No E-Bay DD

I am not going to share any pyrogen stuff but I have found a way to build a simple, reliable wiring system that will fire every time off a 1S 300mah lipo. I have now tested a hand full of them and they fire very quickly.

I am using a 26g ribbon wire I found on Amazon. I split it down to two conductors and it splits quite easily. Since I am working a deployment system that does not use an electronics bay I am making the wires 12-14" long.

I then split the two conductors back about .75". One of them gets stripped down to the yoke of the "Y". The other one I only strip about .125". I now take a single strand of wire from the stripped leg and twist it with the short section I stripped on the other wire. I do a quick solder on those just to make sure they stay put.

I then cut away the rest of the stripped wires I did not use. I also fold over the soldered tip so I have a nice clean tip. I then dip that in a simply pyrogen formula. I only need enough to burn through a thin piece of fishing line.

I have been working on this in an effort to create a deployment system that I can drop in any of my rockets without an electronics bay. This bit I just made is used to burn through a piece of fishing line that is used with my chute retainer.

The goal has been to design a reliable system I can use with a quark. The Quark will be used with the 1S lipo I mentioned and a USB charging system. The Quark and the battery will be a self contained unit. The charging jack is also the switch. When the charging jack is plugged in it is off, when the plug is pulled it is live.

I can charge off a simple power bank, put it in any rocket with no issues. The chute retainer itself is tiny and it can be as far from the Altimeter system as I want to make the wires.

I could even drop a small charge down inside the rocket behind the chute and some wadding and use this system for apogee seperation. I would simply make the leads to the charge long enough to reach down into the rocket. The altimeter system will actually be up near the nose attached to the shock cord.

At the pad I simply pull the switch jack out, listen for my beeps and put the nose cone on.

I will try to shoot some pics when I have the whole unit assembled. The Quark is on the way.

This very interesting, considering I don't know much about DD.
I would like to highly suggest some drawings be added.
I'm sure people who do DD understand better than I.
But drawings would be a great help understanding.
If, you have the time.

Yeah, I'd be interested in seeing some photos.

I need to see what it is like to build the Quark but this may be a system I would be willing to build for folks.

I will shoot some pics and do some sketches I can post up tomorrow. The more I look at the components the more excited I am getting about the whole thing. I can actually make the charger part of the on/off plug. It will be as simple as plugging the unit into any micro USB to charge it. When it is charged unplug the USB and when ready to launch pull the charging plug out of the unit.

Here are some pics of the rough draft. I think I will add a small attachment point for the band so we only have to replace the burn through link. I think the tube should be a smaller ID so I will probably insert another carbon tube inside this one and re-cut the slot for the containment band. If the tube has a smaller ID it should remove any chance of an incomplete burn through. I like this because once the altimeter starts the pyrogen it takes over and the altimeter is out of the equation. This seems like a plus because not all altimeters have the feature of a prgramable energized time.

I imagine it will require sizable vent hiles in the airframe for the internal AV bundle to register correctly for apogee

Nytrunner said:

I imagine it will require sizable vent hiles in the airframe for the internal AV bundle to register correctly for apogee

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I had not even considered the vent holes, Thanks ! My primary use will be to use it for my primary and let motor ejection take care of the apogee event.

However what do you think would be a good method of using this system for apogee. I am thinking a simple cloth cover for the altimeter and it is mounted right below the nose cone on the shock cord. I would think three .125" vent holes equally spaced around the air frame would work.

Any Ideas?

You need to consider if the Quark baro unit can handle the overpressure from an ejection charge. And since it won't be in a traditional A/V bay, it will be exposed to the harmful gasses of the ejection charge, which is very corrosive. You need to keep it safe from those gasses while still venting it to the atmosphere. Units like the Jolly Logic Chute Release are designed with that in mind. The atmospheric pressure to the unit has to equalize very quickly for accurate apogee detection, which may be hard to do in a bay that does not have a direct path from the vent holes to the altimeter. And the board does need to be physically protected from being banged around during the ejection charge, descent, and landing.

And of course once you add 'energetics' to the mix, you have to comply with the new TRA rules if you are flying at a TRA launch. But your solution of just popping the nosecone to turn it on should work, as long as the switch physically disconnects the battery.


Tony

Vent holes need to be sized for the volume of bay where the elctronics are. Check eggtimer's manuals for the proper vent area to volume ratio.

Nytrunner said:

Vent holes need to be sized for the volume of bay where the elctronics are. Check eggtimer's manuals for the proper vent area to volume ratio.

Click to expand...

Thanks Bud, will do.

manixFan said:

You need to consider if the Quark baro unit can handle the overpressure from an ejection charge. And since it won't be in a traditional A/V bay, it will be exposed to the harmful gasses of the ejection charge, which is very corrosive. You need to keep it safe from those gasses while still venting it to the atmosphere. Units like the Jolly Logic Chute Release are designed with that in mind. The atmospheric pressure to the unit has to equalize very quickly for accurate apogee detection, which may be hard to do in a bay that does not have a direct path from the vent holes to the altimeter. And the board does need to be physically protected from being banged around during the ejection charge, descent, and landing.

And of course once you add 'energetics' to the mix, you have to comply with the new TRA rules if you are flying at a TRA launch. But your solution of just popping the nosecone to turn it on should work, as long as the switch physically disconnects the battery.


Tony

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Tony, I appreciate your concerns but I believe you are over thinking things and possibly "looking for" the negatives. As for the gases, and being over pressurized by the time any of those gases reach the altimeter it will be in open air and away from the main BT. This could also easily be dealt with through the use a simple piston.

As for getting banged around, did you really think I would just hang the altimeter in the breeze with no cover of any kind. If you had read through the thread a protective bag or enclosure was mentioned.

As for the TRA's new rules, I thought I made it clear how the switch works. In order to charge it would clearly have to cut off the flow of energy to the unit.

I really wish you had posted questions about the design instead of assuming I did not think this through very thoroughly.

ThreeJsDad said:

I had not even considered the vent holes, Thanks ! My primary use will be to use it for my primary and let motor ejection take care of the apogee event.

However what do you think would be a good method of using this system for apogee. I am thinking a simple cloth cover for the altimeter and it is mounted right below the nose cone on the shock cord. I would think three .125" vent holes equally spaced around the air frame would work.

Any Ideas?

Click to expand...

ThreeJsDad said:

Tony, I appreciate your concerns but I believe you are over thinking things and possibly "looking for" the negatives. As for the gases, and being over pressurized by the time any of those gases reach the altimeter it will be in open air and away from the main BT. This could also easily be dealt with through the use a simple piston.

As for getting banged around, did you really think I would just hang the altimeter in the breeze with no cover of any kind. If you had read through the thread a protective bag or enclosure was mentioned.

As for the TRA's new rules, I thought I made it clear how the switch works. In order to charge it would clearly have to cut off the flow of energy to the unit.

I really wish you had posted questions about the design instead of assuming I did not think this through very thoroughly.

Click to expand...

My questions go directly to the design of the system. You say you had not even thought about vent holes and then accuse me of thinking you had not thought it through? The only reference to any kind of protection is "a simple cloth cover", which may not sufficiently protect it, there is no mention of an enclosure. The parachute compartment is pretty much instantly pressurized when the ejection charge fires, anything in that compartment will be exposed to both hot gases and extreme pressure. I have flown many radio trackers inside parachute bays and have seen what happens if they are not adequately protected.

So if the way to turn off the power to the unit is through the charger cable as you state, does that mean I need to have the cable plugged into the unit all the way out to the pad? Can you post a picture or schematic of how inserting a micro USB connector will physically disconnect power to the unit?

You asked for opinions regarding your system and I replied with what I thought were helpful, constructive comments, all of which were intended to help you with your design and based on my personal experience. If that's not what you wanted, I guess I misread your questions to the forum.


Tony

ThreeJsDad said:

Tony, I appreciate your concerns but I believe you are over thinking things and possibly "looking for" the negatives. I really wish you had posted questions about the design instead of assuming I did not think this through very thoroughly.

Click to expand...

Looked to me like Tony was just trying to help. First thing that came to my mind as did others posting was the venting for the alt. The purpose of someone trying to help is to turn possible negatives into positives. I personally have not seen enough yet in the thread about the design besides the venting issue to come to any possible positives. All that comes to my mind is possible negatives with the design so far, which until further info on the design I will not comment on.

I think Tony was trying to help, too. This is an open forum, you are asking for input. Best course of action is to read the replies, then

if you find it helpful, express thanks
if you are not clear on what the poster is saying, ask for clarification (often leads to useful discussion)
if you don't find it helpful, ignore it.
if you find it offensive, ignore it.
if you find it REALLY offensive (pretty rare, IMO), report it and then ignore it.

Note: this works well with personal interactions with people at work, too!

Vast majority of people on this forum want to help each other fly safe and fly well and have fun.

What are we looking at in post #5? The operation and design of this thing is not clear, as others have mentioned. I assume it is some kind of tether. How is it different/better than the numerous chute releases, cable cutters, and fishing line melters that have been tried?

How much current does that one strand draw? I tried this once, and decided that it was more than I wanted to expend... plus the Chinese ematches are about 99.99% reliable. And, a Quark on a 1S LiPo will easily fire it... others have done fishing-line cable cutters using just that.

Sorry I was so testy and defensive. I apologize for my reaction.

Buckeye said:

What are we looking at in post #5? The operation and design of this thing is not clear, as others have mentioned. I assume it is some kind of tether. How is it different/better than the numerous chute releases, cable cutters, and fishing line melters that have been tried?

Click to expand...

You make some valid points, nothing different or unique.

BABAR said:

I think Tony was trying to help, too. This is an open forum, you are asking for input. Best course of action is to read the replies, then

if you find it helpful, express thanks
if you are not clear on what the poster is saying, ask for clarification (often leads to useful discussion)
if you don't find it helpful, ignore it.
if you find it offensive, ignore it.
if you find it REALLY offensive (pretty rare, IMO), report it and then ignore it.

Note: this works well with personal interactions with people at work, too!

Vast majority of people on this forum want to help each other fly safe and fly well and have fun.

Click to expand...

Sage advice.

manixFan said:

My questions go directly to the design of the system. You say you had not even thought about vent holes and then accuse me of thinking you had not thought it through? The only reference to any kind of protection is "a simple cloth cover", which may not sufficiently protect it, there is no mention of an enclosure. The parachute compartment is pretty much instantly pressurized when the ejection charge fires, anything in that compartment will be exposed to both hot gases and extreme pressure. I have flown many radio trackers inside parachute bays and have seen what happens if they are not adequately protected.

So if the way to turn off the power to the unit is through the charger cable as you state, does that mean I need to have the cable plugged into the unit all the way out to the pad? Can you post a picture or schematic of how inserting a micro USB connector will physically disconnect power to the unit?

You asked for opinions regarding your system and I replied with what I thought were helpful, constructive comments, all of which were intended to help you with your design and based on my personal experience. If that's not what you wanted, I guess I misread your questions to the forum.


Tony

Click to expand...

Tony, I am apologizing to you personally because I was rude and there is no need for that. I try very hard to be kind and considerate to people and in this case I failed so please accept my apology.

Paul

It does seem clear this has some real issues. I will find another fun project to work on until my classes start up.

paul

Hey, thank you for the apology! Accepted and appreciated, not sure it was needed though. Pretty rare these days unfortunately.

I think your project could work along the same lines as the JLCR, but it would take some experimenting. If you could get it to work with a Quark the price sure would be right.

Good luck on whatever project you choose,


Tony