On 7/27/2016 5:33 PM, son_of_flubber wrote:
The 'Single 180 Turn From Downwind to Final' (aka 'military style pattern')
and 'Stall-spin on Turn from Base to Final' are both well discussed as
independent topics on RAS. But I've not seen anything about how these
pieces fit together.

So how many glider pilots are in the room and how many opinions will they have
regarding your implicit question?! (Chortle.) As always, the devil is in the
details, and in my (experience-based) view there's no single "absolutely
right" answer. There are many very good reasons we're instructed to "fly
regulation glider patterns," but the accident record clearly shows that
attempting to do so is far from a panacea. If it's possible and it helps you,
then fine - do it. You'll likely have full approbation of the glider
community, instructors included. But never lose sight of what a landing
pattern is intended to do: help you make a safe landing, at the spot you've
selected.

Some years ago I flew an original-spanned HP-14 with the as-designed (see next
paragraph) ailerons from a busy, non-towered GA airport with 3 parallel
runways (Boulder, CO). Back then, the paved/lit one was "the power runway"
(legally available for glider use, of course). (An estimated) 100 feet
center-line-to-center-line to the north were two, unpaved "glider only"
runways. The northernmost one was the one from which 99.9% of all gliders
launched (trailers/tiedowns/assembly-area being immediately north of it), and
maybe 70% of the gliders and 50% of the towplanes landed. The center one
(rarely) launched and (variously) landed the remainder. Occasionally
non-towing taildraggers would use one or the other of "the glider runways."
The glider runways' landing percentages varied with traffic volume, landing on
the northernmost runway being the default, traffic permitting. When the sky
occasionally rained gliders, gliders would sometimes "land long," overflying
ships landed short, though this wasn't common. Point being, it was/is a *busy*
airport, and pilots were/are taught/expected to keep their heads on a swivel.
Shoot, we practiced their "situational awareness" long before it became a
catchphrase, as a means of NOT having to do anything "unusual" in the landing
pattern! (Google Earthing will show the northernmost runway is now paved. Last
time I looked, there was a glider in the pattern!)

A common mod to original-aileroned HP-14s was to convert the outer 3-feet of
each flap to ailerons, since as-designed, no one would characterize its roll
rate as "spritely." Evidently the increased roll rate was deemed more
worthwhile than the reduced (but still manly) flap-power....but I wouldn't know.

Boulder's published/recommended pattern procedure, is for gliders to fly a
rectangular pattern, crosswind entered at midfield, downwind/base/final inside
the power equivalents, left-hand to the east, right-hand to the west. It's not
uncommon to have a power plane or two buzzing along downwind for company,
though parallel takeoffs are "seriously discouraged"/prohibited and parallel
landings likewise discouraged. At some point in every landing pattern, of
course, the glider's spacing/timing options vanish, though some might find it
surprising how much flexibility gliders bring to the table, assuming good
"situational awareness."

The preceding verbosity can be shortened to: gliders must fly their patterns
inside the power plane pattern. It generally works well.

So - I'm landing a slow-rolling glider with relatively high stick forces in
roll (and light elevator forces), using a pattern distinctly constrained in
size. While it was possible to make 90-degree-turn-patterns in the HP-14 at
Boulder, it pretty much took both hands on the stick to do it and was
something of a distraction/PITB judging when to begin the turn to final. It
was considerably easier, both in stick forces and in
mentally/visually/continuously assessing the approach, to make the transition
from downwind to final a continuously/varying-as-necessary-banked turn. I felt
it was equally as safe as "a standard glider pattern" too, in
traffic-avoidance turns...I could still easily check the power final, for
example, and one can rationalize that banked gliders are easier to spot than
unbanked ones.
- - - - - -

Having recently tried the 'Single 180 Turn...' and LIKED it, I'm wondering
if there is any good reason why I should not fly this approach at an
uncontrolled airport with mostly glider traffic. What about at a
controlled airport with mostly GA power traffic?

There's a lot to be said favoring "When in Rome, do as the Romans," but YMMV.
I've no doubt others will share other (and I'll wager, strongly held!) views
on these questions.
- - - - - -

And I'm wondering if anyone has ever stall-spinned from a 'Single 180
Turn...' pattern and whether there are subtle 'gotchas' associated with
that pattern shape that I should know about.

Having immense faith in human ability to screw up, I'll put real money on
people "departing from controlled flight" in *every* landing pattern known to
mankind! Personally, I think the circling-pattern gotchas not fundamentally
different from *any* pattern's "Gotchas!" Airspeed and coordination rule.
Presupposing those are as-desired, don't hit anything other than the spot for
which you're aiming. As for judging how you're doing relative to bad things to
hit in the landing pattern while in controlled flight, there's considerable
experience favoring certain pattern shapes...and less for others (due both to
less use, and as well to "It's just a bad idea!" for some [e.g.
straight-ins]). In my motherhood and apple-pie view, a pattern is no more and
no less than an unavoidable-vehicle/useful-aid to making safe landings.

I never discerned substantive differences/difficulties between using
rectangular patterns and circling patterns, but YMMV.

When I sold the HP and began flying a Zuni, I transitioned back to rectangular
patterns, following the "When in Rome..." philosophy. The (sole) off-field
landing I made in the HP I used a rectangular pattern, just because the chosen
field was huge, with a no-brainer approach, and I could.
- - - - - -

What is the military's track record wrt 'Stall-spin in the pattern'? Does
it happen just as often with the 'Single 180 Turn...'?

Good luck obtaining hard data on this front! I've read (can't recall where)
the Navy's approach-to-carrier-landings accidents (metric unknown) dropped by
a factor of 3 when they post-WW-II adopted the circling approach in
conjunction with "flying AOA" (early 1950s?). I'd love to see that data.

Bob W.