Apogee shock cord The shock load from the drogue is far smaller than that from the main deployment. Mar 23, 2020 · If you use a large charge that causes the upper section to slam to the end of the apogee shock cord, the pin(s) have to hold against the inertia of the nose cone and recovery gear hitting the nose cone. . Jun 11, 2012 · The worse part, other then a part fouling the main, is the fin can continuing to fall past the main chute, payload section, and hitting the end of the apogee shock cord very hard. The Mako model rocket is a sleek 42-inch tall kit inspired by the ocean's fastest predator. This setup allows the Kevlar to handle the initial force of deployment while the elastic cord provides additional cushioning. Aug 9, 2022 · You have to wrap the shock cord at the lip of the BT to prevent zippering but I've only seen 75-100lb KEVLAR fail after a CATO. Tape the streamer to the shock cord, near the nose cone. Tim at Apogee Rockets has a video on how to do this with a small (18mm) rocket cord. com/shock_cord. 54 J-B Weld 8277 WaterWeld Epoxy Putty Stick - 2 oz. Alpine Butterfly knot -- to connect parachute to shock cord. The purpose of the shock cord is to keep the rocket coming down in one piece, so you don't have to retrieve multiple parts. most of the products i order from apogee is because of quality and the quick delivery. This special anchor system is designed for Apogee's PNC-74A nose cone and provides a simple, lightweight attachment point. A. Gluing the shock cord as shown will result in a flatter mount (Fig-ure 6). e. The main shock cord between the NC and the air frame is the black object in the foreground. Makes it much easier to pack, less likely to tangle. 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. You do need a good strong swivel if you are going to do that. Reply Nov 28, 2010 · I'd suggest tying an overhand loop knot in the shock cord, one third the way down from the screw eye. com -"When flying dual-deployment rockets, how long do you make the shock cords? And which one (long or short) is put in the back of the kevlar shock cord was the exact size i was looking for and received it shortly after i ordered it . Tie one end of the Kevlar® shock cord to the loop on the base of the nose cone. Continued on page 4 Figure 4: The engine mount of the rear ejection rocket. That will then require a larger main charge to shear them. Dec 7, 2013 · Inside the bag is the main and most/all the shock cord with a small section of the cord threaded through button holes at the opening of the bag. Wind the shock cord around the front end, and it will slide off easily at motor ejection. ) Fits the most common sizes of Kevlar shock cords: 100# and 300#. The fin can spins like crazy on the way down, but always stays well below the upper section and the shock cord is never twisted up. There is also a quick link that allows you to detach the elastic shock cord and unwind the shock cords after the rocket lands. Figure 7: The burrito style parachute roll. In the real world the shock cord and parachute deploy at some angle other than straight out. 11. The tri-fold can block a smooth ejection of your parachute or streamer. Cut to 20 feet long, and both ends sewn with loops for easy attachment. He learned this from the TAPS when building for L3 cert. This loop is much stronger than tying a knot on the ends of the cord where it attaches to the rocket. Instructions suggested using a teabag and I had good luck with that except for flight #1 where I didn't have good teabag adhesion to the airframe I've flown that rocket about 10 times since and May 27, 2023 · The largest loads are usually when the two halves hit the end of the shock cord at apogee when the charge goes off. Oct 31, 2020 · IT will have a lower airframe housing a drogue chute, an upper airframe housing the main chute, with an AV-bay in-between. Years ago Estes recommended glu-ing the shock cord at an angle down the cardstock mount. Elastic is a blight on the oily forehead of rocketry! Edit: Forgot to add HPR choice. Mar 26, 2013 · The Apogee Aspire kit is a minimum diameter kit that includes a kevlar shock cord (so no motor mount to tie things to if you leave out the thrust ring). Tri-Fold shock cord mount is bulky, es-pecially in BT-5, 20 or 50 sized tubes. Let's change the terminal speed on the drogue, and plot the two deployment shock loads. Supplies. Slim Beauty -- connects two lines to each other, specifically, knotting kevlar cord to an elastic cord 3. im a very impatient person lol May 27, 2018 · Apogee Payload Altitude Rocket Build, Part 6, Shock Cord and Parachute The Kevlar shock cord is glued into a tri-fold mount. But I can not seem to find them for rockets using dual deployment. View attachment 277680 Here you can see the drogue deployed shortly after apogee. The shock cord is available in lengths of 20, 25, and 30 feet. Apogee Components is dedicated to helping you achieve your model rocketry goals and taking you as far as you want to 10. Shock Cord Parachute 2nd Centering Ring Mar 26, 2024 · Another potential factor is using too short of a shock cord for the drogue. Has 45lb test strength Feb 17, 2025 · Explore the essentials of model rocket deployment shock cords with this in-depth guide, focusing on Apogee Rockets' options, their importance, Oct 15, 2011 · In the past I simply tied the end of the shock cord to the nose cone base, too. Aug 2, 2009 · That shock load can be calculated BTW. On single deploy rockets 15-20'. The unique feature of this shock cord is that the ends are doubled over and sewn together to form a loop with Kevlar thread. Selection of shock cord length and width is the same as for single-event recovery. , 03/17/2023 Product exactly as described and reasonably priced Aug 2, 2009 · The main chute had a short shock cord that attached to the eye-bolt and the D-bag had a short cord attached to the top of the main chute so everything came down together. Round elastic shock cord good for mid-power The shock cord is available in lengths of 20, 25, and 30 feet. The drogue opening, if it pops open before the two halves hit the ends of the cord, will usually reduce the shock some because the opening and drag reduces the speed the two pieces are moving apart. Aug 4, 2019 · Since you wrote that you are starting your first LPR scratch-build, I am going to guess you won't be using tubular nylon for a shock cord. A good rule-of-thumb for shock cord length is three times the length of the rocket. These are serviceable, but not very durable. I have used it to replace rubber shock cord on any new models as well as my older models where the rubber has hardened and broken. Oct 20, 2020 · The kit is supposed to come with two tubular nylon shock cords (a 10' and a 15'). Model Rockets & How-To Rocketry Information Sep 15, 2012 · Where I fly I generally use a shorter shock cord. Two antidotes: Buddy in our local club Braids the 1" wide nylon cord on his 43 pound L3 rocket. I am aware that you want the parachute for the apogee event and main event located not in the middle of the shock cords because the parts of the rocket might collide during descent. A third loop in the middle is for parachute attachment. Figure 8: The tie wrap sinched down against the para-chute and the shock cord. This will allow excess material to tie the knots with. 75 Zing-It. The remainder of the guy line is 1. 99 Aug 11, 2022 · Second method is to braid the shock cord. If you added nose weight and the NC is heavy, I would attach the drogue to the NC anchor with a 2-3x length of shock cord and it should have its own blanket. Then the shock when the payload section reaches the end of the cord can break the shear pins. 3/4-inch wide width to prevent zippers on cardboard tube, and test strength of 4,500 lbs. Finally the streamer is attached to the shock cord, and the shock cord is the attached to the nose cone, as well as the body. In my experience, these forces are much higher than main chute deployment forces under normal circumstances. May 31, 2018 · As long as you NC isn't heavier than your airframe, you can go drouge-less. Photo 1: Kevlar shock cord. Ejection charges controlled by electronics are used to split the rocket into the appropriate sections to deploy the drogue recovery system at apogee and the main recovery system Apr 20, 2005 · If you still have room in your payload bay - you do not have enough shock cord. asp) because it is fireproof, super strong, and fairly inexpensive. Choosing the latter requires finding a way to attach a shock cord inside the nose cone, as modifying the nose cone for parachute storage involves removing the standard shock cord attachment point on the shoulder. Apr 10, 2022 · The is a great shock cord very strong a great cord for any mid power and some high power rockets. Figure 5: Wrap the streamer or parachute neatly around the tube so that it will unfurl slowly at ejection. 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. The build is pretty straight forward and the video walks you through it well. Also I saw that 550 paracord could resist 550 lbs and that there’s type of paracord but if the rockets not that big it should be strong enough to hold everything together. Fluorescent orange color helps increase the visibility of your rocket to make it easier to find if it drapes over a bush or tree. We truly believe that, because Apogee Components has been in business and helping rocketeers achieve success for more than 25 years (since 1987). I recommend Kevlar® (www. Finally, there is an eyebolt for base of the payload bay. May 9, 2015 · 1. 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. com Manufactured by: Apogee; Additional Info: 100 lb test strength braided cord. ApogeeRockets. , Off White Amazon. Spread wood glue over one side of the paper and position the free end shock cord behind the parachute, and wrap the wire tie around both the parachute and the shock cord. Model Rocket Building I think the Estes Designer kit comes with rubber-band shock cords. Manufactured by: Apogee; Additional Info: Round elastic shock cord good for mid-power size rockets that use E, F, or G size rocket engines. assuming: V_drogue deployment = 60 m/s Feb 3, 2024 · Tubular nylon is a cheaper alternative to Kevlar® for shock cords. For this steerable parachute system, a cord length closer to 4-5 rocket lengths is preferable to a shorter cord. Another options would be to drop the Bp amount down enough to ensure opening, but not push the parts to the end of the shock cord and let the drag of the drogue chute and gravity extend the apogee shock cord to get the right flight profile. As long as you can avoid entanglement, there's no such thing as too much shock cord. Feb 5, 2025 · Tfish, in amateur rocketry, the shock cord's length is crucial to ensure a safe and successful recovery. http://www. Therefore, essentially the shock cord and eye bolt must be sized for 30 kN, or about 3 tons. Particularly length seems to have a lot of variation in the answers I get. Jan 14, 2013 · As for twisting up the shock cord, I put the swivel on the end of the shock cord where it attaches to the fin can. Dual deploy I use 25' feet at apogee and 15' for the main. By the last fold, the shock Aug 6, 2019 · Also google “apogee rockets model rockets deployment shock cord” for a nice video on using a crochet hook to daisy chain the Kevlar. C. ¶ Optimization This is kinda annoying. However, if things always worked out optimally you wouldn’t be reading this. (Basically the same as using too strong a charge. If I want to do dual deploy with the total lenghth of a 15 pound rocket almost divided in half at the AV-Bay, is there a general rule of thumb for the Dec 26, 2010 · Yeah, I start with only 12" of 1/8" nylon shock cord to make my loops and end up trimming an inch off both ends of the knot, so I'm really using only 10" of shock cord for the loops. Now this can obviously be taken to an extreme - but the point is - for a couple of extra bucks - it can't hurt to have the extra length provided it fits comfortably in the rocket. Apr 17, 2003 · As one person noted in this thread, too much can cause entanglement, but this method of packing keeps that potential to a minimum. Stevedore knot -- a stopper knot used at the terminal ends of cords, i. Lately, though, I have started putting a clip on the end of the cord (a coastlock swivel for the small stuff, and a small quick link for the bigger ones), in order to make it easy to unhook the cord so that I can slide a Nomex chute protector onto it. Recommended for A,B,C size model rockets. Sep 11, 2017 · I want to start a new thread on shock cords because I have not seen a thread that answers all the questions to the point. TIP: Glue the line (whether it's elastic, rubber or Kevlar) diagonally down the card stock. The “anchor” is where the cord attaches to the rocket. My kit was missing the 10' shock cord, but not too concerned, I have plenty of nylon. Longer cords can help with flat spins and circling. For LPR, you might start by looking at Chris Michielssen's blog. Stewart L. I saw on apogee components, that the shock cord should be 3 times the overall length of the rocket, as for the paracord it depends what type. Rocketrage 1" (4,000 lb) Cobra 3D shock. I have heard 2x all the way up to 5x the rocket length. Extra-strong Kevlar shock cord for extreme high power rockets. More tips and other discussion can be found here. of the shock cord anchor. I try to keep the anchor inside the body tube and have the shock cord handle the exit to minimize possibility of zipper. Keep it separate from the main and it's shock cord to avoid tangling. Make sure the wire tie is very tight around the parachute and shock Figure 6: Insert the tie wrap, and the assembly is done. Dec 24, 2024 · AceCamp 1/8 Inch Shock Cord Pole Repair, Replacement Bungee Strap Rope for Worn & Old Tents, Emergency Stretch Elastic Cord, Moisture UV Weather & Abrasion Resistant, 65 Feet AceCamp $6. Jul 9, 2020 · People are constantly being surprised by high forces at apogee deployment causing unwanted main deployment, usually when using low-elasticity kevlar shock cords. In a typical rocket setup, the nose cone and rocket body are connected with a shock cord that is around 3-4 lengths of the rocket. Photo 2: The four-strand harness attached to the body Manufactured by: Apogee; Additional Info: Round elastic shock cord good for mid-power size rockets that use E, F, or G size rocket engines. To make sure the knot holding the nose cone to the shock cord holds, I added a few dabs of superglue to the knot. 2. Make sure the streamer is securely attached so that it can’t come off. The kit has very high quality materials and includes everything except the electronics. Model Rockets & How-To Rocketry Information Aug 2, 2009 · Centering ring Cord Mount: This is The standard method in apogee kits, cut a small notch in the centering ring that centers the Motor Mount to the Body Tube and slip the shock cord thru the notch and tie. You'll probably need an extra pin or two. On the top of the bag is a swivel-attached pilot chute which extends outside the airframe (or NC) to both act as a drogue and pull the whole eRockets Polypropylene Shock Cord 300# 3/4" x 15ft Assorted Colors ERO 9208-15 eRockets Polypropylene Shock Cord 300# 3/4" x 15ft ERO 9208-30 Strong, water-resistant polypro… Now: $4. This small piece of shock cord is held by the tether. The ideal shock cord length depends on several factors: 1. Kevlar cord is definitely the best way to keep them together with Apogee having a good selection to choose from. For size I have seen people say rate to Model Rockets & How-To Rocketry Information The shock cord is available in lengths of 20, 25, and 30 feet. The large vinyl decals provide a bold design to the rocket and are beautifully printed with sharp edges and solid color. the point you are anchoring your shock cord. The longer the cords, the larger the speed differences and the higher the shock loads. Cut to 25 feet long, and both ends sewn with loops for easy attachment. Attach the parachute's snap swivel to the loop and you are ready to go! With the parachute tied on 1/3 the way down the shock cord, your rocket will fall in three separate parts, all tethered together by the shock cord. Fits the most common sizes of Kevlar shock cords: 100# and 300#. That way, I never have to worry about the knot coming loose, and destroying a perfectly good rocket. Has 45lb test strength Model Rockets & How-To Rocketry Information Shock Absorption: While Kevlar does not stretch as much as elastic cords, its use in combination with elastic shock cords can enhance shock absorption. , for shock cord to nose cone or kevlar to eye-bolt. Aug 2, 2009 · Yes, there are general rules of thumb or guide lines for shock cord lengths. Cut a piece of your favorite cord material two inches longer than the mea-surement you just took. Even if the ejection charge isn’t overly strong, too short of a cord does not allow enough energy to dissipate. The most important thing is that the anchor is strong enough to resist tear-out from the rocket. It isn't nearly as strong, but it is softer and has less of a tendency to zipper a body tube. *Rocket size and weight*: Larger, heavier rockets require longer shock cords. We've seen how rocketeers have gone on to shape the future of space exploration. 40 foot is $24 60 foot is $28 Extra-strong Kevlar shock cord for extreme high power rockets. (red arrows) and the shock cord never contacts the body tube. Cut the paper shock cord mount anchor from the pattern sheet. This works well for much larger rockets. Build with premium parts like Baltic birch plywood fins, a 30" diameter nylon cloth parachute and a smooth plastic nose cone. That much strength is not needed but it's easy to work with and not much of anything is actually lighter. R. humcvet omnyvyu omum rxypzm mush jknfg ynbls xljuy zhob sui oetk ryad wzr yysv eac