Photos of E-Z-Just Jam Jar Nozzle

[larry cottrill]

These closeups show how the thing is done. First, the basic structure; then an assembled view showing the maximum area of two of the ports.

Comments?

L Cottrill

[Mark]

That's a nice looking setup Larry. I have some metal canisters that I have attached little nubs of tubing to to enhance combustion, one in which is a sphere with a short nipple of less than an inch.
While I can only speak for myself, I have found a few things out about my Smuckers and quilted crystal 12 ounce jars. Keep in mind, the outdoor humidity and temperature can cause results to vary. But anyway here goes. One other caveat, nipples are a whole/hole other ball game, requiring their own testing to "optimize" results I'm sure.
Using a step drill and drilling a half inch hole in the lid of a Smuckers jelly jar of the size you presented, I found this size hole to do poorly. Then I stepped down to a 15/32 and this had a noticeable improvement. Funny so tiny a change in diameter is detectable. The intial flutter is great on both but dies down after a few seconds and the jar with the 1/2 inch hole and slowest combustion heats up very hot, very quickly near the bottom. I tried a hole as small as a 3/8ths and it ran fairly well and the tempo stayed steady for a longer period, but I could sense it might be a bit starved for air.
For the longest running, even paced tempo, I would tend to hang around the 13/32nds diameter or 7/16ths. These tests I did ran the most vigorously, steadily, and happily. And for me, the very fast, very steady runs with the 13/32nds also had the strange benefit of keeping the jar the coolest for longest time.
I don't know if this anology might be coming into play, but if you launch 2 or 3 liter plastic coke bottles with methanol vapor, if you make the cap hole too small or if it is too humid out, the heat from the one shot burn will melt and deform the plastic bottle. But if it is cool and dry air out that day, you can reuse your bottles many times without damage. A slow burn allows the heat to take its toll. Yet you would think a fast burn would dump a greater amount of heat, but not in this case, it is a time element, the heat is shot out and doesn't have time to melt the walls of the plastic bottle.
Perhaps too, the higher velocity hole kicks up the pool in the bottom and the methanol spashing cools the lower walls of the jar where a jar usually cracks from.
I was thinking it would be fun to try some additional "prejudical ports" and see if I could make a really energetic, short lived glass jar.
Nice to see someone toying with the "simple" jam jar.
Mark

[Mark]

And if you tire of fire and colorants in your jam jar, don't forget there is the smell-o-rama effect you can create to spice up your jam jar experience.
http://www.kemcooil.com/products.php?cId=5
Mark

[Mike Everman]

My favorite glass jar is a tall Salsa Autentica jar from Trader Joe's. The first dozen or so runs smell like salsa, and formaldehyde. ;-)

[Mark]

If you made a King Kong sized pulsejet, I would go with the Banana Blast scent for sale on the site I previously posted. I remember touring Universal Studios in Los Angeles and as our tour progressed though some building, a giant animated robotic King Kong figure roared and his air compressor breath was scented with bananas. The tour guide said "and if you think you are smelling something like bananas, you are.
Mark
http://www.bartleby.com/61/21/B0052100.html
http://www.approvedgasmasks.com/banana-oil.htm
http://www.mentalfloss.com/archives/arc ... -07-20.htm
http://www.totallyfuncompany.com/kong.htm

[Mark]

There's a lawyer that always comes in the library and calls me "The Taco Kid" because he once saw me just coming back from Taco Bell for lunch with a bag of food. And he often asks about my pulsejet hobby. So I thought it would be nice to give him a present, a little token for him to play with. So he will get this Taco Bell jar with a green glass bottle of methanol and the Reynst page on jam jars, both instruction sheet and methanol tucked conveniently inside the jar. He should like it I think, he use to be in electronics so he is somewhat science minded. I often wonder how startled people are the when they first fire up a jam jar, so simple and yet so stimulating.
I kind of hate to part with this little guy, it runs so well.
Mark