On 13/08/2014 15:29, The Natural Philosopher wrote:
....
Kelvin should have known better: birds which are heavier then air flying
machines already existed. However if he didn't know about the internal
combustion engine, he as in fact quite correct. Without the internal
combustion engine heavier than air flight was impossible....

In 1894 Hiram Maxim managed to build a 3.5 ton, 110ft wingspan steam
driven aircraft that produced an estimated 10,000 lbs of lift. It made
successful restrained flights, but he was still working on how to
control it in free flight when it broke free of its restraints and
crashed. However, he did demonstrate that steam powered flight was
feasible.

There was also quite a lot of interest in steam powered flight in the
early 1930s and at least one steam powered aircraft made several
successful flights in the USA.

--
Colin Bignell