPEED CARS.

They’re no longer light weight if you have to carry enough water to quench them.
The only thing that works reliably for the government is to blow the propellant up using high explosives.

 

[ebruce1361]

For your application, I would say that hybrid motors would work better since they can be throttled and even stopped and restarted in some cases like a liquid propellant engine, but offer more simplicity akin to solid propellant motors. While there are some rocket hobbyists that use hybrid motors, that is a subject that goes beyond much of what this forum is about. 80% of what is discussed here are vertical launch rockets made out of cardboard tubes and plastic with simple motors that burn completely and pop out a parachute in just a couple of seconds. While what you are looking to do does involve rocket propulsion, this isn't really an ideal venue for that topic. Maybe look into drag racing groups and forums? I know rocket and jet engines are occasionally incorporated into drag cars, so you might have better luck with your project looking that way.

At any rate, good luck! Be safe!

 

[Nytrunner]

The only thing that works reliably for the government is to blow the propellant up using high explosives.

Until you get to space where blowout panels begin to shine

 

[Charles_McG]

The only thing that works reliably for the government is to blow the propellant up using high explosives.

Until you get to space where blowout panels begin to shine

Nope, still loving the mental image of shutting down the motor by detonating it, leaving scattered pieces of burning fuel grain littering the salt flat in your wake.

 

[LARRY A ROSA]

not really..... it does have the type of solid rockets i want to use...... i just need to learn how to instantly shut down a solid rocket after it has been started

 

[LARRY A ROSA]

Second that.

Also please consider:
- solid rocket motors aren't 'light'. They are high thrust, but actually quite heavy for the amount of impulse they provide.
- most propellant burn rates are -very- sensitive to chamber pressure. See post 2. Jettisoning the nozzle would kill the thrust even if the motor doesn't stop burning.
- anything you try to inject into the motor will be against that chamber pressure, and increase it, maybe over the burst rating.
- Hybrid rocket motors have a solid fuel and controllable oxidizer. I think Scaled Composited only killed one person developing the motor for SpaceShip One.

i like that one idea, jettison the nozzle......one could make a variable nozzle that could be opened and closed like a camera lenz............

 

[3stoogesrocketry]

not really..... it does have the type of solid rockets i want to use...... i just need to learn how to instantly shut down a solid rocket after it has been started

Respectfully , you cannot .

 

[LARRY A ROSA]

Second that.

Also please consider:
- solid rocket motors aren't 'light'. They are high thrust, but actually quite heavy for the amount of impulse they provide.
- most propellant burn rates are -very- sensitive to chamber pressure. See post 2. Jettisoning the nozzle would kill the thrust even if the motor doesn't stop burning.
- anything you try to inject into the motor will be against that chamber pressure, and increase it, maybe over the burst rating.
- Hybrid rocket motors have a solid fuel and controllable oxidizer. I think Scaled Composited only killed one person developing the motor for SpaceShip One.

i should have told you...... these rocket cars are 48' ft. long .

 

[lakeroadster]

Shut down the motor... or shut down the thrust?

If you are wanting to just shut down thrust how about building a "Krushnic Effect" ring? Envision a device that looks something like afterburner flaps on a jet, but in this case it would render the rocket thrust useless.

 

[LARRY A ROSA]

Until you get to space where blowout panels begin to shine

one could machine blowout panels that are opened with a mechicanical cable or rod ?

 

[LARRY A ROSA]

Shut down the motor... or shut down the thrust?

If you are wanting to just shut down thrust how about building a "Krushnic Effect" ring? Envision a device that looks something like afterburner flaps on a jet, but in this case it would render the rocket thrust useless.

shut down all thrust, zero forward propulsion thrust.

 

[curtisheisey]

The three conditions for burning are heat, fuel and oxidizer. To shut down the burning, you would need to kill one leg of the triangle.

You cannot smother it (oxidizer and fuel are mixed together in propellant). You would need huge, huge volumes of water to reduce the heat, or maybe liquid nitrogen. Bill Spadafora used to do a demo at CMASS club launches in which he fired an estes rocket motor in a bucket of water.

There may be other means to reduce thrust, such as reducing pressure via a blow out panel as someone above suggested.

 

[LARRY A ROSA]

i like the idea of blow-out panels...... i`m having a brain storm on that idea......with a water injector system...... with the actual car being 48` ft. 4-5 gallions of water will not make any difference....... first open the blow out panels & inject water to the solid fuel core

 

[LARRY A ROSA]

blow out panels with no water......ok.

 

[LARRY A ROSA]

interesting...... i have learned alot today...... blow out panels...... any examples of those on the rocket..... i`ll look on the net myself also

 

[jadebox]

i should have told you...... these rocket cars are 48' ft. long .

This is way off topic for this forum. But, I would suggest that you look into what The Rocket Racing League did. Their racers seem comparable to what you are considering.

https://en.m.wikipedia.org/wiki/Rocket_Racing_League

 

[dhbarr]

i like the idea of blow-out panels...... i`m having a brain storm on that idea......with a water injector system...... with the actual car being 48` ft. 4-5 gallions of water will not make any difference....... first open the blow out panels & inject water to the solid fuel core

With respect, 5gal of water is enough to make your nozzle damp, that's about it.

Any rocket that's useful for accelerating a vehicle will essentially ignore such a small bucket, leaving aside how you're going to inject it quickly enough to do anything useful.

 

[lakeroadster]

shut down all thrust, zero forward propulsion thrust.

Then the "Krusnic Effect" ring is the answer to your question. It collapses down, encircling the nozzle and thus the thrust is negated....

 

[rcktnut]

I think you would be better off with figuring a full burn motor with the characteristics needed to achieve what you wish to accomplish with the vehicle.

 

[heada]

The easiest way to stop producing thrust would be to rapidly drop the internal pressure. Blow a hole in the side of the motor case or pop the nozzle out of the end and you're left with basically a road flare.

 

[LARRY A ROSA]

With respect, 5gal of water is enough to make your nozzle damp, that's about it.

Any rocket that's useful for accelerating a vehicle will essentially ignore such a small bucket, leaving aside how you're going to inject it quickly enough to do anything useful.

i see, thank you !

 

[LARRY A ROSA]

The easiest way to stop producing thrust would be to rapidly drop the internal pressure. Blow a hole in the side of the motor case or pop the nozzle out of the end and you're left with basically a road flare.

that is sounding like the solution i am looking for..... take a 4" nozzle & mecanically open it up to 12" & instant zero volosity.... spelling most word right......