Proposed pressure tap for the M40

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Skynet
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Proposed pressure tap for the M40

Post by Skynet » Thu Apr 23, 2015 2:54 pm

Hello All,

My name is Leron and I have been fascinated by the valveless pulsejet after reading about them on this site, so for my first pulse jet I decided to build the M40 (many thank's Metiz for the plans). I got it running at near idle last Sunday on propane and when I throttled it up the injectors melted because I did not realize that part of my assembly was made out of aluminum, so I am in the process of making new injectors. When I get the system stabilized I am going to run it off of gasoline. As you can see in the images below the entire system is overbuilt for experimentation and one of the things I need is a way to sense that the jet is running so in the last image I have drawn a proposed pressure tap, tank and transducer that would shut the fuel pump off if the pressure drops below a predetermined threshold. So my questions are:

A) Will tapping into combustion with a small line cause problems with the combustion cycle.

B) Given the way the pulse jet operates is there a danger of the proper amount of fuel and oxygen accumulating in the tank and exploding.

C) If the answers to A and B warrant such a modification, where would be the ideal place to tap the combustions chamber?
pj6.jpeg
pulsejet.jpeg
photopj40lateral.JPG

metiz
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Re: Proposed pressure tap for the M40

Post by metiz » Thu Apr 23, 2015 10:55 pm

Oh crap. I hate to be the bearer of bad news, but it looks like you build the wrong version of this engine, and it won't run.

I think you build this version download/file.php?id=12647&mode=view
when you actually want download/file.php?id=13105 this one.

The original thread became kind of a mess at the end. If you did build the wrong version, you'll need to redo the combustion chamber, intakes and part of the rectifier. Check the actual plans for any other mods, can't remember anymore.

It's a very nice build regardless. Nice test stand too! The mods can be done without rebuilding the entire engine so not all is lost.
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Skynet
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Re: Proposed pressure tap for the M40

Post by Skynet » Fri Apr 24, 2015 12:45 am

Wow, that's a bummer, in fact that is the one I built. It came up and self sustained with a nice blue flame, but on a continuous burn, "not pulsating", I assumed I wasn't getting enough fuel because of the regulator. Since the intake tubes are the same dimensions, how critical is the 75 degree separation?

metiz
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Re: Proposed pressure tap for the M40

Post by metiz » Fri Apr 24, 2015 7:27 am

The intake angle isn't that critical. What IS critical is the regulator: get rid of it or it'll never run, regardless of design.
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Skynet
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Re: Proposed pressure tap for the M40

Post by Skynet » Fri Apr 24, 2015 1:16 pm

Ok thanks, I am sure you'll get tired of repeating the bit about the regulator, lol... But you know us newbies always have to try it anyway :)

Skynet
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Re: Proposed pressure tap for the M40

Post by Skynet » Sat Apr 25, 2015 3:54 am

Nothing like cutting a pulse jet in half.
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metiz
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Re: Proposed pressure tap for the M40

Post by metiz » Sat Apr 25, 2015 11:38 pm

It's going to be worth it when it fires up, thrust me :) Just make sure you make all the mods. Intake angle isn't essential, but dimensions are. Same goes for the combustion chamber and the rectifier (which I see you're already modifying)
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Mike Everman
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Re: Proposed pressure tap for the M40

Post by Mike Everman » Wed May 27, 2015 7:02 pm

Wow, that thing is beautiful!
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Chook
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Re: Proposed pressure tap for the M40

Post by Chook » Sat Oct 31, 2015 6:11 am

Brilliant construction!!!!! VERY nice work.

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