I'm going to attempt to create a hot air balloon. This is part of a high school assignment. The goal is to make something that's able to fly and carry a pocket lab data censor. I was inspired by Ned and George Mehler, but made some changes to the project. The budget for this project is 10 dollars.

Supplies

3 garbage bags
Packaging tape
Tin foil
24 Candles
15ft of thin wire

Step 1: Creating the Envelope

The first thing I did was create the envelope for the balloon. I cut the top off from one garbage bags, and then taped both bags together, in order to make a garbage bag twice the size.

Step 2: Creating the Wire Frame

The next thing I did was create a wire frame for the bottom of the envelope (picture 1). This frame will hold the burner in place while also forcing the bottom of the balloon open. I did this by making a wire circle with a diameter of about 1 foot. Then I crossed two wires over the circle in order to make it more sturdy.

The next step was to make the second half of the frame (picture 2). I started by making two more circles out of the wire. The first circle was one foot in diameter, and the other was two inches in diameter. I attached them together using three pieces of wire.

After I finished both parts of the frame I put them together. I did this using three pieces of wire, each about 4 inches long. I also made sure that the part with the burner holder was on the bottom (picture 3).

Step 3: Attaching the Frame to the Envelope

The next thing I did was attach the frame to the bottom of the envelope. I used hot glue for most of the process, but I also used tape for areas where the glue gun couldn't reach.

Step 4: Creating the Burner

Now it was time to create a burner so that the balloon could fly. I started off by making a small cup out of foil. I also added a rim so that it could attach to the wire frame. Finally, I put the candles in the cup to complete my first version of the hot air balloon.

Step 5: Test Flight #1

For my first test flight I used a heat gun instead of lighting up the candles. Unfortunately the balloon was too heavy and wouldn't lift off the ground. The heat also ended up melting the part of the balloon and created some holes towards the top and bottom.

Step 6: Modifications

Because my first test flight was a fail, I decided to make some modifications to the hot air balloon. The fist thing I did was patch the holes that were created by using tape. These were very small so it wasn't a big problem. The next thing I did was cut off the top of the balloon and add a third garbage bag. I did this so that the balloon would be able to hold more hot air, and therefore have a better chance of flying. I also decided to change the heat source to a heat gun, and remove the candles from the balloon entirely.

Step 7: Test Flight #2

After making the modifications I tried to fly the hot air balloon again. It still wouldn't lift off because the foil candle holder was preventing the hot air from entering. It was removed as a final attempt to make the balloon fly. While balloon was finally able to lift, large holes were created due to the plastic melting. The downside of this was that the balloon only lifted when the heat gun was directly under it.

Step 8: Final Thoughts

I learned a lot of new things from doing this project, and if I were to try it again I would do a lot of things differently. One of the most important things I learned is how much heat is required to lift the balloon. The weight of the cold air displaced is the weight the balloon is able to lift. If I were to try making another hot air balloon then I would make the envelope a lot bigger so that it could hold more air. I also learned that plastic melts really easily, even when it's not directly contacting the flame. This could be prevented by making the envelope out of flame retardant paper instead of plastic. The last thing I learned is that it's important to consider where the hot air travels. The hot air started cooling before it even reached the top of the envelope. Because of this, the balloon didn't lift as much as it could have. This could be fixed by making the balloon wider instead of taller. By learning from these mistakes, and making modifications, I think I would be able to make a successful hot air balloon.

Introduction: Hot Air Balloon