Using Protection! Yes! Rubbers for your rocket!

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K'Tesh

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Someone on FB was talking about how their old rocket's shock cord had become dried and brittle, and there's all kinds of suggestions on how to replace them with Kelvlar. While I don't fully agree with them, I don't fully disagree either.

Here's the rub...

But first a warning: Do NOT attempt to recover items (kites, rockets, drones, etc.) from overhead utility lines*. Contact your utilities company if you find yourself in that situation.
The benefit of using the rubber shock cord is that it is the weakest material in the rocket. If the rocket gets caught up in a tree, the UV light will deteriorate it quickly. Thus you should hopefully get the cardboard and wood portion back with the least amount of damage.

By the time UV light breaks the rubber cord, the cardboard of the rocket would be soaked and destroyed from rain, no?
Depends on the weather. If the cardboard is painted, that'll afford you some protection. Soak some thin CA around the inside of the top of the body tube, and that'll help things quite a bit. Use wood hardener on the inside,and you've got a nearly waterproof rocket. And the fins will likely hold up for a while, presuming that the winds aren't bashing the rocket too much.

I had a rocket that I literally filled with water, and launched under water (it didn't torpedo as planned). And after I allowed the rocket to dry completely, I was able to get the motor out (by unraveling it from the inside). That rocket has flown again, and is completely capable of flying to this day.

Here's some more to think about. The nosecone would likely survive a fall, even without a parachute, from a tree with little to no damage. The body tube likely will also do well in a fall (even better if you can have someone catch it). Parachutes are likely what will tangle in a tree, but they're easily replaceable. The cardboard and wood is where we invest most of our time in building a kit. Lose a parachute? No worries. Lose a nosecone, you can replace it. Lose the cardboard tube, fins, paint and decals? You're back at square zero.

The fragile nature of the rubber allows you easily cut it, and recover the hard to replace part quickly before weather damage occurs. If you can't recover the nosecone for a while, you might be able to replace it from another source. With a replacement for the rubber, a new parachute, and a recovered or replaced nosecone, you're back in business.

Given my preference for rockets that are too short to get a baffle, but not minimum diameter, I'd use a length of Kevlar with a loop on both ends, The line is passed alongside the motor tube, and the loop is "tied" around the outside of the motor mount (accessible from the bottom of the rocket). Tie a rubber shock cord to the other end of the line, with the junction just below the top of the body tube. You can then replace the rubber shock cord if it gets too old, and you can inspect the Kevlar for wear and tear by pulling it back along the motor mount. This way you get the best of both worlds. The benefits of the unrestricted "neck" of the body tube (preventing the parachute or streamer from getting caught inside), and the "If stuck in a tree" benefits of the weakness and replaceable nature of rubber.

Now, the best thing is not to get stuck in trees. However, if you do, a slingshot with a lead weight, a bow and arrow, or a crossbow can launch a Kevlar line up into the tree. and If you can catch the shock cord, you can "saw" thru it.

*I've got a high school buddy who is a double amputee (both arms) who had an encounter with a powerline as a kid. He's got one that was amputated below the elbow, and the other was removed at the shoulder. Be safe
 
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ebruce1361

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Well, it worked, @K'Tesh

Your thread title ABSOLUTELY got my attention and I read the whole thing expecting to read some crazy hack where a Trojan was used as a rocket part. I have come away from this read slightly disappointed, but also impressed, bemused, and with a renewed appreciation for rubber shock cords.

Bravo. Carry on.
 

K'Tesh

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Well, it worked, @K'Tesh

Your thread title ABSOLUTELY got my attention and I read the whole thing expecting to read some crazy hack where a Trojan was used as a rocket part. I have come away from this read slightly disappointed, but also impressed, bemused, and with a renewed appreciation for rubber shock cords.

Bravo. Carry on.
Thanks!

Sorry to have disappointed you. But when it comes to condoms, I thought that everybody knows that you use unlubricated ones to keep your ematches and your black powder dry in damp environments.

Guess I was wrong. :p


All The Best!
Jim

Oh, and the rings of condoms make great rubberbands, which you could use to hold your reefed chute closed when you use a cable cutter.
 

K'Tesh

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Just got word from the Estes Model Rocket FB page that someone took my suggestion of firing a line attached to an arrow and was able to recover his lost Estes MAV, intact.

K'Tesh had a brilliant suggestion on my earlier post. I attached a line to a blunt arrow, shot it over the branch where the MAV was stuck (look real close 2/3 way up the tree and you can see it hanging). The recovered MAV is intact and flyable except for the shredded chute.
upload_2020-4-8_9-20-53.png


Changed my name to the handle everyone knows... Saves confusion, and reduces the "Sheldon?" question. NO! I'm not an actor, nor do I play one on TV.
 
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Greg Furtman

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I built one of these. I used some Kevlar string at the end of the rubber tubing and renotched the featherless arrows.

 

K'Tesh

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I built one of these. I used some Kevlar string at the end of the rubber tubing and renotched the featherless arrows.

Brilliant! And it can't be mistaken for a weapon. Though IMHO, the warning about powerlines should be first... and I'm editing my OP to reflect that.
 

ebruce1361

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I have a collapsible fishing rod with a dulled size 1/0 treble hook for pond recovery, but I really should build some kind of tree recovery rig. I like your setup @Greg Furtman ! Maybe an alternate version that would reduce the chance of breaking the fishing line would be to use a fly reel and use all 150# kevlar line. I'll have to add such a device to my list of projects to build!
 

Greg Furtman

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I have a collapsible fishing rod with a dulled size 1/0 treble hook for pond recovery, but I really should build some kind of tree recovery rig. I like your setup @Greg Furtman ! Maybe an alternate version that would reduce the chance of breaking the fishing line would be to use a fly reel and use all 150# kevlar line. I'll have to add such a device to my list of projects to build!
@ebruce1361 I took a large eye off of an old fishing rod & taped it to the front bottom side of the aluminum tube for the fishing line to go through. When fired the line easily comes off of the reel and follows the bolt nicely.:)
 

ebruce1361

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I was thinking more in terms of breaking the line while tugging on it after the bolt is in the tree, but you raise a good point that the line could break when the bolt is fired without a guide of some sort.

Another idea I had was to have a triangular frame around which to wrap the line to prevent tangling and eliminate additional moving parts. Similar to how the rope is coiled up with this setup (minus the rest of the craziness):

 

Greg Furtman

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I was thinking more in terms of breaking the line while tugging on it after the bolt is in the tree, but you raise a good point that the line could break when the bolt is fired without a guide of some sort.

Another idea I had was to have a triangular frame around which to wrap the line to prevent tangling and eliminate additional moving parts. Similar to how the rope is coiled up with this setup (minus the rest of the craziness):

@ebruce1361 I bought 100' of parachute cord. The plan is to shoot the bolt with fishing line attached over the offending branch and get it down near the ground. Pull the fishing line off the bolt & tie it to the paracord. Then reel in the fishing line until the paracord is in hand & use that to work the rocket off of the branch. Theoretically it should work. :rolleyes:
 

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