Low power dual deploy

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sl98

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Virtually, any Estes kit can be easily modified to dual deploy. My first foray into DD was with an Estes Mega Sizz and an original Eggtimer. With the Mega Sizz, I learned the key to LPR/MPR DD is to keep everything as light as possible. I moved to the Quark with a micro 1S lipo for all of my LPR/MPR DD. I’ve since added an Estes Monarch, Vagabond, STM-012, and D-Region Tomahawk. I also have a number of DD scratch builds using BT-50, BT-55, and BT-60 and 29mm body tube. The FlightSketch Sport may also be a nice alternative when it becomes available.

LPR/MPR DD is a great way to learn DD. I continue to fly more LPR/MPR DD than HPR DD because I can fly LPR/MPR at my local flying field. If you are interested, here are a few threads with pictures of some of my LPR/MPR AV bays.



 

sl98

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Maybe. I’m not an electrical engineer. Worse case scenario you can just use an ematch to nothing.
Before the release of the Eggtimer Apogee, I used a Quark for single channel deploy. The apogee channel has the charge. For the main, I wired on a small incandescent X-mas bulb in lieu of a charge.
 

Neutron95

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Before the release of the Eggtimer Apogee, I used a Quark for single channel deploy. The apogee channel has the charge. For the main, I wired on a small incandescent X-mas bulb in lieu of a charge.
Why would you need to do that? Every altimeter that I'm aware of will fire the main chare whether or not there's a charge attached to the drogue, and vice versa.
 

sl98

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Why would you need to do that? Every altimeter that I'm aware of will fire the main chare whether or not there's a charge attached to the drogue, and vice versa.
I'm sure @cerving could explain much better than I can.. With the Quark you need resistance across both the apogee and main channels; otherwise, you will get a continuity error and the unit won't arm. I am slowly replacing this setup with the new Apogee for the rockets where I only need apogee deployment.
 

MetricRocketeer

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Hi everyone,

I was thinking about using a Jolly Logic Chute Release to do low-powered dual-deployment. This would eliminate the need for any kind of black-powder charge.

I wanted to use an Estes Firestorm that I have lying around. My question is this. The diameter of the Firestorm air tube is 4.17 cm (that is, slightly more than 1.6 inches). Would I be able to fit the JLCR inside the rocket and have the parachute wrapped around it to accomplish the goal?

Thank you.

Stanley
 

SecondRow

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Jolly Logic recommends a tube size of at least BT-60 (1.6 in) which is what the Firestorm is. It will be a tight fit, but is doable. Practice your chute packing.
 

Nytrunner

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That's a BT-60 tube. The chute release will fit in there, and the plastic estes chute rolls small enough that it won't interfere sliding out.

Notes:
-Pay careful attention to the recommended chute wrapping technique. There's a video on the site (and/or youtube)
-Make sure to do a release check to make sure there's enough tension in the rubber band to spring away from the chute. (sometimes with the small estes chutes, I have to put a piece of a stick in the bundle too, otherwise there isn't enough tension to release cleanly)
-When bundled up, give it a good shake to make sure its on securely (not as big a deal for low power, but it's real annoying for it to shake off a chute at 4k')
-Don't forget to tie it to the shock cord loop you attache the chute to.
-Don't forget to turn it on before flight (most common failure mode)
 

MetricRocketeer

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Hi SecondRow and Nytrunner,

Thank you for your very helpful posts.

Stanley
 

gtg738w

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Russ, any updates on the FS Sport or SST
We were so close on the sport... Around New Years there were supply issues with a few parts so we made some substitutions, did another prototype run and got an order out on 1/28. Unfortunately, the fab house sat on it for almost two weeks and then had other parts unavailable. Order was cancelled on 2/16 and now it looks like parts won't be in until June-July at best. Ublox is even worse for the tracker. There was a fire at one of their subs for TCXOs so they are way out. It will probably be fall before any qty is available. We're recycling parts off of old boards to continue with prototypes... But trying to stay positive, if anything it will give us time to focus on some much needed web and firmware updates.
 

Scott_650

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...like parts won't be in until June-July at best. Ublox is even worse for the tracker. There was a fire at one of their subs for TCXOs so they are way out. It will probably be fall before any qty is available....
Now, at the very least, I can plan on what I’m buying myself for Christmas 😉
 

MetricRocketeer

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Hi everyone,

I was thinking about using a Jolly Logic Chute Release to do low-powered dual-deployment. This would eliminate the need for any kind of black-powder charge.

I wanted to use an Estes Firestorm that I have lying around. My question is this. The diameter of the Firestorm air tube is 4.17 cm (that is, slightly more than 1.6 inches). Would I be able to fit the JLCR inside the rocket and have the parachute wrapped around it to accomplish the goal?

Thank you.

Stanley
Hi everyone,

I am now thinking about the Jolly Logic Chute Release again.

Let me make sure, please, that I understand the mechanism.

When the motor ejects forward, that force pushes against the parachute. The parachute, around which the JLCR is bound, then pushes against the nosecone. So the combined JLCR tied around the parachute pushes against the nosecone, and now the nosecone separates from the body tube. Is this so far correct?

Here is what happens next: The nosecone is tethered to the JLCR-parachute bundle, and that bundle is tethered to the body tube. Meanwhile, the JLCR-parachute bundle may have a drogue parachute tied to the bundle, it may have a streamer tied to the bundle, or it may have nothing tied to the bundle.

Finally, at the altitude previously set on the JLCR, the JLCR will release the main parachute, and the main parachute will open up for a slowed-down landing of the nosecone and the body tube. The JLCR itself goes flying off, and hopefully the rocketeer can find it.

Is this all correct, please?

If so, I am going to ask a followup.

Thank you.

Stanley
 

Scott_650

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Hi everyone,

I am now thinking about the Jolly Logic Chute Release again.

Let me make sure, please, that I understand the mechanism.

When the motor ejects forward, that force pushes against the parachute. The parachute, around which the JLCR is bound, then pushes against the nosecone. So the combined JLCR tied around the parachute pushes against the nosecone, and now the nosecone separates from the body tube. Is this so far correct?

Here is what happens next: The nosecone is tethered to the JLCR-parachute bundle, and that bundle is tethered to the body tube. Meanwhile, the JLCR-parachute bundle may have a drogue parachute tied to the bundle, it may have a streamer tied to the bundle, or it may have nothing tied to the bundle.

Finally, at the altitude previously set on the JLCR, the JLCR will release the main parachute, and the main parachute will open up for a slowed-down landing of the nosecone and the body tube. The JLCR itself goes flying off, and hopefully the rocketeer can find it.

Is this all correct, please?

If so, I am going to ask a followup.

Thank you.

Stanley
You have it, in essence, correct though the ejection charge pressurizes the body tube, the nose cone is ejected and it’s inertia mostly (plus the “bullet in a gun barrel“ effect on the recovery gear) gets everything out of the airframe. I use a streamer with my JLCR mostly for tracking, the shock cord, bundled chute and open rocket fall fairly slowly without the streamer. Summing it up, the JLCR doesn’t control the beginning of the recovery event - that’s still the built-in ejection charge and delay of the motor - but does control deployment of the chute. A total electronic deployment system controls both the timing of chute/streamer deployment and the altitude when each phase of recovery occurs.
 

MetricRocketeer

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Hi Scott_650 and anyone else,

Thank you for your reply.

Here is my followup question. I am thinking of doing this at NARAM-62 coming up in late July at Geneseo NY. Also, I realize that this topic may no longer be best in a thread aimed at low-powered rocketry. I will be glad to more the discussion elsewhere if readers want me to.

I was thinking of buying the Vertical Assault 3.0 manufactured by Giant Leap Rocketry. It has two body tubes, with the main parachute in the aft body tube and a drogue parachute in the forward body tube. In between the two lies an avionics bay. Thus, the Vertical Assault is set up for dual deployment.

I don't want to use black-powdered charges for dual deployment. I want to use the Jolly Logic Chute Release. But then I am unclear as to how to set up the system. Here is my idea:

I put the bundled main chute in the aft body tube. I seal the forward body tube with a bulkhead at its aft end. I just don't use the avionics bay at all. And finally, the shock cord would be tethered to the bulkhead, from there to the bundled main parachute, and then from there to the inside of the aft body tube. I would also make sure that the nosecone doesn't separate from the forward body tube.

Does this make sense, please?

Thank you.

Stanley
 

RalPh8

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The JLCR itself goes flying off, and hopefully the rocketeer can find it.
The JLCR only goes flying off if you forget to tie it to the shock cord. If you do you can be assured you’ll never find it. It has a tether for a reason. Use it so you don’t lose your investment.
 

MetricRocketeer

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The JLCR only goes flying off if you forget to tie it to the shock cord. If you do you can be assured you’ll never find it. It has a tether for a reason. Use it so you don’t lose your investment.
Hi RalPh8,

That makes sense. Thank you.

Stanley
 

shockie

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I'll take a JLCR in bt-20 Size 🤔😳.

Question: do most or some dual deploy altimeter give you the option of 1st stage deceleration detection with a delay time like a delayed staging ability?
 
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