Any Non-Pyro System Advices?

John Feller · Dec 10, 2018

Hi all!

I want to make my dual deployment ejection system as non-pyro. I have already searched on CO2 systems. But if you have any systems that you used before, different than CO2, I want to know them. All advices about non-pyro systems are welcome, thanks!

rocket_troy · Dec 10, 2018

Been flying 100% non pyro for 8 years now (dual deploy for ~7 years) and will never go back (famous as those last words are). Can't provide much in the way of references though as I use my own home-brew deployment devices.

TP

DAllen · Dec 10, 2018

rocket_troy said:
Been flying 100% non pyro for 8 years now (dual deploy for ~7 years) and will never go back (famous as those last words are). Can't provide much in the way of references though as I use my own home-brew deployment devices.

TP

Any chance you could share some photos of said system? What is it based on? Springs?

rocket_troy · Dec 10, 2018

Dave,
https://www.propulsionlabs.com.au/Pyroless_Release/

TP

DAllen · Dec 10, 2018

rocket_troy said:
Dave,
https://www.propulsionlabs.com.au/Pyroless_Release/

TP

Wow! Thats a awesome system!

rocket_troy · Dec 10, 2018

Ta Dave. Not mentioned in there yet is that I've recently changed the fill connection from that underrated compressed air spike to a standard paint ball connection which is rated to much high pressures, much more compact & easier to make.

TP

jmwoody · Dec 11, 2018

Really great concept and presentation rocket_troy. I'm looking forward to your updates. Commercial availability for the HP community in the future?

DAllen · Dec 11, 2018

I've contemplated using springs but have yet to figure out a release mechanism.

jmwoody · Dec 11, 2018

Electric solenoid such as used as an in out switch ... example ... on a auto starter motor? Or ... could hold spring in tension and release on switch pulse. On the toy level (small) train set track switch. Solenoids are available in many sizes and impulses with some phenomenally strong for the size.

Not meaning to detract from your fine efforts rocket_troy ... so back to your presentation.

rocket_troy · Dec 11, 2018

jmwoody said:
Not meaning to detract from your fine efforts rocket_troy ... so back to your presentation.

No, please don't just focus discussion on one system. My system is complex and beyond the reach of most hobbists to make. I'm sure there are simpler alternatives so bring on the ideas.

TP

rocket_troy · Dec 11, 2018

jmwoody said:
Commercial availability for the HP community in the future?

I've been promising a small production run for years now and other stuff keeps getting in the way; so the intention is there

TP

DAllen · Dec 12, 2018

I'm wondering if there is a home brew option for those of us without extensive workshops can come up with to make pyro-less option. Something that most people can construct with some basic hand tools and works with existing technology. Something that will work with altimeters already on the market.

I think the answer is with springs. Just have to figure out a way to hold the spring down and a way to release it. Now that I am seeing this pressure vessel option it has me wondering...

That would be super cool.

-Dave

Nytrunner · Dec 12, 2018

A Turkish team used a coiled spring ~3" diameter (4" project) with a screw actuator in the center. It engaged in a nut on the other section of the rocket. When commanded, it would unscrew and the spring would eject the other section

rocket_troy · Dec 12, 2018

DAllen said:
I'm wondering if there is a home brew option for those of us without extensive workshops can come up with to make pyro-less option. Something that most people can construct with some basic hand tools and works with existing technology. Something that will work with altimeters already on the market.

I think the answer is with springs. Just have to figure out a way to hold the spring down and a way to release it. Now that I am seeing this pressure vessel option it has me wondering...

That would be super cool.

Well if you’re interested and happy to publish all results, I’m happy to donate one of my heavy duty latches to experiment with (I used them for main chute retention for dual deployment). Should be good to hold and release a pretty strong spring compression or multiple small tension springs.

The latch is probably beyond the capabilities of most hobbyists to make themselves, but it might assist in providing a reference to the practicalities of using springs perhaps.

TP

DAllen · Dec 12, 2018

rocket_troy said:
Well if you’re interested and happy to publish all results, I’m happy to donate one of my heavy duty latches to experiment with (I used them for main chute retention for dual deployment). Should be good to hold and release a pretty strong spring compression or multiple small tension springs.

The latch is probably beyond the capabilities of most hobbyists to make themselves, but it might assist in providing a reference to the practicalities of using springs perhaps.

TP

Heck yeah!

In fact, I do you one better, my USLI team might be able to use this. They are wanting to use springs for their main deployment. They have the OK from NASA to try it out so a device like this could be extremely helpful.

rocket_troy · Dec 12, 2018

Cool, PM me a shipping address and I'll get one together.

Cheers,

Troy

OverTheTop · Dec 13, 2018

Troy's stuff is very well engineered. That's what separated the V2 sections apart. 20bar and 30bar pushing on about 5" diameters give a good shove!

Wallace · Dec 14, 2018

DAllen said:
I'm wondering if there is a home brew option for those of us without extensive workshops can come up with to make pyro-less option. Something that most people can construct with some basic hand tools and works with existing technology. Something that will work with altimeters already on the market.

I think the answer is with springs. Just have to figure out a way to hold the spring down and a way to release it. Now that I am seeing this pressure vessel option it has me wondering...

That would be super cool.

-Dave

Use the KISS principle. A burn string is the simplest option for hold down and release of a spring. No moving parts, minimal weight gain, inexpensive, repeatable and easily employed by those w/out "workshops". Nothing more than a resistor or piece of nichrome wire is needed. The key is in finding the correct "string". I've found through testing that elastic string or band works best. It "cuts" easily and has a self releasing property since it's under tension. Try it, you'll like it....

jlabrasca · Dec 14, 2018

DAllen said:
I'm wondering if there is a home brew option for those of us without extensive workshops can come up with to make pyro-less option. Something that most people can construct with some basic hand tools and works with existing technology. Something that will work with altimeters already on the market.
-Dave

What tools do you have available and are you most comfortable using?

John Beans made some very points in his NARCON presentation

NARCON 2018 Next-Gen Model Rocket Deployment - YouTubehttps://www.youtube.com/watch?v=a0sYNnySuo0

DAllen · Dec 14, 2018

jlabrasca said:
What tools do you have available and are you most comfortable using?

John Beans made some very points in his NARCON presentation

NARCON 2018 Next-Gen Model Rocket Deployment - YouTubehttps://www.youtube.com/watch?v=a0sYNnySuo0

Wow...Thanks! That video gave me a bunch of ideas!

MClark · Dec 14, 2018

I made a compressed air system about 20 years ago. No moving parts.
Air tank was a plastic pop bottle, will hold over 100 psi. there’s a lot of air in a liter bottle. Release was through a plastic burst disc, an e match gave enough heat to weaken disc causing failure. I made a circuit to use a hot wire but never flew it.
Used e match system twice, worked. I use black powder.

Any Non-Pyro System Advices?

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