"RST Engineering - JIm" wrote:
Those might get me airspeed but I'm not at all sure how you would get
theta from any one of these schemes.

I believe he means the vane is lightweight and freely pivots up or down so
that it is always pointing into the relative wind. The angle the vane makes
with some reference line on the wing or fuselage is thus the AoA. I'd post
a link to a picture of what it would look like (pretty simple concept) but
can't see to find one!

Just think of the yaw string on gliders (e.g. the red string in this
pictu http://www.highonadventure.com/Hoa08...eYawString.jpg)
but used to show vertical component of the relative wind, not horizontal.

Use variable capacitance, variable reluctance, resistor strip or
synchro connected to a vane. For a real giggle do as some Air Force
systems and employ a slotted, rotating cone for a probe. It involves
a feedback loop.

Dan, U.S. Air Force, retired