Draft "L" Engine on gasoline

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PyroJoe
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Draft "L" Engine on gasoline

Post by PyroJoe » Mon Feb 04, 2008 4:20 pm

Here is a "L" draft engine built for gasoline. A oxygen canister (approx. 3" dia. 10" long) for the CC and a 1.5" dia. tailpipe 32" long.

I measured the volumes of the original "L" engine and found the CC volume matches closely the tailpipe volume.

I used this 1:1 ratio in volumes to construct this engine. Filled the CC with water, closed off the bottom end of the tailpipe, poured the CC water into the tailpipe, marked and cut the pipe at the water level.

I started with a 5/16" dia. opening and stepped drilled up with each unsuccessful run. At 1/2" dia. used a circular file to remove material. At about 3/4" switched to a semi-circular file. At about 7/8" dia. it started sustaining for several seconds. At 1"dia was optimum amplitude & frequency. Ended at 1 - 3/16" dia. as seen in vid and pictures..it runs till fuel is spent.

Gees, with that size of opening I was thinking I may end up with a open ended pipe. ha

While running the tailpipe bellows smoke at an astounding rate. It is not rich enough to burn when trying to light it, but is still overcoming. If it flames out at the CC then the tail can be lit and does the "organ pipe" thing, down the pipe to re-ignite the CC.

I think it may need a Reynst type internal ring, or Logan type side port for better mixing. Maybe a smaller I.D. CC to concentrate heat? Maybe shorter CC? Could be just the bottom feed problem again. Arrrr, so many things.
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GRIM
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Post by GRIM » Mon Feb 04, 2008 4:58 pm

Hey Joe

That is terrific , I was so taken with the first L engine you posted the other day that i built one the same day out of scrap ,

I didnt have any threaded fittings so bodged an elbow out of flat bar , and as you say started right up on a 5/16 hole , revved up and done the shake thing , really great fun ,

well i got a bit bored and welded a short intake on it and spent a whole bunch of time with different lengths of just about everything , never did get it to sustain but came really close , machine gun type popping and banging on propane and a small rosscoe ,

I learned a hell of a lot about injectors that day ,(blisters on my thumb and 2 dead bic lighters) which led me on to the other small engine ,

great stuff and keep experimenting , this is great !

heres a pic of my first L
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PyroJoe
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Post by PyroJoe » Mon Feb 04, 2008 5:25 pm

That one looks good! I keep trying to add an intake, but keep coming back to just an opening. Must be the jam jar tendency in me.

This petrol one did run on propane, I cut a 1/4" copper line (left wide open and unsmashed) and would center it at the center of the opening. It cycles, but feels weak compared to the petrol. Probably needs a smaller opening for propane.

I did mix/try 50:50 vegetable oil and gasoline. It boiled the gasoline out of the oil while running. It wouldn't run on the remaining vegetable oil.

This one often blows small smoke rings. I bet if I kept making the hole larger it would be a fully auto smoke ring gun.


Gasoline is strange stuff, this one didn't want to draft because the gas vapor was heavy and when cold, it doesn't want to draft up the pipe. I had to start it with my Map torch pushing the flame into the CC until it was hot enough to support a upward draft.

GRIM
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Post by GRIM » Mon Feb 04, 2008 5:47 pm

I found that the propane injector position and shape are really critical, with or without inlet tube, just to get it to gurgle (kind of jam jar sound ),

a rosscoe, just cut off the end with side cutters , worked about the best , a straight end stinger would likely not work well .

I wish I had tried one of the 3 point injectors , the sucker might have sustained, hell i might just weld the inlet back on and give it a try , the blisters are nearly healed now LOL

PyroJoe
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Post by PyroJoe » Mon Feb 04, 2008 6:03 pm

I really like the looks of those three point injectors. 2 blistered thumbs up.
Will give the drill chuck a squeeze next weekend.

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Post by Mike Everman » Tue Feb 05, 2008 6:10 am

Yeah, I'm going to try one of those injectors soon too! Great stuff on this new genre!
Mike Often wrong, never unsure.
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PyroJoe
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Post by PyroJoe » Mon Feb 11, 2008 7:24 pm

The three point injector works well with this engine.

The throttleing is a little strange. As I increase propane pressure, I have to pull the injector away from the opening. A moving "sweet spot". Probably has to do with air entrainment and where combustion is being sustained.

It is much easier than trying to run a jar on propane. On rare occasion it will go rich and stop cycling for lack of air.

It is easy to purge the propane and restart in a matter of seconds.

This is a fuzzy picture of the injector. The injector slots are about the thickness of 2 or 3 pages of notebook paper.
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GRIM
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Post by GRIM » Mon Feb 11, 2008 9:49 pm

Hey Pyrojoe

I am pleased you tried the 3 leg injector , i am having some great success with them , and there are many different variations one can do,

I also found the moving sweet spot deal , thats why I welded on an inlet tube and got to a machine gun style sound , almost but not quite resonating, you have a larger cc there , give it a go its all good fun

Hows the bleeding fingers?, Hell i gave up and welded a spark plug in there, but only because i had the spark generator at hand, and it does complicate an oh so simple design

Be warned though, if you get that to resonate like a pulsejet , you will be DOOMED, kinda hotel california really

Thanks for posting

Have fun

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Post by Mike Everman » Tue Feb 12, 2008 2:54 pm

GRIM wrote: Be warned though, if you get that to resonate like a pulsejet , you will be DOOMED, kinda hotel california really
Ha ha ha ha, Hotel California, that's rich
Mike Often wrong, never unsure.
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PyroJoe
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Post by PyroJoe » Tue Feb 12, 2008 3:19 pm

I tested a smallish internal tube last night. Didn't observe much change. It was small enough to pass through the opening, maybe it was to small to give the mixing a better chance.


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Prisoners of our own device

Post by Mark » Tue Feb 12, 2008 4:20 pm

"I'm pretty sure this was not Henley's intent when writing this, but when listening to it there are some very obvious similarities with Homer's "The Odyssey." It?s been a long time since I read it so I can?t be very specific without confusing a lot of people, but just something to think about."
- Christopher, Derwood, MD
http://www.songfacts.com/detail.php?id=1121
http://www.youtube.com/watch?v=IBJTNx5q ... re=related

"Hotel California is a metaphor for that lifestyle, which the Eagles discovered that once they were immersed in it, they were trapped."
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And still those voices are calling from far away,
Wake you up in the middle of the night
Just to hear them say...
Welcome to the Hotel California
Such a lovely place (Such a lovely place)
http://www.azlyrics.com/lyrics/eagles/h ... ornia.html
Presentation is Everything

GRIM
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Post by GRIM » Thu Feb 14, 2008 11:52 pm

Hey joe I have been experimenting with my l shape engine

I tried lots of different inlet sizes and lengths , the best so far is an inlet about the same diameter as the exhaust and about the same length as the cc , yeah real long and really noisy ha

cant post pics right now , my wife took the camera (visiting her sister) but i will when i can.

PyroJoe
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Post by PyroJoe » Fri Feb 15, 2008 2:24 pm

Wow, great work!! I only tested intakes to about 1/2 CC length. Was it earmuff loud? ha

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