4 ms·
I tried to find a more precise answer but technically an ion-drive is an electric motor, so I'm guessing it's comparable. The thing is that based on the couple
by CSSer 4y ago
I tried to find a more precise answer but technically an ion-drive is an electric motor, so I'm guessing it's comparable. The thing is that based on the couple demos I watched the flight seems really erratic. It makes me wonder if the fuel supply is somewhat inconsistent i.e. air turbulence makes the actual theoretical energy efficiency moot.
- justusthane 4y agoI'm having trouble understanding why it would necessarily be comparable to a traditional electric motor in efficiency. Whether or not it's "technically" an electric motor, it's operating on completely different principles. The first things that come to mind are there are no moving parts to generate friction and heat, and it requires much higher voltage. Wouldn't those aspects alone swing the efficiency one way or the other?
- brianpan 4y agoBoth use electromagnetic force to move something. They are much more similar to each other than combustion, which is a chemical reaction. https://electronics.howstuffworks.com/brushless-motor.htm https://electronics.howstuffworks.com/brushless-motor.htm
- CSSer 4y agoIt was a big guess for sure. To be clear, I don't know. I did find this in my search, which suggests it's not exponential[0], so it seems you're correct. There's a drop-off at higher exhaust speeds, but it's unclear to me why that is. [0]: https://en.wikipedia.org/wiki/Ion_thruster#Energy_efficiency https://en.wikipedia.org/wiki/Ion_thruster#Energy_efficiency
- IIAOPSW 4y agoKinetic energy of the particles (which has to ultimately come out of the battery) is proportional to mv^2. Momentum of the particles (which is ultimately equal and opposite to thrust) is proportional to mv.
- tom-thistime 4y agoAn ion drive isn't really physically similar to a normal electric motor using an electromagnet.