| The problem is that airplanes cost energy to stay in the air. There’s a well-known relation that an airplane operated at best economy (most are) costs ~0.4kWh/ton-km [1]. That per ton of total mass in the sky. So the problem is that, with current battery technology, the total weight of a battery electric plane is around 3x that of a fossil plane[2]. Taking into account typical efficiency, that means a battery plane requires more energy to move a given amount of cargo a given distance. And that’s with using relatively ancient fossil fuel engines. Unless batteries get markedly better, you’re better off just synthesizing liquid hydrocarbon fuel from atmospheric CO2 and solar panels. [1] https://www.withouthotair.com/cC/page_274.shtml [2] I’ve seen battery conversions of a Cessna 208 and a Cessna 337. After conversion, they have roughly the same payload of a Cessna 182 and Cessna 172, respectively. The gross takeoff weight of the battery plane ends up about 2.5-3x that of the smaller fossil plane, assuming same payload and fuel to fly equivalent distance. In both instances range drops from ~800 miles to ~200. For another example, look at the Pipistrel Velis Electro: with daytime VFR reserves, range is less than 70 miles (my estimate, because Pipistrel actually doesn’t quote a range estimate, stating that endurance for training sorties is “the appropriate parameter to quote”). A Cessna 162 has the exact same gross weight (both are LSAs), but a 38% higher rate of climb, and roughly 5x the range with same payload. Pipistrel also had to make other compromises: 162 has a 20% shorter takeoff roll and 20% lower stall speed, too. |