Staging Question

[kelltym88]

I have a project in mind. It is a 2 stage. Is it possible to ignite an AT single use motor using a D12-0? If so, let's say it's 24mm to 24mm. Then would it be possible to go from a D12-0 to a 29mm?

 

[powderburner]

Short answer: no.

I suppose it is possible that by some odd chance it might work for one of your attempts, but in general an Estes-type BP motor will not ignite a composite motor. Aerotech-type AP motors need to be ignited near the head of the grain to operate correctly.

If you want a composite-powered upper stage you usually have to use some on-board electronics to trigger an electric igniter.

 

[shreadvector]

Not directly (like a black powder motor to another black powder motor). APCP motors need a lot of heat and pressure to get started. The average Aerotech motor is ignited near the top of the hollow bore running through the propellant. That way as the burning propagates it travels downward and out the nozzle. if you ignite them at the bottom, there are some nasty ignition instabilitiies - i.e. it "chuffs" and keeps trying to 'blow itself out'. You have probably seen this sputtering ignition occur. Not pretty.

To ignite an APCP motor in an upper stage you would need an altimeter or other electronic controller and a poser source on-board and an electric igniter. An it had better be a RELIABLE igniter.

For folks not flying "Model Rockets", you can get an LEUP and buy thermalite cord. It can be used to ignite APCP motors and the cord can be ignited by the BP booster motor. The cord needs a sleeve for the lower portion so it does not ignite the lower end of the APCP motor grain. You will also want to use the faster burning cord (it comes in several grades).

Originally posted by kelltym88
I have a project in mind. It is a 2 stage. Is it possible to ignite an AT single use motor using a D12-0? If so, let's say it's 24mm to 24mm. Then would it be possible to go from a D12-0 to a 29mm?