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Take a look at the more economical modern GA aircraft. A Cirrus SR22 can run at 10 gallons per hour, with a ground speed of 160+ mph. Yes, it’s more total fuel

by _jss 2y ago

Take a look at the more economical modern GA aircraft. A Cirrus SR22 can run at 10 gallons per hour, with a ground speed of 160+ mph. Yes, it’s more total fuel consumption than a car (but in an hour covering 2x the distance, and allowing to travel more directly) but not at all close to turbine or turboprops. At the extremely cheap (accessible to more pilots) side for pressurized planes, fuel burn is going to be 40gph and it just goes up from there. There are many variables, and winds work for or against—but by doing good flight planning you use the winds to your advantage. There is also a lot of research on better aviation fuels (100ll :(((). I’m excited about that part of it, more so than the current electric planes (although electric self-launching gliders are pretty neat) MOSIAC is going to make light sport aircraft more useful, which will also help in this area. Tons of interesting stuff happening here!

n_ermosh 2y ago
yep! lots of interesting stuff indeed! Our plane will be ~7 gph at cruise burning unleaded fuels and fly ~170mph over the ground (with no wind)
- entropie 2y ago
  For my part, I find it questionable to invest in and develop a transport technology that consumes seven times as much fossil fuel as a car. You give consumption of 7 gallons in cruise mode. I don't want to know what is burnt during take-off or landing.
  - lutorm 2y ago
    How do you get seven times? Takeoff constitutes a negligible part of the total fuel consumption. Climb to altitude uses more, but you get that back when landing since you're then using your stored potential energy. Small-aircraft GA is a vanishingly small fraction of total fossil fuel use, and it will be quite easy to replace that with some renewable fuel solution (compared with the huge amounts of fuel consumed by transport aircraft). For my part, I think it would be a shame to kill GA because of a temporary and relatively unimportant concern.
    - Aachen 2y ago
      > Small-aircraft GA is a vanishingly small fraction of total fossil fuel use OP wrote: "We want people who don’t think about airplanes as a mode of transportation to start flying" They're meaning for this to become a larger fraction, besides that the relevant measure is pollution per benefit or per capita or something rather than absolute amount of pollution
      - lutorm 2y ago
        So you're concluding that there is no benefit to general aviation because, presumably, you don't fly? I think we should absolutely keep airplanes as a mode of transportation, because the alternative is that all small airports go away and then it won't matter when renewable fuels become a reality because there will be no longer be anywhere to land and take off. Those airports would not come back.
        Aachen 2y ago
        > because, presumably, you don't fly? First off, you've got this backwards. One doesn't have an opinion because one flies or not; conversely, one flies or not because one concludes their situation does or does not warrant the pollution for a particular destination But equally weird, why are you making this about me personally? If I say I don't fly, that's probably unusual where you're from so I'll be the environmentalist out-group whose opinion is too extreme and can be dismissed. If I do I'll be considered a hypocrite (like what you called someone in the other thread). I can tell you the answer is a middle ground but I don't think it helps anyone here to make this about me. I'd much rather make this about facts and science rather than opinions and feelings > I think we should absolutely keep airplanes as a mode of transportation I agree, but since nobody said anything to the contrary, that seems like a given
    - entropie 2y ago
      > How do you get seven times? I asked chatgpt what the average consumption of a car is; the answer was 0.5-1 gallon on a highway.
- callalex 2y ago
  That’s only 25 mpg which is widely considered to be unacceptably unsustainable even in the short term.
  - pbronez 2y ago
    A Quick Look at FuelEconomy.gov shows many modern cars for sale with highway efficiency of 25mpg or less. Some (many?) people may judge it unconscionable, but it’s clearly acceptable to the broader market and current regulations. These models seem to be big (Volkswagen Atlas, Subaru Ascent, Ford F150) or fast (Audi RS5, Porche 911, Kia Stinger). If you can get similar mpg from an airplane that carries four people and their luggage at 100+ mph ground speed on a more direct (shorter) route… that’s very compelling to me. https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&year1=2023&year2=2024&minmsrpsel=0&maxmsrpsel=0&city=0&hwy=25&comb=20&YearSel=2023-2024&make=&mclass=&vfuel=&vtype=&trany=&drive=&cyl=&MpgSel=02025&sortBy=Comb&Units=&url=SearchServlet&opt=new&minmsrp=0&maxmsrp=0&minmpg=0&maxmpg=0&sCharge=&tCharge=&startstop=&cylDeact=&rowLimit=50&pageno=32&tabView=0 https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform...
  - FabHK 2y ago
    So, reducing car emissions by a just 1% would be way better for the environment than entirely removing all piston engine aviation. There are about 15m cars sold in the US every year, but around 1500 piston engine planes. That's a factor of 10,000. There are some 210m cars in use in the USA, but around 150k piston engine planes. That's a factor of 1400 (reflecting the fact that planes have a much longer life than cars, further contributing to their lower environmental impact). Every day, cars burn more fuel than light airplanes burn in a year. This project is a minuscule rounding error in climate change drivers.
limitedfrom 2y ago
You can argue for its convenience/speed/fun, but fuel efficiency does not look good for GA aircraft. Even for your modern GA aircraft example, it literally comes to 16 mpg. This is as bad as worst of the trucks out there. While it's great if existing use cases of GA aircrafts would become more efficient, adding demand in this area (more hobbyists, more rich people shuttling use, encouraging people to live in very remote areas, etc.) and using it as transportation-mode will unlikely ever become environmentally reasonable.
- _jss 2y ago
  All that is true, but it’s also getting better. And 16mpg over shorter routes (a 100nm flight vs 200 mile drive is not unusual) makes it harder to compare apples to oranges. We don’t really have hybrid planes yet, which will likely help in the most inefficient parts of flying (climb). My comment is to add more information to the discussion to consider many aspects, not to make claims that it’s a fuel-sensible method of travel. I am excited for innovation here, just like I am excited for the continued improvements in hybrid and electric cars.

by _jss 2y ago

n_ermosh 2y ago

yep! lots of interesting stuff indeed! Our plane will be ~7 gph at cruise burning unleaded fuels and fly ~170mph over the ground (with no wind)

entropie 2y ago
For my part, I find it questionable to invest in and develop a transport technology that consumes seven times as much fossil fuel as a car. You give consumption of 7 gallons in cruise mode. I don't want to know what is burnt during take-off or landing.
- lutorm 2y ago
  How do you get seven times? Takeoff constitutes a negligible part of the total fuel consumption. Climb to altitude uses more, but you get that back when landing since you're then using your stored potential energy. Small-aircraft GA is a vanishingly small fraction of total fossil fuel use, and it will be quite easy to replace that with some renewable fuel solution (compared with the huge amounts of fuel consumed by transport aircraft). For my part, I think it would be a shame to kill GA because of a temporary and relatively unimportant concern.
  - Aachen 2y ago
    > Small-aircraft GA is a vanishingly small fraction of total fossil fuel use OP wrote: "We want people who don’t think about airplanes as a mode of transportation to start flying" They're meaning for this to become a larger fraction, besides that the relevant measure is pollution per benefit or per capita or something rather than absolute amount of pollution
    - lutorm 2y ago
      So you're concluding that there is no benefit to general aviation because, presumably, you don't fly? I think we should absolutely keep airplanes as a mode of transportation, because the alternative is that all small airports go away and then it won't matter when renewable fuels become a reality because there will be no longer be anywhere to land and take off. Those airports would not come back.
      - Aachen 2y ago
        > because, presumably, you don't fly? First off, you've got this backwards. One doesn't have an opinion because one flies or not; conversely, one flies or not because one concludes their situation does or does not warrant the pollution for a particular destination But equally weird, why are you making this about me personally? If I say I don't fly, that's probably unusual where you're from so I'll be the environmentalist out-group whose opinion is too extreme and can be dismissed. If I do I'll be considered a hypocrite (like what you called someone in the other thread). I can tell you the answer is a middle ground but I don't think it helps anyone here to make this about me. I'd much rather make this about facts and science rather than opinions and feelings > I think we should absolutely keep airplanes as a mode of transportation I agree, but since nobody said anything to the contrary, that seems like a given
  - entropie 2y ago
    > How do you get seven times? I asked chatgpt what the average consumption of a car is; the answer was 0.5-1 gallon on a highway.
callalex 2y ago
That’s only 25 mpg which is widely considered to be unacceptably unsustainable even in the short term.
- pbronez 2y ago
  A Quick Look at FuelEconomy.gov shows many modern cars for sale with highway efficiency of 25mpg or less. Some (many?) people may judge it unconscionable, but it’s clearly acceptable to the broader market and current regulations. These models seem to be big (Volkswagen Atlas, Subaru Ascent, Ford F150) or fast (Audi RS5, Porche 911, Kia Stinger). If you can get similar mpg from an airplane that carries four people and their luggage at 100+ mph ground speed on a more direct (shorter) route… that’s very compelling to me. https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&year1=2023&year2=2024&minmsrpsel=0&maxmsrpsel=0&city=0&hwy=25&comb=20&YearSel=2023-2024&make=&mclass=&vfuel=&vtype=&trany=&drive=&cyl=&MpgSel=02025&sortBy=Comb&Units=&url=SearchServlet&opt=new&minmsrp=0&maxmsrp=0&minmpg=0&maxmpg=0&sCharge=&tCharge=&startstop=&cylDeact=&rowLimit=50&pageno=32&tabView=0 https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform...
- FabHK 2y ago
  So, reducing car emissions by a just 1% would be way better for the environment than entirely removing all piston engine aviation. There are about 15m cars sold in the US every year, but around 1500 piston engine planes. That's a factor of 10,000. There are some 210m cars in use in the USA, but around 150k piston engine planes. That's a factor of 1400 (reflecting the fact that planes have a much longer life than cars, further contributing to their lower environmental impact). Every day, cars burn more fuel than light airplanes burn in a year. This project is a minuscule rounding error in climate change drivers.

limitedfrom 2y ago

You can argue for its convenience/speed/fun, but fuel efficiency does not look good for GA aircraft. Even for your modern GA aircraft example, it literally comes to 16 mpg. This is as bad as worst of the trucks out there. While it's great if existing use cases of GA aircrafts would become more efficient, adding demand in this area (more hobbyists, more rich people shuttling use, encouraging people to live in very remote areas, etc.) and using it as transportation-mode will unlikely ever become environmentally reasonable.

_jss 2y ago
All that is true, but it’s also getting better. And 16mpg over shorter routes (a 100nm flight vs 200 mile drive is not unusual) makes it harder to compare apples to oranges. We don’t really have hybrid planes yet, which will likely help in the most inefficient parts of flying (climb). My comment is to add more information to the discussion to consider many aspects, not to make claims that it’s a fuel-sensible method of travel. I am excited for innovation here, just like I am excited for the continued improvements in hybrid and electric cars.