Hello,

The changes in density are pretty minor with temp, more with altitude.
The airfoil
doesn't really feel the change, but if an airplane going 100mph climbs into
thinner air,
the airplane feels less drag so it speeds up. At the higher speed, the quick
thin air feels
just like the thicker slower air. A lear jet that is doing 250 kts at sea
level, is really
going about 250kts. The same airplane showing 250kts on the airspeed
indicator at 45,000
feet is actually moving about 450kts.

Al CFIAMI



"TravisRogers" wrote in message
...
Hi All,

The density of air changes notably with changes in temperature which
results in differences in lift to an airfoil. After putting on my mad
scientist cap, I got to wondering -- are there any other methods of
altering the density of air? Perhaps using radiation of a particular
wavelength (from radio to gamma) or other perhaps other methods?

In particular, I'm wondering if it is possible to change the density of a
specific predetermined volume of the atmosphere. The idea is to create an
area of the atmosphere that is far too thin or far too thick to be
compatible with an airfoil, thus denying the area to (terrorist) aircraft.

This whole thing sounds pretty far out there but it's amusing to think
about. Any thoughts?