Gravity powered aircraft concept

[hesham]

Hi,

Watch this project in youTube site and I think,it is just
imagine project;

https://www.youtube.com/watch?t=3&v=FnEzJpn6ZNs

picture via http://www.planetthoughts.org/?pg=pt/Whole&qid=2196

 

[Sundog]

We already have gravity powered aircraft. They're called gliders