On Sep 13, 4:24 pm, Bob Moore wrote:
es330td wrote

I know that planes gain efficiency at altitude but
I don't know how high one must go to realize those gains.

Very true with jet engines....not so much with piston engines.
If you aren't turbocharged, you'll never make Class A airspace.

Bob Moore

The specs on the Aerocanard FG state that with an LIO-360 engine the
service ceiling is FL250. Not that I would be trying to make Class A
but according to the definition of service ceiling shouldn't this
plane be able to at least make FL180 and then some?