Startup of a Steam Pulse Jet Driven Model Boat - VIDEO

[Nick]

check out this link it shows how it works

http://www.fieldlines.com/story/2004/12/9/41413/0938

Nick

[Nick]

I just copied this straight out of the page from the link above

"Hi Ed!
If you have a flame as a heat source, you could make it even simpler by using a "putt putt" steam jet. These have been used in toy boats for more than 100 years. They make great pumps.

You keep the dual ball-checkvalve and the horizontal tube. Except now the tube is longer and the very end of it is brazed into a block of solid metal.

Flame heat goes to the block until it causes the water inside to burst into steam. This pushes the column of water in the tube. As the steam expands down the tube, it hits a cool section and the steam condenses. This sucks water back in through the lower checkvalve and back into the block. Then the process repeats.

The only hitch is that you need peak temperatures high enough to boil water.

The better news is that the boiler never reaches explosive pressures and there's a long mechanical thrust to push the water through the pipes.

Here are a few sites describing the process better.

http://www.saturdayscience.org/page12.html

http://www.nmia.com/~vrbass/pop-pop/

http://www.buzzboats.com/how.htm

"end of copy

How weird is that, these guys were looking at it from the "other end" of the spectrum, ie stirling engine enthusiasts looking at pulsing propulsion when we were looking at a stirling/hot air pump!?

Life's wierd

Nick

[yipster]

in answer to webpilots earlyer qestion on bigger boats http://www.knatter-tom.de/geschichte.html says

Mr. Rowland Payne befasste sich in den 70er Jahren intensiv mit einer Einrohr-Variante eines Reaktionsantriebes mit, der er es schaffte, ein 9 Meter Boot mit 0.3 m/s fortzubewegen.

also at
http://www.nmia.com/~vrbass/pop-pop/ i read:

And then there is Peter R. Payne, whose interest in the engineering aspects of the water pulse-jet led him to some fascinating experimentation using them in full-sized boats. If you want to take your construction project to the leading edge of the technology, Payne's work is the handbook for your efforts.

and no i havent seen these papers yet, while having visitors here i see above some more interesting post.
what i've been wondering about is how about a sort of water augmented pulse jet as heat source?
anyway, had these links allready on waiting to send:
http://www.delphion.com/cgi-bin/viewpat ... &MODE=fstv
http://www.delphion.com/details?pn10=US02848972
http://www.delphion.com/details?pn10=US00789641
http://www.delphion.com/cgi-bin/viewpat ... pdf&PAGE=2
http://www.delphion.com/cgi-bin/viewpat ... FORMAT=pdf
http://www.delphion.com/cgi-bin/viewpat ... &MODE=fstv
http://www.delphion.com/details?pn10=US03079751
http://www.delphion.com/details?pn=US06698183__

[yipster]

http://enstrophy.colorado.edu/~mohseni/ ... mics1.html

[WebPilot]

Nick,

Life is weird, especially when a little "synchronicity" is added.

--------

yipster,

http://www.knatter-tom.de/geschichte.html

I really enjoyed this link you posted.

Looking at www.delphion.com in your links made me remember the days when I thought I was going to have to "pay" someone for patents.

Concerning,

http://enstrophy.colorado.edu/~mohseni/ ... mics1.html

I remember a fellow who posted up on the Old Forum named, Norman, who really got off on vortices.

I am still looking for the picture I have of a Payne type tube in a rowboat. Bear with me, I am busy on another project.

I wish you fellows had posted back when I was idling.

Later,

-fde

[larry cottrill]

Forrest -

Now that you have a nice working boat, you ought to try flaring the pipe ends. Just the lightest tap with a small drift punch, making just a little flare, should be fine. Or, solder on a brass eyelet of appropriate size for a really smooth flare.

Just an idea, something I've never seen done on such a drive. The reason I like the idea is that it seems to me that the resistance to water going in around that edge would be HUGE compared to turning air effectively into the tail of a pulsejet.

Of course, I'm assuming that getting water efficiently back into the pipe is a good thing! I wonder ...

L Cottrill

[Greg O'Bryant]

Larry Cottrill wrote:

Is there any chance that larger ones don't work just because it's impossible to keep a liquid lock against the vapor, ...

Bigger ones do work with some simple tricks I made a much larger simple putt putt engine. It is about 24" total length with the boiler 3 1/2" x 10". They do suffer from a loss of liquid lock against the vapor so if you run one with the boiler above the water it wont work. So I simply drilled a hole in the lower side of a bucket and used a gromet to insert the tail pipe so that now the engine is effectively lower than the water it is in and it runs for a limited amount of time. Now the problem with them is that they ingest too much cold water and stop working. I think what is going on in the smaller sizes is the surface tension of the water forms kind of a plug between the hot and cold water so they don't mix. I use my charcoal chimney to get it going when i'm having a BBQ. I noticed that when it is heating up because the tail pipe is a large enough diameter,1/2", the hot water from the boiler will actually rise up and out of the engine. Then when it is running if you stick your hand in the water you can feel the hot water shooting out of the engine. So I think a good way you could make a larger one work would be by not letting the boiler water and the ambient water ever come in contact , and keep some sort of head preasure so you don't get the problems with loss of vapor lock. For exampl I was thinking of making an engine that uses a boiler like mine and then having the tail pipe stick strate up in the air for about 4 or 5 feet and then curl around and go down into the ambient liquid. Only the boiler and the end of the tail pipe would have water in them this way a barrior of air would keep the two from mixing and gravity would make shure that the water would go back into the boiler. I'm now going to attempt posting a picture of my engine the bad news is that the last time I ran my engine it sprung a leak and I will need to fix it. For anybody wanting to make a small one I would go to "Salter Harrison's Science Toys" He has a very good engine that you make from a soda can and straws it works very well I have made several myself.

[Mark]

I wonder if it would work to use a flat bundle of smaller exhaust tubes to get around the air lock problem of scaling up to a good people-sized boat.
Mark

[Mark]

I was looking at that collection of putt putt boats that fellow had in the link and was wondering if his submarines run submerged or not. It doesn't seem too hard to imagine a chimney effect or some design that might work with snorkels or valves.
Too, the exhaust heat might be able to drive a secondary "motor" too perhaps. Just dwelling on how it might be done, submarining a putt putt boat that is.
Mark

[Mark]

With all the vast links on putt putt boats, I don't remember if this site has been mentioned but you use plastic flexy drinking straws for the exhaust tubes! It's a very creative design I thought, if not a bit more time needed for the constuction.
Mark
www.sciencetoymaker.org

[Lockblade]

Why don't you seal the joints with silicone or epoxy or even bondo?

[Mark]

Here's the page with plastic flexy soda straws plan. Who would have thought of using plastic? PS I like the satire of "carbonated sugar water with flavorings" cans. A scream!
Mark
http://www.sciencetoymaker.org/boat/asembCartonl.html

[Mark]

I see Greg already posted the soda straw putt putt. I was at work and didn't review as well as I should have. Too many things going on. Today my house was bombed by hail, some on the news was 2 inches in diameter. My screened in back porch roof has dents all about the aluminum roof! My dogs were so frightened from all the noise of hail pelting the house, even though they were inside. Stormy weather and lightning today, unfortunately I missed the hail phenomenon, but my wife called to tell me and I saw it on the news later too. Funny what 11 miles can do. I was too chicken to leave work today until the worst of the storm was over, black as night out and cloud to ground lightning was all I saw. Spring is in the air.
Mark

[Greg O'Bryant]

Ha Ha!
I fixed my big putt putt with silicone " thanks Lockblade" and I figured out a way to get it to keep running. Remeber in my post I said that I was able to deal with the vapor lock problem by having the engine below the water levle, and then I ran into the problem of it ingesting too much water. Well I put the gromet into a tin can and let the water heat up. Now the water was warm enough that when it entered the engine it could still boil it. I also tried heating the water in the can to a boil and this made so my engine wouldn't run. This demonstrates that there is also a cooling cylcle to these engines that is vital for there cycle. My engine isn't that impressive not that much force and a lot of wasted heat but I'm still excited becuase it shows that these engines can be scaled up! Next I'm going to make a bigger one out of two tin pans riveted together and seald with silicone. By the way a while ago I did try to make a larger putt putt with pipes, but I was unable to get it to work, that is why I am making diaphragm type engines besides they usually have more power. Well it is off to work for me.
Good luck

[WebPilot]

Nothing new to add here.

I am just repairing the broken links found
on page 1 in the start of this post so I can
reference them from another post.

-fde