It was something that i originally made as a small rock cannon. Then i found out that it that it could be made into a simple pulse jet.
Its easy to make and only cost $15.
Gatorade bottle with cap
Some flammable fluid. (I used hairspray and nitro gas for the rc cars)
2 screws about 1 inch or half (depends on the size of bottle)
Hot glue gun
Step 1: Step 1
First take the cap and drill 1/4 size hole.
Then drill 2 holes the side of the bottle. (Make the small enough that the screws can grip the plastic)
Take the screws and put them in the holes. Before tightening wrap wire from grill igniter around the screw.
Screw in the rest of the way and hot glue the top of the screws so that the wires wont fall off. Also if you have your hands on the screws you will get shocked.
Tape the igniter to the bottom of the bottle.
Step 2: Finished!!!!! How to Use!!!
Now you spray 5 or more seconds of hairspray or put 2 teaspoons of nitro. Put the cap on and click the grill igniter.
If it doesn't work make sure the screws have a spark ark between them. If the screws are too close then the spark will be to small. If they are too far apart then there will be no spark.
If it still doesnt work you may need to blow a breath of air into the bottle and try again.
If it doesnt pulse then you need to experiment with the amount of fuel and the size hole depending on the size bottle.
One thing that you may think is that the bottle is plastic and may melt. As long as you dont put too much fuel in the bottle it wont melt. The gatorade bottle is perfect for this because it is thick plastic. It may melt but not quickly.
I also pressure tested this bottle to 40+ psi so it can take the force of the explosion.
Step 3: Cannon Design!!!!
Also if you take the cap and make a big hole that can fit a piece of pvc pipe in and glue it with 30 min epoxy you can have a small potato gun. I use it as an airsoft cannon by putting paper in then bbs and then more paper. It shoots better then the airsoft grenade launchers. Spray 1 or 2 second of the hairspray(it can be a different amount depending on the size bottle and the length of barrel. I use it all the time and battles and get a kill every time i shoot it. I once got 3 kills at once! If it doesnt shoot and you get a bid smoke ball its not packed enough with paper. The more paper the more powerful. If you shoot rocks out of it they can go very far distances! If you can try and use propane it works alot better because hairspray freezes up the gun.
Try at your own risk. DONT point at face!!!!!!!!! I burnt my eye brow off.
Any questions please ask!
Also check out my instructable on a Airsoft pressure plate mine!