Kevlar shock cord rocketry The rocket zippered (a little of a late delay) but I think nylon wouldn't have zippered the tube. These Shock Cord Protectors are the perfect way to protect your nylon shock cords. $2. Attached the streamer to the shock cord Jul 25, 2021 · That (the crochet method) looks like it would work amazingly well. This shock cord is not heat resistant, so it is best to use it in conjunction with a sturdy Kevlar shock cord. http://www. I use 10' of kevlar for my rockets of that length. Tailored for Rocketry: Whether securing payloads, attaching parachutes, or ensuring the safe recovery of your rockets, our Kevlar Shock Cord is the ideal choice for high-power rocketry applications. Tie your shock cord to the top side of the piston and connect your body tube when a length of elastic shock cord is tied onto the free end of the Kevlar. So here are the questions. Kevlar shock cords are good, but you have to know what you are doing or you can get big zippers. 1/2in Tubular Kevlar 2 Loop High Power Rocketry Recovery Payload Harness / Shock Cord with 2 sewn Loops. Add To Cart. I would like to use heavy duty Kevlar from bolt on engine mount to nose cone, about 8 to 10 feet long. I prefer to use only Kevlar as a shock cord. The force of ejecting the nose pulls these bundles apart absorbing energy. These Shock Cords are about as good as it gets. Could it be Nylon instead? Based on my limited Apr 16, 2022 · The Cherokee E is several feet long so we're talking around 8' of shock cord, not 4'. On smaller rockets I look to 3-5 times the length. I knead some up and put a good long blob of it around the shock chord as my anti zipper strategy. Dry fitted the fins to the rocket with the jigs, two for the mains and one for the tiny forward fins. Mar 12, 2024 · I've watched rockets with long kevlar or nylon shock cords- the nose cone comes off with some velocity but it plus the laundry slows down before hitting the end of the shock cord. I don't think shock cord length prevents zippers. Kevlar Shock Cord - 4500# - 20-feet long - 2 loops cord materials that should answer all your questions about which type of shock cord you could use in your rocket. Next up, the nose cone altimeter bay. :) Seriously, Kevlar is awesome. This is the good stuff! Kevlar Shock Cord $20 for 100 Feet. Glued the body coupler in place, then glued the two main body tubes together. ApogeeRockets. 5' of cord between nose cone and rocket body. 100 pound stuff. Protect them with sleeves of Kevlar®!Made of high temperature Kevlar®!Surrounds your shock cord with protection! Jan 1, 2013 · All of my rockets have their own full recovery system, harness and chute(s). $57. For any rocket over 50 pounds, I just use Onebadhawk kevlar cords. These are made from 1/2" Tubular Kevlarthat is rated at 5800 lbs. Since starting this program I've yet to loose a shock-cord to burn thru Kevlar. That said, I only use Kevlar with ModelRockets. It is yellow, but it has a soft silky feel to it that makes me think it may not be. On some of my bigger rockets (over 100 pounds), total shock cord lengths are 150 feet or more. Jan 18, 2009 · As many have mentioned here, our baffle kits attach the kevlar thread to the baffle itself. 00. Start with Kevlar Shock Cord, which is a durable, flame resistant fabric cord that is great for this purpose. This sheath of fire-resistant fabric gives it extra protection and prevents fatal cord damage that can occur, allowing the rocket to separate at deployment. I attach both the Kevlar and the shock cord to the ring with anchor bends. Extra-strong Kevlar shock cord for extreme high power rockets. If the cord is too long, the chute opens but the rocket continues to fall, increasing the shock when it reaches the end of the cord. Anyway below are a couple pictorial methods for setting up either Kevlar/elastic or Stainless/Kevlar/Elastic retro-fit shock-cords. These are made from 1/2" Tubular Kevlar that is rated at 7200 lbs. Feb 15, 2025 · If you want to protect from Zippers, you use the Quest model rocket method of Kevlar cord and shock cord. It is around . Oct 8, 2004 · I'm not sold on the kevlar anchors - first of all, kevlar itself is kinda expensive - and I've seen tube zippers using thread/string - I'm more confident with a 1/4" or so wide shock cord. Our Kevlar Braided Shock cords are the strongest, most compact, and highest quality in Low, Mid, and High-Powered Rocketry. Sep 9, 2019 · Shock cord material differs depending on the type of rocket being built. Jun 9, 2015 · I bought braided kevlar line (kite line) on Amazon. I can then attach the Kevlar to the baffle using a screw eye and that becomes my permeant attachment point for an Elastic shock cord. Jan 17, 2019 · A sturdier and more reliable method is to attach a Kevlar shock cord directly to the motor mount. com - There are many ways to make a shock cord mount. This material is, as you know Fire Resistant. R. For larger rockets, it's easier to hook up since none of the connections are in the middle of a shock cord. 2. Jun 5, 2010 · The Screamin' Mimi model that broke twice (once the kevlar broke, once the rubber cord broke) was built with the kevlar attached near the side wall so as not to be in direct line of the ejection, and it was just short enough that the rubber shock cord was about an inch recessed into the model to avoid zippering on the kevlar. With nylon and particularly Kevlar having less give, you need lots of length to make up for it. Rocket-Fibers, LLC 3050 Campus Apr 6, 2015 · I now put heat shrink on all my Kevlar shock chords, mainly to prevent abrasion to the Kevlar rather than anti-zipper. Depending on what size BT your using will determine the size of Kevlar to use. I have a roll of Kevlar Shock Cord. I had remembered from the old days to put in lots of extra elastic, and generally thicker than Estes includes in a Aug 6, 2019 · Use Kevlar for the whole shock cord and leave the elastic out. Bonded Kevlar cord is treated to resist fraying, and is a bit stiffer and High Power Rocketry Recovery Harness / Shock Cord with 2 sewn Loops. See pic. 9mm; 12 feet of 3/8" Nylon Webbing with ends sewn: 3/8″ Nylon webbing 12′ long with ends sewn. On my Sumo, G-Force, and hpr, I use good chute packing techniques and the chute and most of the cord go into a kevlar heat shield to make 1/2" Elastic Shock Cord - 12 foot PKG: 1/2″ Elastic Shock Cord – 12′ long; 6 foot kevlar cord: 6′ of Kevlar cord, 1. Whether you're a beginner or an experienced rocketeer, Zipper Shield™ offers peace of mind and extends the life of your model rockets by preventing rips of the tube from the shock cord. Aug 18, 2009 · I use it to attach the shock cord to the screw eye in the base of the nose cone, and to connect the shock cord to the shock cord leader (usually Kevlar). 88 / Count) Honmein 2-Pack Safety Goggles, Anti-Fog Lab Goggles, Over Glasses Safety Glasses for Chemistry Lab, Mowing, Woodworking, Painting, Construction, Industrial Use Honmein Direct Oct 5, 2011 · With this Stainless/Kevlar/elastic shock-cord set-up I haven't lost a shock-cord in more then 8years with some of the smaller models having as many and 30 flights so far. 3mm Kevlar(r) generally has an advertized strength of 1500 lbs among the various sites I have visited. I pack our Estes Maxi Alpha 3 as you describe. This is the good stuff! Mar 26, 2013 · I always use a length of 100# kevlar about twice the length of the rocket as the primary shock cord, usually with the OE cord tied to one end. You mount the Kevlar to the motor mount your favorite way. us Small 150lb Braided Kevlar Shock Cord - Small diameter . The tension at ejection will be spread out more. Ronz Rocketz Kevlar shock cord is incredibly strong for its weight and is heat resistant, so it makes a great shock cord in model rockets. If the rocket is going fast enough during deployment, zippers can happen. I suggest (but haven't bothered to use) a kevlar or nomex cord protector that's an inch or two short of the edge of the airframe. A 1/2" Onebadhawk kevlar cord can be used on rockets up to 150 pounds and folds neatly into a very, very small bundle. Kevlar shock cords are specifically attached to the engine mount, and a thread of elastic is tied to the end of the Kevlar cord and tied to the nosecone. Aug 9, 2022 · I'm currently building an Estes Yankee and I'm using an ejection baffle plus 150 pound Kevlar shock cord. We use this cord for our Iris compact parachutes bridle and anywhere we need the ultimate in strength. This conforms to Mil-Spec Kevlar standard PIA-C-87129D and material is sample tested at the manufacturer. If the rocket is BT55 or larger and I have enough length in the body tube I'm more than likely going to build a baffle for it. What I've started to use (for shock chords that are not wide/flat) is Kintsuglue flexible epoxy putty. To install either type: Feb 9, 2010 · I have done this before on small rockets. Feb 2, 2013 · The two disadvantages are that the shock cord is not replaceable (but unless your rocket is very very wide, almost all are not replaceable) (also, if you take good precautions (nomex sleeve and/or kevlar cord), the BP damage will simply not weaken the cord until long after something else fails), and that you have to remember to glue it in when Rocketarium - 10 ft Kevlar Shock Cord (250 lb Strength)When you order multiple lengths, one single long piece will be shipped. Thanka Nov 27, 2011 · I have some 3/8" tubular kevlar shock cord that I'd like to sew some loops to on the end. The spec breaking strength is 750 lbs. 5" and larger rockets - Our Best! 6,000 LBS Test! 1/4" Kevlar Shock Cord For 3" and 4" rockets 3,000 LBS Test! 1/8" Kevlar Tubular Shock Cord For 1. Nov 22, 2014 · Case in point: I never had any problems until recently when moved from a C11 to a D12 in one of my models. This will do three things: It will make packing the packing the parachute much cleaner and reduce the chances of fouling. I like to loop my shock cords back on themselves and tape every 3- 5 loops together. Suitable for small to medium sized model rockets. Pulling the tape apart will absorb a considerable amount of the shock forces. Dec 15, 2020 · Finally, I attach the lower shock cord tether to the screw eye in the baffle. May 28, 2015 · The Albright Knot is often used to join thicker leader material to fishing line, which is a good application for joining a thick shock cord to thinner Kevlar cord. This article will show you how. I found this Rockets, engines/motors, electronics, build and launch supplies. 3 flights in with no shock cord damage until I went with the larger motor; my 120lb kevlar cord fried clean through right where it was anchored to the engine mount. Other end of OE cord tied in a loop for recovery attachment. S. Dec 24, 2024 · Hello all I'm building the Apogee zepher for my L1. Jun 8, 2012 · Based on a suggestion in a TRF post a while back, I've started attaching the rocket body to the nose cone with a shock cord then connecting the parachute to the nose cone with a separate short shock cord. Most smaller rockets I use a 2-3' piece of elasticMid power I still use elastic 2-3 times the BT length. Supplies. Jul 24, 2013 · Always felt it was the rocket body that determined the shock cord needed, as the weight is so much greater, thus more kinetic energy to dissipate. 00 / Colors may vary Jan 15, 2014 · There is no second shock cord. Cut to 25 feet long, and both ends sewn with loops for easy attachment. 10 ft Kevlar Shock Cord (250 lb Strength) When you order multiple lengths, one single long piece This is an exceptionally high-quality Kevlar shock cord custom-made for Fruity Chutes. However, usually the thicker line forms the single loop (gold cord in example picture) and the wraps are made by the thinner cord (blue cord in the picture). Shop strong and durable Kevlar Cord, braided from 100% U. Kevlar shock cord is incredibly strong for its weight and is heat resistant, so it makes a great shock cord in model rockets. 1 inch diameter. Once the rocket is completed and ready for flight, I'll run 20 ft. 030in 1500lb test, flame resistant, braided kevlar shock cord. You can used this method on any sized rocket. This method eliminates any shock cord mount on the inside surface of the body tube. Model rocketry is recommended for ages 10 and up with adult supervision for those under 12. use tublar kevlar and weave the ends into each other then use kevlar thread to hold it in place - think finger trap. 00, 20% Off Discount: $137. Since only fly rockets up to "D" motors (for now) these rockets are all fairly small and light Sep 23, 2020 · Amassing parts so that I can clone an Astron Sprint. Usually caused by Far To Short a shock-cord. Earl-Stanley H. Braided Kevlar cord is perfect for any Vander-Burn plywood upgrade kit, or for replacing your old shock cords in heavier model rockets. Mar 10, 2024 · I had a little zippering, which damaged the kevlar shock cord. the knots with. For the small, minimum diameter rockets, I just use the trifold mount. Made of 100% Dupont Kevlar Fiber, braided, 550 pound high strength, high toughness, excellent abrasion resistance, with high thermal stability. This Kevlar thread has a 1. I will have to try this. Apogee Rockets : Shock Cord - Model Rocket Kits Rocket Motors Launch Accessories Rocket Software Rocket Books & Videos Building Supplies Electronics & Payloads Wearables Gift Certificate Rocket Novelties and Gifts Garage Sale Ejection Systems Display Stands Customization ARC Supplies Advertising Rocket Building Supplies, T. tensile strength, while mid power rockets will do better with 250 to 750 lb tensile strength. That's it for now. ¼ Scale Limited Edition Miss Riley Rocket Kit; Showtime Rocket Kit; CSXT Space Shot 2004 Rocket Kit; Jolly Logic. These harnesses are perfect for 4" Rockets. I recommend Kevlar® (www. The main reason to go longer with shock cords is for shock absorption. 12 feet is a good length to order for a Vander-Burn upgrade kit. Mar 6, 2007 · Model Rocketry Logbook: Detailed Log Book for All Levels of the Rocketry Hobby | Model Rocketry Level 1, Level 2, and Level 3 Amazon. A fix recommended at the launch was to cut the line below the damaged section. 25″ Tubular Nylon Shock Cords; Streamers; Shock Cord Protectors; Recovery Harnesses; Rail Guides; Hardware; Charge Wells; Bulkhead Wire Retainers; Rocket Kits. OnebadhawkThese are made from 3/8" Tubular Kevlar. 120in 2,000lb test, flame resistan,t kevlar shock cord. Hope these suggestions and comments help. made Kevlar in a variety of breaking strengths, colors, and lengths. Applications in Model Rocketry. 0lbs Rocket Weight …$137. Any knot will weaken the material, Kevlar is much more subject to this. Our 1/8" cord is perfect for mid power rocket air-frames. We've all tied shock cords on this way. For a foot-long model rocket like the Crossfire, use a 3 foot section of Kevlar shock cord. Though the 3 Mar 4, 2008 · 1) Shock cord should be 4 or 5 lengths of the rocket (minimum) 2) I use 9/16" Tubular Nylon for 3" and larger rockets 3) I use 11mm braided Kevlar for rockets less than 3" 4) I use 3mm braided Kevlar for Mid-powered rockets 5) When in doubt, use the next size up. In our baffles, we have a small notch in the outer parimeter of the rings. Bonded Kevlar cord is treated to resist fraying, and is a bit stiffer and more slippery than other string, which makes it easier to work with and helps deploy your recovery device nicely. How long should a Kevlar shock cord be? As a rule of thumb, the shock cord should be 2-3 times as long Braided Kevlar Shock Cord; 5/8″ and 1. I have 1500 lb. I hold both cords side by side and tie a Our 3/16" ( 2-32oz rockets) tubular nylon is an excellent choice (375# tensile strength) to replace either elastic or kevlar and has loops sewn into the ends. This works well for much larger Jun 30, 2022 · Retired and back i the hobby, doing mainly mid power scratch build. This chord is working well and doing the job as intended. Feb 9, 2016 · * If using a combination Kevlar/Elastic shock line I've found 30" of 70-100lb Kevlar with 30" of 1/8" Oval elastic makes a great shock-cord that eliminates the dreaded "Estes Dent" Where the NC recoils back into the bodytube at ejection. The cord is mounted permanently around the motor mount, so repair is kind of difficult. What id like too know is what knot should I use. On the right is some 100 pound kevlar line that I had in my parts bin. This is incredibly strong material. braided Kevlar from the loop on the lower shock cord tether, to the loop on the upper shock cord tether. Jan 21, 2021 · On a RTF rocket with a pre-installed shock cord like the Spirit, I would just leave it and use it as it. 20. Nov 13, 2021 · The bowline is extremely efficient and can can be untied without damaging the cord. The issue doing post assembly is getting the kevlar through the two holes. That particular flight was an absolute wipe-out, but anything short of a tail-slide deployment, and forces can go off-scale in less than a heartbeat. Offered in several conveniently sized spools. However, I must have two left thumbs because half the time with LPR, the Kevlar turns into a rat's nest. 7 – 3. Bonded Kevlar cord is treated to resist fraying, and is a bit stiffer and more slippery than other string, which makes it easier May 3, 2011 · How I go about it all depends on the rockets diameter and length. asp) because it is fireproof, super strong, and fairly inexpensive. e. Any thoughts appreciate. There is no knotted elastic where the Kevlar makes contact. 9mm; 15 foot kevlar cord: 15′ of Kevlar cord, 1. I have several that were built prior to discovering this forum and kevlar mounts. It will easily out-live nylon or elastic shock cords. This shock cord is supposed to be 1/2 inch tubular Kevlar. 1: What size/thickness/strength is Here is a selection of shock cords and harnesses for your parachute / recovery system You can t go too wrong here with whatever you choose to use although we quite like a long piece of Kevlar cord or tubular nylon with sewn loops You ll need to setup a good secure system to attach this to your rocket Smaller Kevlar Shock Cord - 4500# - 20-feet long - 2 loops: 29572--240" (609. Aluminum Bulkplates; Kevlar 12-Strand 1/8 Shock Cord. 1" and 2. Pull the nose cone and body tube sections apart and the parachute should come out of the nose cone. Most popular shock cord where a wide cord is needed, to prevent zippering, the wide nylon works perfect for 6” and larger diameter rockets. May 14, 2018 · For example, you may have noticed that Micro Maxx rockets all use a Kevlar thread for the shock cord. test round Kevlar cord which will run from top centering ring …. The sewn loop on 3/8" Kevlar did fail, but the bowline on 1700lb cord held while the Kevlar broke. ModelRockets. High power rockets do best with 1500 lb tensile strength. I agree with bobkretch, and I am sure multitudes of others - I just replace stock shock cords in kits with elastic from JoAnn's fabrics. I just use the Estes shock cord. Jul 31, 2008 · But for large model rockets and mid-power rockets with airframes between 1. I'm planning to put epoxy on the know too for extra safety. What type of glue is recommended to put on the knot between the kevlar and elastic shock cord, white yellow, CA or epoxy? Forums. I used this cord as part of a rocket shock cord assembly on several rockets. 65 9KM DWLIFE Black Kevlar Cord, High Tensile Strength, Flame Resistant, Braided Fishing Line, Wind Chime String, Kite Line, Camping, Model Rocket, Outdoor Apr 5, 2013 · Once saw a shock cord made of 2" nylon webbing (seat belt material) put a 6 foot long zipper in an airframe made of 1/4" wall extruded 6061 aluminum tubing. Not forgot, but deliberately, so I could have a shock cord that could be replaced. Price is by the foot. These harnesses are perfect for 4" Rockets. 3/4-inch wide width to prevent zippers on cardboard tube, and test strength of 4,500 lbs. The Thread use Kevlar is very heat-resistant, which makes it an excellent candidate for model rocket shock cord material. Made by Rocketry Warehouse, they are 100% Kevlar! The loops are sewn at both ends with High Performance Kevlar thread then further protected and strengthened with a high heat protective shielding. Comes with 2 1/2 foot section of Kevlar 12-Strand 1/8 Shock Cord and 5 foot section of 1/8" 550lb test Nylon Cord. Not only are they stronger than steel, strength vs weight, but they’re designed at a fair price, we have Kevlar Shock Cords rated for 950, 1200, 2,800, 5,300 and 8,600lbs! We recommend 15+ feet of cord for up to 4” diameter rockets, and 20+ feet for larger rockets. Braided Kevlar Shock Cord; 5/8″ and 1. By the time I'm done I have a taped bundle of shock cord. Jun 23, 2016 · Here's how Quest shows to tie the Kevlar to an elastic shock cord. I have built a lot of rockets and I always feel uneasy about the shock cord length and size, so let's start a discussion and agree on a standard. 75" Round elastic shock cord good for mid-power size rockets that use E, F, or G size Jun 30, 2022 · I am designing and scratch building a Level 1 cert. Mar 20, 2011 · emma kites 100% Black Kevlar Braided Cord 100Ft 50Lb High Strength, Abrasion Flame Resistant, Tough Survival Tactical Cord Model Rocket Paracord Snare Line Fishing Assist Cord EMMAKITES $26. Tim at Apogee Rockets has a video on how to do this with a small (18mm) rocket cord. For LPR and MPR rocketry i would still use the elastic rubber shock cord, the reason why i prefer the rubber shock cords over Kevlar, is they are easier to get for cheaper prices, also anyone can make/buy rubber bands and cut them. Mar 23, 2024. With the added benefit of the bigger the spool the bigg What you want to do is bundle your kevlar cord into several sections of coils and then secure them with masking tape. Users liked: Kevlar cord is durable and heat resistant (backed by 2 comments) Kevlar cord is strong and abrasion resistant (backed by 3 comments) Kevlar cord has minimal stretch (backed by 2 comments) May 29, 2017 · Estes Rockets 0651 Der Red Max Rocket Kit, shock cord- kevlar plus rubber? bjphoenix; Mar 11, 2024; Techniques; 2. Jun 22, 2007 · Plain old sewing elastic works great for shock cords in small-medium model rockets. 00 / Colors may vary Full Package Typically: $172. On the left. Cut to 20 feet long, and both ends sewn with loops for easy attachment. The tensile strength for this shock cord is 250 lbs, sufficient for just about any low power model rocket. Nov 18, 2024 · 9KM DWLIFE Kevlar Line, High Strength, Abrasion Resistance, Flame Retardant, Fishing Assist Cord, Kite String, Model Rocket Shock, Hammock Tarp Ridgeline, Tactical Survival 9KM DWLIFE $7. Price is per Yard. The 1/2" is Rated Dec 30, 2002 · The first time I've used kevlar was just for the length of the rocket body then I attached tubular nylon. Bonded Kevlar cord is treated to resist fraying, and is a bit stiffer and Mar 29, 2012 · Put the shock cord into the nose cone first followed by the parachute. This webbing is Rocketarium Model Rocket Kits, parts and launch supplies : Shock Cords, Straps - 1 meter of Braided Kevlar Shock Cord 1500 lb strength. 1/4" Tubular Kevlar 25': 1900lb test 1/4″ tubular Kevlar 25′ with end sewn loops. Thank You Preserves the integrity of your rocket from rips due to deployments at wrong times; Fits the most common sizes of Kevlar shock cords: 100# and 300#. In my career have had two memorable rockets come apart under a significant load - one on early deployment and the other was a coupler fold. Share Share on Facebook Tweet Tweet on Twitter Pin it Pin on Pinterest Customer Reviews The first 5ft is covered in Kevlar/Nomex material with pure Kevlar thread. It's flat nylon shock cord 1/2in wide. Spot tacked, let dry, then removed the jigs and filleted the fins. 99 Bushcraft Gear Hand Auger Drill,Survival Tools with Folding Saw Making Wooden Rocket Stoves, 1”Dia Drill Peg and Scotch Eye Maker Settlers Wrench for Rocketarium Model Rocket Kits, parts and launch supplies : Shock Cords, Straps - Kevlar Braided Shock Cord 1mm (140 lbs) $21. For bigger rockets, the shock absorbency ( or lack thereof) of Kevlar comes into play. A. I researched the Emma Kites 100 Kevlar Braided String Utility Cord 100Ft 100Lb and I thought you might find the following analysis helpful. The heatshrink keeps the Kevlar from zippering. Since the shock cord is probably mounted to one side, exactly how far up it meets the body tube will depend on whether it's running straight up the side or across the tube. Nylon is tougher? Which type of shock cord is more commonly used? Apr 17, 2003 · On smaller rockets, I run Kevlar cord/thread just outside the bodytube, then tie it to the shockcord and cover it with heatshrink. It is of course much easier to do before putting the motor mount in. Braided Kevlar is widely used in model rocketry for several reasons: Shock Cord Replacement: It serves as a replacement for traditional rubber shock cords, providing a more durable and heat-resistant option. Rocketarium - 1 meter of Braided Kevlar Shock Cord (1500 lb Strength with a hollow core)When you order multiple lengths, one single long piece will be shipped. Braided Kevlar shock cord is incredibly strong for its weight and is heat resistant, so it makes a great shock cord in model rockets. Feb 25, 2022 · A shock cord protect isn't needed, assuming your Kevlar loop is about 2-4" below the top of the rocket body tube (it'll all be on top of the wadding / recovery blanket) Click to expand On the rocket end, I have the original LOC arrangement of the kevlar loop epoxied to the inside body tube. I'm willing to go to 75 pound Kevlar line, but only if it's replaceable after installation. I have some 150 pound single end strength kevlar and wanted to try using it instead of the rubber elastic cords. For years I've tied the elastic on like this. A "general rule of thumb" stating 3-5 x the total rocket length is followed by many of you because "it Mar 4, 2017 · Some have said that 1/8'' is okay then others say no less than 1/4'' kevlar on a rocket that size. Just trash the rubber band shock cord, make an elastic replacement that is 2 or 3 times the length of your rocket. I hit the sewing department at Wal-Mart every time we go there. It has 3 inch tube, 29 mm motor mount, and all in is about 42 inches long. . Our 3/8" tubular nylon (1-7 pound rockets) comes in with a 1020# tensile strength and has loops sewn in for easy attachment or replacement. I do have access to a sewing machine (my Mom's) but I have no clue on what thread type to use or what type of stitching pattern is strongest, etc. This Braided Kevlar cord is perfect for any Vander-Burn plywood upgrade kit, or for replacing your old shock cords in heavier model rockets. Some of the rockets have come with a kevlar shock cord and I was thinking that this would not be a bad way to do all of our rockets so I have some questions. Virtually unbreakable Totally fireproof. and High Powered Rocketry. I was concerned that the tight knot might weaken the tightly cinched elastic. I could just tie a bowline or something, but it looks ugly, and I want to keep things all pretty. These are made from 3/8" Tubular Kevlar. 88 ($9. The reason for this is to get some of th e-Commerce by Rocket Power About Cookies We and our partners process information about you, your devices and your online behaviour using technologies such as cookies to provide, analyse and improve our services; to personalise content or advertising on this or other sites; and to provide social media features. May 7, 2018 · Attach the shock cord to the top of the kevlar loop, when its time to replace the kevlar loop, cut it and use it as a leader to pull through a new kevlar loop in place, easy to stitch kevlar. Suitable for larger sized mid-power and high power model rockets. It is MIL C 87129A Type 6 Kevlar Braid. I went overkill here because I can't replace the Kevlar shock cord in this rocket. Rockets, engines/motors, electronics, build and launch supplies. May 29, 2023 · Back before the dawn of time (well, the early to mid 1960s) Estes used Sig contest rubber, which was intended for model airplane use, as the shock cord material. On long all-kevlar shock cords in competition models I have made loops by wrapping around, say, three fingers, then taping the middle together with 1/4 inch masking tape, then stuffing the resulting bundle in the modelbut sometimes the tape doesn't let go. These payload harnesses are perfect for 6" and 8" Rockets. 2mm diameter. IMO you can't have a SC that's to long, as for zippering you can "try" to prevent it but if you have a rocket coming in ballistic and then pop the main? it WILL zipper no matter what the BT is made of, that is if the SC doesn't break 1st. The other end of the kevlar runs down the inside of the body tube and out the bottom. Kevlar Tether 1/2 Inch. 1/2" Kevlar Cord For 5. These recovery harnesses are unbelievably strong and resilient. Second method is to braid the shock cord. I attach a piece of kevlar inside the rocket and let it stick out at least 6" with a loop in it, then I connect my 10' to that, so I have more like 10. Estes-style shock cord mounts have been known to interfere with parachute deployment. 100ft Rubber Shock Cord 1/4" wide. Dec 14, 2013 · I have been looking for some lightweight yet strong shock cord material for a two-stage rocket I am planning. Rated for 4,400lb tensile Aug 2, 2009 · After an exhaustive search on line, including this forum, I am unable to find any formulas for calculating shock cord sizes, lengths, etc. AltimeterOne; AltimeterTwo "We use Kevlar thread to sew the button holes on our Nomex chute protectors" or something like that. Adhesive on the knot weakens it even more, again Kevlar is real bad about this. You then attach a fabric elastic cord to the Kevlar cord outside of the body tube. Both of the cords Shock Cord Protector Sleeves of Kevlar®WARNING: Nylon shock cords repeatedly exposed to hot ejection blasts will degrade and eventually fail. com/shock_cord. May 8, 2012 · I know the most common would be nylon or Kevlar, but there seems to be "no give" and literally causes "shock / stress to the rocket" but with an elastic type cord I think personally it would work better or perhaps have a portion of the recovery harness with elastic and then either nylon or Kevlar. Easy enough to test - Pack the shock cord in first, then the chute. What I have found are opinions about cord lengths. I also have some Sig rubber from the early 1970s at the latest, and it’s fine. Elastic doesn't ball up on me like Kevlar. Flat kevlar and bungee cord is only needed for larger medium to high powered rockets. Its superior properties make it an essential component for hobbyists, educators, and aerospace engineers alike. Size the Kevlar appropriately. Jun 30, 2018 · Used a loop instead of a knot on the Kevlar shock cord. 18 feet of 5/8" Tubular Jul 2, 2012 · If you do use a thin shock cord, especially kevlar, you can also reduce the risk of zippering by wrapping some masking tape around where it meets the edge of the body tube. 00 for shipping (no matter how many pieces you want) Oct 16, 2002 · Well, I've had several stock shock cords break on mine and my nephews low power rockets so far. They happen to be the ones that Nov 23, 2018 · I'm going for my Level 1 Cert in a few weeks, but I'm undecided on a shock cord. At ejection the shock cord (on top of the parachute) helps pull out the parachute. Stays flexible but strong. 75" I used this cord as part of a rocket shock cord assembly on several rockets. Adjust them as necessary to make the rocket hang level then set the knot at the swivel with some white glue. Aug 11, 2022 · What I have been doing and works very well is either make three bundles of the Kevlar shock cord and tape them. I have used both methods above (one LOOOOONG kevlar cord and a kevlar "tether" ending just past the BT and attaching an elastic cord from that point to the NC). 4. The NC is tied about 1/3 the way down the OE cord. -- 03/11/2020 Aug 2, 2022 · For dual deployment, the drogue cord should be even longer. It seems to be merely “twisted” not “braided”. What you'll see in this video are three ways. I am selling 100 foot lengths of it for $20 plus $5. Oct 13, 2003 · I found a way to mount shock cords in Estes type rockets that have been flown and need a new cord. That said, when I attempt dual deploy via cable-cutter, I will be going with a shorter shock cord as recommended due to the ejection charge wire needing to be half again as long as the shock cord. 27 / Foot) Feb 27, 2024 · For my schools rocketry program I have been assigned to the recovery team and we decided on using a combination of braided kevlar and nylon shock cord together to minimize stress on the shock cords, is this even a good idea or should I only do nylon or kevlar? If I end up doing both, what are Apr 13, 2015 · By separating out the attach point, you can ensure you get a very secure mounting in your rocket that will not fail, you know it is centered and has a built in swivel and then you can easily attach any shock cord you want in the future by quick-linking it to the swivel (for small rockets, you can even use a small zip-tie to secure the shock Tubular Kevlar is the shock cord of choice when you want maximum strength for the least amount of weight (~4gr/meter). High Power Rocketry Recovery Payload Harness / Shock Cord with 2 sewn Loops. As they keep your high power model rocket’s shock cord against the heat of the parachute deployment charge. How long should a shock cord be for a high power rocket? 3''? 4''? rocket assembly your single shock cord (2-3x the rocket length) is tied to the other end of the swivel to complete the harness. Kevlar seems to be a bit less expensive, supposedly stronger in some cases, and definitely more flame resistant. 5" to 3" rockets 800 LBS Test! 1/16" Kevlar Shock Cord For Estes rockets 225 Tailored for Rocketry: Whether securing payloads, attaching parachutes, or ensuring the safe recovery of your rockets, our Kevlar Shock Cord is the ideal choice for high-power rocketry applications. For other kits, I run kevlar on mostly just the larger ones (i. Wildman Rocketry is your best source for rocketry supplies, rocket motors, and rocket kits for Tripoli, NAR, Team America (TARC), IREC, and NASA SLI along with hobby flying. I have one model I built back then whose shock cord is still good (it’s over 50 years old now). These payload harnesses are perfect for 6" and 8" Rockets. 6" in diameter (roughly, ST-11/BT-52 to BT-80), bungee cord material ranging in diameter from 1/8" to 3/16" (depending on the rocket's recovery weight) might be a better alternative to wide sewing elastic for use as a shock cord material. us Large 2,000lb Braided Kevlar Shock Cord - Large diameter . Rocketry Techniques & Types. Slowly designing and building a level one rocket to try out this spring. Thanks in Extra-strong Kevlar shock cord for extreme high power rockets. The quick links are for separating sections of the rocket and for part replacement as needed. 48" Rubber Shock Nov 16, 2003 · I did do a search on this but none of the threads answered my question. Jul 9, 2022 · Use enough Kevlar that the rocket reaches the ground before the chute deploys. For high-power rockets I second the PML knot above, but I tape the free end to the standing part with electrical or blue tape to keep the knot from loosening. The shielding protects the loop/thread plus also prevents fraying of the ends. Some good hints on the blog: Glue on a diagonal to keep the trifold mount flatter, curve it around something round while the glue sets up, etc. Feb 5, 2025 · 9KM DWLIFE Kevlar Line, High Strength, Abrasion Resistance, Flame Retardant, Fishing Assist Cord, Kite String, Model Rocket Shock, Hammock Tarp Ridgeline, Tactical Survival 9KM DWLIFE $21. 1 meter of Braided Kevlar Shock Cord 1500 lb strength [45103]. Jul 8, 2014 · The result was a broken shock cord and ballistic return as there was no unfurling of the chain and in essence my recovery cord was only 12"s long from the cord knot and the bulkhead. Depends on the how much a beating the other materials can take, balsa and cardboard I err towards 5x. Dec 17, 2015 · For Micro, Standard and MPR models this usually means about 12"of Stainless Shock-cord anchor , 30" to 72" of 70 to 130lb Braided (tubular) Kevlar, and another 30" to 48" of 1/8" Oval, or up to 72" of 1/4" flat elastic in Standard and MPR rockets. When used in a shock cord, Kevlar is typically used to anchor the shock cord inside of the rocket and then elastic is used as the actual shock connecting to the nose cone. The button holes on chute protectors are for threading your shock cord through so when you eject your parachute, you don't loose your chute protector. This is incredibly strong material. 9mm; 12 foot Kevlar cord: 12′ of Kevlar cord, 1. Connect your main chute directly to the hard point in the nose cone. Aug 2, 2009 · For the larger rockets in this size and weight range, I have been using a three-part shock cord: Kevlar or steel leader for the first part, a short (1'-2') of flat elastic, and then a long section of polyester-blend paracord (a k a shade cord or Venetian blind cord). $1. AltimeterOne; AltimeterTwo It depends, on my level 3 rocket both of them are 25ft long tubular kevlar on a 10ft rocket, but it's also all fiberglass and u-bolts so it can take a beating. It won't be bothered by hot ejection gases. Replies 48 Views 3K. I've launched LPR with stock rubber shock cords where the nose cone went to the end of the cord, stretched it out, then snapped back and damaged itself and/or the High Power Rocketry Recovery Harness / Shock Cord with 2 sewn Loops. When the anchor cord is tied to both the piston, and the anchoring point, the piston should be hanging about halfway out of the tube. Aerotech's elastic shock cord is a strong, springy shock cord suitable for mid power rockets. I thought that the braided stuff would not unravel as easily. Kevlar Shock Cord - 4500# - 20-feet long - 2 loops: 29572--240" (609. You really need a plenum to thread it through. This combo give the best combination of flame proofing at the base and elasticity at the nose cone end. Feb 3, 2009 · This works opposite on shock cord for main deploy on dual deploy systems. It stays attached to your shock cord which runs through it. Kevlar on end protects the nylon cord where it’s needed most, near the motor or ejection charges. of 350 lb. Nov 28, 2024 · I have a length of shock cord that came with a kit and I am not sure if its Kevlar or Nylon. Would like to use kevlar for the shock cord (at least up to the top of the body tube but not above to minimize the 'zipper risk', but I've been racking my brains without success to arrive at a solution that will allow me to install the shock cord in a way that it would be replaceable. A steel shock cord will destroy your a/f. Bulkplates. 99 ($0. Low power rockets can use 100 lb. 25. Mine is the Lariat loop around the aft of the motor tube. C, D and up rockets). 2 – 900lb 15ft Braided Kevlar Shock cord with 3 Loops 3ft Standard Parachute Package, Recommended for 1. Rocketry Warehouse; Components. Another problem is that they melt at 150 C which is lower than Nylon or Kevlar so the lifetime might be short. C. This material is, as you know Fire Resistant. Then knot the line and add a replacement line above that knot. As an added bonus, it is long-lasting. I do the latter with the help of a split ring, or with a welded ring in larger rockets. attempt rocket. 6cm) 0. com $9. The booster was recovered with the daisy chain intact and the other end an ematch still caught in the cinced down loop and the cord broke where it would have been Aug 1, 2019 · For low-power rockets I usually use a figure eight on a bight to put a loop on the end of the cord and then a lark's head or cow hitch to attach the cord to the nose cone. and here is the question: how long should Kevlar shock cord be Jul 5, 2006 · I agree with all the notes above regarding replacing shock cord with a 100-150lb kevlar tether. 3/8 inch diameter, and available in 2 different sizes: 6 feet or 8 feet in length. com -Some model rocket kits have both a Kevlar shock cord, and an elastic (or rubber) cord. This is particularly useful for heavier rockets or those that experience high stress during flight. Now you can hold the rocket in the air by the shock cord and see if your suspension lines are all even. When you assemble them, you tie a knot in the kevlar cord (included with the baffle) and thread it through both of these notches. Apr 15, 2009 · A problem with these fibers is that they have little stretch, which is also a problem with Kevlar,so they really don't absorb shock very well. ieenrttnavdnwjltvlzasifvllokyrbmzzulexpqdhyofgckneyqebxasefviohjmehmlfpetpoylj