Jet engines combine oxygen from the surrounding air with on-board fuel to burn at very high temperatures and create thrust in the direction of the flame. Rockets, which we will learn about in a later post, are similar but carry oxygen internally and can therefore function in space!
Contrary to popular belief, jet engines are not hard to make. In just a few minutes, you will be on your way to starting your own personal NASA program! It all begins with the glass jar jet engine!
- Methanol (antifreeze is almost pure methanol)
- Glass jar with a metal screw cap
- Hammer and nail (or a drill)
- Safety goggles
- Long match (or a ruler to tie a small match onto)
Long matches will keep you a safe distance from the flame.
Step 1 Set Up the Lid
Begin by removing the screw-on lid from the glass jar and placing it onto a piece of junk wood, cardboard, or something else you don't mind drilling a hole into.
The wood will stop the drill from scratching the table, too.
Step 2 Drill a Hole
Drill a small hole at the center of the cap. It's better to start out really small than too large. Later on, you can experiment with different hole sizes to see how they affect the performance of your jar jet engine.
If you don't have a drill, a hammer and nail will work fine.
Step 3 Freeze the Jar
Place your jar in the freezer for a few minutes. This will decrease the likelihood of your glass jar cracking due to overheating.
Wait until the glass frosts, then remove the jar from the freezer.
Step 4 Prepare the Jar
Place the frosty glass jar in a safe, non-flammable environment. I set mine on the shell of an old VCR that I sacrificed to the scavenging gods.
The metal shell will keep heat and broken glass off of the table.
Step 5 Pour In the Methanol
Pour a tiny bit of methanol into the jar, as shown in the following photo.
Just a spoonful or two will be enough.
Step 6 Fasten the Cap
Make sure it is on really tight.
Step 7 Ignite the Jet Engine
Attach the match to the end of your ruler or stick. Light the match away from the jar. With the match extended away from your body, bring the flame to the opening in the cap.
- Before lighting your jet, put on safety goggles and make sure all sentient beings are well clear of the jar.
- Always have a fire extinguisher on hand when experimenting with fire.
- Be sure to let the glass cool down for a few minutes before touching it again.
Step 8 Laugh Maniacally
Part of the methanol that's trapped inside the glass jar floats around as vapor. This vapor flows toward the opening at the top of the jar. When the match flame meets the vapor, it ignites the entire vapor cloud.
The combustion consumes the oxygen in the jar, while more oxygen is sucked in through the lid. This results in the upside-down tornado shape of the jet flame.
After the first run, the inside of the cap was burned in a circular pattern! If you look closely, you will see that the burn is slightly lopsided. The hole is likely off center, so the escaping fire oscillates around the opening.
The constant heat caused this jar to break after three uses.
Now, try making your own miniature jam jet engine at home and share your experience with the community! Make sure to post any pictures and videos that you take of your valveless jet engine onto the community corkboard, and if you have any questions, ask them below in the comments or in the forum. I am always here to help make your science dreams a reality.