um...pulsejet?

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Eliseb
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um...pulsejet?

Post by Eliseb » Fri Jun 03, 2005 7:30 am

Hi! We are two sixteen year old students from the Netherlands and we are planning to build a (valveless) pulsejet as a school project. As we do not know a lot about this subject, we want to keep it as simple as possible. We have already searched the internet for this topic, but it was not easy to find a good workable plan (the english language is not our first language and therefor sometimes translation problems occur, though we are able to understand most of it). The plans we did find were most of the time unclear.
So does anyone have a simple plan for us which we can use to build a pulsejet without too much trouble?
Thanks!
Nina & Elise

Bruno Ogorelec
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re: um...pulsejet?

Post by Bruno Ogorelec » Fri Jun 03, 2005 9:33 am

Guys, my suggestion would be to go to a hardware store, go to the plumbing department and try to find plumbing fittings that closely correspond to this thing. It is has been called 'Pipewood' by the people involved, for reasons that may become obvious to you later on.

Those parts -- normally used to make water supply and drain systems in houses -- are simply screwed together. A hole is bored at the side and tapped to accept the spark plug. Propane is fed into the engine through a small bent copper or steel pipe you can buy in model aircraft stores.

I don't think there is a simpler way to build a jet engine. See the picture.
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Bruno Ogorelec
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re: um...pulsejet?

Post by Bruno Ogorelec » Fri Jun 03, 2005 9:37 am

Just so that you don't think I'm kidding you, here's a picture of the plumbing jet working in the dark.
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mk
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re: um...pulsejet?

Post by mk » Fri Jun 03, 2005 3:11 pm

Hello guys!

A pulse jet engine seems to me like a nice choice for a school project.

For sure Bruno's suggestion depicts the easiest jet.

Easy, too, but surely less expensive would be a "Kazoo" Lockwood-Hiller type engine.
You'd just need some gutter pipe of the right length, probably around 76mm/3" in diameter and something to crush it with.

No welding for both cases.

----------

Where the hell are French people/pupils/students interested in pulse jets?
At least not in the forum.
mk

Bruno Ogorelec
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re: um...pulsejet?

Post by Bruno Ogorelec » Fri Jun 03, 2005 3:42 pm

Marten, I agree that the Kazoo is elegantly simple, but it does require some special equipment. You have to find the circular clamps that will prevent the combustion chamber from deforming, for instance. You have to make a wooden former that will squash the pipe nicely. Also, what are you going to use to squash the pipe with? Car jack?

Ideally, you'd want some kind of a rig in which you could fix the tube and make sure that the squashing is done in a controlled direction. It all looks easier than it is because Mike Everman did it properly the first time out. But, he's an engineer and heads a pretty impressive workshop. Mike, tell me if I'm wrong, but I would only recommend the Kazoo to someone who already has some experience in fabrication.

In contrast, to build a the plumbing jet you only need to saw through a couple of pipes and screw a few parts together. You don't even really need a spark plug, I think.

Eliseb
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re: um...pulsejet?

Post by Eliseb » Fri Jun 03, 2005 3:59 pm

thanks for the fast reply's!
we'll have a look and see what we can find in the hardwarestore.
but if anyone has some more idea's / advice, we will be glad te hear it.

thanks! Elise & Nina

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re: um...pulsejet?

Post by Graham C. Williams » Fri Jun 03, 2005 4:03 pm

Hi.
If you want to push your skill levels a little more try the Linear FWE motors. Stephen Bukowsky's plans are nice and clear.

A step further up would be Larry’s Short Lady and similar FWE motors.

The big advantage of these and the pipe motors is that the designer and builders are right here on the forum. If you are not clear about any aspect I'm sure Larry and friends will be more than happy to help.

Have fun.
Graham.
Last edited by Graham C. Williams on Fri Jun 03, 2005 6:30 pm, edited 1 time in total.

Bruno Ogorelec
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re: um...pulsejet?

Post by Bruno Ogorelec » Fri Jun 03, 2005 5:26 pm

Ladies, if you don't mind me asking, what brought you to pulsejets? It is not a very common interest.

Eliseb
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re: um...pulsejet?

Post by Eliseb » Fri Jun 03, 2005 7:09 pm

I read an article about using a jam jar to show the effect of a scram jet. Me and my dad tried this out, but it did not work as we were told it should, so we looked up some information and we got interested.
When I was told we had to do this project for school, I thought it might be a nice idea to try to build a pulsejet.

Elise

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Re: re: um...pulsejet?

Post by Bruno Ogorelec » Sat Jun 04, 2005 7:02 am

Eliseb wrote:I read an article about using a jam jar to show the effect of a scram jet. Me and my dad tried this out, but it did not work as we were told it should, so we looked up some information and we got interested.
When I was told we had to do this project for school, I thought it might be a nice idea to try to build a pulsejet.
Very nice indeed, I agree. Well, you will certainly get every possible help from the combined minds of this forum to get you where you wish to arrive. Good luck!

pabloenlucky
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re: um...pulsejet?

Post by pabloenlucky » Fri Jun 10, 2005 9:20 pm

Hi!

We have spend some more time googling our way through the web and we found this link:

http://www.home.no/andreas.sunnhordvik/ ... less_e.htm

this valveless pulsejet seems not so hard to build and it has a complete discription of how it was build + images and everything.

Since this is a pulsejet constructed after the patent by Lockwood, we wondered if this was the "kazoo" some people mentioned before. We are also interested in your opinions on the pulsejet described on the page above.

For the school project we want to compare the amount and type of fuel used with the thrust our engine will (hopefully) generate (can you call it efficiency?) and we wanted to build some type of mobile unit to place the pulsejet on and measure its speed, but will this work? We have no idea of how heavy the pulsejet will be and no idea on how fast the unit will move once propelled forward. Does any of you can give us an indication of these things and perhaps an alternative for the measuring?

Thanks a lot!

Nina and Elise

mk
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re: um...pulsejet?

Post by mk » Sun Jun 12, 2005 8:41 pm

Elise and Nina,

Take a look at the "sticky", please. You can find some useful drawings and descriptions just by following the links.

If you could get the proposed engine running, measure thrust, frequency and specific fuel consumption (SFC), things would be complex enough as a school project.
Powering something with a pulsejet would be great, of course, but the effort would be much larger.

Also the engine depicted in your link is pretty large and would need quite some fuel (propane vapore), though. What size for a pulsejet did/do you have in mind -- comb. chamber ID or length etc.?
mk

A.G.G.
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Re: um...pulsejet?

Post by A.G.G. » Sun Jun 12, 2005 9:54 pm

hello

good another very simple pulsejet that is also facil to construct and is a box pulse a Web of this pulse is:

http://www.vhp.co.uk/turbine/pulsejet.shtml
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Eliseb
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re: um...pulsejet?

Post by Eliseb » Mon Jun 13, 2005 12:44 pm

we had a few more questions,

We went to the hardware store to have a look for the materials for the plumbing jet posted bij Bruno Ogorelec. They only had these pipes in alluminium. Is this strong enough?

Some of these jets are just straight. But if we want it to go forward, we would have to make a u-bend in the pipe, right? Will this give us problems?

http://www.home.no/andreas.sunnhordvik/ ... rawing.jpg
http://www.vhp.co.uk/images/pulsejetlayout.jpg
We were looking at these two plans, does anyone have any comments on these, or why we should use one or the other?

What size for a pulsejet did/do you have in mind -- comb. chamber ID or length etc.?
We have no idea, it will problably depend on the materials we can get.

Elise and nina

Mark
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re: um...pulsejet?

Post by Mark » Mon Jun 13, 2005 1:46 pm

Aluminum melts too easily, and it will soften even sooner. Maybe if you wanted to demonstrate melting ....
Mark
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