Quadcopters tend to have very poor efficency because of their high disk loading. High disk loading– that is, how much weight each square meter of area swept by the propellers must carry–is almost ...

Barring the smallest manned airplanes, most aircraft that are pulled around by a prop have variable pitch propellers. The reason for this is simple efficiency. Internal combustion engines are most ...

Now that we have definitely arrived in the 21st Century, you'd think that the military with their substantial budgets would have only the latest and most fancy technology flying in the sky. They do, ...