"Andrew Sarangan" wrote in message
oups.com...
On Sep 13, 10:41 pm, "Matt Barrow"
wrote:
"Andrew Sarangan" wrote in message

ups.com...

The airframe gains efficiency with altitude, but the engine loses
efficiency with altitude.

How does the airframe "gain efficiency" at altitude, aside from
generating
less drag?

It gains efficiency because you can move faster for the same engine
power.

That's not the airframe gainning efficeincy, that's called a reduction in
drag.

If you disregard drag, then you might as well disregard the
engine too because thrust = drag at level unaccelerated flight.

I'll have to dig through my library of physics books to 'splain that one.
:~)

The engine loses the _ability_ to generate power, but that has noting to do
with your T=D formula.

Think: turbocharging.

The airframe is static, so there's no gain or loss in efficiency.

Now, if you have a wing like the F-14, that could be considered as a whole
different story.