• Hildegarde@lemmy.world
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    3 months ago

    The plane in the article is a 4 ton airplane, they mention plans to make an 8 ton commercial aircraft.

    The Learjet 31 is 4.4 tons. It seats 8 passengers. The Cessna CitationJet CJ3+ is right around 4 tons with a maximum of 9 passengers.

    The future 8 ton aircraft is around the size of the 10-ton Dash 8 Q200 with a maximum of 40 seats.

    There are commercial uses for aircraft this small, but these jets are significantly smaller than most commercial aircraft.

  • rockSlayer@lemmy.world
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    3 months ago

    For battery tech nerds like me, the battery is a more efficient lithium-iron battery, called Lithium Manganese Iron Phosphate or lmfp. It has a theoretical energy density of 525Wh/L, compared to normal lithium-iron theoretical density of 325Wh/L

    • Hildegarde@lemmy.world
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      3 months ago

      For context jet fuel is around 9,720 Wh/L. However, energy density(energy per volume) is less important in aviation than specific energy(energy per mass) as weight is far more likely to be the limiting factor.

      A standard lithium ion battery has 100-265 Wh/kg

      The article claims 500 Wh/kg in this new battery.

      Jet fuel has around 12,000 Wh/kg.

      Though this is a major improvement in battery tech, batteries are unlikely to ever improve to the point to even approach the energy storage of liquid fuels.

      Batteries cannot run commercial aviation as it currently exists. Battery planes will need to fly slower and shorter. There is no other way.

      • sexual_tomato@lemmy.dbzer0.com
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        3 months ago

        What’s the efficiency for turning jet fuel into mechanical work? I’d suspect the efficiency is somewhere around 45% for liquid fuel where it’s nearly 100% for electric. So you’re really trying to reach the equivalent of 5500 Wh/kg.

        • Hildegarde@lemmy.world
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          3 months ago

          I got the number from wikipedia. Following the references, the number came from a BP datasheet about Jet A-1, where it is listed on a typical properties table, and the number is the net specific energy, which means it accounts for the inefficiency of the engines. Or at least that’s my assumption.