www.pulse-jets.com

Thought I'd post this as it's own thread, since I'll be adding to it this weekend. Pictures and such.

I had a very productive night with jam-jars. I was joking with Bruno recently about pointing jam jars at each other to see if they phase up, BCVP style, and they do! (or did). It was wild, much louder than two running seperated.
Best spacing of 5 positions longer and shorter was 1.9", caps off. I band-clamped two Pint jam jars to a stick with 1/2" lid holes (wood spade drills work well, hold tight to a wood block).

It ran for about 2 sec. Jam jars won't run long on their sides because the mixing is off when the fuel pools along one of the sides, so I needed a way to get them to run longer when laying down. I made circle pad of red shop towel and soaked it in methanol. It sticks naturally to the bottom of the jar and the jar can then function on it's side; it can even be inverted(!) A small feed hole in the base could keep the cloth saturated easily.

I tried this on a quart jar, and it ran on it's side, accelerated steeply, and was still increasing in energy when it shattered about 2.5sec later (usually you can run 8-10 sec before it cracks. It was fascinating, it didn't pop; more like collapsing. I'll be making a set of water cooled glass jars for sure now! Well, Friday maybe, got to hit the road/air to Minnesota in the morning.

When I pick this up again, I'll likely just rig some water flow in the garage sink to cool the two jars.

I did one more experiment last night before I went to bed:
I took my best small performer, a round jar about 2.5" diameter with about a L/d of 2.5 or so, and lay it on it's side with the fuel pad in the bottom. It disintegrated almost immediately. I am thinking it is because the convective cooling is mostly defeated near the table, and it doesn't take much to break it in that case.

Fascinating! I can't wait to get back to it this weekend.

Fascinating stuff mike, cant wait to see the pics/vids or whatever. as regards a non burning fuel absorbant material some one used vermiculite (spelling?) in the bottom of a jamjar type jet sometime ago, maybe some of this under a mesh to keep it in place?.

Someone suggested a while ago carving pumice for high temp shapes quickly. I'm thinking a thin slab of that fastened to the bottom, though the cloth seems to work well; doesn't seem to want to burn if kept saturated. I haven't run for very long, and keeping it saturated needs doing, too. Fun weekend coming up!

I keep looking at all the pyrex and quartz glassware around here and dreaming of an elaborate lab bench setup where 20 jam jars all connect to a fuel source and run together, interacting and singing like the muppets gone glass.

I'll have to get my boss interested in pulse engines. He's seen the videos and seems to get excited when I tell him about new projects. Time to break out the jars on his desk.

Mike, I may need a job if this doesn't go well. I'm blaming you, btw.

Keep us updated over the weekend. Hourly pictures, a webcam, video, and play by play from Kyle will be sufficient.

:-).

Chris

I love this! Especially as I told Mike it wouldn't do anything! Misjudgements sometimes bring more knowledge with them than the right calls.

Chris, I will make room for you somewhere if you get downsized. Can't make Baby Brick if you're malnourished!
Bruno, I don't know if they were pounding against each other, or in synch or what, but I will find out; but they sure were humping.

As I sit in the Denver airport, dreams of high speed video capture and the neverending search for stainless jam-jars (with Mark's tireless help;-p), MY WI-FI IS ON FIRE!
Can't wait to get to work. I've got to do just enough "honey-do's" so Cindy will bring me a beer at the workbench later.

I came home and tried a single glass quart jar, on it's side with cold water running on the ouside. Lasted about 3 sec, then shattered into ittle bittier pieces than any before. Exhaust smelled very different, too. Water coverage wasn't the best, I'll try submerged but I'm out of jars!

I'm thinking glass just can't handle the delta t just across it's wall thickness, no matter how well I cool it. The vessel search continues...

Well, why don't you lower delta T by using hot water to cool the jar instead of cold?. In Formula 1 engines, oil is cooled not by ambient air but by the engine coolant, which reaches over 100 C at times.

Mike Everman wrote:I came home and tried a single glass quart jar, on it's side with cold water running on the ouside. Lasted about 3 sec, then shattered into ittle bittier pieces than any before. Exhaust smelled very different, too. Water coverage wasn't the best, I'll try submerged but I'm out of jars!

I once had a quart sized rounded corners but square kind of a jar that held grapefruit slices with a nice sealing lid. I fired it up and about 3 seconds later it just bit the dust. It was a thicker kind of a glass jar. But it ran well. I once bought some new 1, 2 and 3 liter Erlenmeyer flasks, etc. from an elderly chemist in West Hartford, Ct. and he said the thinner Pyrex glass is less prone to cracking. He had a lot of stuff he was getting rid of.
Mark

brunoogorelec wrote:Well, why don't you lower delta T by using hot water to cool the jar instead of cold?. In Formula 1 engines, oil is cooled not by ambient air but by the engine coolant, which reaches over 100 C at times.

I'm thinking Gallium for a coolant, it melts at 29 C, but doesn't boil until 1600 C. That's a lot of heat to hold before boiling. Or how about using methanol for a coolant, like the old days when it was used in car radiators. Or lots of little bees with wings beating. Or peanut oil, it's a high temperature cooking oil. Seriously though, it is a challenging task, not insurmountable, but simply quizzical.
Mark

resosys wrote:I keep looking at all the pyrex and quartz glassware around here and dreaming of an elaborate lab bench setup where 20 jam jars all connect to a fuel source and run together, interacting and singing like the muppets gone glass.
Chris

I once lit/had three different odd jam jar devices going all at once. Interesting to listen to the blend of erratic sounds. One time I had thought to line up all my jars, but jars crack and the three I had going were all metal.
Mark

Thanks. I'll for sure try the hot water first, think I'll skip methanol as coolant and go straight to bees from there, I have a bee-keeper friend! Gallium is good (hate for it to go down the drain, though), so would molten salt... Trying like hell not to have a recirculating pump and radiator, but if I go to that, then it's probably going to be glycol and water.

The only reason I'm hot on glass is that we can watch inside, and I'm imagining a blow-molded, water jacketed L-H for that purpose, with high speed video.

Mike Everman wrote:Thanks. I'll for sure try the hot water first, think I'll skip methanol as coolant and go straight to bees from there, I have a bee-keeper friend! Gallium is good (hate for it to go down the drain, though), so would molten salt... Trying like hell not to have a recirculating pump and radiator, but if I go to that, then it's probably going to be glycol and water.

The only reason I'm hot on glass is that we can watch inside, and I'm imagining a blow-molded, water jacketed L-H for that purpose, with high speed video.

I've submerged small jars completely in water, but they still crack, with hot water, the initial starting whoose is going to be tricky, a hot rich fuel mixture produces a very long lazy tongue of fire about a pencil length and then a calm ensues in the jar. A hot jar is hard to start if not impossible.
Maybe the water could be almost boiling and the jar lit and instantly lowered mechanically to almost complete submersion into a sparkling clear view-master viewing tank. There is some liquid, I can't remember now, with almost the same refractive index as glass and if you put a glass rod into the liquid the glass becomes almost invisible.
I guess glycerine is what I was thinking of. http://chemweb.calpoly.edu/chem/124/Lab ... ncept.html
Imagine the illusion of a cone of fire under water with no outline of the glass vessel. Would be interesting to see just how far you could scale it up, perhaps even use another cooling liquid besides glycerine that is near the refractive index of Mr. Glass or Mrs. Quartz. I'd like to see a 3 or 4 foot tall glass vessel, (invisible though in the cooling liquid ) running merrily, dancing and whirling hypnotically to Pink Floyd or some other choreographed medley. Remember too, you could taint the fuel to produce the vivid spectral lines/bands of your choice, maybe have several colors/jars in the show side by side, in the same dissappearing refractive bath water.
And some jam jar shapes will easily support combustion with a length of straight tubing joining or fused on atop the jam jar shape. In this case the tube could snorkel up invisibly to the surface to breathe for the jar as well.
Mark

I gotta say guys, the only way you will get reliable running is with something that with our limited tech is by using steel, copper or whatever but nevertheless metal. The Reynst pot i built (vid link posted) has a water jacket built in and that is the only way it stays running for as long as it does (even that boils about a litre of water in about 2 mins!)

What im saying is, test the bcvp jam jars in metal(with water cooling)and see if and for how long they work. Then and only then work on a glass or transparant variety to see what they are doing.

Experiment results in hard fact, theorise why later.

Nick