Make a Vacuum-cleaner Bazooka

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Introduction: Make a Vacuum-cleaner Bazooka

Make It Move Challenge

Finalist in the
Make It Move Challenge

Launch It! Challenge

Grand Prize in the
Launch It! Challenge

In five minutes, you can build an air-powered bazooka. The bazooka launches plastic capsules about 100 feet. And with some tweaking, you might stretch that distance quite a bit.

Although everything you need to know is in the pictures, the video tells the whole story just as well…

If the video is not playing, have a look at it here...

All you need to know to build this low-pressure kid's gun is described in the texts, as well as in the comments with the pictures. Have fun building and shooting! But please be careful, don't point your self made bazooka to living creatures.

Step 1: Stuff You Need

Stuff you need:
  • A vacuum cleaner. Any model will do.
  • Straight piece of PVC tube, at least 1 meter long. Longer is better (see the text on tweaking)!
  • Inner diameter 35 mm (1.4").
  • A PVC 3-way junction with an angle of 45°, that fits the straight PVC tube.
  • Duct tape.
  • A projectile: I used the plastic capsule that is inside "surprise-eggs" (see picture). Old school film containers work as well. Whatever you use, make sure that the projectile's diameter is just a little smaller than the PVC tubes'.
  • A small piece of cardboard (business cards are perfect).

Step 2: Make It

  • Attach the 3-way junction to the straight tube, using duct tape (you can glue the parts with PVC glue, of course, but there's no good reason to do so).
  • Wrap duct tape around the tip of the vacuum cleaners' hose, so that it fits snugly into the slanting tube. This fit should be as air-tight as possible.
  • Push the vacuum-cleaners' hose into the slanting tube of the pvc junction part.
  • Test whether the projectile can run smoothly through the assembles PVC tubes, when the vacuum-cleaner is attached.
  • That's it :D

Step 3: Lauch It and Tweak It

Launch it:
  • Power up the vacuum cleaner.
  • Cover the tubes' ending with the PVC-junction with the business card. The vacuum cleaner will now suck air from the other end of the PVC tube.
  • Hold the projectile firmly, and insert it in the air-sucking tip of the pvc tube.
  • Let go and enjoy!

Tweak it:
  • If you extend the straight pvc tube, the projectile will be accelerated over a longer period. And so the projectile's velocity will increase. So extend that piece of tube!
  • Add some weight to the projectile. We filled the capsule with rice, but sand might work better. Experiment to find the right weight for the projectile.

Again: Have fun! Don't shoot in the direction of living creatures, though. So be careful, too.


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99 Comments

This is really awesome guys, way to go on winning the challenge!

user

Thanks!!! We're having a ball here :D

Here's how I did mine. I used 1-1/4" sch 40 PVC pipe for the launch tube, and 3/4" sch 40 PVC pipe with caps for the projectiles. They fit perfect with no modifications.

Home Depot didn't carry a 45 degree 1-1/4" Y or T joint, so I went with a regular 90 degree Tee. I used a 1" elbow to get some angle on the inlet. The 1" elbow fit tight enough inside the 1-1/4" T. I didn't use cement on any of the joints.

I tried 2 different lengths for the projectiles (about 6" and about 3"), with and without sand for weight. They seemed to fly farther without the sand. I also tried a shorter launch tube - 2 ft instead of 3 feet. The longer tube launched them farther as well. I didn't measure, but it was probably in the 50-60' range, depending on the angle.

The ID of the 1" elbow was a good fit for my vacuum cleaner's hose, so I didn't need any tape there.

Thanks for posting a great instructable! Hope you win the contest!

Vince

SANY0081 (Large).JPGSANY0083 (Large).JPG

A good example of matching the energy level of your vacuum system to the weight of a projectile. If you wanted to find the ideal length of tubing to use for a projectile, you could try firing the tubes into a cardboard box that has a pillow inside. Then measure how far the box slides on each shot. I would add some packaging tape to the bottom of the box, because the amount of force to get the box to start moving needs to be both low and consistent over many shots.

user

Thanks! And thanks for your pictures, too! The pvc projectiles look impressive. Adding the sand makes them just too heavy for your vacuum cleaners' power, I guess. The Kinder egg capsules weigh almost nothing, compared to your projectiles...

As it was a perfect day here, I pulled out this project again and shot a few shots with my 22 year old son, hehe. And there is stillthe hunt for perfect projectiles. As we use the Dutch 40mm white PVC pipe.......

1. Film canisters, which you need in huge quantities anyway for using with Alka Setlzers. These are a very tight fit so the closing edge might need a tiny bit of sanding.

2. A modification of the perfect Guhl caps (see below): fill with water and find the perfect champagne cork to close it **)

3. (for the pro's) D-size batteries. They weight about 135 grams. THIS IS DANGEROUS!!

**) I shot one of these straight up and it went way over the top of my house. My guestimate is 12 meters. Weighting 50 grams the potential energy at that point is h*g*m = 12 * 10 * 0.05 = 6 Joules. 6 Joules in kinetic energy is 6 = 0.5*m*v-squared, so v, the muzzle velocity > 15 m/s, > 55 km/h (35 mph) :-o :-o :-o

Ynze, I found the surprize eggs just a fraction too big when the two halves are put together. If only the long half was used, all went fine. However I found a slightly more powerful but absolutely super snug fit protectile: the clear plastic caps on "Guhl" 125ml bottles. http://www.uwplein.nl/img/producten/300x300/952313.jpg They are an incredible tight fit in white 40mm PVC tubing. I haven't tried, but in the DIY shop the grey pipe seemed to have a slightly thicker 3 layer wall, middle part foamed, so it might not work.

user

Thanks! I'll give it a try...

@erik.teichmann: I saw what you did there ;-) You are secretly thinking of an automatic. That would require a loader box too. Hmmmm!