Little Logan sounds

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Mark
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Little Logan sounds

Post by Mark » Mon Feb 16, 2004 1:50 am

I just ran my little Logan in my room to record the sound it makes, although the silicone fuel line, which is really the only gas tank it has, is getting rust and debris floating in it which is choking it and being that it is just resting on a phone book in my room, I didn't have a way to mount it properly. It is kind of loud though and the fumes are rather obnoxious, but I wanted you all to hear how it runs albeit briefly.
Here goes another attempt. The diameter of the combustion chamber is 3/4 inch plumbing pipe and the tail part is 1/4 inch pipe by 12 inches long.

PS I tried to post a sound with this message but it wouldn't allow it, although I don't think the file was even very big.
Alas,
Mark
Last edited by Mark on Mon Feb 16, 2004 4:26 am, edited 1 time in total.

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Post by Mike Everman » Mon Feb 16, 2004 4:03 am

Here's the sound file Mark's talking about.
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Post by Mark » Mon Feb 16, 2004 5:08 am

Thanks Mike for posting the sound. Again it was from that little valveless that I posted last week that was held in my vise, it was running in the pictures but you had no sound and it didn't appear to be doing much if anything. It is plenty loud though and pretty easy to build, you have to drill one hole and then tap it with a 1/8 inch pipe thread. It doesn't have spark plug. You can just light the tail or even the side port. It's basically a typical pulsejet shape with a side port where a spark plug might go.
The plumbing pipe just screws together, no welding.
I still have to perfect the fueling, I suppose I could use another simple bell fitting and make it a Schubert front breather valveless. I have run it with a front breathing tube and the side port breathing tube both working together and it still cycles up nicely, it isn't very fussy, a kind of three orifice pulsejet mutant, perhaps like Chris's or Mike's jet when the spark plug region is breached, only the extra hole is proportionately larger in my case.
Mark

vhautaka
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Post by vhautaka » Tue Feb 17, 2004 11:35 am

Nice, especially thinking it's just plumbing supplies put together the right way.

What are the dimensions for this one?


- ville

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Post by Mark » Tue Feb 17, 2004 2:28 pm

My little Logan is about 17 inches long. The combustion chamber is 4 inches long and 3/4 inches wide, threaded plumbing pipe. The tail piece is 12 inches long and 1/4 inch wide. There's a bell that connects these two pieces. You can cap the head with a 3/4 inch cap.
The side port is 1/8 inch pipe so you would drill a hole midway in the center of the combustion chamber and thread/tap it so the 1/8th inch pipe about 1.25 inches long can be screwed on into it. You only want to put a few threads so the pipe doesn't protrude into the combustion chamber, rather make it flush with the inside.
That's pretty much it, you have to inject fuel somehow or do what I did, bleed the pressure off the combustion chamber to push fuel over to the side port entrance where it gets sucked in.
Sometimes the segments of pipe have a lip inside where they were cut and threaded on the ends. I like to smooth the burr out so air can flow in and out better, especially on the little 1/8 inch side port.
It's not so loud that your neighbors will hate you which is a plus. If anyone builds on, I can help with the other little details. You might find an easier way, it's just a prototype, and pretty easy already though. I like to hear it false start a few times and then catch suddenly. I spray a puff of methanol down the tail, then wave a flame over the tail and it quickly springs to life after a few tries, very often on the first lick of a flame. You might suffer hearing loss if you ran it often enough without ear protection though.
Mark

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Post by vhautaka » Tue Feb 17, 2004 2:53 pm

Thanks! :)

Am I the only one to think that _this_ would be pretty damn easy to implement in pyrex glass, given the everyday tube dims and small size?

And then, a slightly larger diameter clear plastic tube to act as a water cooling jacket / shield from shards should the very thinkable happen..


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Post by Mark » Tue Feb 17, 2004 11:01 pm

A glass valveless pulsejet would certainly be a welcome sight and very interesting to see running. The thinner glass is less prone to cracking though, its heat gradient is equalized faster and expansion is more uniform and less "stressful." With pure quartz glass you can heat thin sheets to a red heat and instantly dip them in water without damage.
Some of those 2 to 3 foot long glass heater elements/tubes with the metal coils inside the quartz glass tubing get red hot in just a few seconds without harm over and over. Flash bake ovens use quartz glass heating as well. I looked at some quartz tubing for industrial purposes with heating elements in them and they were 6 feet long and a much wider diameter than typical household quartz glass heaters.
Pyrex might work if you didn't run them too long and worked out the problems and accepted some cracking every so often.
Mark

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small kazoo Logan - problems

Post by mk » Fri Feb 20, 2004 10:04 pm

Hey Mark (or anyone else, who is in the theme),
do you have any further information about Logan pulse jet types or did you just guess the measurements of your small Logan?

The small Logan I built today with the measurements you posted to the forum, but as kazoo type out of copper pipes, doesn't want to run.
I used a 20mm (=7/9in ~ 3/4in) ID pipe for the cc and tail pipe. The cross sectional area of the tail pipe should than be ~32square mm (0.049square inch) for ~7mm (1/4in) ID pipe, whereof the area of the kazoo tail pipe has to be 32mm*1mm (3.14*20mm=63mm) without taking care of rounded edges in this case. I brazed the inlet pipe just the place you did it to (middle of cc length). It is made of 4mm (~5/32in -> ~1/8in) ID pipe. The fuel compression nozzle at the cc has an ID of ~2...3mm (~3/32in). The fuel supply consists of a hose loop, which is connected with the intake nozzle injector, made out of a (medical) needle. It injects the fuel ~3...4mm (~1/8in) away from the opening (to "free nature") slightly in air flow direction. The cc is ~103mm (~4.06in), the conical section is ~25mm (~1in), the tail pipe is ~307mm (~12.12in) and the intake is ~33mm (~1.3in) long.

I tried starting it with ethanol without success and later with methanol (contains nitromethane and some kind of oil, R/C-car fuel if you will), where I got a "whoosh" two times and a "whoosh tip tip tip" only one time.

Could it be that the kazoo type engine doesn't run because of overfueling? Or perhaps because of too much friction loss?
And where did you get the 1/8" and 1/4" (plumbing) pipes from (at a "construction market" I can just buy 1/2" to 3/2" ID plumbing pipes)?

Can somebody help me?
mk

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Post by Mike Everman » Fri Feb 20, 2004 11:42 pm

mk,
let's see a picture of the kazoo! The dimensions I crushed the 75mm to were a bit different than the calculator, which may be why it worked! You'll have a real uphill battle getting any tiny engine like that going, so they say. You really must use the collars to hold the CC roughly cylindrical, as shown. I made a 1" dia that I haven't tried yet...
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Post by Mark » Sat Feb 21, 2004 12:08 am

I would use pure methanol for the small pulsejets, when you need all the advantages you can get. Here again is the picture of the little Logan running full steam and loud with a blue fire inside, you can see how simple the "fuel tank" is, it's the pink fuel line so it only runs for ~10-15 seconds. I tried some larger tubing and the fuel line pressure gets spongy and doesn't work for any much longer, so I will try using a micro reed in the fuel line to hold the pressure head high enough to continue pumping fuel.
Mike, is there no stopping you? Yet another pulsejet banged out! Nice work you fiend!
Mark
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Post by Mark » Sat Feb 21, 2004 12:16 am

PS I guess in these photos the fuel line is clear, in the past I also used a pink silicone fuel line, amoung other sizes and colors. There is nothing to this jet, the monstrosity of odd stuff on the jet itself is just a fisherman's fly tying vice that I clamped on to the combustion chamber to use to hold the tiny copper fuel line.
Mark

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Post by Mike Everman » Sat Feb 21, 2004 12:28 am

Apologies, Marten said Kazoo and I got all giddy. Re-reading it, I see he was attempting a Logan by smashing pipe. Point remains, it's likely he needs sharper transitions than obtained from not collaring the CC. Then, he needs to move to Florida, learn how to vote; (it's simple really, Mark, you can call me in November and I'll walk you through it) and then screw around endlessly with his sub-mini Logan, under your tutelage, until it works! ;-)
Ha ha ha!
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Boric acid and/or copper tubing, that is the question

Post by Mark » Sat Feb 21, 2004 2:53 am

Mike Everman wrote:Apologies, Marten said Kazoo and I got all giddy. Re-reading it, I see he was attempting a Logan by smashing pipe. Point remains, it's likely he needs sharper transitions than obtained from not collaring the CC. Then, he needs to move to Florida, learn how to vote; (it's simple really, Mark, you can call me in November and I'll walk you through it) and then screw around endlessly with his sub-mini Logan, under your tutelage, until it works! ;-)
Ha ha ha!
I have been toying with the idea of using copper tubing for my next pulsejet too Marten, Project Green Hornet, for the green flames it will be making. I have been stockpiling copper diameters for a few years now. The copper will probably form a nice patina too after heating and cooling. Copper will catalyse methanol, a fine copper wire coiled into a spring will continue to glow red hot in methanol vapor if first preheated. It eventually melts and/but it is not as good as platinum wire. Still it ought to be fun to make a discardable cheap pulsejet out of copper. I have produced some barking flashes with copper tubing and the flames emit/flash a beautiful vivid green, picking up traces of copper or its oxides inside the pipe. I simply must capture these colors on camera. I say who wants a boring sodium yellow flame when a blue green copper flame/flower is so much more impressive? Yes, now you too can reproduce the vivid iridescent blue-green science-fiction book cover layered sky of the air pollution in Los Angeles as seen by me one late afternoon driving in from Las Vegas, which has it's own unique air.
Maybe we can have a dangling chad vote on who's jet is the most preposterous. I'm expecting to win the majority vote. And never stay up late to see who is your next president if the vote hinges on Florida. I was born in England and actually only like the Gulf of Mexico part of Florida. ha ha
Mark

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Post by mk » Sat Feb 21, 2004 8:47 pm

I'll try posting some pictures soon, but I don't have a digital camera (good ones are actually too pricy for me)!

I shouldn't have said "kazoo". Maybe "crushed" or "smashed" would have been better, but "smashed" or "crushed engine" sounds too violent in this case. So I thought "kazoo type" is optimal.

The cc is cylindrical along the mentioned length, though copper isn't very stiff.

The fuel reservoir with the supply line/needle is nearly like yours, Mark, but mostly the flame just lights up very short at the exhaust or intake, in dependency where I light it with the torch. After that it just disappears.
I really don't have any idea what could be wrong, because I also tried without the fuel line, closing the pressurization nozzle, of course.
I've been thinking about solding a 8mm (~0.3in) ID pipe to the end of the cc. Of course it has to be squeezed together a bit as well.
Holidays are over now and thereof time gets rare again...perhaps I'll try something next weekend...
Mark wrote:Maybe we can have a dangling chad vote on who's jet is the most preposterous. I'm expecting to win the majority vote.
I don't think so! with some chemical tricks I might be able getting some very strange flame colors out of my engines...like deep red or so. But the competition isn't important to me.
mk

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Post by Mark » Sun Feb 22, 2004 1:10 am

mk wrote:I'll try posting some pictures soon, but I don't have a digital camera (good ones are actually too pricy for me)!

I shouldn't have said "kazoo". Maybe "crushed" or "smashed" would have been better, but "smashed" or "crushed engine" sounds too violent in this case. So I thought "kazoo type" is optimal.

The cc is cylindrical along the mentioned length, though copper isn't very stiff.

The fuel reservoir with the supply line/needle is nearly like yours, Mark, but mostly the flame just lights up very short at the exhaust or intake, in dependency where I light it with the torch. After that it just disappears.
I really don't have any idea what could be wrong, because I also tried without the fuel line, closing the pressurization nozzle, of course.
I've been thinking about solding a 8mm (~0.3in) ID pipe to the end of the cc. Of course it has to be squeezed together a bit as well.
Holidays are over now and thereof time gets rare again...perhaps I'll try something next weekend...
Mark wrote:Maybe we can have a dangling chad vote on who's jet is the most preposterous. I'm expecting to win the majority vote.
I don't think so! with some chemical tricks I might be able getting some very strange flame colors out of my engines...like deep red or so. But the competition isn't important to me.
Oh sure, choose another color such as calcium red or strontium red, just when I am pontificating the beauty of green. I have lit off some nice red fire by mixing calcium hypochlorite with sulfur activated/spontaneous combustion with only water. By the way what ever happened to calcium hypochorite in the stores these days? It has all but disappeared. Another fun thing with calcium hypochlorite was to mix it with ammonium nitrate. Snap, crackle, pop, it went off like hot popcorn, now all that I see is some strange new pool chlorine substance. I once was detained in the principal's office for igniting calcium nitrate and sulfur at my junior high school. The principal spoke to me and told me not to do it again and then I was off on a bus trip to the Miami Seaquarium, for we had a field trip that day. That was a close call for a amatuer scientist.
Mark

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