Mine depends on conditions.
Some of my driving is on rough roads with big long hills, so the char gets shook off the grate or gets sucked off by WOT in second gear on half mile long hills. Under those conditions It slips about a gallon in 40 mile, and under better conditions ‘’ smother roads’’–’‘flatter ground’’–’‘longer trips’’ it will slip about a gallon every 100 mile.
Your gasifer might be fine, just take a look your conditions.
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Herb, I meant my words as a statements of facts. I did not mean, you or others did not know these things, I apologize for stating my words wrong, it was not my intention. I do agree that our gasifier’s both work great, making good gases to run engines on. And all so the builds are different in nozzle numbers and hole sizes. I visualize the air coming though your nozzles at a much higher voloisity than the air coming though my nozzles at the same volume of air. Both gasifier’s are still doing the same thing making charcoal and making good gases to burn. This shows how the WK Gasifier is so flexible in design and still works great. You and I and others can agree to this, because it is fact. Thanks for your input, I’ve learned a lot from you and everyone here on DOW, every day.
Bob
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Hi Kristijan, yes it does seem like a lot of charcoal, and yes I do screened the fine char and ash out and put it back into the hopper. Others have stated that it perfect popcorn size for the charcoal gasifier and that will be great for the charcoal gasifier that I’m building. Can’t complain about power lost because I have plenty of that. It’s on the other end of the wood pile, keeping up with the making of fuel. Lol that will change once I have the chunker up and running.
The main reason I would like to slow the slippage down is because of all the frequent stops to reload the hopper. I would like to see 60 to 80 miles between refills of wood. When traveling between destinations. Then I will not have to carry as much wood to go the same distance. Right now it about 50 lbs. of wood with out adding any charcoal, will give me 40 to 45 miles depending on the terrain I’m driving, and my Right Foot, as Chris mentioned. Lol
By adding the hopper extention this would give me more distance, but more wind resistance going down the road, it kinda counter productive doing that. At lower speeds below 40 mph. It wouldn’t matter much. But here where I live hi way speeds are 50 mph and higher. It all about learning the other 75 % of our gasifier’s, a lot more for me to learn on driving it and balancing the gasifier system out for running continuous.
Bob
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Thanks Jim, @Wayne, @greghenze, @TomC, this is all great things to know. It helps me get a better picture of whats going on in side my gasifier when it running going down the road, and to know it’s doing what it is supposed to do make good gas to run down the road.
Bob
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Well Bob, since you need charcoal and have enough power it seems you have a wining situation then!
Only sift out the dust for charcoal gasifier, those fines are gold! (at least from my experiances)
We Europeans with our moskito engines (good one JO 
) have a lot more truble sustaining good power thain your big ship engines…
About the hopper… Can you make it wider? Thats what l did.
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Ha, Ha, that is a good one guys, on engine sizes. I would like a larger hopper but the only side to expand would be going straight back of the truck bed. Square or Oval shape might work, something to think about on the new hopper build when it’s time.
I like what you and @TomC, and @JO_Olsson have been talking about the reduction tube area of keeping the speed up on the gases to compete the reaction taking place. That what I think the brake drum was doing , it was the reduction tube area being a lot smaller than 12". Being about 9-1/2" to 8" and have ash insulation around it causing the gases to speed up and then out to the grate ball room area, as Tom puts it. I took it out on the rebuild. It’s differently going back in below the choke plate to see if there is some improvements. I could also cut me a tube that would go below the choke plate straight to the gasifier support flange.
OH so many things you can do to make a gasifier run better. Just like adding cold AIR to the mix when needing more power.
Bob
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How far can a dakota go on the gallon of sliped char if not sliped,And if some char is not sliped too be reused else place or back in hopper then you have penitraited the charbed with oxegen and would tend too be causing heat problems around ash door seals.??or be running in too heater mode.???
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Posibly adding a small rim around the grait perimeter and adding the tube with restritcor would help.I still have too bolt on a grait shaker assembly aperatice.
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I dont know for the Dakotas, but l culd drive for about 15 miles with my charcoal powered Seat on the charcoal Bob says is sliped from his 100 mile drive.
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Ok Kristijan L. Thanks for your results with your design.
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Bare in mind always these three thermal-chemical gasification relationships.
Temperature. Need a minimum maintianed there. Too high destroys system material.
Turbulence. Need some to promote the best particle surfaces gasses exchange. Too much does not allow enough exchange time.
Time. The thermal-chemical reactions do take some time to completely occur.
If it helps visualize these as a changeable shape, three sided triangle.
Or as a three legged stool.
IF you change one side; the other two sides must change too, to have the same sum results.
Now factor in additional real engineering challenges like fuel stock moisture content; base carbons-to-volitles ratio; mineral ash %, and the melting point of it’s mineral ash and you may have to skew your T,T&T balances to address these.
Some gasifier systems promote one T factor as the Superior to the others. The factory Imberts as ripping Turbulence machines. Dobson’s as balls-out Temperature machines. The FEMA’s as slow, long pathway, Time-in-a-bottle machines.
Most all, other, as more T,T&T balanced systems.
Ha! They can all be made to work as long as you will let me cheat hand select the fuel.
Base your system around the fuel stock that You DO have, and You WILL use, to make your life a whole lot easier.
Regards
Steve Unruh
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I suppose with the light weight mounted gasifiers,the three sides are more fragle. Or moisture content a bit less tollerable.That tool chest gasifier really looks un noticable nice.
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Getting back to Dons original question on this topic of how much intake combustion air do we really need---- I was wondering if you guys that can control your incoming combustion air from inside the vehicle if you have ever played with adjusting ie cutting down incoming air to see what that did for performance? The way I understand it we want to starve the system of air to get the best gas, is this what you find???
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Hi Herb,
I’ve partially closed the air inlet by mistake a few times only to discover high vacuum and low power. I don’t think the air inlet should be restricted. However less oxygene by volume by using preheat is a different story.
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Thanks Jo, I think you may be the only one that has that capability, all the rest that I know of are 100% off or on! I do remember reading about starving incoming air but that must be one of the many meths that are out there!!
I remember one of your vids you shut the air off and killed the engine right away, am I right on that??
I get “the other story” bout hot versus cold air!
Thanks Herb
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Yes, that’s right. I remember Carl ones mentioned he does the same. Not a chance tary smoke will start backing into preheat areas.
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Hi, Herb!
4. of November 2016
Don’s original question asks how much the primary air is to be pre-heated! Not the volume of it!
If you want a certain flow of ready gas, it needs a certain amount of oxygen (in the intake air or partly released by the pyrolysing process).
And the process does not take more air (oxygen) than the chemistry needs for making CO2.
This applies for driving the reduction to CO.
Water is split up and the oxygen is “taken care of” by the char. The hydrogen is set free.
This is not a stove where you regulate the intake air for a certain heat production.
In gasification, the “draft” is regulated by the motor.
Amount and quality are different things.
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Thanks Max, that does clear up some things!!! Much appreciated!! Herb
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Hi Herb!
5. November 2016
Another Phenomenon: By preheating the primary air one cannot change the ratio between nitrogen and oxygen!
It does not change the proportions, whole the mix gets “thinner” with increased temperature.
If you have nozzles calculated for a certain blow-velocity with cold air, and you wish to keep the same velocity with hot air, you have to increase the area of the nozzle-tips in proportion to temperature change, both temperatures beginning from the absolute zero point!
Otherwise, the velocity will increase in proportion to the temperature increase, both temperatures measured from the absolute zero point.
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Okay, I have decided to go without preheat with my planned next build. The only preheat will be the manifold around the nozzles that will live in the hot gas chamber just below the top plate of the ceramic insulated burn tube.
In order to protect the WK design I will post a drawing later in my premium thread because I’m not sure “General Discussion” thread is in the premium section.
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