www.pulse-jets.com

A little while ago I modified an FWE by removing the end plate from the combustion chamber and bolting on a glass window.

I recorded a run using a Casio Exilim EX-F1 at a frame rate of 1200 per second, this only gives between 4 and 5 frames per cycle! which isn't enough for smooth playback unfortunately. (I'll have to build a bigger pulsejet;)

Anyway, here's the video (the intake is on the right hand side, spark plug on the left) the resolution is only 336x96 pixels which is a limitation of the camera.

James D

This is played back at 30 frames/second

And this is played at 3 frames/second

A picture of the general layout.

This is the Lab watch glass used, I wasn't expecting it to last more than a few seconds but it was the leather gasket that gave up first.

And this is a link to download the full video, if anyone wants it.
The gasket consumes itself and leaks gradually more and more as the video goes on, so bear that in mind...

http://www.mediafire.com/download.php?m2on5t2znyq

Its a 43mb .mov file and you might need a fairly recent version of apples (free) quicktime player to view it.

enjoy

James D.

James, that is amazing ,
That video will go in the history books ,
excellent work and thanks for sharing ,

G

Dear James.
An amazing video. I love the way combustion moves about the CC.

Regards
Graham.

It's hard to see what really going on in there sadly, but hopefully it will inspire someone to do better.

I might try again but using smoke to help visualise the intake flow, I'll see if I can come up with a way of producing thick white smoke, or maybe water injected into the intake would be visible.

James D

James D wrote:This is the Lab watch glass used, I wasn't expecting it to last more than a few seconds but it was the leather gasket that gave up first.

I'm convinced that the secret to success is using a thin window (to minimize the thermal differentials) and flexible mounting (your leather gasket being a perfect example). Glass that's too thick, and/or attempting to mount it in some rigid way, are I'm sure quite hopeless (though I think fairly thick Pyrex or quartz would probable work). I think your approach was perfect. I'd never have thought of leather -- sometimes traditional materials turn out to be really useful, if you don't expect them to last forever. And in this case, probably nothing will, while remaining flexible.

That's just unbelievable to see it happening that way! Wonderful work, sir.

What I'd love to see is someone making an FWE from hand-blown quartz. Ha.

L Cottrill

I liked that watchglass look. I would like to see a crystal clear quartz Logan. Oh heck, anything in an all quartz would be fun. If we only had the resources at hand. I keep thinking about it.

Mark wrote:I liked that watchglass look. I would like to see a crystal clear quartz Logan. Oh heck, anything in an all quartz would be fun. If we only had the resources at hand. I keep thinking about it.

There must be an outfit somewhere that specializes in hand-blown quartz labware. Then, how many of us would be willing to chip in ten or twenty bucks to get it done? There's a lot of interest in this -- it might work.

L Cottrill

I suppose it wouldn't be impossible to make a Craftjet out some of my quartz tubing if you didn't mind a copperhead and same where two dissimilar sizes of quartz tubing are joined with copper fittings and copper foil to make the fittings snug on the quartz. I'd have to cut a short segment off the fatter stuff for the combustion chamber and then make a single flapper reed for the intake. Copper expands quite a bit so it may become loose or even crack the quartz from vibration. Not a total quartz wonder but a start. Motivation lacking. Wanting perfection.

Hey that quartz tubing just dredged up a dusty memory.
Yonks ago I remember watching an old guy make Lab
equipment from stock tubing etc.
He looked like he was using some sort of gas torch and was basically cutting,strecthing
and 'welding' the stock into retorts and other weird Lab stuff.
We used to make super fine pippettes etc for bits and pieces at the school Lab
in a similiar way.
I am pretty sure you could make a Pulse Jet in the same fashion.
How about you friendly local glass blower?

You know how pulsejets are addicting and all-consuming? Seeing that watchglass design hypnotically flashing made me wonder if it could be used to erase people's minds. A pure quartz "neural neutralizer" might be too dangerous, might cause a full erase of one's willpower. Dagger of the Mind. ha

Kirk: "What was it like?"
Van Gelder: "Like DEATH!"

http://images4.wikia.nocookie.net/memor ... alizer.jpg
http://www.amazon.com/Star-Trek-Origina ... 6300213153
"This time, Kirk delivers supplies to a penal colony on Tantalus V, where he meets the renowned Dr. Tristan Adams. Adams has been working on the development of a neural neutralizer to control and manipulate dangerous patients. When Kirk threatens to expose him as a dangerous megalomaniac, Adams uses the technology on the unfortunate captain. This tense piece set in a madhouse atmosphere makes for a riveting episode, with a few unhinged performances adding to the fun. --"Tom Keogh
http://www.youtube.com/watch?v=DxHCmM6BGNM

In chemistry class I remember having some straight glass tubing and bending it in a Bunsen burner for use with two-holed rubber stopper and flask. Kind of a water pipe look. ha
I too melted and stretched out the glass to form fine capillary tubing, just playing around. You made me recall, I bought some borosilicate tubing a few years ago, just in case I needed some for something. I had forgotten about it! None of it is a very large diameter and it is not nearly as good as the quartz tubing in my previous presentation. Quartz is said to be 7 times better than Pyrex for low expansion. Thin sheets can be heated red hot and dipped in water without cracking. You can't do that with Pyrex. But quartz is really hard to melt and work. I'd be curious to see if a Dynajet could melt it though if you fed a piece all the way into the combustion chamber, sort of like the way Larry did with some iron or steel.
http://sprott.physics.wisc.edu/demobook/pdfig2-2.gif