Julian Scarfe wrote:

Pretty much without exception GA aircraft are stable in pitch and unstable
in the spiral divergence mode. If displaced in pitch a Mooney will take
more phugoid cycles to get back to equilibrium when you release the
controls, but it *will* get back there.

*if* you keep the wings level, right?

But how about if you're struggling to figure out what "level" is?

Perhaps I'm mistaken, but I don't see the two as unrelated problems.
Yes, from an airplane design standpoint, little Cessnas and Pipers
are also "unstable in the spiral divergence mode", but anyone who
has flown same vs. Grumman/Mooney/Bo will say that the latter are
much lighter in both pitch and roll, and that they require more
attention to fly. I'm no aeronautical engineer type, but someone
told me once that Cessnas are designed to have something like 'positive
roll stability' (meaning if you take your hands off the yoke in a turn,
they want to return to level flight) whereas Grummans (dunno about
Mooney and Bo) are designed for 'neutral roll stability' (meaning if you
take your hands off the stick, they want to stay where you put them).
(even money I've got the terms wrong)

Add this factor to pitch light enough that someone shifting around in
the cockpit will alter the trim, and the chances of it getting "back
there" hands off are much less in any sort of unstable air. IME.

My point is that within your generalization about GA aircraft
design, I think there are details which differ, and those details
make a difference.

The difference between the C172 and the Bo is only to do with the
speed at
which things happen, as more slippery aircraft will tend to reach red
line
speeds more quickly.

That's definately a difference, and I don't have beans in Bo time so
I can't comment, but I don't think that's the only difference.

Otherwise, they'd fly the same, right, and people wouldn't be talking
about "sweet" "nimble" planes vs. "stable trucks".

I guess I'm not certain how being "experienced in instrument flight"
helps very much either, when the topic is "You are in IMC when
*everything* fails!" meaning "all gyros -- AH, DG, TB". This seems
to me to call for a different set of skills than holding 2,2 and 20
on a full panel or even conventional 'partial panel'

Best regards,
Sydney