Flight

["Ken Rogers" <>]

In normal flight, the trailing edge of each wing creates a downward and
backward moving vortex ring.  The reaction to this is an upwards component,
which helps to keep the bird up, and a forward component, which helps it to
move forward.  In the case of Terry's bird, all the thrust was upward and
there was no forward component.  This raises the interesting possibility
that, for a short distance at least, the bird may be able to accelerate
faster upwards than it could forwards!

Ken Rogers