Candle Powered Hot Air Balloon

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Introduction: Candle Powered Hot Air Balloon

About: Eric J. Wilhelm is the founder of Instructables. He has a Ph.D. from MIT in Mechanical Engineering. Eric believes in making technology accessible through understanding, and strives to inspire others to lear...

Build a candle powered hot air balloon using painter's plastic, balsa wood, and birthday candles.

Step 1:

Cut the plastic and heat-seal the edges.

Layout your materials on a large sheet cardboard.

Pull out approximately 6 feet of the painter's plastic and cut it forming a sheet 9 x 6 ft. It's important to have plastic that is 1/2 mil (12 microns) or thinner. Thicker plastic is too heavy to fly.

Fold the sheet in half along the 9 ft side forming a two-ply sheet 4.5 x 6 ft. Use a hot knife to seal the two 4.5 ft edges. An electric hot knife makes this really easy, but it can also be done with an old metal knife heated over a flame.

Check your edges and correct any large holes. A few small holes won't cause problems.

Step 2:

Melt candles together and attach them to balsa. Again, an electric hot knife makes this step a breeze. A heated fork can achieve the same results. Make sure to do both sides.

Once the candles are attached together, melt them to the middle of a piece of balsa wood 3/16 x 1/8 x 36 inches.

Step 3:

Assemble the balsa frame.

Make an "H" with the 36 in balsa and candle piece and two 3/16 x 1/8 x 30 in balsa sticks. Make the joints with a small piece of clear tape.

Step 4:

Tape the balloon to the balsa frame.

Step 5:

Use a stick inside the balloon to hold the plastic away from the candles and light them. Keep holding the plastic up until enough hot air has filled the balloon to inflate it.

Step 6:

It's an amazing feeling when your creation first gets lift and starts to take off.

At this stage, there's about ten thousand things that could go wrong. Carefully think everything through before you actually do it.

I tied some thread to mine so I could fly it inside our warehouse without it getting away and setting the place on fire.

It will drip a lot of hot wax, so keep it over the cardboard if possible. Also, if you let the candles burn all the way down, the balsa will catch on fire. I am currently experimenting with other types of candles to prevent this.

Fly safe!

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    2 Questions

    Hey, I'm a youtuber and I'm gonna be making a video with a hot air balloon, can I show some of your pictures briefly on my channel, you can be credited in the description. Thank you. Talk to you soon.

    My daughter is working on a project and she believes an egg would take longer to drop on the ground if it is attached to a hot air balloon. Would the same materials you use be able to hold up an egg? Thank you!

    240 Comments

    that is cool

    Back when I was in college we used to make these and connect several together with thread into a large circle. We would launch them up wind from an evening event and then call in the "UFO" to the radio station covering the event. A little chrome paint or reflective paint in top makes interesting night lights in the sky.

    1 reply

    sounds like a good troll :-)

    I heard about one of these starting a fire a while back

    The fire started at about 9:00 p.m. on October 8, in or around a small
    barn belonging to the O'Leary family that bordered the alley behind 137 DeKoven Street

    a major contributing factor to the fire’s spread was a meteorological phenomenon known as a fire whirl
    As overheated air rises, it comes into contact with cooler air and
    begins to spin creating a tornado-like effect. These fire whirls are
    likely what drove flaming debris so high and so far.

    120 bodies were recovered, but the death toll may have been as high as 300.

    Please, do NOT make or bring these to Burning Man. They pose a serious risk for fires not only inside Black Rock City, but also in the surrounding landscape. Not to mention if you are not going to track it, chase it down, and pick it up, its MOOP!

    Will this be able to carry a dead hawk?

    i did a similar one but the plastic burned, what am i missing?

    I found a "xmas tree bag" and its got me thinking :-) Extra big, white, and infinitely inflatable :-) I can see myself out in sub zero temperatures making a hot air balloon already! Fun Fun Fun!

    I use to make these out of tissue paper and balsa (with an aluminum foil cup to hold the fuel) when doing science lessons for elementary school kids. For the fuel, I'd recommend melting some vaseline and soaking a cottonball in it. Then put the cottonball in your fuel chamber/gondola. Inflate the balloon with a hair dryer and then light your cotton ball.

    Hi
    I'm a High school student .I'm work About the physics of Paper (lanterns)hot air balloon
    Please Help me for physics and make a Paper hot air balloon.
    Especially About (physics of) Form this Paper hot air balloon.


    2 replies

    Oh, you can calculate the difference directly by PVM/R(1/T1-1/T2)=m1-m2

    Hi! If you google Ideal gas law. That will tell you that PV=nRT. Where P is pressure, V is volume, n is number of moles, R is the gas constant and T is the temperature. All units in the SI-system. You can rewrite it to PV=m/M*RT. Where m is mass and M is the mole mass. Calculate how much a given volume weighs at the ambient condition. Normal values for P is 1.013 KPa and R=8.314 J/(K*mol). Next, estimate how hot the air can be (this could be quite tricky) and then calculate the weight of that air. The difference in mass should tell you how much lift there is

    We did this in 6th grade some 40 years ago. We used crossed kite sticks, Sterno in tinfoil cups one cup for each stick, and a black plastic garbage bag.
    We flew it on an almost windless day. It went up and drifted away.
    I am glad it didn't start a fire in the woods.

    To make this, do you have to use painters plastic ? Can't it be anything else other than painters plastic ? Can someone answer before Friday 16th, i need this for my science Project ! Tnx :D

    How easy would it be to make a longer tube and power it with a Sterno can? I'm looking to build a hot-air airship for a steampunk design.

    modded dollar store lighters would work i think. take off the metal cover and set the flame real high. tape it to the frame, tape the button down, then light it with another lighter. light fuel source and would go for a while. not very wind resistant tho, and probably a fire hazard......

    1 reply

    yea it is a fire hazard cause if the flame is BIG and it burns for a while the valve starts to melt then it kinda just explodes.... its actually pretty cool to watch

    A common dry-cleaning bag also works. It would let you skip this step.

    1 reply

    yea my step mom is the manager of a dry cleaners so i can get thoes bags... but the problem is sealing the hole in the top of thoes bags because of where the hanger hook goes.