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Chamkeeper
Mad Scientist
278 Posts |
 Posted - Feb 02 2004 : 12:56:53 AM
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I am planning on converting a used auto turbo charger into a thrust turbine for a potential hovercraft. Anyone know where to find info on or have experience with the 'hot section'? I was wondering about tube lengths and ignition methods etc.
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Aaron Cake
Administrator
Canada
6718 Posts |
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cirvin
Nobel Prize Winner
USA
1542 Posts |
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Chamkeeper
Mad Scientist
278 Posts |
Posted - Feb 03 2004 : 12:09:41 AM
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I was looking for first hand experiences. I have seen many great sites but some do things I think are a bit odd. External support components make the vehicular application of the technology limited. I was planning on bleed pressure through a welding regulator into an airtight oil tank to provide oil pressure, either a preheat system to use liquid fuel like kerosene or diesel, or a draw through motorcycle carb for a primary fuel system. Looks like a spring scrounging and summer in the garage.
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Feb 03 2004 : 09:23:44 AM
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My plans were basically as follows to eliminate most of the external "junk":
1. Oil system. Fuel injection pump using a thin weight oil (such as the 0W-20 my Insight uses...like water). Little valve to control pressure.
2. Fuel system. Another fuel injection pump (they will make 80 PSI) spraying diesel fuel through a standard fuel injector (gas). A PWM circuit to control the injector.
3. Ignition. HV generator on my cicuits page
This effectively eliminates all of the stuff that make many of those designs bulky. Also, you will REALLY want to watch the two Junkyard Wars jet challenges. In the first, one team constructs a turbojet, the other team builds a turbofan engine. This season, the first team built a wicked pulse jet, and the other ddi another turbojet...Often the camera angles reveal the details even though they don't really get into that on the show.
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cirvin
Nobel Prize Winner
USA
1542 Posts |
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Feb 03 2004 : 7:09:36 PM
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Most of the ones ive seen are air cooled. you would need a metal tank for the oil I would think.
pressurising the fuel that way would only bring it to the same pressure as the jet. It really wouldnt move any oil.
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cirvin
Nobel Prize Winner
USA
1542 Posts |
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Feb 03 2004 : 8:47:18 PM
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thats what the oils for and why you have it in a metal container (like aluminum) it would also be wise to use a microcontroller to run it ie starting and keeping the oil flowing untill the turbo quits spinning and cools down
Edited by - beatonno1 on Feb 03 2004 8:49:34 PM |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Feb 04 2004 : 09:16:28 AM
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quote:
I would think.
pressurising the fuel that way would only bring it to the same pressure as the jet. It really wouldnt move any oil.
Not sure what this means...You don't really need much fuel pressure. Many people just pipe propane directly in from the tank...
quote:
thats what the oils for and why you have it in a metal container (like aluminum)
Yep. A smal oil resevoir and either a specially made oil cooler (expensive) or an old car heater core (cheap) would be needed. Especially with such a lightweight oil.
quote:
it would also be wise to use a microcontroller to run it ie starting and keeping the oil flowing untill the turbo quits spinning and cools down
Or just a switch.  Cut fuel and the combustion process stops, then turn your oil pump off manually afterwards.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Feb 04 2004 : 7:19:58 PM
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When I said:
quote:
I would think.
pressurising the fuel that way would only bring it to the same pressure as the jet. It really wouldnt move any oil.
I was referring to:
quote:
I was planning on bleed pressure through a welding regulator into an airtight oil tank to provide oil pressure
bleeding pressure from the turbojet into the oiltank wouldnt cause the oil to flow through the berring.
as for the microcontroller, that would be to make it idiot proof  . However I think the lots of buttons valves and guages look would be cooler
as for the cooling of the oil there are lots of ways to do it. A well designed oil tank would function just as well as an oil cooler. However, i dont see how you plan to cool it with a heater core.
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Feb 05 2004 : 10:14:42 AM
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quote:
However, i dont see how you plan to cool it with a heater core.
A heater core is just a little radiator. Pump the oil through it, circulate air with a fan.Or even better, put it in the intake stream of the compressor to slightly preheat your combustion air.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Feb 05 2004 : 12:29:07 PM
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Ok gotcha. my trucks got one but ive always called them oil coolers.
I have heard about heating the incomming air, however I would think it would be better to cool it, so that you would have a larger volume of air in the combustion chamber.
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Feb 05 2004 : 3:10:55 PM
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I was thinking that preheating air in a turbine would be better, but you're right. Cold air is always better, no matter the application.
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BEatonNo1
Nobel Prize Winner
USA
1133 Posts |
Posted - Feb 05 2004 : 6:50:42 PM
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I think I saw a site where they had two intercoolers. one cooled the air before it went throught the compressor the second after the compressor, heated it up with the exhaust.
that makes some sence because you would be causing it to expand more, but for all that trouble I dont think it would effect the output that much
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Chamkeeper
Mad Scientist
278 Posts |
Posted - Feb 06 2004 : 12:48:15 AM
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Im glad this post got at least a little rise finally. Good folks on this site always spark intellectual thoughts. From my reading only a few pounds of oil pressure are enough, as long as the oil is cool and clean. Therefore, a sealed vessel, with a few pounds of air pressure on the top side and fresh clean oil on the bottom, plumbed to the bearings from the bottom can easily provide the few pounds of oil pressure required. I have used this system before on other machines. Fuel pressure will be dependent on the injector(s). The two should work fine matched and should help specify an ignition device. Fuel atomization and type dictating initital compustion. It's only suck-squeeze-burn-blow, how hard can it be?
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Turbo to thrust turbine
