Cosmic Unveils Four-Seat Electric Airplane

News Discussion
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Originally published at: Cosmic Unveils Four-Seat Electric Airplane

The company targets a 2028 prototype flight and deliveries beginning in 2029.

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Who is going to build out the infrastructure for charging electric aircraft?
What good is 250 mile range if the destination airport can’t recharge your aircraft?

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This airplane is pure fantasy in the timelines they are laying out. Battery density isn’t increasing that fast. And that’s just for starters.

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No, they unveiled an idea. Hopeful one at best.

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A few thoughts, based on having done some systems engineering on electric aircraft in the past.

  1. The maximum speed may be 250 kt, but the 250 nmi range is likely to be at about 140 kt, based on the “2+ hours duration” calc. (Figure 2.25 hours, allow 30 mins for VFR reserves leaves 1.75 hours. 1.75 hours at 140 kt is 250 nmi.)
  2. It will need to have very low drag, with a max L/D around 25, which is tough but not impossible. The max L/D speed would be more like 90 kt, given that MOSAIC requires a stall speed down near 60 kt. At 140 kt it would have an L/D closer to 20.
  3. It will need high propulsive efficiency. I’m no ducted fan expert but that feels like a challenge for this design. Ingesting the boundary layer isn’t going to make up for the small propulsors. A more efficient design would use one or two (or four) props to get a large propulsor area.
  4. It will need a very high structural efficiency. The battery is going to be about half the total MTOW. When you allow for systems, interior, motors, inverters and passengers, there isn’t going to be a lot of weight available for the actual structure. It’s not impossible. It’s definitely going to require carbon fiber and ingenuity.
  5. Charging. 'Nuf said.
  6. Range. This is a go-places airplane with a very limited range. Training market, sure. Private owners… hmm. Very cool, but a personal airplane that goes 250 nmi and then has to stop AT AN AIRPORT WITH HIGH-SPEED CHARGERS is going to be very limiting. And combine that with a realistic 140 kt cruise speed (or maybe less)… it’s not going anywhere very fast.
  7. Very cool :slight_smile:
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