Hi Wallace,
I started with the FEMA, read about its short comings and tried my hand at the fluidyne design. It’s as Matt says basically built to imbert dimensions. Nothing wrong with that except the 1/2" nozzle dimension and other refinements like preheated air, monorator hopper. SU advised me to start with 1/4" nozzles and increase if needed. I still run 1/4" nozzles with good results. In my vid I had neglected to fully weld the reduction tube to the flange, thus you see the redhot area on the shell. This also is called an internal leak allowing gas to by pass the reduction zone and diluting the finished gas resulting in a lower quality gas and “passing through some tars”. Then I caught up on my reading and learned about preheat, etc and went into my present imbert build. Here’s a few pics and vids of my fluidyne. By the way I used tree branches from 1" dia to 3" dia, cutting them as long as their diameter. I use this same size for my GEK variant and it works well. Check out the rest of my posts once you’re on the site.
I would relegate the fluidyne to experimenter status and move on to the imbert as I did. How were you going to preheat your air. Same question I asked myself, so I went whole hog on my present unit. Yes it’s more involved, but it is time well spent on a proven design and a great learning experience. You’ll get a better quality operation and gas, imho. I was able to salvage much of the fluidyne to move on. Good luck in your quest. Don’t hesitate to ask questions, we’ve all been there at some point.
Pepe
The large plate holding the grate interferes with the free flow of gas and a “cool” spot which may inhibit reduction therefore gas quality. I used a “just big enough” round washer on the next tear down.
Note the FEMA in the left background. It was good for getting into gasification and back into welding, but has many drawbacks, notably tar production. The fluidyne seemed a logical step up in terms of ease of build, but as I said, still not taking advantage of preheat, etc.
Checkout my journey in the Forum, “My first small engine run”. Hope this helps.
Pepe