Richard Riley wrote:
So you build your aircraft engine so it's best fuel economy is at full
throttle. If it's not getting it's best economy during decent and
landing, that's fine, it's at idle anyway.

You must be thinking of fixed-wings Richard. A helo's engine only goes
to idle during and auto not during decent nor landing. Actually during
landing a helo uses a whole lot of power, more than while flying (due
to loss of translational lift).

Bryan "The Monk" Chaisone