Why aren’t there battery powered airplanes or flying cars?
Preface. Batteries are too heavy for airplanes to get off the ground. These two articles explain that in further detail.
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Viswanathan, V., et al. 2018. Why Aren’t There Electric Airplanes Yet? It Comes Down to Batteries. Batteries need to get lighter and more efficient before we use them to power energy-guzzling airplanes. Smithsonian.
“…for a given weight, jet fuel contains about 14 times more usable energy than a state-of-the-art lithium-ion battery….the best batteries store about 40 times less energy per unit of weight than jet fuel. That makes batteries relatively heavy for aviation. Airline companies are already worried about weight – imposing fees on luggage in part to limit how much planes have to carry.”
So what about a flying car (e-VTOL)?
We looked at how much energy a small battery-powered aircraft of 2,200 pounds (1,000 kilograms, including a passenger) capable of vertical takeoff and landing would need. While actually flying, the air vehicle would need 400 to 500 watt-hours per mile, about what an electric pickup truck would need, which is twice as much energy used as an electric car.
But taking off and landing require a lot more power, at least 8,000 to 10,000 watt-hours per trip, or half the energy in a compact electric car such as the Nissan Leaf.
So for an entire flight of 20 miles you’d need 800 to 900 watt-hours per mile — half as much energy as a fully loaded semi-truck. Using that much energy means these aren’t likely to take off.
“Aircraft designers also need to closely examine the power – or how quickly the stored energy is available. This is important because ramping up to take off in a jet or pushing down against gravity in a helicopter takes much more power than turning the wheels of a car or truck.
…click on the above link to read the rest of the article…
