Scrap Queen's first foray into valveless pulse jets

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metiz
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Re: Scrap Queen's first foray into valveless pulse jets

Post by metiz » Wed Nov 04, 2020 10:35 am

...you've built 4 engines already without starting even one? Bold move :lol:
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ScrapQueen
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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Wed Nov 04, 2020 3:33 pm

Hey, its only 3 you know! Big difference. I wanted to build Joe's #4 as my second one but I didn't have bendable steel available at the moment. Then my professor brought in 1/16th " steel and my eyes lit up!

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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Thu Nov 05, 2020 12:18 am

I got it running for real this time, i think!

https://youtu.be/994hZP5Jh6g

I'm so pleased!!!

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Re: Scrap Queen's first foray into valveless pulse jets

Post by metiz » Thu Nov 05, 2020 10:54 am

Sorry...still not running :? You need more gas. Here's a video of an engine built with Pyrojoe's specs from a couple of years back. It's a bit bigger but the same type. I start it using only a Rosscojector. I've uploaded the whole thing, including all the failed attempts. Maybe you can get some pointers. When it does start near the end, I only run it for a second or 2 at basically idle. I live in a residential area and my neighbors would be super pissed
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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Thu Nov 05, 2020 2:15 pm

Well that's poop! I'll have to try again this weekend. It blows out the flame when I open the gas. Once I got the gas fully open and it didn't go out or be particularly louder. Low key frustrated again lol... I was so sure after the tail pipe had changed colors this attempt.

Edit: this is me starting it and turning the gas up til it stops. Just more fiddling with the injector I suppose.

https://youtu.be/AQux7lJDXHo

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Re: Scrap Queen's first foray into valveless pulse jets

Post by metiz » Thu Nov 05, 2020 3:59 pm

Try freehanding the injector to find the sweet spot. If you still can't get it to start, see if you can borrow a compressor somewhere.
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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Fri Nov 06, 2020 6:02 pm

IT LIVES NOW I KNOW WHAT YOU MEAN ILL KNOW!

IM SO EXCITED IM TYPING IN ALL CAPS. It took the new version to run. https://youtu.be/Ae3huXtWEw0

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Re: Scrap Queen's first foray into valveless pulse jets

Post by metiz » Fri Nov 06, 2020 7:14 pm

That's the stuff! Congratulations. Did you feel your bones rattle? :P Looking at your video, I think you can run it a lot harder still.
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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Fri Nov 06, 2020 7:37 pm

My propane tank is nearly empty from all the past attempts. I'll get a refill tomorrow. I was able to fully open the valve without it blowing out! Standing behind the exhaust was a real punch to the chest. Im so freaking happy it runs!!

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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Mon Nov 09, 2020 12:17 am

I ran it again with a full tank and WOW!!!! it went cherry red this time. It might have mildly slightly set the wood on fire once. Ill be making a raised mount in my weld shop tomorrow so that doesn't happen again. I seriously underestimated the full power of this thing.

Here's it starting up and another of it running at night. The night run is sooo pretty!

https://youtu.be/oJ-Tf1a3Q9s

https://youtu.be/ZM6MPpgwq2c

Now I wanna ride something its propelled by!


I wonder how much more I can push this one. Like an augmenter or different fuel or something.

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Re: Scrap Queen's first foray into valveless pulse jets

Post by metiz » Mon Nov 09, 2020 12:46 pm

Good stuff. Try adding some NOx to the fuel mixture for a nice boost. If you want to build an augmenter, check here
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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Tue Nov 10, 2020 4:06 pm

I think I understand the equation. I just tend to learn more with pretty pictures. Sadly that post is showing me I don't have permission to view that attachment. I hope that attachment hasn't been lost to the sands of time.

I have a few hours to kill before the weld shop opens so I'm trying to come up with the augmenter before then

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Re: Scrap Queen's first foray into valveless pulse jets

Post by metiz » Tue Nov 10, 2020 6:36 pm

here it is again
Attachments
Augmenter.jpg
Augmenter.jpg (6.25 KiB) Viewed 587 times
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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Thu Nov 12, 2020 9:52 pm

Sadly I think an augmenter is out of my scope for now. I did however build a cute little one thats half the scale of what I've been making. Id like to put this one on something like a RC ice sled.

Image

I think my professor would really rather have me do my assignments instead now lol :lol:

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Re: Scrap Queen's first foray into valveless pulse jets

Post by ScrapQueen » Sun Nov 15, 2020 10:52 pm

Tried starting this little baby engine today. It didn't even go, it made a couple pops but not even a growl. I think the 1/4" tubing is too big for the .75" intake. Maybe that and its 30f today. Maybe different fuel than propane even.

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