Eggtimer Quark based chute tender

[Charles_McG]

I've been working on a hot wire chute release widget based on an Eggtimer Quark. I'm through bench testing and nearly ready for flying. As is, it fits nicely in BT60. If I used a different hot wire connection, I might be able to slip it in BT55.

Here's the Quark. Jumpers set to 300'


Tucked into a BT50 nose cone base and coupler.


24mm engine tube avbay, 2S 180mAH Lipo and other bay end cap. The tubing is wrapped with a 3M fiberglass tape for some heat protection.


Power end all closed up. No switch for this version. Just plug and pray.


Release band. The cuttable link is 10# fishing monofilament tied across the band. It's wrapped with a nichrome wire. The band is doubled, then stretched around the chute and avbay. It's also tethered, so I'm not littering rubber bands across the landscape.


Chute wrapped, hot wire connected. This Quark has a custom 2 second firing duration. Now that I have a solid connection to the nichrome, it really lights it up.


And finally, the Quark and Eggfinder pair.


First posted to YORF
https://www.oldrocketforum.com/showthread.php?t=15581

 

[KenECoyote]

Very nice! I was thinking of doing the same a while ago, but never got to start the project. :clap:

 

[rharshberger]

Interesting idea, hope it works. Good Luck

 

[bill2654]

I hope Cris see's this thread. I see some potential competition for Jolly Logic. I would be interested.

 

[Charles_McG]

Cris set the custom timing and suggested the monofilament as the cuttable link.

I've also shared the bench test video with him. So he's aware.

 

[cerving]

The 2 second firing time will be standard in future shipments of the Quark, after my substantial current inventory is cleared out. If you have a pressing need for it, let me know that when you place your Quark order and I'll kit it specially for you with the updated firmware.

 

[rharshberger]

The 2 second firing time will be standard in future shipments of the Quark, after my substantial current inventory is cleared out. If you have a pressing need for it, let me know that when you place your Quark order and I'll kit it specially for you with the updated firmware.

This is a neat idea for sure, as would be a Eggtimer/Quark triggered mechanical release, both ideas as alternatives to the Archtype cable cutter (which I will use too!).

 

[Charles_McG]

Tried a first flight today - not especially successfully.

My test rocket is a BT80 upscale Big Bertha. Plenty of room.


The wire connection to the hot wire terminals seems to be a weak connection. It broken in transit and I tried to do a field connection. Passed continuity.

But on an E9, she weathercocked strongly in the light wind. Didn't make much altitude and head straight for the fencerow. The deployment bundle came out and didn't open. Wound up on a branch about 30' up.

The Eggfinder worked on its first flight.

 

[cerving]

Did you get it down from the tree?

E9's are really wimpy, I wouldn't fly anything over about 6 oz on one. Long burn, low thrust motors on relatively heavy rockets = power dive... saw one yesterday at ROCStock (it was on an E9). A better choice for your rocket would be an Aerotech E20, or a F24 load in the 24/40 case.

 

[Charles_McG]

Three 12' bamboo poles, duct tape, a bicycle hook and an orchard ladder later, I have my rocket back.

Beep code says 279'. Continuity test fails, though every thing looks okay. That wire joint that I field repaired must be bad again. I'm going to use some shrink tubing on it next time.

And get some E12 motors, at least. I knew I was pushing it with the E9. 20fps off the rod in OpenRocket. I don't have handy options for 24mm this time of year and got antsy.

Cris, would it even have fired, if it never got above the set altitude (300')?

Oh, and anyone have tips to try to save the LiPo that went flat in the tree over night? My charger doesn't like it anymore.

 

[cerving]

The LDA (Launch Detect Altitude) for a Quark is set at 200', so yes, it would have fired as soon as it nosed over since it was below 300'. If you had a CATO (and E9's and E12's DO CATO...) it would never have made it to 200' so it would not have fired.

Your LiPo is toast. Once you under-voltage one (below about 3.1V per cell), they're gone. With NiCad's and NiMH's, you used to be able to cycle them a bunch of times and get them back, no so with LiPo's.

 

[Charles_McG]

One of the hot wire leads was broken at the board.

And I read 3.6V on one cell and 0.6V on the other. And one side now feels 'puffy' - so yes, I think it's toast,too.

Ideas for next version Cris:
1) Low voltage cutoff for LiPO users.
2) A GPS in the Eggfinder RX, so you wouldn't need phone service - you could display the rocket coordinates or the RX coordinates and walk to make them match. Distance and bearing would be bonus - no idea if you can fit it in that little processor.

 

[Tonimus]

A GPS in the Eggfinder RX, so you wouldn't need phone service - you could display the rocket coordinates or the RX coordinates and walk to make them match. Distance and bearing would be bonus - no idea if you can fit it in that little processor.

Not only do I doubt it would fit in the processor, but then you'd have to add another GPS chip, etc, for the receiver. An old school Magellan is like $25 on eBay. Yeah, it's another doodad, but it is an easy solution.

 

[ksaves2]

Not only do I doubt it would fit in the processor, but then you'd have to add another GPS chip, etc, for the receiver. An old school Magellan is like $25 on eBay. Yeah, it's another doodad, but it is an easy solution.

Or get a B/T board and bond with an Android device. Kurt

 

[Charles_McG]

The processor on the TRS is jam-packed - but the RX is doing a lot less work.

Lots of solutions are available. I should go looking to see if a 2S low V cutout is available as a small board I can add on.

 

[cerving]

There's a philosophical issue here with the TX/TRS: Are you trying to save the battery or get your rocket back? A TX or TRS will keep working down to about 4V, way below when a 2S LiPo dies for good. If you're looking for your rocket and possibly need to get the updated packets to find it because it drifted into some corn patch (yup, had it happen...) then you want the transmitter running for as long as possible, even at the expense of dorking the battery. A battery is cheap compared to the cost of your rocket. I COULD put a voltage-limiter on them so that it shuts off at 6.2V or so, but if I did then you wouldn't get all of the battery life... it would also add some cost to the board.

 

[Charles_McG]

I think you're absolutely right about the TX/TRS. A person might need to eek out every last bit of performance when tracking a rocket.

The Quark has a much shorter mission, but even then a low-cutout might not be desirable - you wouldn't want the igniter pulses to shut down the Quark if the current dragged the voltage too low. You'd also need some kind of flexibility for number of cells. I'm thinking you can't assume 2S.

So while it might be a nice-to-have, even as a little add on board that mounted with pins through the battery lead holes - or optional components that could be left out and/or jumpered across, I can see that it wouldn't be generally desirable.

Edit: I've found several protection circuits from tenergy on Amazon. So they are out there, cheap and as small as 18x7mm

 

[ksaves2]

There's a philosophical issue here with the TX/TRS: Are you trying to save the battery or get your rocket back? A TX or TRS will keep working down to about 4V, way below when a 2S LiPo dies for good. If you're looking for your rocket and possibly need to get the updated packets to find it because it drifted into some corn patch (yup, had it happen...) then you want the transmitter running for as long as possible, even at the expense of dorking the battery. A battery is cheap compared to the cost of your rocket. I COULD put a voltage-limiter on them so that it shuts off at 6.2V or so, but if I did then you wouldn't get all of the battery life... it would also add some cost to the board.

Bottom line is use the biggest battery you can get away with if going with reliability. If the rocket needs nose weight, might as well use something that can perform a useful task with a nose mounted EggFinder. Kurt

 

[Charles_McG]

Finally got to fly my Tender-Quark on a properly powered flight.

Here's the prep.


And the flight of my Cherokee-Argent on an F50. The chute released at 31 sec.
[video=youtube;ncgnU8gOpaM]https://www.youtube.com/watch?v=ncgnU8gOpaM[/video]

And recovery. The Quark reported 913'

 

[Jeffmhopkins]

Very Nice!

 

[Charles_McG]

Flight 2 of the Release Quark didn't fair as well. I can't get a hd res video uploaded at the moment, but this is the rocket I put it in - first flight of my 2.1" Photon Disruptor flying on an AT F39-6.

Ejection went well. Deployment didn't. Ended up in a shallow pool - it being Bong and all. Quark Release was hissing gently when I picked it up. I figured the 2S 210mAh Lipo was toast. The meltable link released as soon as I picked it up, of course.

Rocket seems ok after drying out.

I was surprised to find that every thing except the BT50 housing seems to have come though okay. Once dry, the Quark seems to work and bench-test just fine. Just lost its memory of the last apogee. Even the Lipo seems okay after all.

Looking closely at the nichrome, it seems like it didn't heat up the way the bench tests do. They glow yellow-orange for a second and are rough and grey afterward. This one was black in the middle and silver on the ends. I think I'll have to pay more attention to cutting just 1" lengths AND making sure they are firmly tightened in the terminals.

 

[djs]

Bumping this- Charles did his L1 (Estes Leviathan on a CTI H175SS) this weekend using his diy "chute tender".. everything worked out great, for an easy recovery.

 

[ksaves2]

Bumping this- Charles did his L1 (Estes Leviathan on a CTI H175SS) this weekend using his diy "chute tender".. everything worked out great, for an easy recovery.

Convey my hearty congratulations to the most fastidious L1 projectmeister I've read about in a long time.
Time for him to break out his finest libation to toast to this and future successes! Kurt

 

[Charles_McG]

Thanks Kurt.

L1 wasn't a project that I put a lot of planning and [construction] effort into. I finally did it out of peer pressure, after the Tripoli WI guys made me take my rocket off the rod (Tripoli insurance rules don't allow non-TRA/NAR members to fly at TRA launches. The local club allows LPR - I tried to put on a G. At prior launches, I had my elder boyo with me (NAR L1 jr) and put down his name. But he was off with his aviation club that particular day. )

The embarrassment drove me to an NAR L1, with this - my first PSII.



RE: this thread, what I've learned from my little tender is that it's really hard to get a good electrical connection to nichrome. That part is still a work in progress.

 

[ksaves2]

Hmmmmmm, I thought the NAR/TRA thing was settled a couple of years ago that NAR fliers could fly
certified motors at a TRA launch and vice versa. Must be that the local group felt otherwise and imposed
their own standard. (Which of course any group can do as their purview.) Still, an interesting way to do a certification.
I had to rush mine as the local prefrecture advanced to mixing propellant. Needed bodies for a mixing class and I was
allowed to attend as a freshly minted L1 flier. Rules were different back then and rushed the L2 just so I could fly certifed
motors at research launches. I was planning on 7 years before moving to L2. Ripped off the L2 quickly not knowing
really what I was doing (after one failed attempt) and settled back to LPR, MPR and bunches of H's some I's
and a J every now and then in the L2 cert rocket. Did DD in small H and I rockets to get a handle on that modality.
Thank heavens the rules have changed and no one has to rush anything anymore. Kurt

 

[djs]

Still, an interesting way to do a certification.

Mostly we got him to do it because forum user bertaadele was willing to bribe him with an available H175SS, in exchange for some "liquid fuel".

 

[Charles_McG]

It's less confusing if I make explicit that I wasn't an NAR member at the time. Just lay public. -My son- was the only household member at the time with an NAR membership, but that day he was off working on this:

(Alex is in the middle)

https://falconaviation.org

In subsequent research, I discovered that TRA club insurance doesn't cover non TRA (or NAR) members at club launches (for any impulse, certified motor or not). But NAR does -for LPR-.

 

[Charles_McG]

Mostly we got him to do it because forum user bertaadele was willing to bribe him with an available H175SS, in exchange for some "liquid fuel".

That sped it up, to be sure.

Hmmm, that gives me a thought - but it's not postable on TRF.

 

[Steve Shannon]

It's less confusing if I make explicit that I wasn't an NAR member at the time. Just lay public. -My son- was the only household member at the time with an NAR membership, but that day he was off working on this:

(Alex is in the middle)
View attachment 323097
https://falconaviation.org

In subsequent research, I discovered that TRA club insurance doesn't cover non TRA (or NAR) members at club launches (for any impulse, certified motor or not). But NAR does -for LPR-.

I believe we both (NAR and Tripoli) have something very similar in coverage.

Here's what the Tripoli Insurance FAQ says:
What if our Prefecture has Adult non-members attending our launch. Are they covered by TRA insurance when they fly with us?
No. Adult Non-members are not covered by TRA insurance. To obtain coverage, they must join and become members of TRA, regardless of age or impulse flown. NAR, CAR, and UKRA members may fly at TRA launches, but are only covered by their respective organizations insurance, not TRA insurance.
And also, under another question:
We have in the past asked for, and been granted, adding "named Insured's" to our Policy. These named insureds now include volunteers, members of Team America Rocket Challenge (TARC), Student Launch Initiative (SLI), Boy Scouts of America (BSA), NASA University Student Launch Initiative (USLI), and various other accredited educational concerns.


Here's what the NAR Insurance FAQ says:
My Section often has non-members attending our launch. Are they covered by NAR insurance when they fly with us? Sometimes. Generally non-members are not covered by NAR insurance. To obtain coverage, they must join and become members of the NAR. However, your Section’s coverage and your individual NAR members’ coverage remains, and they are covered by the policy. However, students who are members of teams participating in national student rocketry events officially sponsored by the NAR (currently Team America Rocketry Challenge and the NASA Student Launch Initiative/University SLI program) are covered when they fly at an organized NAR section launch – but not at other times and places. Return to the top of page.


Steve Shannon

 

[Charles_McG]

Now all moot. NAR #103560.