Non-Pyro Ejection

[Sean Witte]

Hey everyone, I am in a situation where I want to use electronic deployment of a drogue chute at apogee then two main chutes at a lower altitude. There is also no engine with an ejection charge in this section of the rocket because the booster is separated after its burn.

The problem here, however, is that I cant put any pyrotechnic deployment charges in the rocket, so these chutes would have to rely solely on other methods to deploy and was hoping some of you have encountered good devices like these and could help to guide me in the right direction to choose one?


On a (similar) side note that is less problematic, what are some of your recommendations for the electronic aspect of this setup I am describing? (one drogue chute at apogee around 850 ft, then two main chutes at a lower altitude to slow the rocket soon before it reaches ground to minimize the total flight duration?)



A little information about the rocket: there is a booster with a class E or F motor propelling a two part rocket that will split when the motors ejection charge fires.

The bottom section will descend with any recovery method that will also be deployed by the motors ejection charge.The top section has, in order from booster to nosecone, a bulkhead to separate the rocket at ejection, a payload bay and an electronics bay that can be switched however, then 3 parachutes that will most likely be put right at the top of the rocket.

This is also very tentative right now and I am open to any suggestions pertaining to the design of the rocket as well as the main topic of non-pyro ejection systems.


Any suggestions would be much appreciated!
I will also try to get some images up about what i'm describing soon.

 

[JohnCoker]

What is your definition of "non-pyro"? (Electric matches are small pyro charges.)

If you mean entirely pyro free, then the only thing I've heard about is using a solenoid to release a compressed spring. This sounds like it will be pretty heavy to lift in an MPR rocket.

A good alternative to black powder charges are CO₂ systems. I've used the Rouse-Tech system extensively and it works well. However, it still requires an electric match and a small amount of black powder to provide the force to puncture the CO₂ cartridge.

To trigger the main parachute (for the forward section), you can use any of the many fine avionics products. I have made a video that shows how to use electronics which may provide some info:
jcrocket.com/electronic-recovery.shtml

 

[Sean Witte]

"Non-pyro" in my position means no use of black powder outside of the engine, I believe that I can use some sort of igniter, just am unable to use it to light any pyrotechnic "charges". So maybe burn through some kind of retention string? I also just watched your video and it was quit informative, thanks for sharing that.

EDIT: What do you think about using a solenoid valve to release a compressed gas instead of pushing it forward with a e-match?

 

[MClark]

Solenoid valves tend to be heavy and require a lot of power.

 

[tfish]

Have you searched this site? There are a couple of clever methods.

I'll narrow it down for you. Check out posts by

rocket_troy
and
The PK

Tony

 

[JohnCoker]

I agree with Tony that a solenoid will likely be too heavy for a MPR. I believe the Peregrine CO₂ system does not require a black powder charge, but have not used it myself.

 

[jlabrasca]

"Non-pyro" in my position means no use of black powder outside of the engine, I believe that I can use some sort of igniter, just am unable to use it to light any pyrotechnic "charges". So maybe burn through some kind of retention string? I also just watched your video and it was quit informative, thanks for sharing that.

EDIT: What do you think about using a solenoid valve to release a compressed gas instead of pushing it forward with a e-match?

This is the 3rd non-pyro thread I've noticed the last month. IIRC, the other two were also from new TRF members. Are you putting this together for a competition?

 

[rocket_troy]

This is the 3rd non-pyro thread I've noticed the last month. IIRC, the other two were also from new TRF members. Are you putting this together for a competition?

I'm not involved in any competition, but I think you're right. Most (maybe not all) of these threads have been started by participants involved in some rocket event in Turkey with a rule stipulating that the recovery needs to be non pyro.

TP

 

[jlabrasca]

I'm not involved in any competition, but I think you're right. Most (maybe not all) of these threads have been started by participants involved in some rocket event in Turkey with a rule stipulating that the recovery needs to be non pyro.

TP

Yeah. I was asking the OP, but you are correct; I am counting at least one of the Turkish rocketeers (Magin) . In addition to the students who've identified themselves as Turkish, there is this one

https://www.rocketryforum.com/threads/non-pyro-system.150015/

 

[JohnCoker]

The site search here isn't great, but searching for "non-pyro" comes up with quite a few results. Not sure why there are several independent threads.