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dghlsakjgyesterday at 7:41 PM2 repliesview on HN

I'm super excited to fly an electric plane, but a lightweight motor isn't what's gonna make that possible. My current plane carries 561 kwh of energy in a 100 pound/ 17gal gas tank.

Even if you say the engine is only 30% efficient, I am still carrying an absolute shitload of energy compared to what I could get out of 100 lbs of lithium batteries.

The actual motor only weighs 84 lbs.

So I have a weight budget of 184 lbs (call it 200 just to be safe), and current capability is a peak output of 50hp (37 kw) and a cruise endurance of 3 hours at 40 hp / 30 kw. So just to math it out, lets say I will need about 90kwh of battery to come close to my current gas capabilities. At an extremely generous 5 kg per kwh, I need a battery that weighs more than my entire airplane's max gross takeoff weight. The weight of the engine is completely irrelevant when the battery weighs 450kg.


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amlutoyesterday at 9:10 PM

Quoting myself:

> Hybrid aircraft? What if there was a battery large enough for takeoff and landing, a small motor (or pair for redundancy) for cruising and to recharge the battery, and motors and fans or propellers wherever is best from an aerodynamic perspective.

Would this be better than a conventional design? I don’t know, but availability of very high power-to-weight motors would help.

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danjermausyesterday at 9:40 PM

Very curious about this because there are electric planes in testing, so how do they do it?

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