8M views · Apr 3, 2017 · 18:03 · 0 HN recommenders · 3 mentions · discussed 2018–2022
Peter Sripol builds and flies an RC aeroplane whose wings are rotating KFC buckets, using the Magnus effect (Flettner rotors) for lift. It is a hobbyist experiment in unconventional aerodynamics.
Why Hacker News points people here: HN cites it as a fun, concrete demonstration that Magnus-effect rotating cylinders can generate enough lift to fly.
“But it sure does produce enough lift to let things fly!”HN comment, 2020
“Always down to experiment and obviously thinks big.”
Peter Sripol's Magnus effect RC plane experiment
I've only seen Peter in his guest spots on Flite Test. One of the sweetest and coolest dudes on that channel. Always down to experiment and obviously thinks big. Edit: Case in point, magnus effect plane - this video
“But it sure does produce enough lift to let things fly!”
Rotating cylinders producing enough lift to fly
Potential flow theory tells us that the lift L is L = rho U Gamma, where rho is the air density, U the flight velocity, and Gamma the circulation, i.e. the tangential velocity of the rotating surface times the circumference. L is then only proportional to the radius, not to the square of the radius. But it sure does produce enough lift to let things fly! this video
“Magnus effect planes are a thing”
Example of a Magnus effect plane
My understanding is that planes don't fly directly upside down, and they angle the wing slightly to make a kinda-sorta-airfoil. How helicopters can turn directly upside down, and fly that way[1], without reversing the direction of their props, that I don't get. (Thinking about it now, I think it turns from a helicopter to a hovercraft? Eg, this is a ground effect?) [1] link Also, tangentially, Magnus effect planes are a thing: this video
