Pickle Jar Jet Engine
This "jet engine" is a simple valveless pulse jet that demonstrates the
principle by making a chugging sound once the alcohol vapor is ignited. It was
discovered by Francois Reynst, a born pyro who made one in his mom's kitchen
as a boy. His first one did not have the copper fitting inside, but without
the fitting, it will run, but only for a very short time when using alcohol.
Pickle jar jet engine's basic parts.
The jar must be 5" high without lid and 3" in diameter. The lid has a 1/2"
hole in the center. Four wires hold the copper fitting 9/16" to 5/8" down
from the lid. The fitting is a reducing coupler for 1 & 1/2" to 1" copper
pipe. The holes in the lid and the fitting for the paper clip supports are
1/16". Center-punch the copper fitting before trying to drill it.
The fitting and lid ready to go together.
After cutting the paper clip wires, put them into the adapter holes and
crimp them in place. Now mark from the top of the fitting 9/16" to 5/8" up
onto the wires. Next put the wires through the lid holes and bend them over
sharply at the marks. Leave about 1/8" past the bend and cut off the excess.
When done, a 1/4" drill bit or rod should fit between the top of the fitting
and the lid rim if the jar lid is like the one shown.
The lid and fitting.
Put in just enough denatured/wood/methyl alcohol to cover the bottom for
each "run". When the fuel vapors and air inside the jar is ignited with the
lighter, they make the first "whoosh" and flame shoots out. The expanding
vapors going out create a suction. Fresh air is then sucked back in which
mixes with raw fuel vapors and this creates the second cycle. This cycling
continues until the air inside the jar has accumulated too much exhaust. If
it goes on for too long the jar may crack. To stop it, put anything over the
hole in the lid. If the jar does break, the lid and fitting will not be
affected. If you want a long run and don't want the jar to crack, put it into
a larger jar of water.
Four of five fuels tested.
We tried these fuels plus gasoline. Only denatured alcohol worked. The
others just made an initial "whoosh". Remove the lid and pour out the old
fuel and blow out the exhaust before pouring in fresh fuel for the next run.
If you care to get glow fuel with 30% nitro, the inner fitting will not be
necessary and the run will continue, so put it in water.
The Coleman Wind Resistant lighter.
This is the best lighter for this jet engine as well as fireworks.
Video of the jet engine.
This is with pure denatured alcohol.
The first frame of the video.