pulsejets

[Joe H]

Here's some pics of my favorite hobby, building valveleless pulsejet engines. These things run really hot, are EXTREMELY loud, totally obnoxious, and about as much fun as you can possibly have with sheet metal. They are almost magical, running with no moving parts at all. They are also easy to build with some basic metalworking skills. One pic is my canoe with a 50lb thrust lockwood-hiller style engine. I wish I had some pics of it in operation. It pushed my canoe to 32mph, could have gone faster, but I chickened out. (canoes weren't meant to go that fast, lol) the other pic is a small FWE type, it's a great noisemaker, and could power a model airplane if built lighter. I am starting to use stainless steel for these, but the sheet I have is .030" and a little too thin for my TIG machine. The third pic is my in-progress Minimax hydroplane to be powered by 1bout 150lbs of pulsejet thrust.

[zapster]

you my friend are out of your mind..

and i like that

...zap!

[teknition]

Too cool!! ...you can go 32 mph in your canoe AND roast weenies on the engine at the same time....yeeehaaaaawww

[Washman]

So the unfinished Hydroplane doubles as a really fast toolbox? LMAO

[Joe H]

Not only roast weeinies! They run on propane, and use lots of it! Just think propane cooled beer coozie!

[teknition]

What more could a guy ask for?

[chopper5]

thats kool i want one now

[smithboy]

I read about these things when I was in high school. Isn't this pretty much a V2 rocket motor, just without the valve?

[Joe H]

Yeah, the old german "buzz bombs" were powered by valved pulsejets. The problem with valved engines is the valves wear out after around 30 minutes or so. That made them perfect for the buzz bombs, it took about that long to get over England, then the valves would wear out and the thing would fall.

[prop-doctor]

Arrrrr Arrrr Arrrrr Mope Power

[prop-doctor]

Lol More Power

[FearcityINC]

I wanna make one....my neighbors hate me as it is. Could you give me a run down on how to fab one up??? Thanks.

[Joe H]

Sure thing! I just need a few specifics from you. Do you want one big enough to power something (a go-kart, etc...) ?? Big engines are probably a little easier for the first engine you build, but a little one like the small one in the pics I posted are pretty easy to get right too. The little one really isn't good for much though, besides annoying your neighbors, they are still very impressive to see running though.

Here, I'll post drawings of a few..


The chinese puts out about 4lbs thrust, and would be great for a model airplane, or boat or something. They are pretty effcient (for pulsejets) too. I have plans for a 50lb chinese too if you like.

The 55lb lockwood is what you see on my canoe. Its not the most effcient, but they are great engines, the effciency can be improved alot by adding thrust augmentors, they also will increase the thrust ALOT. The 55lb lockwood with some simple augmentors behine it will put between 80-100lbs of thrust.

I've got to run right now, but I'll be back and go into a little more detail on construction in a little while...

[Joe H]

Ok, The engines are made simply my cutting out and rolling the cone sections and tubes, and welding all the pieces together. Ideally they should be made from SS, but mild steel works. Mild steel engines will eventually get holes burnt through though. For the smaller engines like the chinese I posted the steel can be very thin. I think that drawing specifies .013". SS that thin is difficult for most of us to weld though. The 55lb lockwood can be made from 18ga sheet, but the U-bend needs to be 16ga at least. If too thin it will collapse when red-hot because of the low pressure on the walls from the very high velocities of the cycling gases. Don't worry, I don't think anyone has ever had a pulsejet explode, if they fail structurally they always implode, crushing a spot on the engine.

If your interested, I suggest browsing around the forums on this site:

www.pulse-jets.com


Those forums have pretty much all of the available known information regarding pulsejets. Very interesting stuff.

[awright]

Last time I checked, it was illegal to have that much fun!

Do you live in the Australian Outback that you can get away with making that kind of noise? Or do you set up bleachers for the neighbors and offer beer?

awright

[Joe H]

Nope, I'm in north georgia. I only have a few neighbors though, and they come over and watch. I try to be very considerate about the noise also. Even I can only stand a few minutes at a time. The big engines literally beat you up with noise, you can feel the ground vibrating from 10' away.

[aluminumman75]

I want one just to make my little newphew scream. As there go cart launches in to space.

[Joe H]

EDIT: CRAP, I didn't mean to post to this thread, LOL. Not sure how I did that.

[woof]

Building regular jet engines check out:
search jet engine at instructables.com
http://www.badbros.net/
http://www.garysjetjournal.com/

This looks like the go-to site for pulse jet bilding
http://aardvark.co.nz/pjet/

[Waldarosa]

Must be the day for pulsed jets

Just welding one up today out of SS. Back to welding.