Gary L. Drescher wrote:

[snip]

Yup, another part of the problem is the invisibility of AoA, at least with
regard to a static picture. Dynamically, though, a pilot can see the AoA by
finding the aim point and noticing its vertical position in the window. I'd
guess that learning to perceive the AoA that way makes it far more intuitive
than using an AoA indicator, which just reports a disembodied number (though
I've never used one, so I can't be sure).

Yep, n a steady-state environment that's probably true. The problem is
that environmental factors (like a significant updraft component) can
cause the out-the-window picture for AoA to change. While a number is
just a number, it's trivial to repeatedly nail the same AoA independent
of conditions by nailing the same number. The other (possible)
advantage of the number is that it tells you where you are relative to
lift reserve, but then that's something that most light aircraft will
let you feel in the yoke as you get to the limits.

I suppose the way I look at it is that an aviator who understands AoA
and is familiar with their aircraft needs an AoA indicator about as much
as they need a stall warning system. For those who are less that
intimately familiar it provides a tool that makes flying at high AoA
easier and safer and would graphically dispel in the mind of the primary
student the notion that AoA is a function of where the nose is pointing
relative to the ground.

But isn't the yoke position a pretty good AoA indicator?

Indirectly. It's a good indicator of what is being commanded; combined
with what the aircraft is doing you can infer whether you're skating
toward an excessive AoA. It's a bit more problematic in, say, the
mountains on a windy, hot afternoon, where AoA can change wildly while
the yoke is held in a constant position (and Va is your new best
friend). There are other -er- more degenerate places where the
relationship between stick and AoA are problematic, like an accelerated
or flat spin, but under those conditions I seriously doubt I'd be
looking at an AoA indicator

--
Chris Kennedy

http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97