High-ish altitude MD with single deploy and GPS tracking?

[SolarYellow]

Getting way ahead of my skis here, but I've been playing in OpenRocket with bigger mid-power motors. Ending up with altitudes ~7k ft AGL when launching from Mojave dry lake conditions.

It's fun to think about the numbers I'm seeing, but it kind of depends on keeping the rocket simple and lightweight, which also favors reliability and structural integrity. Which means single deployment. I have an Eggtimer Quark and Eggfinder Mini in the model for controlled single deployment and GPS tracking to find the dang thing when it eventually comes down. And plan for launching in high desert with miles of BLM land to recover it.

Is that a reasonable setup? I imagine it's kinda like what people did a few decades ago when we didn't have all the electronics.
Is it a case of, "Just bite the bullet and do dual deployment. Accept the loss of performance."
Or is it a case of, "Try it, live it, find out?"

 

[UPscaler]

Getting way ahead of my skis here, but I've been playing in OpenRocket with bigger mid-power motors. Ending up with altitudes ~7k ft AGL when launching from Mojave dry lake conditions.

It's fun to think about the numbers I'm seeing, but it kind of depends on keeping the rocket simple and lightweight, which also favors reliability and structural integrity. Which means single deployment. I have an Eggtimer Quark and Eggfinder Mini in the model for controlled single deployment and GPS tracking to find the dang thing when it eventually comes down. And plan for launching in high desert with miles of BLM land to recover it.

Is that a reasonable setup? I imagine it's kinda like what people did a few decades ago when we didn't have all the electronics.
Is it a case of, "Just bite the bullet and do dual deployment. Accept the loss of performance."
Or is it a case of, "Try it, live it, find out?"

I flew a 38mm MD I500 to about 10k with single deploy and a streamer with a radio tracker.

No problem!

Braden

 

[Steve Shannon]

You stand a greater chance of violating your COA with high altitude single deployment. The addition of a chute release helps mitigate that with very little added mass, but sometimes adding mass results in greater altitude anyway.

 

[waltr]

If you already have a Quark on board, what is the issue to just do full DD?
You could go with a 'cable cutter' to release main chute lower down.

 

[rharshberger]

Getting way ahead of my skis here, but I've been playing in OpenRocket with bigger mid-power motors. Ending up with altitudes ~7k ft AGL when launching from Mojave dry lake conditions.

It's fun to think about the numbers I'm seeing, but it kind of depends on keeping the rocket simple and lightweight, which also favors reliability and structural integrity. Which means single deployment. I have an Eggtimer Quark and Eggfinder Mini in the model for controlled single deployment and GPS tracking to find the dang thing when it eventually comes down. And plan for launching in high desert with miles of BLM land to recover it.

Is that a reasonable setup? I imagine it's kinda like what people did a few decades ago when we didn't have all the electronics.
Is it a case of, "Just bite the bullet and do dual deployment. Accept the loss of performance."
Or is it a case of, "Try it, live it, find out?"

Usually weight is not an issue with MD rockets...space is. That being said altitude and optimum weight go hand in hand. Tracking is a must, dual deploy is preferred, but single deploy can work, I typically fly a 29mm airframe with 24mm G motors to 3500' and use a Quark set up for single deploy to kick out a 10'x2" mylar streamer (single deploy) at apogee, depending on upper winds it typically recovers from 500' to 1500' from pad if launched slightly down wind.

 

[Chad]

Consider your ejection charges at high altitude since there will be considerably less initial air pressure in your airframe. On my L3 flight to about 20k feet my advisor suggested doubling the charge size. The idea is "better to blow apart than to lawn dart".

You stand a greater chance of violating your COA with high altitude single deployment. The addition of a chute release helps mitigate that with very little added mass, but sometimes adding mass results in greater altitude anyway.

I second this, if for no other reason than to save yourself some walking.

 

[SolarYellow]

You stand a greater chance of violating your COA with high altitude single deployment. The addition of a chute release helps mitigate that with very little added mass, but sometimes adding mass results in greater altitude anyway.

Am I missing something? I don't see that a COA is relevant to a Class 0 launch.

I would definitely make the investment for DD if going Class 1.

 

[rharshberger]

Am I missing something? I don't see that a COA is relevant to a Class 0 launch.

I would definitely make the investment for DD if going Class 1.

there is no Class 0, a rocket is either Class 1, 2, or rarely 3. Lets not go down the rabbit hole again of Class vs Cert, FAR vs NFPA definitions.

 

[SolarYellow]

Okay, call it a no-class launch.

Still, I looked around and found where COAs were discussed, and didn't see that they apply.

 

[rharshberger]

Okay, call it a no-class launch.

Still, I looked around and found where COAs were discussed, and didn't see that they apply.

If it weighs less than 1500g/3.3lbs and has less than 125g/4.4ozs of propellant no COA (aka Waiver) is required.