Staging question.

I'm looking for the simplest form of staging. I'm wondering if making a tube that will fit 2 D motors tapped together would work. It's fine of the motors eject because they won't be used to release a parachute. Basically I just need two Ds to stage with no worry about recovery.

The simplest form of staging is to simply tape the top end of a D12-0 booster motor to the nozzle end of the D12 upper stage motor using one careful wrap of cellophane tape.

No tube required.

When the fuel element of the booster motor burns through at the top, it sends burning particles of the fuel into the nozzle of the other motor, igniting it. The ignition of the upper stage motor blows the case of the booster motor free of the tape

This is called CHAD staging (CHeap And Dirty).

No recovery system needed if this is on a rocket sled. Note that adding mass to the rear of the rocket sled could have stability effects on it.

If this is being used for a two stage rocket with no fins around the booster motor, additional stability questions need to be dealt with.

This I'll be for the rocket sled. I'm going to build a whole new mount for it so I can control where the CG is. CHAD does sound pretty poor haha. I was afraid that the first stage might go side ways and rip it's self free. Is it just a better idea to make a tube long enough to cover some portion of the first stage?

mbecks said:

This I'll be for the rocket sled. I'm going to build a whole new mount for it so I can control where the CG is. CHAD does sound pretty poor haha. I was afraid that the first stage might go side ways and rip it's self free. Is it just a better idea to make a tube long enough to cover some portion of the first stage?

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Look up rack rockets, that might work for staging.

That idea looks like it will work. Do you still tape them together using the rack idea?

mbecks said:

That idea looks like it will work. Do you still tape them together using the rack idea?

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Yes, they are taped together. The one I saw in person used 3 dowels to hold the 3-24mm motors (the 'rack')

I -think- the only difference between CHAD staging and rack rockets are the dowels.

McKailas Dad said:

Yes, they are taped together. The one I saw in person used 3 dowels to hold the 3-24mm motors (the 'rack')

I -think- the only difference between CHAD staging and rack rockets are the dowels.

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Pretty much that is true, rack rockets also allow the thrust to exit the airframe as the motor stack gets shorter.

rharshberger said:

Pretty much that is true, rack rockets also allow the thrust to exit the airframe as the motor stack gets shorter.

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I'm kinda slow sometimes. What do you mean by "allow the thrust to exit the airframe as the motor stack gets shorter?" Isn't the point of thrust to exit the airframe toward the bottom-side in order to push the rocket toward the top-side? I'm obviously not understanding what's going on here, clarification would be cool; I've been thinking about some sort of RackAlpha thing, and want all the info I can get before I start.

kyle said:

I'm kinda slow sometimes. What do you mean by "allow the thrust to exit the airframe as the motor stack gets shorter?" Isn't the point of thrust to exit the airframe toward the bottom-side in order to push the rocket toward the top-side? I'm obviously not understanding what's going on here, clarification would be cool; I've been thinking about some sort of RackAlpha thing, and want all the info I can get before I start.

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In rack rockets the motors are in a continous stack like staging, only its the motors that drop off, not the stage they are carried in, the airframe is designed so that as the motors drop away the motor exhaust can be exposed to the environment without much damage to the rocket. Here is a link with video about a rack rocket test, the rocket airframe minus fins is inverted in a static fixture and demonstrates how they work. https://sites.google.com/site/theskydartteam/projects/model-rocketry/rack-rocket-design

Here's a file for my only staged rocket.
It is rudimentary, but fulfills the basic requirements of the mission.



View attachment 2 Stage Patriot.ork

Great shot, TopRamen! From a drone camera?

Marc_G said:

Great shot, TopRamen! From a drone camera?

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No... I had to do a double take on why they weren't running for cover...

That is a 3D screenshot from OpenRocket,

I've decided to go with the rail idea because it can also be used to house an E9 for the rocket sled. I should have a video up soon.