Staging rocket motors

[rxckitralph]

I have a few questions pertaining to staging. After some research, do the motors HAVE to be black powder in order to fire the second motor? Other propellant uses a core, black powder does not and thats where im lost.

 

[rocketace]

Start off with how black powder rockets work.
https://www.apogeerockets.com/Tech/How_Rocket_Engines_Work

Then review how composite rocket motors work.
https://www.apogeerockets.com/Tech/How_Composite_Rocket_Engines_Work

For staging black powder motors check this out!
https://www.apogeerockets.com/Tech/How_2-Stage_Rockets_Work

For staging composite motors check this out! This requires electronics.
https://www.apogeerockets.com/education/downloads/Newsletter91.pdf

 

[cerving]

The Apogee newsletter describing composite staging electronics is very dated... mercury switches and roller switches are no longer allowed for direct firing of motors (and you probably can't buy mercury switches anymore anyway...). Modern altimeters use an electronic barometer pressure sensor and/or accelerometer sensor to determine altitude and velocity/acceleration, and can generally fire a motor at some time from launch and/or some time after the burnout of the first stage.

 

[rocketace]

Thanks Cris for pointing that out. I didn't look over the links close enough.

@rxckitralph There are a lot of really cool altimeter options available now a days, just do some research to see what they have to offer. Some of the big ones off the top of my head are Eggtimer, Featherweight, and Altus Metrum.

 

[JoePfeiffer]

Direct staging, in which the booster motor ignites the sustainer, requires the sustainer to be black powder.

You have to use electrical ignition to light a composite sustainer.