On 4/9/2015 9:51 AM, Jonathan St. Cloud wrote:
I do have a comment about coming out of the cloud in a spin. How many
times have you tried to sustain a spin in your glider? I would do this
before I tried spinning out of a cloud. The reason is in some aircraft a
spin will turn into a spiral dive. They look the same but spin recovery
technique will not work recovering from a dive and the airspeed builds very
fast in a spiral dive. First time this happened to me was a real eye
opener, just because I have never considered the glider would transition
from spin to spiral dive. I did recognize it right away and recovered no
problem, but it got my attention as I had never considered this before. I
was in very clear smooth air with lots of altitude. I know the POH for an
ASG-29 says spins will turn into spiral dive in a few turns. Just know
what your gliders does. When practicing spins I do not remember ever
letting the spin go more than 2 revolutions, what if it takes 10
revolutions and on the 3rd revolution your glider spirals.

Good thread though with lots to think about.


Indeed...lotsa good stuff to contemplate, and ideally practice beforehand,
against the time you might (willingly or unwillingly) need to use any of it.

Spinning - what could possibly be surprising in a bird with an Approved Type
Certificate, rated for spins? Ignoring the certification fact that an explicit
number of turns was tested (usta be 3 in the U.S.), and if you go beyond that
you're now officially an unpaid test pilot, and ignoring the fact that spins
are sufficiently complex aerodynamically as to be still "inexactly
predictable" via computational methods, and nodding in the direction that
flight testing of spins and flutter are two things even professional test
pilots still pay Serious Respect to, many years ago I opted intentionally to
become an unpaid test pilot in my 1-26A (still airworthy today!), building my
skills and confidence by exploring spinning behavior. Over the course of a
summer, on days with about 10,000 vertical feet of spin-worthy airspace, I
incrementalized my way into extended spins in both directions...entries,
partial rotations, single turn spins, 2-turn spins, 3-turn spins, etc.

By the time I was up to 3-turn spins, it was becoming clear the ship had
distinctly different behaviors between left and right spins. One direction (I
forget which after all these years), the spin was "textbook classic" - nose
well down, spin rate constant, only full aft stick w. "the correct" (neutral?)
aileron and into-turn rudder convinced the ship to remain in the spin. Similar
control conditions the other direction showed considerable up-and-down
oscillation of the nose throughout each turn, in concert with variable spin
rate, slowing as the nose rose, and increasing again as it dropped. Had I not
seen before in college a US Navy film of A4 Skyhawk spin testing displaying
similar behavior, ALL of the varying-spin behavior would have been 100% new to
me (as a possibility, I mean), though I *was* also aware of the concept of
unrecoverable "flat spins."

Before I sold that 1-26, I'd convinced myself that example would spin "all day
long" the one direction in a stable, unchanging manner...at least up to 17
turns, which was the most I ever did. I also convinced myself it would NOT
ever remain in a stable spin the other direction, never being able to get more
than 5 turns from it before it staggered out from the nose-high condition.
Further, depending on how I positioned the ailerons (against the turn,
neutral, into the turn) the variable spin behavior ranged from "mostly an
'instant' uncoordinated spiral dive" through variable-over-time spinning
behavior followed ultimately transitioning into some form of uncoordinated
spiral dive. Arguably, in the absence of that knowledge, had I ever "needed to
spin through the clouds" I'd'a had a 50:50 chance of doing so in an intact
airframe.

I found it all very instructive and thought-provoking, one obvious conclusion
being not to expect consistent spin behavior just because a ship has an ATC
and is approved for spins! I'm not bashing the 1-26 or certification
procedures. The 1-26 is a wonderful ship for pilots of all skill levels,
allowing all manner of hamfistedness with relatively low risk to Joe
low-time-or-incautious Pilot. Certification procedures have necessarily
defined-before-the-fact conditions which must be met, and it's up to Joe
Pilot to decide how meaningful to him are those limits.

One other conclusion was, I really hoped/planned never to put myself into a
position where I seriously had to consider using my 1-26's spinning
capabilities to bail my butt out of cloud-coffin-corner! Flight in "wet waves"
to my way of cowardly thinking would be really tweaking the tiger's tail more
than I was ever comfortable with as a generic concept...though the devil is
always in the details, ground-to-cloud clearance and terrain beneath being two
obvious considerations...

In the Colorado Rockies (site of most of my soaring), we pretty much never
have to be concerned with wet waves of the sort relatively common in the
eastern U.S. mountains (where I grew up and got into soaring). Nevertheless
the most ice I ever picked up was when I fell out the bottom of a "somewhat
wet" Rockies' wave into a mild band of rotor-cu, beneath/ahead of which I'd
climbed to get into the wave. Being in a 90-degree flapped ship, in a known
location with known ground-to-cloud clearances, I was mostly aggravated at
losing the wave (I was sidling XC, and non-wave flight would slow my
progress). I simply put on flaps and resigned myself to having to re-thermal
my way back into the wave once I dropped below the cloudband. As I recall, the
clouds were ~2k feet thick, and in the time I was in them, I picked up about
an inch of rime ice on the main wing leading edge (and presumably on the
all-flying stabilator, though flying qualities weren't obviously affected).
The accretion rate thoroughly impressed me. Once in the (above freezing)
clear, it sublimated/slid off about as rapidly as it had accreted.
(Considerably chastened, I re-thought that day's XC plan!)

Bob W.