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CNG alternative? Dual-fueled Husky to be at AirVenture
http://www.aviataircraft.com/cng/
Kinda surprised by this, but can't tell if the 7 hour claim is CNG only or CNG + LL tanks from the story: Q: How long can you fly the Husky CNG on full fuel tanks? A: The demonstration aircraft can be flown approximately seven hours at a 65 percent power setting. Q: What does GGE mean and how does that relate to AVGAS? A: GGE stands for ?gas gallon equivalent,? that is the amount of compressed natural gas it takes to equal approximately one gallon of gasoline in terms of energy. One GGE of natural gas is 123 cubic feet and weighs approximately 5.66 lbs. vs. 6.01 lbs. for 100LL AVGAS. |
So the fuel is close in weight, not surprising considering they both come out of the same hole in the ground.
What comes immediately to my mind is; What is the tank weight???? If it is hard to find Mogas at an airport, what do you think it is going to be like to find a CNG pump?? |
I saw these guys yesterday. I was going to stop and ask the same question about the tank. I'm also curious how they maintain a consistent pressure. I'm going back on Thursday, I'll ask when I go by.
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Neat
All the way at the bottom of the page...
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After reading the linked info.........
So, the full tank weighs just under 150 pounds, and it seems that you would usually have to take it somewhere to fill it.
Then, put it back in the plane------oh my aching back:rolleyes: Here is an interesting quote lifted from the link, " We have noted several performance advantages using CNG over aviation gasoline. One is increased power output given that octane rating of natural gas is typically 138 vs. aviation gasoline?s 100." Am I the only one who has a bit of trouble with this statement??? |
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Also, the BBQ runs on propane, not CNG. |
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The increased power output is a bit of a stretch - cube for cube and all other things being equal, CNG engines normally deliver about 80% of the horsepower that an equivalent gasoline engine will at the same RPM and manifold pressure. |
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Horse power is not effected by octane. http://www.whitfieldoil.com/www/docs...p-racing-fuel- |
Correct, but higher octane fuels have higher detonation margins can be run leaner and with more advanced timing, which directly leads to more power.
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With a higher octane fuel you can do a few things to boost power that a lower octane fuel will not support without detonation. But changing the fuel alone will not make a difference if the engine is tuned for the lower octane fuel. It is all about inter cylinger pressure. Supercharging, higher compression ratio, advancing timing, intake runner tuning, exhaust tuning------all can lead to higher ICP, and that is what will give more oomph------and will likely require higher octane to keep the engine from self disassemble. But the octane is not the cause of the power increase in any significant percentage. Read what the quote from the link says, not what you extrapolate from the statement. Quote:
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This exercise is more a PR stunt than a realistic alternative to avgas. I can see limited applications, but the availability/infrastructure problem will make it impractical for a long time. All of the buses and trash trucks in my town are CNG powered, but that is easy, they all return to the same spot every evening. Because of that, they do not require dual-fuel ability and can be built to get the maximum performance on CNG by running very high compression, they are converted diesels, to take advantage of the octane available.
John Clark ATP, CFI FAAST Team Representative EAA Flight Advisor RV8 N18U "Sunshine" KSBA |
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Now, when they fly a Husky on used fryer oil from Maccas.... |
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