Hey Matthew. Where you from? Billy (alabama)
Scaling and sizing the engine is tricky to say the least because you need to figure out the HP at your target RPM and small engine HP ratings differ between manufacturers and applications. Unlike an automotive engine they are simply rated at there peak output. Not the case on small engines, industrial engine, farming application and so on. Some are rated at 3600 rpms others rate at much lower RPMs. Most small engines are rated around this 3000 / 3600 rpms. So you must factor in where the engine will be in its power curve at your target running rpm. For 10 kW the smaller engines are not going to do it unless your going to run at 3000 or 3600 rpms depending on if you are 50 or 60 hz. Unfortunately your choices for a small engines after 30 hp get very slim and you may need to start looking at a small automotive engine. To create 10 Kw at 1800 RPMs I would estimate you will need at the minimum a 1.5 ltr engine. Now days it will be a challenge to find a small four cylinder engine that is not computer controlled. Not to big of an issue if you can get the ECM for it. You can still very easily convert one to wood gas, the ECM will need to be there to control spark if it uses coil packs. If you can, avoid interference engines; do research on the engine and make sure it will not smash a valve if one gets stuck on you. You can woodgas interference engines but getting one that is not, will ensure you will not have big issues if you get into a tar event for whatever reason. This is especially being new and testing a new machine. If you are thinking you need 10 kW for your peek needs, then I would recommend using a battery bank and inverter instead of building something oversized to produce this output for a short time. Look at building something smaller in the (5-6 kW) range to charge your bank during of peak hours. This keeps the smaller engine as options open and are less sophisticated to build. Otherwise your systems will be too big and inefficient and a major chore to keep in operation full time. A practical gasifier is a gasifier you run the least. The less you have to run it and it meets yours needs the more practical it is. Indeed this will be one your best experiences you will ever encounter in your life I guarantee it and it is quite magical. However this is not free, somewhere in this there will be labor involved and eventually the work involved will take out the fun of running your new magical wood gas engine 
. Whether its making fuel yourself or you purchase it, you will need to pay for it some how and your time is worth something. Unless you have a free source of already processed fuel it wont come free. If you do end up making fuel your self, then you are also in the right place for the fuel processing side of it. Many threads on chunkers here or you can get a small chipper if it will make actual chips. Mulch will not work and many of the small machines make more mulch than they do chips. Your fuel moisture will need to be less than 15% in a machine of this scale, many make claims of higher moisture content, that is simply not realistic in machine of this scale. Its not that it cant be done but like some have stated you will encounter less potent gas and other issues. Mainly flow issues that will cascade into other events leading to the machine fully crashing. The exception here are more advanced machines that are at a higher scale that better manage heat and flows.
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Good Morning TomC
I am only responding on this topic because Matthew Moore has said his interest is in a stationary electrical power generating system from wood energy in.
The first, biggest beginners mistake on these is getting too involved with Vehicle system demanded constraints.
Wet wood works just fine on a stationary space&weight not-a-problem system.
Your engine and generator head has enough shed off heats to reduce 60% by weight chunked wood down to a gasifier hopper in-wood moisture content of 20%. And that as good as all of my sun/air dried wood gets back up to by high humidity air sucking back in by mid-November, and stays at until after mid-June the following solar year.
Most all hopper condensing gasifers are able to handle 20% moisture wood quite handily.
The second big mistake is pushing everyone with small systems desires directly to charcoal gasifing. Ok for motorcycles and very small cars.
Most places in the world it is very difficult to make the wood charcoal, true full cycle “smokeless” and non-neighbor intrusive.
Even IF you can make the charcoal in small system quantity needs; you will charcoal fuel fall short trying to upscale to a true family multi-passenger/usable loads capable road traveling vehicle.
On small stationary systems inputs of wood/weight volume versus electrical kW/hours out I, and many other gasifier system operators will beat any charcoal system hands down in the wood volume, wood quality used overall.
Just the facts maths/energys facts of it man.
Steve Unruh
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Lots of good info, I was planning on using wood (mostly because I didn’t realize making charcoal was a thing until a few days ago), the numbers are a bit over my head at the moment, but I’m sure I’ll figure it out with time, but there’s certainly more math and precision to it than it seems at first… I’m not deadset on the 10kw figure, in fact I thought it was pretty high compared to what most on youtube and the like run (3-5kw gens).
@Matt I’m not off-grid so I will never have to worry about whether or not I’m producing at peak efficiency or peak output for the generator, this is more of a fun project for me, hopefully it’ll break even of course, but if it doesn’t, I’ll still have fun with it, and at least I have done something a little greener for the planet. Again the numbers are a bit over my head at the moment, but at least I’m starting to figure out things that won’t work, all the better to figure that out before construction begins right?
@BillyAlabama I’m located about 2 hrs from the man who wrote the book @Wayne in Cartersville, GA. Thanks everyone for all the info
@Carl The link to Patrick J’s gasifier didn’t work, I looked at his profile and couldn’t find the post there either…
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I think Patrick’s page was called “Wood gas in South Africa”
Not sure why you can’t get to Patrick. I assume you are a premium member, so a simple click should do it. Maybe Chris can help us out here.
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For some reason he wasn’t activated. Try it again please.
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Ah hah I hadn’t even considered it being in the private section… Thanks Chris
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Matthew, Never been to Cartersville. But funny thing happened, the day after you posted that you were from there I drove through there on way to do a job in Dallas, GA. Anyway, looks like the guys are filling your questions with answers. Those will breed more questions----it’s kind of like gremlins. careful if you get them wet.
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Also, went to an auction in Bowdon, Ga last weekend and bought a hay baler for $50.00. Was planning to use the gear box for a chunker, but my brother thinks the baler will probably work with a new drive belt, so I may have to get it running and sell it and make some money on it. We’ll see. Running square balers are bringing over $2000 now.
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Never heard of Bowden, I did a few jobs out in Dallas with service master… Some well off people out there
Hi Matt, I’m Bruce from the dark side. I saw some comments about charcoal making and smoke earlier in this discussion. I just posted pics of my Air Sheet Kiln in the Making Charcoal Without Smoke discussion on this site. If you are still trying to sort out the wood vs. charcoal issue:
I use the following crude and approximate comparisons:
• Wood has 50% more power than Charcoal by volume.
• Charcoal has 50% more power than wood by weight.
• A charcoal gasifier weighs 50% less than a wood gasifier.
• Engine grade charcoal is 100%more difficult to make than wood chunks.
• A wood gasifier is 100% more difficult to build than a charcoal gasifier.
• A charcoal gasifier is cleaner, smells better and is easier to maintain.
• Charcoal is better for a vehicle with a smaller engine (better power to weight ratio).
• A wood gasifier is more energy efficient (unless you have a use for the excess heat given off by making charcoal).
Charcoal is a good choice if you are willing (or like) to make charcoal
and you have 50% more space to carry charcoal (on board or in trailer) or are only doing short runs.
and are willing to refill more often.
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Wow Bruce, I realize it’s generalized data but still very interesting to see, luckily for me I don’t need to worry about weight as the wood won’t be hauling anyone down the road. Sorry it took 3 days to respond, when I’m not busy I’m either reading the book or reading through Patrick Johnson’s project, 700 posts there 
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For my engine size, I need a ~10.5 inch od pipe for my firetube… I found one online for around 100 bucks, but was wondering if anyone knew of a good scrap item to try sourcing that would be around that size?
Hey @pepe2000: what did you use for your firetube? I was gonna look to see how far off on measurements you were and re-reading it realized you built the same size as me basically
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I had a great find in my brother’s scrap pile. It was a 10" od ice chute from a Zamboni. Happy birthday and I have a piece for another project. I’m looking for some info (dimensions) on the air ejector I used for my FEMA. It worked quite well, but had a 1/16" nozzle hole that would gradually get coated and poop out. Remove and clean, fun.
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Happy Birthday, Pepe!
15. 0f November 2016
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Whoops, Max, thanks for the wish, but I meant it felt like my birthday when I found the ice chute. But close enough as my birthday was just last month.
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Thanks Pepe, I was reading through your thread but I was worried I’d read something that had failed being as you had such a rough start early on, no sense following others mistakes when they’ve already done the learning for you lol
Happy belated birthday 
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I just took a piece of flat stock that I found at the junk yard and cut out a rectangle the proper size. Then I took that to a shop and they rolled it into a 10 diameter fire tube. This way you can get what ever gage you need and don’t have to settle for something to heavy or light.TomC
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Good morning Matthew.
Wow !! That is a lot of money !! I would expect to pay 10-15 bucks but nothing near 100.
If you can find a larger diameter pipe it is very easy to shrink it down to the size you want .
The below thread shows how I change the diameter .
http://forum.driveonwood.com/t/waynes-international-gasifier-build-thread/1209
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