Kevlar Confused

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DeepOvertone

DeepOvertone

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Hello all and thanks for helping out a poor confused individual.

I'm looking to replace the provided nylon shock cord from my Madcow 2.6" fiberglass lil goblin rocket. I haven't built it yet and I want to get all of the advantages of kevlar right off the bat since theres not a whole lot of room inside that rocket. I'm looking around and I'm having trouble picking the diameter of the kevlar I'm going to need for this bird. I found this nylon cord that appears to be the same as the one in my kit. Its listed at 1500lbs breaking strength. First, I doubt I'll be needing that much strength to begin with and second, I'm not sure which diameter kevlar would match its strength, if that much strength is in fact needed. If not, I'd love to know how much strength I do need and a recommended resource to purchase it. I've found/know of many places that sell it but most of them do not quote the strength but only the diameter and type.

Further info, I plan to use a chute release and a streamer(for extra drag and visual tracking) for recovery.

Many thanks to the hive mind and its respective wisdom and experience!

DO
 
Contact Ted Chernok (sales 'at' onebadhawk 'dot' com), tell him what you have, answer his questions, and he will not only tell you what you need, but he'll make it and sell it you. Best in the business.
 
Typical rules of thumb for shock cords:
3x the rocket length (or more) for shock cord length. if the rocket is 28" long, you should plan for 84" (minimum) of cord. Kevlar has no stretch. ideally, you want a bit of stretch / give to absorb any sudden jolts. Nylon cord allows some 'give'.
150x the rocket weight for loading. So, your 1lb rocket (fully loaded) should have a shock cord rated at 150lbs min..

But, you don't want to use a piece of 1/16th cord, which will definitely have "zipper potential" or only require a little abrasion to cut in two.. There's also the cost of "all Kevlar"..

If I were you, I would have a 2-3 foot length of 1/8 or 3/16 Kevlar cord in the rocket, and about 4-6 feet of tubular nylon outside the rocket.. (make a knot eye in the upper end, and just beyond the top edge of the body tube to add the nylon portion. You only really need the Kevlar in the rocket, in the "hot area"..) I would also add a wad of tape around the cord where it touches the edge of the body tube, to not allow the edge of the BT to 'cut thru' cord..
 
DeepOvertone said:
Those look awesome and I'd love to try one out. I'm curious though if you'd be able to customize those for me(I've heard you can). I'm thinking id like some hardware sewn into the loops if possible.

Thanks,

DO
Click to expand...

salesatonebadhawkdotcom
 
Onebadhawk said:
You'll never look back...

They just simply work...
Click to expand...

I have one in the mail. No regrets about the price either. I had a pound nosecone fall from a mile during a cert on a RB-05A sport scale kit from an inferior paracord clone fake shock cord. It bore a hole 8" into earth with a thud. We couldn't pull it out of ground with our hands. The first thing TRF members recommended were OneBadHawk 3/16" Kevlar cords. These OneBadHawk cords should come standard in rocketry kits, because there is a quality difference in materials.

Its worth the money versus the alternate.
 
My rocket weighed 3.5 lbs loaded and had approx 2.3" diameter for the final Kevlar 3/16" decision if it helps OP.
 
Andrew_ASC said:
I have one in the mail. No regrets about the price either. I had a pound nosecone fall from a mile during a cert on a RB-05A sport scale kit from an inferior paracord clone fake shock cord. It bore a hole 8" into earth with a thud. We couldn't pull it out of ground with our hands. The first thing TRF members recommended were OneBadHawk 3/16" Kevlar cords. These OneBadHawk cords should come standard in rocketry kits, because there is a quality difference in materials.

Its worth the money versus the alternate.
Click to expand...

Thank you so much Andrew...
I do have a belief in quality materials Andrew,,
But for the purpose of this conversation in my humble opinion
it's more about manufacturing methods and techniques...

Teddy
 
Yes sir. The right knots, techniques, and experienced mentors go a long ways. Even the best shock cord can fail if used improperly.
 
DeepOvertone said:
Hello all and thanks for helping out a poor confused individual.

I'm looking to replace the provided nylon shock cord from my Madcow 2.6" fiberglass lil goblin rocket. I haven't built it yet and I want to get all of the advantages of kevlar right off the bat since theres not a whole lot of room inside that rocket. I'm looking around and I'm having trouble picking the diameter of the kevlar I'm going to need for this bird. I found this nylon cord that appears to be the same as the one in my kit. Its listed at 1500lbs breaking strength. First, I doubt I'll be needing that much strength to begin with and second, I'm not sure which diameter kevlar would match its strength, if that much strength is in fact needed. If not, I'd love to know how much strength I do need and a recommended resource to purchase it. I've found/know of many places that sell it but most of them do not quote the strength but only the diameter and type.

Further info, I plan to use a chute release and a streamer(for extra drag and visual tracking) for recovery.

Many thanks to the hive mind and its respective wisdom and experience!

DO
Click to expand...

For rockets the size of your Lil Goblin, I like the 750# Kevlar available from Balsa Machining Service. The 750# stuff from BMS is just a bit smaller than the 1/4" stuff from Wildman. 15 feet of the 750# stuff should leave plenty of room in your Goblin .
 
I buy from emmakites.com very cheap, fast shipping and good quality. In this case you can have all three. I've use their 750 lb in a 9lb rocket on many flights.

Sent from my HTC6535LVW using Rocketry Forum mobile app
 
The stock stuff will work, just add some finesse to get it all packed in there.

Or:
https://www.strapworks.com/Nylon_Webbing_p/tnw12.htm
Rated for 2000lbs

Simple and cheap. A bit like the stuff Mike includes with his Binder Design kits. It works.
I used it in my level 1 and level 2 birds. My level 2 was 10lbs on the pad. Grab you a nomex harness protector or kevlar sleeve, tie a good knot, and you're GTG.

Or if you want to pack smaller, pick up some 1/4" Kevlar, most is 1200lbs as well. Tie a good knot and you're still GTG. The 750lb stuff from Sirius will work just fine. Put some heat shrink or tie a ring to it where it will contact the airframe to prevent zippers or rubbing through the cord. Heck, I've use a piece of balsa attached to the cord to that end.
 
Ravenex said:
I buy from emmakites.com very cheap, fast shipping and good quality. In this case you can have all three. I've use their 750 lb in a 9lb rocket on many flights.

Sent from my HTC6535LVW using Rocketry Forum mobile app
Click to expand...

dmgrime said:
Also used emmakites.com 750lb on a few small MPR birds and their 380lb is great for LPR.

Sent from my SM-G920V using Rocketry Forum mobile app
Click to expand...

Here's Emmakites offering---

https://www.emmakites.com/index.php?main_page=product_info&cPath=336_365&products_id=629

Here's my offering---

https://onebadhawk.com/light-kevlar.html

I'm a dollar less then she is..
I bring a truck full of everything you'd ever need to fly a rocket to every launch I go to..


Way to go supporting someone who supports your great interest / hobby...

Teddy
 
A chain is only as strong as its weakest link. Even 1500-lb Kevlar will fail if the loops are poorly made. If you buy Kevlar cord. you'll also need Kevlar thread and a sewing machine. I buy from One Bad Hawk because he does all the work and backs up his product. That's one less failure I have to worry about at launch time. Never had one of Ted's cords or loops unravel or break on me. And, I can grab some Loki HW or loads and get it all shipped at a fair rate.
 
Simple fact...
You can buy your own kevlar, tie it, and hope that it works for ya.
OR...
You can buy from OneBadHawk, and have a guaranteed product made from the best kevlar from someone who KNOWS and FLIES rockets, so he knows what he uses and sells that. All at GREAT prices.
For me, the choice is obvious. Besides all that, if you call/e-mail Teddy with all the specs on your rocket, he'll get you exactly what you need. Never too little, and never too much, just exactly the perfect harness for the application. I've literally got OneBadHawk in every rocket I own over a sport size (and even one or two of my sport sized rockets!)
The exact right product for the exact right price from a flyer for flyers. I can't think of any reason to go anywhere else, honestly.

As far as specs... I've had rockets have "less-than-optimal recovery sequences" and never had a OBH harness fail. I have seen nylon cut, torn, and snapped. Nylon that I would've thought would be impossible to snap on a given rocket has snapped. Teddy offers nylon, with a kevlar sleeve to help prevent that from happening. Seriously, for $20, you're set. Just my humble opinion.
 
Ted -

Please accept my apologies!

I had no idea you had LPR "friendly" offerings ... when I got back into the hobby a couple years ago I spent quite some time learning about the vendors - both that uniquely serve our small community such as yourself, as well as those with materials, etc. that we find useful. I didn't really look too deep to HPR oriented suppliers at that time.

At that time, I did not find many sources for Kevlar that was useful to LPR flying, and as I was just starting back out a BT60 was large in my fleet...

Now that I know you've got the LPR/MPR side covered, you'll be getting an order from me in the near future as I'm both running out of what I had, as well as moving up larger birds and ultimately shooting for my L2 next year.

Again please do accept my apologies - I meant no offense and fully appreciate the need to support vendors such as OneBadHawk as without you, our hobby couldn't be what it has become today.

Thanks for your feedback.

Dave
 
Onebadhawk said:
Here's Emmakites offering---

https://www.emmakites.com/index.php?main_page=product_info&cPath=336_365&products_id=629

Here's my offering---

https://onebadhawk.com/light-kevlar.html

I'm a dollar less then she is..
I bring a truck full of everything you'd ever need to fly a rocket to every launch I go to..


Way to go supporting someone who supports your great interest / hobby...

Teddy
Click to expand...

I'm assuming your 1/8" kevlar is rated at 1500lbs so as to be equivelent to the emmakites product you linked to, though I don't see any rating on your page you posted. In that case this is not a apples to apples comparison, the emmakites product I was reffering to is this one here:
https://www.emmakites.com/index.php?main_page=product_info&cPath=336&products_id=623

It is .078 inch, substantially thinner than 1/8". It packs a bit tighter and has proven to be plenty for my fiberglass HPR rockets up to 3" and 10 lbs. It seems to have fit the bill of exactly what the OP was looking for and is another alternative.

That said, I have never seen anything but high praise for your harnesses and your customer service. I personally have not use your products, but I have no reason to believe your product is anything but the highest quality. I prefer to use spliced loops on my braided kevlar instead of sewn loops, which is just my preference for a number of reasons. Also when I think of Onebadhawk I tend to think of a quality heavy duty finished product with sewn loops, not raw materials. Before this thread I didn't even realize you went down to 3/16" let alone sold thinner raw kevlar. While the 3/16" sewn harness you recommended would without question do the job and I'm sure the OP would be thrilled with the quality and service he would get, I feel it may be more than necessary for the rocket he described and so offered my opinion.

As I said my suggestions to use something other than your product was simply an alternate option, and had no malice. Your closing line of "Way to go supporting someone who supports your great interest / hobby..." was just filled with attitude and sarcasm towards me and Dave, and goes against everything I have heard about you in the past. Keep in mind that while I may not have been at it as long as you, I too sell product I design and manufacture to this hobby. If someone else sold a competing product to mine that was equally or better suited to my customers application I would not take offense at it being recommended to them. I want everyone to get the best, most cost effective solution to their situation, even if it meant sending them somewhere else.
 
Last edited:
Ravenex said:
. Your closing line of "Way to go supporting someone who supports your great interest / hobby..." was just filled with attitude and sarcasm towards me and Dave, and goes against everything I have heard about you in the past.
Click to expand...

I took this the same way. I was disappointed to see a vendor bashing someones choice to use a different vendor or "someone who doesn't support the hobby". I bought some glue from hobby lobby, sand paper from lowes, paint from an auto parts store, and so on... Does this make me a bad rocketeer too?

Anyway, I've found someone willing to make what I wanted at a very fair price. Thank you all for your comments and suggestions.
 
I'm not bashing anyone.
Don't make what I said sound any worse then it does, I generally don't say things like this at all anyway,
so it doesn't sit all that well with me as it is..
Do a search.
I don't even know ( a half dozen ) how many times people do this exact same thing.
Your recommending in a public post to go outside of our community and buy and it isn't even cheaper,
my prices are less than Emms Kites.
And I offer my product on the field you fly at,, that's expensive,, does Emma Kites ??
Brian you seemed to take great offense to my post..
How many times and how often should I watch what you posted by different people
and stand by quietly because that's what I'm expected to do..
I didn't even say anything so terrible,, but you must admit,,
after a while again and again you can see this wear thin..

Teddy
 
DeepOvertone said:
I took this the same way. I was disappointed to see a vendor bashing someones choice to use a different vendor or "someone who doesn't support the hobby". I bought some glue from hobby lobby, sand paper from lowes, paint from an auto parts store, and so on... Does this make me a bad rocketeer too?

Anyway, I've found someone willing to make what I wanted at a very fair price. Thank you all for your comments and suggestions.
Click to expand...

Now hold on a moment. Teddy is not bashing anyone, possibly I am missing something so feel free to highlight it for me?

I would argue that you are unfairly characterizing Teddy's comment. I understand that interpretation is subjective, and I have an advantage in knowing Teddy to believe that he is likely simply frustrated because he feels the value of his product is disproportionately high for the price, and I would agree. I would also agree that he can do a heck of a lot better job at making a harness than most people. I own a couple of dozen One Bad Hawk harnesses, both off the shelf and completely custom. I don't even know how it's worth his while making them when you factor cost of goods plus his time. Of course if you don't believe that your time is worth anything then that is another story, but I am going to guess that you don't work for free.

I would also take Teddy's general message of supporting the vendors one step further. Do you realize that the vendors pay to participate in this forum and in doing so help to support it financially? Do you realize that Teddy actively attends launches all over the country and if you met as well as took the time to know the guy, you would realize he is both justifiably proud of his workmanship. Heck I would characterize Teddy as one of the good guys who would give you the shirt off his back.

Beyond Teddy I would also expand the discussion and say that it is the enterprise efforts that have disproportionately made this hobby what it is today. I would even go as far as to say without their involvement that this hobby would be a mere shadow of itself and may not even legally exist at all.

Do I think we should support our vendors, heck yes...it's common sense!

And shame on you.
 
Teddy,

I was not planning to respond further to this thread to avoid making things worse, but I've had some time to reflect on it. So, yes I did take offense to the sarcasm of your post. I understand your position you have every right to be proud of the product you offer and agree we should support our vendors, but not at the exclusion of what's best for the flier. Your products are high quality and it shows in the glowing recommendations you get in every discussion of recovery products. But as I stated I don't feel I was pointing the OP at the same product at a higher price outside of the community, I was pointing the OP to a lighter, less expensive material than what you offered because I felt it would meet their requirements. Personally I buy at Emma Kites because of the large variety of 200 - 2000 lb loose kevlar that allows me to pick exactly what I feel I need for a given size rocket and I can get it all in one place. I prefer to make my harnesses myself using different methods so this is the most cost effective solution for me. If you were to offer a wider selection of loose kevlar or when I build a large project I would happily come to you for my kevlar needs. When it's apples to apples, I definitely say buy from one of our own, but when someone with comes in with a question like the OP's I feel it's best to let them know what their options are and I don't think someone deciding that the right option for them is to go outside of the community for product makes them a bad person. People buy all kinds of materials from other sources when similar product may be available from a vendor for all sorts of perfectly valid reasons.

Michael,

You may be right that I am misjudging Teddy's comment, but I don't think I was. I think he felt a insulted / hurt / annoyed by me suggesting a different vendor an he came back with a harsh sarcastic response. It's an understandable response even if I took some offense at it. I have talked breifly to Teddy on a few occasions, he seems like a great guy who cares about his customers and other hobbists, which is why I felt the response was out of character. That said, I think your being to harsh on DeepOvertone he was simply agreeing with me and my judgement of the situation. Regardless of Teddy's positive qualities and support of the forum and hobby, his comment could reasonably be taken to mean exactly what DeepOvertone and myself took it to mean, and DeepOvertones response was measured and and appropriate given that interpretation. There is no reason to shame him for it.

I think this all got a bit more heated than it should have and I apologize for the part I played in it.
 
Ravenex said:
Teddy,

I was not planning to respond further to this thread to avoid making things worse, but I've had some time to reflect on it. So, yes I did take offense to the sarcasm of your post. I understand your position you have every right to be proud of the product you offer and agree we should support our vendors, but not at the exclusion of what's best for the flier. Your products are high quality and it shows in the glowing recommendations you get in every discussion of recovery products. But as I stated I don't feel I was pointing the OP at the same product at a higher price outside of the community, I was pointing the OP to a lighter, less expensive material than what you offered because I felt it would meet their requirements. Personally I buy at Emma Kites because of the large variety of 200 - 2000 lb loose kevlar that allows me to pick exactly what I feel I need for a given size rocket and I can get it all in one place. I prefer to make my harnesses myself using different methods so this is the most cost effective solution for me. If you were to offer a wider selection of loose kevlar or when I build a large project I would happily come to you for my kevlar needs. When it's apples to apples, I definitely say buy from one of our own, but when someone with comes in with a question like the OP's I feel it's best to let them know what their options are and I don't think someone deciding that the right option for them is to go outside of the community for product makes them a bad person. People buy all kinds of materials from other sources when similar product may be available from a vendor for all sorts of perfectly valid reasons.

Michael,

You may be right that I am misjudging Teddy's comment, but I don't think I was. I think he felt a insulted / hurt / annoyed by me suggesting a different vendor an he came back with a harsh sarcastic response. It's an understandable response even if I took some offense at it. I have talked breifly to Teddy on a few occasions, he seems like a great guy who cares about his customers and other hobbists, which is why I felt the response was out of character. That said, I think your being to harsh on DeepOvertone he was simply agreeing with me and my judgement of the situation. Regardless of Teddy's positive qualities and support of the forum and hobby, his comment could reasonably be taken to mean exactly what DeepOvertone and myself took it to mean, and DeepOvertones response was measured and and appropriate given that interpretation. There is no reason to shame him for it.

I think this all got a bit more heated than it should have and I apologize for the part I played in it.
Click to expand...

Hi Brian,

Perhaps I was a bit harsh on DeepOvertone with my comment "Shame on you", I admit to losing a bit of restraint while responding. I am also in full agreement with the right solution for the right flier and that we should all do what is within our means and or simply what we prefer, including scratch everything if that works for you. My objection was at the suggestion that Teddy's comment was motivated by anything more than sincere frustration, I don't believe this to be true.

Regardless I do feel that I owe an apology to DeepOvertone for my comment, so DeepOvertone please accept this as an apology.
 
Thank you so much Michael..
You are a good friend..

My apologies to all as well..
I did get frustrated and it got the better of me..

Teddy
 
CzTeacherMan said:
Simple fact...
You can buy your own kevlar, tie it, and hope that it works for ya.
OR...
You can buy from OneBadHawk, and have a guaranteed product made from the best kevlar from someone who KNOWS and FLIES rockets, so he knows what he uses and sells that. All at GREAT prices.
For me, the choice is obvious. Besides all that, if you call/e-mail Teddy with all the specs on your rocket, he'll get you exactly what you need. Never too little, and never too much, just exactly the perfect harness for the application. I've literally got OneBadHawk in every rocket I own over a sport size (and even one or two of my sport sized rockets!)
The exact right product for the exact right price from a flyer for flyers. I can't think of any reason to go anywhere else, honestly.

As far as specs... I've had rockets have "less-than-optimal recovery sequences" and never had a OBH harness fail. I have seen nylon cut, torn, and snapped. Nylon that I would've thought would be impossible to snap on a given rocket has snapped. Teddy offers nylon, with a kevlar sleeve to help prevent that from happening. Seriously, for $20, you're set. Just my humble opinion.
Click to expand...

Track record. Sewn loops aren't the only way to fly Kevlar and tied knots allows more configurations which is a customer preference. OneBadHawk could consider expanding into raw supplies market for more customers. You may source sizes not sold by OneBadHawk elsewhere, but at the same time you are testing that configuration yourself until another flyer proves it works. After a recovery failure I went with OneBadHawk. It wasn't the dollar amount. It was the fact I don't see flyers Sh*t posting OneBadHawk product reliability. I can still tie the onebadhawk harness in any config I want. I have a piece of mind of OneBadHawk flying gear has been field tested and is well spoken of by many others. Others may see it as Kelvar versus Kevlar and cost differences. Most vendors don't tell you the specific threads used. Or processes of manufacture. Or quality control. In the end those extra steps matter in ways you don't see.

The best part of rocketry forum is people apologize for just preferring different techniques and products.
 
I started manufacturing harnesses because no one else did..
I have zero desire to compete with anyone..
I will not sell raw material simply because others do..

Teddy
 
You're all missing the real point, which is Teddy's talent is wasted making harnesses.

He should be selling those sandwiches I got with my last order. Hell I kinda wanna buy motors just to get another one next time I see him ;)
 
Dear Mr Teddy.....

Last year I undertook the making of my own harness's, as I am a cheap Ba$tard.

I found some clothesline that blew into my yard after Hurricane Matthew. Since I can't sew worth a $hit, I decided to use staples for my loops.
I cop friend of mine told me they had a recent "suicide attempt" where the victim tried to kill himself by stapling his head over 500 times.:y: Since the case was closed, I could have the staples FREE. Hmmmm.....

So I cut the line to length & using the recycled staples made my harness's loops, for "free". WOW free American made stuff...Yeah!:smile:

Upon launch everything went haywire at apogee...it was ugly..clothesline and staples flying everywhere. :eyeroll::eyeroll::lol::lol::lol:

Anyhow I learned my lesson & in the future will be purchasing all my recovery needs from you. Especially since I read somewhere you have extensive experience in sewing... I.E. holes in socks and underwear repair. :jaw:
You do use kevlar thread, correct?
I figure if your sewing expertise will hold together material exposed to massive Blasts from farts & folks chewing on socks, you skills will surely keep my harness together.

From now on you are my go-to guy!
Just wish I knew about your services sooner.
 

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