3 ms·

Biological propellers: https://www.valhallahelicopters.com/wp-content/uploads/2019/02/AdobeStock_217364794.jpg https://www.valhallahelicopters.com/wp-content/up

by efitz 4y ago

Biological propellers: https://www.valhallahelicopters.com/wp-content/uploads/2019/02/AdobeStock_217364794.jpg https://www.valhallahelicopters.com/wp-content/uploads/2019/...