This idea came to while lying in bed a few moments ago. I was thinking about how great it would be if I could use dual deployment (im under 18 so i cant handle black powder, making conventional DD impossible). While there are products like the tender desender on the market, i want to create my own BP-less dual deployment systems.
Here is the basic idea:
Motor ejection will occur at apogee.
The main chute will come out but will "squibb".
The Squibbing will occur because one or more of the parachutes shroud lines will be held down by a seperate nylon cord attached to a seperate eyebolt.
The rocket will decend quickly to the altimeter's programmed altitude.
At altitude (lets say 500') an igniter and sliver of blue thunder propellant will ignite.
The igniter and propellant package are secured to the nylon cord by a soda straw.
The propellant burns through the wire, releasing the nylon cord and the parachute fully opens, resulting in a gentle landing.
If this isnt very clear, i'll upload pics of the sketch i drew tomorrow AM.
The tricky thing will be to get the nylon cord strong enough to hold the shroud lines down, yet weak enough to be cut easily by the igniter and propellant mix.
This will require a lot of testing but the reward of dual deployment to me is to great to pass up.
Thoughts? Is this worth a shot?