Hacker News Reader

Comment by gsinkin | Hacker News Reader

What are the benefits of having an electric motor? I imagine that fewer moving parts means less maintenance and lower odds of failure, but what are the other advantages? Quieter perhaps? Are these aircraft going to be loaded up with battery packs? How is that going to work?

View on HN

this article does a fair amount of discussion on advantages. Basically it is quiet, has no on-site emissions, and is theoretically more efficient. They also go on to mention that it loosens some design constraints. http://www.technologyreview.com/news/516576/once-a-joke-batt...

Those would be advantages of an all-electric aircraft, however this article is not about that. This article is about an electric motor that could be used in a series-hybrid aircraft, that is, one with a fixed-speed combustion engine and small battery or capacitor.

The original article mentions hybrid but does not say the motors are exclusive to hybrid drives, merely that the motor will be flight tested in a series-hybrid DA36. Besides, the MIT article I linked enumerates the benefits of the hybrid drive. The word 'hybrid' is in the subtitle. I suspect Siemens is focusing on hybrid tech at the moment because battery tech is such a moving target and they want to use an existing airframe. Ultimately, I think all-electric aircraft will find their market in short-flight urban transport applications where noise, pollution, and reliability are huge factors.

The quiet aspect probably has a lot of value in military applications. And it'd be useful in the solar powered unmanned planes we see, but maybe the energy requirements for this are too high.

Even if the motor is quiet you still have the propeller making a lot of noise. I (honestly) don't know if you can really get it quiet enough for the motor's noise to be important.

> The propeller, even at 500 feet over the maintenance area, made only a light flutter, heard just as it approached.

http://en.wikipedia.org/wiki/Lockheed_YO-3

The largest source of propeller noise is transonic flow at the tips, so turning the propeller slowly helps significantly. The tradeoff is a larger propeller and more expensive engine installation due to the required gearbox.

A solar-powered sea-plane would be pretty awesome. Probably not enough range to cross an ocean in one go, but you just land, do some fishing, then take off again the next day.

Reply on news.ycombinator.com