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#41
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Bill Daniels wrote: You know, I just don't buy the "skin radiators won't work" theory. The pre-war Schneider Cup Seaplane racers did use skin radiators to cool some really big engines. There are LOTS of reasons skin radiators weren't used on WWII fighters - bullet holes being one. Since then, piston aero engines have been air-cooled. I don't either. A diesel fuel-cooled plant would NOT use raw fuel in its coolant passages. It would have a conventional glycol "primary loop", with a radiator-behind doors or (in front of) cowl flaps, a cabin heat exchanger ("heater core" in autoese), and an intercooler with fuel circulated through it and returned to tanks. It would be designed so the fuel loop could be shut off-bypassed- when the rad had its doors open as would be done when the aircraft was very low on fuel, or in high thermal load situations. At altitude (this is a turbodiesel and flies at high FL) the ambient temperature is very cold and the normal radiator could be blanked off largely or entirely. If the tanks are designed with a lot of surface area they will cool a large percentage of the engine's total heat rejection and additionally provide anti-icing. The main requirement as I see it is the system has to be default failsafe and provide single lever power control. Unless you want to make it a two person flight crew aircraft and haul a FE along. |
#42
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GeorgeB wrote: On 26 Sep 2005 14:47:36 -0700, " wrote: The lubricity issue is one that I asked a buddy of mine aobut when Thielert said their "auto based" engine would run JetA ... Enquiring minds would like to know more. Detroit Diesel sent out a notice recently that their Series 50 and 60 engines are now authorized to use DF-1, DF-2, JP-5/Jet-A and JP-8 with full warranty support. Airports have always run ramp tugs, fuel trucks (the Brits call them "bowsers"), and start carts on Jet-A. Jet-A is NOT K-1 Kerosene, it has a lubricity standard which is higher, and it's fine in most diesel pumps. Adding some SAE 30 nondetergent oil to the fuel, or filtered drain oil NOT contaminated with lead deposits, helps lubricity and will offer added protection. I would not use two cycle oil because it has octane improvers in some cases-octane improvers are cetane killers! There is good reason to find a far higher percentage of diesel car ownership among airline and corporate A&P's than one would expect. |
#43
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Alan Petrillo wrote: Philippe Vessaire wrote: No anti-froze agent needed, just an fuel/water heat exchange and the whole tank become warmer when the engine is runnig. For pure biodiesel, the car choice is an exhaust/fuel heat exchange. I've never seen this. All of the biodiesel/vegoil cars I've seen have used coolant/fuel heat exchangers. AP A lot of the car retrofits bypass the fuel return. The piston-pump diesels typically have 2 fuel lines, one up and one back. If you had a consistently high flow you potentially could use the return line to feed heated oil to to the tank. In the case of biodiesel this would probably be sufficient to heat the tanks. Though it would make plumbing fuel tank selector a bit more complicated. -Matt |
#44
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Alan Petrillo wrote: Morgans wrote: wrote The other possibility would be to stick a radiator in each wing root and funnel ram air through the radiator into the wing cavity. The warmed air would then be the heating element. I wonder if that would be sufficient to prevent gelling and also provide some minor wing heat without all the complexity. You really need to take some physics and thermodynamics. Right now, you need to buy a vowel. I'm only kinda kidding. What you are proposing isn't being done, because it won't work. Sorry. Well, again, has anyone done the engineering on this? As I understand it, what he's talking about is simply using underwing radiators and ducting the exhaust air from the radiators through the interior of the wings before allowing it to flow out of exhaust ports. I can see how it might work, the question is how well it would work. Would it provide enough heat to the wing skin to keep ice from adhering to it? AP Thanks Allan, One of the remaining issues of course is that it is my understanding that it typically isn't the wing ice that kills you. It is the ice on the elevator and horizontal stab. Doh! You end up trimming out the effect of the ice until there is no more trim left and... Bonzai! I only have 250 hours, and have never experienced icing personally. Given that cabin heaters are only a foot or two of exhaust pipe, I to have to second guess Jims assessment of the situation. Though I do remember being a little frosty at 10K MSL in the winter in my M20E, I did at least get _some_ heat. 1. With a liquid cooled engine you _have_ to have an auxillary heat sync of some kind. 2. If waste heat can be used to improve safety or performance it should be. 3. Using biodiesel presents additional safety hazards related specifically to loss of thermal energy that _have_ to be engineered out for the fuel to become suitable for aviation use. From where I stand all of that kind of goes together. Wait... let me get my rain coat. I hear Jim comming. -Matt |
#45
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Well you see, there are these things called electric heating elements.
And low and behold some are even certified to install in real live flying machines! And if we are really quite and sneak up on the guys who manufacture them... Can I buy an "o" -Matt |
#46
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wrote A lot of the car retrofits bypass the fuel return. The piston-pump diesels typically have 2 fuel lines, one up and one back. If you had a consistently high flow you potentially could use the return line to feed heated oil to to the tank. In the case of biodiesel this would probably be sufficient to heat the tanks. It would seem to cause a problem if the tank were sitting for a period of time in the cold, yes? What then? -- Jim in NC |
#47
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Here is the VW tdi as an industrial engine.
Given the application I would expect there is a big honkin flywheel on this thing that would be removed for aviation purposes. Then after replacing the the alternator etc etc. It would still be heavy, but potentially doable. http://www.maesco.com/products/vwp/v...dieselpto.html Anyway, it's something interesting to look at. -Matt |
#48
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wrote in message Here is the VW tdi as an industrial engine. Given the application I would expect there is a big honkin flywheel on this thing that would be removed for aviation purposes. Then after replacing the the alternator etc etc. It would still be heavy, but potentially doable. I would wonder about the potentially doable part. It is nearly 300 lbs, and only 78 HP. Even if you could get 100 lbs off of it, (doubtful) that would still be 200 lbs, for less than 80 HP. That is bad in anybody's book. -- Jim in NC |
#49
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If I had said "spectacular" I would understand your beef.
Here are the respective weights of a few engines for comparison. Engine HP Weight(lbs) Comments ------------------------------------------------------------------------------------ Continental A-65 65 173 Limbach L 1800 66 154 Limbach L 1700 66 161 Rotax 618 74 136 Includes 20 lbs radiator, etc. Great Plains VW 2180CC 75 165 Franklin 225 75 230 _______________________________________________ "doable". It wouldn't be efficient. But it would fly. If one fiddled with the wastegate or injection computer they could probably get more power. The guys with the powerstrokes are doing some crazy things these days and some of that tech would probably carry over to the TDI. What do you fly by the way Jim? Can i get an "s" ? -Matt |
#50
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Maybe some of these will help. Seem to be working well in the cars.
http://dieseltuning.ca/ http://www.upsolute.com/eng/index.html Some talk about the rocket chip: http://www.upsolute.com/eng/index.html Some controls can be programed with this: http://www.ross-tech.com/ David Ervin wrote in message oups.com... Here is the VW tdi as an industrial engine. Given the application I would expect there is a big honkin flywheel on this thing that would be removed for aviation purposes. Then after replacing the the alternator etc etc. It would still be heavy, but potentially doable. http://www.maesco.com/products/vwp/v...dieselpto.html Anyway, it's something interesting to look at. -Matt |
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