Making parachutes from Mylar balloons...

[luke strawwalker]

Here's something that's come up a few times over the last couple years, that I thought I'd share with anybody who's interested... How to make a parachute out of a mylar party balloon (helium balloon).

What's neat about this is, party balloons come in a wide variety of colors and graphics... and you can get them for free a lot of times after parties or events like graduations... I have some neat green "anodized" looking balloons my wife brought home from her school she used to teach at after graduation, complete with the school's "Hightower Hurricanes" logo on them... Also got some solid red "anodized" ones that landed in the fence after Valentines day-- they were heart-shaped, but I cut them down to round ones, and without much waste in material either. What's also nice is that basically you can make ANY size parachute you want from about 20-24 inches on down using balloons...

Here's a couple balloons I'll be using for this thread...

First you want to take your balloon and smooth it out as much as possible. It'll probably still have some residual helium trapped in it, and probably string or ribbon tied to it. Smooth it out and cut off the string or ribbon and toss it.

Next, carefully cut away the balloon's stem and valve. The valve is a long flap-like piece of clear plastic that is inside the mylar neck or stem. Use sharp scissors and cut this part away.

Now you can smooth the balloon out completely and squeeze out any remaining helium gas... don't worry if the balloon won't lay absolutely flat and smooth, but get it as flat and smooth as you can.

Using your sharp scissors, start to cut away the edge of the balloon where the front and rear halves are "welded" together... cut just inside the seam to preserve as much of the balloon's size as possible, usually about a quarter inch will work well.

It usually helps to keep a slight pull on the "ribbon" of cut off material as you work-- mylar is slippery and tough, and will tend to "scooch forward" on the blades of even pretty sharp scissors without a little pressure to keep it taut. Don't be afraid to stop and smooth things out a little more as you go, if necessary.

Once you've cut all the way around, the two halves of the balloon are now free of each other... you'll have a front and back panel. Slide them apart, and toss any parts of the valve flap that might remain between them on the inside of the former balloon...


More to come! OL JR

 

[luke strawwalker]

Here's something to watch out for-- mylar is not very forgiving of nicks and tears...

Mylar is an unusual plastic in that nicks or tears in the edge tend to concentrate the force and cause it to RIP wide open under a load... so you want a smooth, uninterrupted edge to prevent concentration of forces during deployment or under load, to eliminate spots that could tear or lead to a rip of the material. Simply cut such areas away, as close as possible.

Don't worry that the balloon isn't "perfectly round" as it's not THAT critical-- but you don't want to have to cut out a chunk a couple inches in from the edge... if the damage is that extensive, save the panel for making a smaller parachute-- you can cut blanks any size you want from the round sheet of material (using whatever circular template you want to use-- coffee cans, large kitchen bowls, cardboard templates, whatever is the size you want).

I want eight shroud lines, so the simplest way of doing that is to fold the parachute in half, then fold it in half again to make quarters, then in half again to make eighths. The creases mark where the shroud lines will be attached...

Next I install ring-binder "tape rings" I got from Wal-Mart. A pack of about a hundred is like $2 in the school supply section. Apply the rings right where you want the shroud lines to go.

I use a GOOD hole-punch (a nice office-type one, not the dinky, cheapy school ones) that has a SHARP double-wedge blade (one with a "V" notch in the hole punching part) to punch neat, clean holes in the mylar in the center of each ring... a clean, smooth edged hole will prevent tears or rips from developing under stress, unlike a "slit" cut in the canopy inside the ring, which potentially could tear out. Slitting the canopy inside the ring is okay when using trash bags or other materials, but for mylar, it will create a spot that can tear or rip. Don't try to "poke" a hole through it either using a bamboo skewer or test light probe or something, either-- that works fine on trash-bag chutes, but with mylar-- another stress point to rip.

Now for the shroud lines-- I use heavy "carpet thread" that I get from Walmart or wherever I can get it (sewing stores are good suppliers, as are craft stores like Michaels or Hobby Lobby. I like a shroud line that is about 1.5 times the chute diameter. The easiest way to accomplish this is to merely pull the string across the width of the chute 3 times (since each shroud line will go from one ring, down to the swivel, and back up to the ring on the direct opposite side-- therefore a line 3X the width of the chute will make a shroud line 1.5 times the length of the canopy width when installed). Cut the number of shroud lines you need (half the number of rings on the chute).


More to come... OL JR

 

[luke strawwalker]

Tie the shrouds onto the canopy using side-by-side rings for the first shroud, and then the next ring out on either side of the first two for the next shroud, working your way around the canopy in this manner until you tie the last shroud on to the last two remaining congruent rings... this will keep your lines all PARALLEL to each other, and greatly simplify attaching the swivel and leveling the chute later. I prefer the "surgeon's knot" for shroud line ends... and I use smooth-jawed hemostats to help my fat fingers tie the knots... Loop the shroud through the ring, tie a slip knot in it then double it up like you're tying a square knot, but give it an additional loop (pass the loose end through the loop TWICE) then pull tight.

Try not to cinch it up tight against the chute, but leave a slightly loose loop of material with a tight knot in it... this will prevent "pressure points" that would be weak spots that could rip...

Cut the knot's "tail" off so that it's about 1/4 inch long, for neatness...

Next we need a swivel... I prefer "Coastlocks" because I HAVE had the simpler "brass and wire" snap swivels pop open or straighten out under a late deploy or hard deploy situation... dropping the rocket from altitude when there's nothing wrong with either it or the chute because of a failed dinky swivel is never any fun, so I just use the coastlocks, which I've never had fail... they "lock" in place securely and tighten on themselves under load, so it takes a LOT of force to destroy one (but I HAVE seen it happen-- nothing is absolutely bulletproof!)

Next, "level" the chute and shroud lines in preparation for the swivel installation. Put each shroud line over your finger, then pull the canopy into a triangle by the very center apex of the chute... all the shroud rings should be side-by-side-- if any are higher or lower, tug them down (or the opposite one down which should be high) until they're all the same level. I usually keep the shrouds clamped in this position with a smooth-jawed hemostat clamp til I can install the swivel.

Make a loop in the shrouds at the center where your finger was-- then pinch that loop down and slide it THROUGH the ring of the swivel.

Pinch the loop and pull it through a bit... this will give you room to put the swivel through the loop...

Pass the swivel THROUGH the loop, and then gently snug the shroud line loops up around the bottom ring of the swivel...


More to come...

 

[luke strawwalker]

Snug the loop up around the swivel ring until it's a nice snug knot.

The knot won't really want to stay on its own, so I rub a single drop of white glue into the knot to "lock" it in place-- this keeps the shrouds from slipping and getting the parachute "cock-eyed" and unlevel at some point... Don't go crazy with the glue-- rub it ONLY into the knot itself-- rubbing glue into parts of the line that will flex can cause them to eventually break...

Last, a test run of the completed parachute by clipping it to the fan.

My daughter Keira has a "Disney Princess" party balloon salvaged from her birthday party a few years ago that she loves to fly in her Fatboy rocket... works like a champ!
Enjoy! OL JR

 

[GregGleason]

Very nice OL JR!

So where did you get your smooth-jawed hemostat?

Greg

 

[luke strawwalker]

Very nice OL JR!

So where did you get your smooth-jawed hemostat?

Greg

I start off with regular hemostats like you see for sale for about a buck each at various hardware stores and Harbor Freight and places like that... of course in their "native state" they have serrated jaws to help them grip slippery wet tissue inside people during surgery, but these serrations play heck for using them for rocket building, since they will emboss this pattern into anything it's used to clamp up.

SO, I took my assortment of hemostat clamps over to the farm shop and opened them up, and ran them lightly against the grinder for a few passes to grind off all the serrations, leaving the jaws smooth. Be careful doing this, because you don't want to take off too much metal-- just the serrated parts of the jaws. Taking off too much metal will 'loosen up' the clamps too much so they don't clamp tightly together anymore.

Now, knowing not everyone has access to a farm shop and a table wheel grinder, you can achieve exactly the same thing with a Dremel with a grinding wheel, albeit it slower, or with a plain old file (even more slowly, but doable).

I find that my smooth-jawed hemostats are THE handiest tool I own (except for a sharp hobby knife that is) and are indispensable for building kits like many of the Dr. Zooch offerings that use a lot of cardstock parts, often rolled into cones or tubes...

Later! OL JR

 

[aerostadt]

This is very clever! The Happy Birthday chutes look really good. I have used the silver mylar from thermal blankets bought at a nearby Sports store. The material is not as colorful, but it is cheap and makes really large parachutes. The good thing about this material is that very large chutes can be made that take up very little space.

 

[luke strawwalker]

This is very clever! The Happy Birthday chutes look really good. I have used the silver mylar from thermal blankets bought at a nearby Sports store. The material is not as colorful, but it is cheap and makes really large parachutes. The good thing about this material is that very large chutes can be made that take up very little space.

Yep... I've got some space blankets for just that purpose myelf... along with some gold mylar that was used to stuff some big gift bag or other... probably for my birthday. Seem to recall being more excited about the big sheet of gold mylar than the gift in the bag LOL (like a kid-- give them every toy in the world and they end up playing in a cardboard box).

I like the "color" aspect of it. They almost look "anodized" and of course you can even get mylar balloons with "mirrored" textures. One can cut them up into streamers as well, which is even simpler than making parachutes.

Later! OL JR

 

[lvgdgts]

This is a great tutorial. Should answer any technique question that comes up.

I think it would be great to have a big Mike from Monsters, inc. balloon made into a chute. Having that big eye looking at you while the rocket descends would add to launching fun.

 

[Handeman]

Great tutorial. I've made a few chutes from balloons my self.

A couple of comments:

• The mylar from the balloons seems a little thick and stiff for me, I prefer the "space blanket" mylar myself.
• If possible, use a hot knife to cut the mylar with, single layer only. It leaves a melted edge that doesn't have any of the nicks and tears you can get from using scissors. I bought a cheap 25W soldering iron and flattened the tip to a spade shape. It works great for cutting mylar and rip-stop nylon.
• Add a piece of very sticky tape over each hole and shroud line after tying the line on. This will make the whole attachment stronger.

Hope this may help a little

 

[luke strawwalker]

Here's some pics of a five-sided chute I made from a star-shaped balloon... Same process, just cutting around the star shape just inside the "weld line"...

The panels from the balloon come out actually looking like regular pentagons... I installed five shroud lines on this particular chute, with each one going from the point on one side directly across the center to the "V" bottom (or center of the flat of the pentagon) on the other side... I used small duct tape squares for reinforcement on this one, and after burnishing them down, rubbed baby powder around them to eliminate any "stickiness" from the tape edges which could prevent the chute from opening properly.

Since the chute is star-shaped, and since the center of the V's or flat sides are closer to the geometric center of the pentagon than the points or apexes are, the shroud lines are different lengths-- longer going to the points, shorter going to the V's or flats. The chute works well, though-- I've flown it many times.

When I built it, I considered just using five individual shroud lines to the points, but I figured that wouldn't be enough, and the points would pull inward too much and the "billows" or flats would get baggy outwards too much under load... so I made the shroud lines go from one point to the opposing "V" or center of the flat side. Since they all cross in the center, once you put the swivel on, the lines do overlap each other somewhat, but no worse than a typical Estes chute. When the parachute is inflated under a load, the points still pull inward more than the flats do, because they're further away from the center of the canopy... but the chute works fine... I might take the second panel from the balloon and make a five-shroud-line chute and see how it performs-- after all six shroud lines is the standard, and that works fine (but 8 or more actually makes a more uniform and stable canopy IMHO).

I also have some pics here of a bunch of panels I cut from balloons in various colors and stuff, including chrome... balloons CAN be stiff, but I find that if you wad them up very tightly and unfurl them a few times, you can "work soften" them so they are quite easy to pop open as well as fold up... it takes the stiffness out of them.

I even have a pic of a "smiley face" chute made from one of those Walmart balloons...

Enjoy! OL JR

 

[K'Tesh]

Looks Cool...

Got any shots/vids of one of them being actually used? I'd love to see what they look like in flight.

 

[luke strawwalker]

Looks Cool...

Got any shots/vids of one of them being actually used? I'd love to see what they look like in flight.

Nope, unfortunately... I haven't gotten into videoing launches yet, and I take photos in burst mode of the launch phase of my flights with my digital camera, but it takes 33 shots in about 2-2.5 seconds at 3MP, then has to write them from the buffer to the memory card, which usually takes about 15-20 seconds... usually by that time the rocket is under chute. I don't take pics on the way down because I'm more focused on where it's landing and the landmarks on a line behind it, so if I have to wade out into deep grass or crop fields I have references for distance and direction to go by so I don't lose my rocket...

Later! OL JR

 

[AfterBurners]

Cool chute JR. I l like the Happy Face ....

 

[kmcquown]

Here's a pic of my Batman balloon chute and some of the final product. Made from the Dollar Store crayon bank and a LOC nosecone. Flew great on a D12-3.

 

[K'Tesh]

I've modified the basic instructions just a little...

First I cut the edges off of the balloon, thus freeing the two 'chutes. Working one 'chute at a time, I carefully fold it, then cut off the bottom edge using a brand new #11 blade, a metal ruler to guide the knife, and a piece of junk mail (makes a wonderful cutting board). I have been getting some very nice octagons from this. Folded up again, I'll fold the point down, then cut an arc along the crease, this gives me a nice spill hole.

I'll then use 1/2" wide clear "magic" tape to reinforce the bottom edge (from the underside) I think this should help stop any nicks from tearing the canopy apart. I apply my reinforcing rings on the upper side, punch my holes, and then apply a 2nd ring on the underside.

I'm getting 14" parachutes out of pentagon shaped balloons from the dollar store, and 17" chutes from 18" (round) balloons from the party stores.

Now I'm looking for balloons that match themes for some of the rockets I'm building/built.

Anybody know where I can score a yellow jacket themed round or star mylar balloon? Say some school's mascot? Now that I think about it, I should get a nice Hulk balloon for my Gamma build (JK ).
.

BTW... Not that it's anything big or important, but this was my 1000th post.

 

[accpool]

How about this? https://www.partycity.com/product/g...i&srccode=cii_17588969&cpncode=27-254496982-2

 

[K'Tesh]

How about this? https://www.partycity.com/product/g...i&srccode=cii_17588969&cpncode=27-254496982-2

Well, it is on topic... I was hoping for something that would say "Yellow Jacket" or "Yellow Jackets" w/o the school name.

 

[accpool]

Sorry, thought it was a tribute Rocket.

How about this? The best I can do. https://www.discountpartysupplies.c...5&cadevice=c&gclid=CMSdpdTTsLsCFcQ9QgodDXoAhQ

 

[ThirstyBarbarian]

Good explanation. I especially liked the tips on how to attach the shroud lines --- how to reinforce the rings, the order to attach the shrouds, the tip on the kind of knot to use. Thanks for the recommendation on the type of swivel and the tip about glueing the shrouds in place on the swivel.

The one thing I wonder about though is the problem mylar has with tiny holes and nicks tending to "run." I know from experience with space blankets (while backpacking, not for chutes) that some kinds of mylar seem to easily tear to shreds once they have any kind of a hole started. You mentioned to be careful to not leave any cuts or nicks in the chute when cutting it out, as that can be a place where a run might start. But what about the tiny holes that can happen when an ejection charge gets through the wadding, or any other one of a million ways chute might get a small hole or nick? It seems like once it is damaged even slightly, then it is useless.

The other thing to worry about is if there is any danger at all of the rocket getting into power lines, the metalized mylar can be very dangerous, as it is a conductor. A small chute might not actually short between lines, but a large one could. Making a streamer out of metalized mylar also might not be the greatest idea. I've seen videos of people releasing large "bouquets" of party balloons and having them drift into power lines, causing a short and a transformer explosion.

Anyway, I liked the clear and detailed demo of the techniques, and they can be applied to many different canopy materials. i'm just not sure this material would be my personal first choice.

 

[K'Tesh]

The one thing I wonder about though is the problem mylar has with tiny holes and nicks tending to "run." I know from experience with space blankets (while backpacking, not for chutes) that some kinds of mylar seem to easily tear to shreds once they have any kind of a hole started. You mentioned to be careful to not leave any cuts or nicks in the chute when cutting it out, as that can be a place where a run might start. But what about the tiny holes that can happen when an ejection charge gets through the wadding, or any other one of a million ways chute might get a small hole or nick? It seems like once it is damaged even slightly, then it is useless.

If the canopy gets damaged, and doesn't run, you can use piece of "magic" type tape (from the underside) to repair it. as long as it doesn't get wet, it should hold for some time.

 

[K'Tesh]

Sorry, thought it was a tribute Rocket.

How about this? The best I can do. https://www.discountpartysupplies.c...5&cadevice=c&gclid=CMSdpdTTsLsCFcQ9QgodDXoAhQ

Thanks!

Next time I head out to my wholesaler (I'm a balloon artist) I'll check out what they have.

All The Best!
Jim

 

[luke strawwalker]

Good explanation. I especially liked the tips on how to attach the shroud lines --- how to reinforce the rings, the order to attach the shrouds, the tip on the kind of knot to use. Thanks for the recommendation on the type of swivel and the tip about glueing the shrouds in place on the swivel.

The one thing I wonder about though is the problem mylar has with tiny holes and nicks tending to "run." I know from experience with space blankets (while backpacking, not for chutes) that some kinds of mylar seem to easily tear to shreds once they have any kind of a hole started. You mentioned to be careful to not leave any cuts or nicks in the chute when cutting it out, as that can be a place where a run might start. But what about the tiny holes that can happen when an ejection charge gets through the wadding, or any other one of a million ways chute might get a small hole or nick? It seems like once it is damaged even slightly, then it is useless.

The other thing to worry about is if there is any danger at all of the rocket getting into power lines, the metalized mylar can be very dangerous, as it is a conductor. A small chute might not actually short between lines, but a large one could. Making a streamer out of metalized mylar also might not be the greatest idea. I've seen videos of people releasing large "bouquets" of party balloons and having them drift into power lines, causing a short and a transformer explosion.

Anyway, I liked the clear and detailed demo of the techniques, and they can be applied to many different canopy materials. i'm just not sure this material would be my personal first choice.

Well, as far as the electrical problems, I'd think it's much more of a risk with a LONG streamer than it would be for a model rocket size parachute. I wouldn't go very big on a mylar chute-- about 24 inches is the limit IMHO... mylar does have its good and bad qualities, as you mentioned. It does tend to "rip" easily from any nick or tear... and the "star" balloon parachute I made I used small squares cut from duct tape and then hole-punched through them both to make the shroud holes. IMHO the duct tape is probably at least 2-3 times as strong as the paper binder reinforcement rings... but it's heavier too. Good thing about duct tape is, once it's on, it's on for LIFE... the parachute will crumble to dust before the duct tape dries out and lets go... the glue on paper rings is nowhere near as long-lived. BUT, since I had the rings, figured I might as well use them. I'll see how they hold up over time. The only other risk with the duct tape 1/2 inch squares is from extraneous adhesive from the tape sticking things together you don't want stuck-- but a good dusting of talcum powder after everything is stuck down good and tight will take care of that.

I'd tend to think that with most power lines that any mylar happening to drape across them would simply be instantly zapped and incinerated... basically at the voltages of even fairly common feeder lines (around 6,000 volts and up) just about EVERYTHING is conductive, which is why 1) the wires are SO far apart and 2) the insulators they use are rather large and have a pretty complex shape. We had a barn cat that liked to run across the yard as fast as she could go and hit a tree or light pole and go straight up it lickety split... well, one day she decided to do that with the power pole by the road, and ran straight up the pole to the transformer... she got within about a foot of it, it jumped an arc, we heard a loud ZZZAAPP!!! followed instantly by a loud MRROOOOWWWWWW!!! screech and then it was just a fireball coming down trailing smoke... cat was dead before it hit the ground... those power lines are NOTHING to mess with, lemme tell ya! SO if even a "regular" plastic streamer managed to drape itself over the common (return) wire and the hot wire, I'd lay odds that it would get zapped, or overnight enough dew would settle on it to create a voltage leak which would roast/burn it... When I worked at the nuclear plant, I worked in Building 26, a "small" steel framed/steel covered building used as a welding toolroom, contractor toolroom, and fab shop on the other end. Well, we were right under the three power wires coming from the Unit 2 power house over a big tower and out to the transformer yard... talking those big semi-truck size transformers, not no little ones... Anyway, it's kinda hard to fathom how much power is going through those three wires up there on that tower... we're talking about megawatt reactors here... anyway, twas a foggy night one night and I had to go to the can, so walked out to the porta pots and I heard this distinct frying and buzzing noise... looked up at the tower, with their ~10 foot long or so insulators suspending the wires over my building from the tower, and you could see the "lightning bolts" of electricity crawling all over the insulator like one of those plasma lamps they sell in Spencer's Gifts and other assorted "herb boutiques" (so to speak). Anyway, it was just frying and popping away... I did my business and when I got back to the building, I asked one of the old hands about it... "Isn't there a danger of burning the wire through?? After all, it's arcing..." "Nah, don't think so-- does it all the time-- whenever it's foggy..."

Anyway, as far as the "burn holes" in the chute, they might be an issue-- but I haven't had any problems... I think that the problem comes in when there's a CUT or other "sharp edge" or end to the imperfection that allows the resulting "crack" to spread and run... It's sorta like with steel or cast iron-- if it gets a crack, and you want it to stop cracking any further, you drill a round hole at the end of the crack, which then relieves the stress AROUND the hole in a circular fashion out into the material, evenly around the hole, instead of it being CONCENTRATE along either side of the end point of the crack and creating a high stress point... sort of the same reason that the early Comet airliners suffered cracked fuselages and failures from having square cornered windows, which created a stress point at the crotch of the right angle that would then crack. When airplane manufacturers switched to squarish windows with ROUNDED corners, which eliminated the blind corner and eased it to a circular radius, it eliminated the stress point and stopped the cracking problems.

I'd tend to think that burn holes would tend to be round (ish) and thus tend to spread any stress around them, instead of concentrating it like a tear or cut would, causing it to spread or run. Course, I don't usually get any holes in my parachutes... if you're using dog barf and wadding correctly, you SHOULDN'T get any holes, or only get one pretty rarely... I've got chutes that have been used on dozens of flights that are hole-free or nearly so... It's not that it can never happen, but if you're using enough wadding or barf, it should be a very rare occurrence.

Thanks for pointing out that the materials and methods can be used with your choice of materials... doesn't have to be mylar per-se... I'm trying to find one of those big red star "Macy's" shopping bags on the white background without the "Macy's" on it... that'd make a terrific parachute for a Russian rocket like a Soyuz or Proton or N-1...

Later! OL JR

 

[ThomasL]

Here's some pics of a five-sided chute I made from a star-shaped balloon... Same process, just cutting around the star shape just inside the "weld line"...

The panels from the balloon come out actually looking like regular pentagons... I installed five shroud lines on this particular chute, with each one going from the point on one side directly across the center to the "V" bottom (or center of the flat of the pentagon) on the other side... I used small duct tape squares for reinforcement on this one, and after burnishing them down, rubbed baby powder around them to eliminate any "stickiness" from the tape edges which could prevent the chute from opening properly.

Since the chute is star-shaped, and since the center of the V's or flat sides are closer to the geometric center of the pentagon than the points or apexes are, the shroud lines are different lengths-- longer going to the points, shorter going to the V's or flats. The chute works well, though-- I've flown it many times.

When I built it, I considered just using five individual shroud lines to the points, but I figured that wouldn't be enough, and the points would pull inward too much and the "billows" or flats would get baggy outwards too much under load... so I made the shroud lines go from one point to the opposing "V" or center of the flat side. Since they all cross in the center, once you put the swivel on, the lines do overlap each other somewhat, but no worse than a typical Estes chute. When the parachute is inflated under a load, the points still pull inward more than the flats do, because they're further away from the center of the canopy... but the chute works fine... I might take the second panel from the balloon and make a five-shroud-line chute and see how it performs-- after all six shroud lines is the standard, and that works fine (but 8 or more actually makes a more uniform and stable canopy IMHO).

I also have some pics here of a bunch of panels I cut from balloons in various colors and stuff, including chrome... balloons CAN be stiff, but I find that if you wad them up very tightly and unfurl them a few times, you can "work soften" them so they are quite easy to pop open as well as fold up... it takes the stiffness out of them.

I even have a pic of a "smiley face" chute made from one of those Walmart balloons...

Enjoy! OL JR

The pentagon shape works as good as a hex or oct, and looks pretty nice coming down! I can get two 16" (roughly) chutes out of one balloon, with a 2" spill hole. And your point about no nicks is crucial! I also use a smaller hole punch (from my other haf's scrapbboking supplies), which is only an 1/8" hole, and also reinforce with tape dots over after the lines have been tied on...

Good instructions all the way around!