Whats the simpliest valvless that i can build?

[grant richardson]

I need something that requires only regular tools to construct since i dont have a welder or a lathe or any special tools.

I was thinking of usings some sort of pipe like galvinized or either chain link fence post or conduit. I posted in the valved pulse jet forum but i think now i want to go valvless because its more simple to build! I devised a hairspar can connected to a peice of fence post. It looks like a minim potato cannon. I drilled a 5/16 hole in the side of the can to stick my tourch in it. All i get is a lound bang like a tater cannon! I poured methanol into the can and shook it to get the vapor. Any ideas to how this can work? or can it?

[resosys]

I need something that requires only regular tools to construct since i dont have a welder or a lathe or any special tools.

I've been thinking about this for a few years, but haven't had the time to try to build anything. My current plan would be to hit the plumbing section of the local hardware store and find non galvenized steel pipe fittings that form the basic shape of a straight through valveless pulsejet.

A T fitting could be used to supply propane into the intake stack.

My guess is it would be extremely hard to get running. Tuning could be achieved by altering the lenght of the tailpipe. Even using a sleeve over the tailpipe that has had some slits cut in one end with a hacksaw, and clamped on with a band clamp or exhaust clamp would work. Sort of a pulsejet trombone.

My first layout would be this:

A 2" steel pipe for the combustion chamber, as close to 3.5 inches as possible.
A 2" to 1" reducer for the front combustion chamber cone.
A 4" piece of 1" steel pipe for inthe intake tube or a 3" pipe with a reducer (expander?) that steps it up to the next available pipe size as an intake cone.
A 2" to 3/4" reducer for the exhaust side of the combustion chamber.

The tailpipe could be done with a straight pipe or possibly graduated via reducers stepping it up to 2". It should be 25+ inches long. With an engine this small, I'd try a straight exhaust pipe first.

The whole thing could be doubled if you have access to a plumbing shop with a good selection of pre threaded 4" parts.

You'll either have to drill and tap for a fuel inlet on or near the intake reducer (front cone of the combustion chamber), or figure out a way to put a T in close to that area. Fuel could be fed into the engine at the intake mouth as well, though I've never tried this method.

You'll need spark or flame somewhere to get it going. You'll also need some forced air from a compressor or leaf blower.

The engine will probably be very picky about the amount of propane you feed it.

The above is just some thoughts I've had on building a no weld valveless pulsejet. I've never tried it and can't even fathom a guess as to whether it will work or not.

Be careful, test it outside, and wear eye and hearing protection.

One of these days I'll give it a go.

Bruce Simpson made a valved pulsejet body run as a valveless here:

http://www.aardvark.co.nz/pjet/pjet3.htm

A friend of mine built a 17 note pulsejet powered pipe organ and all his engines use straight pipe with no cones or tapers at all.

Ok, back to work here. I hope this gives you some ideas to try out.

Chris