Long-Range Snowball Launcher

This was our Christmas break engineering project. Today my son and his friend fine-tuned our invention for this Instructable.

What the launcher offers...

1. 1-person operation
2. Long range -- approximately 200 feet, depending on ammunition, skill, and conditions.
3. Launch in any direction and at any angle
4. Simple construction (and it works without solvent, so you can re-purpose the PVC parts for other projects)
5. Portability -- breaks down for travel or storage
6. Does not require rock-hard snowballs. [Today's snowballs were super dry and fluffy -- but having a snowball maker was key]
7. Versatility -- Skip to step 13 if you like watching manic dogs chasing tennis balls in the snow. In addition to snowballs and tennis balls, this launcher can probably throw a great variety of projectiles. Small water balloons would definitely work.

** In the spirit of full disclosure, we have discovered that when it's really cold, surgical tubing shrivels up and won't work as a spring. However, when it warms back up, the tubing seems to be as good as ever. We live in Vermont, and this has only been a problem once.

Materials: [You can get everything except the launch cup at Lowes or Home Depot.]

1. Three 10' lengths of 1" Schedule 40 PVC (Make sure that you don't get the thinner variety of PVC; it will be too flexible)
2. One 5' length of 1" Schedule 40 PVC
3. Six 1" PVC Elbows
4. Two 1" PVC Tees
5. 10' of 3/8" latex tubing (surgical tubing)
6. Access to a 3-D printer and 52g filament (I used Ultimaker "Tough PLA") -- for the launch cup
7. One or two feet of paracord
8. A few inches of thicker rope (exact thickness is not important)
9. 2 feet of 1/4" Steel Rod
10. 4 nuts (we used 1/4" nuts, and they were fine; but 5/16" might be more secure if your fingers are strong enough)

Optional Materials:

1. Rubbing alcohol -- to help insert the nuts into the latex tubing
2. PVC Solvent [We didn't actually use it. That way we can reuse all of the parts in future projects.]

Tools:

1. Drill and 3/8" bit
2. Mallet (or a piece of wood for pounding the PVC together)
3. Dremel with sanding bit (or just sandpaper to smooth edges of drilled PVC holes, so tubing won't get cut)
4. Saw
5. Heavy hammer for pounding in the stake

Helpful Accessory: Standard snowball maker, capable of producing 2.75" diameter snowballs -- this is the size snowball made by all of the commercially-produced snowball makers that we have used. Today was not a great snowball day (dry and cold), but these snowball makers could still make a snowball. Amazon.com : Flexible Flyer Snow Ball Maker : Snow Sleds : Sports & Outdoors

The rest of the build goes quickly, so try to get this done ahead of time! My STL file is attached. If you don't have a 3-D printer (or know someone who does), most schools have them, and many communities have makerspaces. You can also use an online 3-D printing service.

I used Ultimaker "Tough PLA," but regular PLA should be fine. I used supports of the same (PLA) material. The supports were easy to remove with needle nose pliers and a nail to poke into the holes. I used the fastest print setting, and it took 5.5 hours and 44g of material.

While I'm not 100% certain that a typical water balloon launcher "pouch" won't work as well as this cup, I'm pretty close to certain. If you use a regular pouch and have success (especially with powdery snowballs), let me know.

Cut the following lengths from one 10' section of 1" PVC:

• Four 13" lengths
• Two 30" lengths

As the third picture shows, this project does not require perfect measurements. :-)

You will have a little left over. There's no reason why you can't scale this part of the launcher up to make use of the entire 10' pipe. You should get some more range that way.

• Drill 3/8" holes through four elbows, as shown.
• Be careful! Find a way to clamp the elbows. Drill bits have a way of biting into PVC parts and ripping them out of your hand.
• We had trouble finding a way to clamp the elbows on our drill press. Our solution was to insert small pieces of wood into the elbows -- and then we were able to securely clamp the wood pieces (and therefore the PVC, too).

It's a good idea to smooth the entrances to all of the holes (both sides of each elbow), to prevent the latex tubing from getting cut or abraded. Our small Dremel sanding head worked perfectly for this. You could also use sandpaper wrapped around a small stick.

Additionally, the 3/8" holes may also be a little snug for the 3/8" tubing, so you may want to run the drill through them a few more times, wiggling it around.

The first picture shows what you're going for. The tug cord is a length of paracord with a knot at each end. Orion sized the paracord so that it would make a loop about 6 inches long, as shown. Then he tied an "alpine butterfly" as close as he could to the cup. But you can tie any old knot, and it should work as well (though you may have more trouble if you want to loosen it).

The part that you grab to pull back the launcher is a knot of thicker rope which is tied on the end (it looks a bit like bird poop in the picture). Any knot will do, as long as it makes a nice sized ball.

Alpine Butterfly Loop | How to tie a Alpine Butterfly Loop using Step-by-Step Animations | Animated Knots by Grog

The first picture shows what it should look like. Here are a few notes that may help you to re-create this picture...

1. Cut the latex tubing into two equal lengths.
2. Turn the cup so that the little knots at each end of the paracord form a line with the PVC Tees.
3. The open mouth of the cup and the open sides of the PVC Tees should face in opposite directions.
4. The tubing should poke through each elbow in the same direction that the cup's open mouth is pointing.
5. Adjust the tubing so that there's no slack, and so that the cup is in the center of the square.
6. Make sure that you have at least 4 inches of excess tubing coming out of each of the four elbows. You can trim off any beyond that, if you want, but you should always think twice before trimming. You can't put it back, and you may want to change things around later.

At this point, you could just tie knots in the tubing where its short ends exit the PVC elbows. But we like to secure the tubing with nuts. It's much cooler, and more easily adjustable. If you do a search, you can find slingshot enthusiasts who show how to use ball bearings for this, but it's easier to find nuts, so that's what we used.

I was able to cram 5/16" nuts into the tubing, but the boys could only do 1/4" nuts, so that's what we used. It worked fine; the nuts held, and the tubing didn't come loose.

1. Dip the free end of the tubing in rubbing alcohol. Water can work, too, but rubbing alcohol is nice because it evaporates quickly.
2. Grasp near the end of the tubing with your non-dominant hand.
3. Use your dominant hand to cram a nut into the neck of the tubing.
4. Push squeeze the nut down the tubing until it is snug against the elbow.

1. Cut four 4' lengths for the legs. [Each leg has two four foot sections, so it can be disassembled for travel or storage.]
2. Cut one 30" length for the foot.

1. Drill a 1/4 hole in the center of the 30" length of pipe that you cut for the foot.
2. Pass some paracord through the hole and tie a knot at one end of the paracord, to prevent it from slipping back through the hole.
3. On the other side of the PVC, tie a loop in the paracord. This loop will be used to stake down the launcher

Assemble as shown. A few tips...

1. Our favorite tool for assembling this type of thing is a wooden mallet. If you don't have one, you should make one.
2. The legs are the hardest part to get really secure. You need to brace them against something solid and tap them together. In the second picture, you can see that Orion is bracing the legs by standing behind the foot while Liam hammers the legs together from the other end. Bracing against a wall would be even better.

The launcher won't work without something to brace it against; hence the stake.

We have tried a variety of stakes, and most have not held up. We finally settled on this style, which is sturdy and fairly easy to make.

1. Cut a 2' length of 1/4" steel rod.
2. Sharpen the ends a little. We used a sander for this, but a grinder would have been a better. Throwing sparks into my sander probably isn't that good for it.
3. Bend the rod into a tight U.

It's probably easiest to watch Orion do it, but these instructions may also be helpful...

1. Find a snowy spot where you have a lot of fun targets within a 200' radius.
2. Assemble the launcher. Make sure that it's securely pounded together.
3. Stake down the foot. Put the stake through the loop of the stake string. Pound patiently with a heavy hammer.
4. Make some nice 2 3/4" snowballs. If you have a commercial snowball maker, use it!
5. Grasp the tug cord with your dominant hand.
6. Insert the snowball with your non-dominant hand.
7. Hold the snowball in place with your non-dominant hand.
8. Walk backward toward the stake. As the tubing tightens, lift the launcher off of the ground.
9. Time to experiment. You should be able to control both the angle of the launcher and the amount of power. You can launch straight up or in any other direction. When you're ready, let go of the tug cord.

If you watched our first video, you probably heard the dogs' incessant barking. They just wanted a turn.