system
Given the following post, respond as if you're commenting on Reddit:
human
[Eli5] Why are wind turbines on a horizontal axis like a traditional windmill? Do they turn into the wind? If at a slight angle from wind direction doesn't efficiency drop? Wouldn't a tower-style set up, with blades spinning around a vertical axis spin regardless of wind direction?
gpt
Horizontal axis wind turbines do indeed turn into the wind. On some older smaller systems this was done by the help of a rudder so the wind would push the wind turbine in the right direction. However modern turbines use motors to turn them into the wind at all times. This would obviously not be needed with vertical axis wind turbines. And this style is being researched as a possible better alternative. However a big problem with vertical axis wind turbines is that the blades are only catching the wind perfectly once per revolution and is even going against the wind at times. While the blades on a horizontal axis wind turbine always have the perfect angle into the wind.