How Low to Spin??

Kirk Stant wrote:

I disagree with your conclusion about steep bank angles. It is
usually a lot harder to spin from a steep turn, and a lot easier to
recover from an incipient spin, for a simple reason (see Piggott for
more details): a properly flown steep turn is flown at a
significantly higher speed, and the elevator is limited, making it
harder to reach stalling angle of attack, and much easier to reduce
the angle of attack if needed due to the higher speed.

Not always true. An aircraft that has done a complete 180 during the
spin still has momentum, and is now to some degree flying backwards.
The excess forward momentum translates into excess reduction of airspeed.

Think about it for a minute. If you're going 50 knots in one direction,
and then one-half second later the nose of the glider is 180 degrees
pointed the other way, does this mean you are doing 50 knots in the other
direction? That's some G's, and I don't feel them in a spin.

This is why aircraft oscillate pitch up and down for a few turns before
stabilizing in a spin. For the first few turns, the aircraft momentum
is still slogging through the air.

But some of what you point out is true. Aircraft without enough
elevator authority to stall, and with forward CG, won't have the
ability to stall in a steep bank. But if the CG is back a bit, the
elevator has a lot of authority because the glider is designed for a
wide range of speeds, and the pilot has in aileron to resist overbanking,
then whoa nellie!

A properly flown steep turn at higher speed isn't what I'm talking about.
I'm considering a 30-45 degree bank turn at low speed.

You mention in an earlier post about making shallow, fast turns during
a low save. Why shallow? If the thermal is narrow, you usually need
to be steep (and fast) to stay in the (probably a bit turbulent) core.

This thermal was very smooth and regular and wide. I was feeling it
out on the first turn, and was not eager to make any coarse inputs or
lose sight of my landing site or get vertigo during the circle.

A shallow turn is asking for the classic base-to-final spin entry,
The classic spin entry from a shallow bank is uninteresting.
I won't be jamming in the rudder for a skid at some obviously
low speed close to the ground. I think the focus on the classic case
is niave and dangerous. Yes, it's easy to teach and demonstrate,
but it ignores too much. The more complex, less discussed
spin entry is the one in the accident reports: tight pattern,
higher speed, steep bank, lots of inside rudder, pilot focussed on
keeping the yaw string straight, quite a bit of opposite aileron
in the steep bank, in vertigo, pulling stick back to tighten up the
turn, and then wham! I'll look back through the accident reports, but
the ones I recall, and the B-52 and the DG spin I saw on video, involved
stabilized, 30-45 deg bank turns before each of the spins. In each,
it looked like the craft was overbanking, and the pilot put in more
opposite aileron and more elevator and WHAM! Instant spin...

Too much rudder, maybe, but it wasn't because he moved it. It was
because the pilot put in more dragging aileron without RELEASING
inside rudder.

unless you fly so fast that any climb is more luck than skill!

This is usually the case for me on cloudless days (like that one).
High over the terrain, I usually just bump into a thermal. Of course,
at altitude, while thermalling, slow is good, and trim is your friend...

Methinks your power background is showing (all those shallow turns!).

Shallow turns in power? Why? Just jam the throttle all the way in,
full flaps, and yo-yo base to final at 60 degrees. Gas is a good
substitute for brains ;PPPP

Power planes (except maybe the DA-20) often have lower
aspect ratios. Some even have frieze ailerons. And if the left turns
are flown with power off, there's even a little slip provided by the
P-factor of the prop. There's enough differences between the two
that the USA CFI practical tests require training and evaluation in each
category seperately (CFI transition from one to the other requires
spin training in the new class, except for Sport Pilots, but that's
another thread).

Even though I also have a power past going way back, I now find my
glider bias showing when I fly a stinkpot; I find myself whipping into
nice 45 to 60 degree banks, scaring the daylights out of my power-only
friends...

Power flying can be boring. If an autopilot can do it, why do they
need me?

Anyway Kirk, I welcome some more discussion. As you can see, there
are quite a few points where we agree, and a few nuanced ones where
we don't. I hope you have time to continue another response...
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Mark Boyd
Avenal, California, USA