Are 'Single 180 Turn From Downwind to Final' and 'Stall-spin on Turnfrom Base to Final' mutually exclusive?

Bruce Hoult wrote on 11/19/2016 12:50 AM:

Define "coordinated". No problem to spin with the string perfectly
centered.

It's true in any glider with enough elevator, but the Blanik is
excellent for demonstrating it. Shallow turn, very graaaadually slow
it down, maintaining constant bank angle with aileron and keeping the
string in the middle with the rudder. Pretty soon you've got a whole
heap of out of turn aileron and into turn rudder. But the string is
in the middle and the nose isn't even very high. And then BAM full-on
incipient spin.

Bruce describes how I practice incipient spins in my ASH 26 E (also the
way I practiced them in my ASW 20 C). One moment I'm doing a smooth,
coordinated turn; an instant later, the inboard wing is rotating down -
no warning.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

On 11/22/2016 8:20 PM, Eric Greenwell wrote:
Bruce Hoult wrote on 11/19/2016 12:50 AM:

Define "coordinated". No problem to spin with the string perfectly
centered.

It's true in any glider with enough elevator, but the Blanik is
excellent for demonstrating it. Shallow turn, very graaaadually slow
it down, maintaining constant bank angle with aileron and keeping the
string in the middle with the rudder. Pretty soon you've got a whole
heap of out of turn aileron and into turn rudder. But the string is
in the middle and the nose isn't even very high. And then BAM full-on
incipient spin.

Bruce describes how I practice incipient spins in my ASH 26 E (also the way I
practiced them in my ASW 20 C). One moment I'm doing a smooth, coordinated
turn; an instant later, the inboard wing is rotating down - no warning.

Blame this somewhat-thread-drifting post on winter finally trying to put in an
appearance in this part of the northern hemisphere...

I'm guessing what Eric's "no warning" comment means is "in the absence of a
distinct separation-induced burble," or something similar (I've not flown
either an ASW 20 or ASH 26). I'm gonna "winter-quibble" with the concept "no
warning."

My club used to have a 2-32 (eventually sold) about which the same thing was
routinely said, and in fact the ship did routinely and enthusiastically drop
the same wing before beginning a rapid rotation if not "immediately and
properly countered." If it really did catch someone out, going through at
least 90-degrees of an incipient spin, and WAY nose down before recovery - was
in your immediate future. Many club pilots of roughly equivalent time as I
then had might accurately have been described as "unduly frightened" of the ship.

But "no warning?" Surely you jest (and my name isn't Shirley). True, before
the wing "let go" there was (almost always) an absence of aerodynamic burble
felt through the stick or one's butt or merely "drummed" through the metal
fuselage, but by the time the wing did let go, "all the other usual suspects"
had put in their appearances: low wind noise; nose noticeably high; controls
(especially stick) getting sloppy; etc. Subsequent to checking out in the
ship, I found it "intellectual fun" to mess around with it in slow flight
"trying to find the burble." Abrupt departure from controlled flight - yes,
indeed! "No warning?" - not by a long shot.

Bob - a big fan of coordination AND "sufficient airspeed" - W.

Bob,

you've stated that you haven't flown an ASW20C, but still you comment on its flying characteristics, citing a 2-32 as reference?!

What a nonsense.

I have flown an ASW20C (15 m, no winglets, CoG towards the rear limit), and there is no warning _what so ever_.

Bert


Le mercredi 23 novembre 2016 06:06:50 UTC+1, Bob Whelan a écritÂ*:
On 11/22/2016 8:20 PM, Eric Greenwell wrote:
Bruce Hoult wrote on 11/19/2016 12:50 AM:

Define "coordinated". No problem to spin with the string perfectly
centered.

It's true in any glider with enough elevator, but the Blanik is
excellent for demonstrating it. Shallow turn, very graaaadually slow
it down, maintaining constant bank angle with aileron and keeping the
string in the middle with the rudder. Pretty soon you've got a whole
heap of out of turn aileron and into turn rudder. But the string is
in the middle and the nose isn't even very high. And then BAM full-on
incipient spin.

Bruce describes how I practice incipient spins in my ASH 26 E (also the way I
practiced them in my ASW 20 C). One moment I'm doing a smooth, coordinated
turn; an instant later, the inboard wing is rotating down - no warning.

Blame this somewhat-thread-drifting post on winter finally trying to put in an
appearance in this part of the northern hemisphere...

I'm guessing what Eric's "no warning" comment means is "in the absence of a
distinct separation-induced burble," or something similar (I've not flown
either an ASW 20 or ASH 26). I'm gonna "winter-quibble" with the concept "no
warning."

My club used to have a 2-32 (eventually sold) about which the same thing was
routinely said, and in fact the ship did routinely and enthusiastically drop
the same wing before beginning a rapid rotation if not "immediately and
properly countered." If it really did catch someone out, going through at
least 90-degrees of an incipient spin, and WAY nose down before recovery - was
in your immediate future. Many club pilots of roughly equivalent time as I
then had might accurately have been described as "unduly frightened" of the ship.

But "no warning?" Surely you jest (and my name isn't Shirley). True, before
the wing "let go" there was (almost always) an absence of aerodynamic burble
felt through the stick or one's butt or merely "drummed" through the metal
fuselage, but by the time the wing did let go, "all the other usual suspects"
had put in their appearances: low wind noise; nose noticeably high; controls
(especially stick) getting sloppy; etc. Subsequent to checking out in the
ship, I found it "intellectual fun" to mess around with it in slow flight
"trying to find the burble." Abrupt departure from controlled flight - yes,
indeed! "No warning?" - not by a long shot.

Bob - a big fan of coordination AND "sufficient airspeed" - W.

On 11/23/2016 12:50 AM, Tango Whisky wrote:
Bob,

you've stated that you haven't flown an ASW20C, but still you comment on
its flying characteristics, citing a 2-32 as reference?!

What a nonsense.

I have flown an ASW20C (15 m, no winglets, CoG towards the rear limit), and
there is no warning _what so ever_.

Bert

Snip (of all but the offending post, immediately below)...

Blame this somewhat-thread-drifting post on winter finally trying to put
in an appearance in this part of the northern hemisphere...

I'm guessing what Eric's "no warning" comment means is "in the absence of
a distinct separation-induced burble," or something similar (I've not
flown either an ASW 20 or ASH 26). I'm gonna "winter-quibble" with the
concept "no warning."

My club used to have a 2-32 (eventually sold) about which the same thing
was routinely said, and in fact the ship did routinely and
enthusiastically drop the same wing before beginning a rapid rotation if
not "immediately and properly countered." If it really did catch someone
out, going through at least 90-degrees of an incipient spin, and WAY nose
down before recovery - was in your immediate future. Many club pilots of
roughly equivalent time as I then had might accurately have been
described as "unduly frightened" of the ship.

But "no warning?" Surely you jest (and my name isn't Shirley). True,
before the wing "let go" there was (almost always) an absence of
aerodynamic burble felt through the stick or one's butt or merely
"drummed" through the metal fuselage, but by the time the wing did let
go, "all the other usual suspects" had put in their appearances: low wind
noise; nose noticeably high; controls (especially stick) getting sloppy;
etc. Subsequent to checking out in the ship, I found it "intellectual
fun" to mess around with it in slow flight "trying to find the burble."
Abrupt departure from controlled flight - yes, indeed! "No warning?" -
not by a long shot.

Bob - a big fan of coordination AND "sufficient airspeed" - W.


Bert - I'm also a big fan of, "If it happens, it must be possible."

As you likely grasped, I sought not to comment upon the ASW 20C's specific
low-speed, essentially-1g, departure from controlled flight characteristics,
as on the *concept* of departing from controlled flight "in the general
vicinity of" those flight conditions...which is why I included the
experience-based provisos leading into the guts of my post.

FWIW, I've yet to encounter a glider or single-engine general aviation
airplane that has not provided *some* other clue(s) Joe PIC is in the vicinity
of the sandbox near an unintended departure from controlled flight. (N.B. I'm
also not power certified, my experience in powered planes being limited to
riding along in lots of different types, with lots of different pilots, doing
"the usual range of stuff" from stall practice to "straight-n-level" hard IFR.
Nor do I have any supersonic aircraft time. )

As always when discussing any aeronautical topic having even the slightest
hint of nuance, YMMV.

Bob W.

P.S. Apologies if some form of this post appears twice; the first attempt
seemed to have disappeared into the bit bucket without trace, despite an hour
of searching...

Bob, I've flown about 40 different types of gliders, and did voluntary spins with about half of them, wingspans ranging from 10 m to 26 m.

And the ASW20C was stunning in this respect - pulling from cruise into thermal a bit sharply, and the sky turns green although the glider just felt perfectly normal. In Germany in the mid-eighties, this behaviour did kill a couple of ASW20C pilots. Moving the CoG forward changes the behaviour to "normal".
The only other glider I came across having this behaviour was a Fox - but then, this one is designed to do exactly that.

So, there ARE gliders out there that bite without barking first.

On Wed, 23 Nov 2016 08:36:45 -0800 (PST), Tango Whisky
wrote:

Bob, I've flown about 40 different types of gliders, and did voluntary spins with about half of them, wingspans ranging from 10 m to 26 m.

And the ASW20C was stunning in this respect - pulling from cruise into thermal a bit sharply, and the sky turns green although the glider just felt perfectly normal. In Germany in the mid-eighties, this behaviour did kill a couple of ASW20C pilots. Moving the CoG forward changes the behaviour to "normal".
The only other glider I came across having this behaviour was a Fox - but then, this one is designed to do exactly that.

So, there ARE gliders out there that bite without barking first.


Hi Bert,

the ASW-20 is a nice example of how little airfoil differences can
make huge differences.

I've flown two different ASW-20's.

The first was a 20L with slightly modiefied leading edge radius.
Performance-wise it was probably the best ASW-20 ever, and, stalled
with flaps 4, it had that sudden departure into a spin that you
descibe.

The other one was an ASW-20C. As docile as it gets - it was even
possible to thermal it with flaps 4 and less than 80 kp/h without the
slightest sign of a stall, not to mention that it didn't even drop a
wing if stalled.
CG a little bit more forward than in the 20L, though. This pilot got
heavier over the years.


And then there are those open class ships. I was quite surprised how
smoothly the Nimbus 3D went into a spin when I was checking out its
low-speed thermalling manners...



Viele Gruesse aus der Pfalz
Andreas

On 11/23/2016 12:50 AM, Tango Whisky wrote:
Bob,

you've stated that you haven't flown an ASW20C, but still you comment on
its flying characteristics, citing a 2-32 as reference?!

What a nonsense.

I have flown an ASW20C (15 m, no winglets, CoG towards the rear limit), and
there is no warning _what so ever_.

Bert

Snip...
Blame this somewhat-thread-drifting post on winter finally trying to put
in an appearance in this part of the northern hemisphere...

I'm guessing what Eric's "no warning" comment means is "in the absence of
a distinct separation-induced burble," or something similar (I've not
flown either an ASW 20 or ASH 26). I'm gonna "winter-quibble" with the
concept "no warning."

My club used to have a 2-32 (eventually sold) about which the same thing
was routinely said, and in fact the ship did routinely and
enthusiastically drop the same wing before beginning a rapid rotation if
not "immediately and properly countered." If it really did catch someone
out, going through at least 90-degrees of an incipient spin, and WAY nose
down before recovery - was in your immediate future. Many club pilots of
roughly equivalent time as I then had might accurately have been
described as "unduly frightened" of the ship.

But "no warning?" Surely you jest (and my name isn't Shirley). True,
before the wing "let go" there was (almost always) an absence of
aerodynamic burble felt through the stick or one's butt or merely
"drummed" through the metal fuselage, but by the time the wing did let
go, "all the other usual suspects" had put in their appearances: low wind
noise; nose noticeably high; controls (especially stick) getting sloppy;
etc. Subsequent to checking out in the ship, I found it "intellectual
fun" to mess around with it in slow flight "trying to find the burble."
Abrupt departure from controlled flight - yes, indeed! "No warning?" -
not by a long shot.

Bob - a big fan of coordination AND "sufficient airspeed" - W.


Bert - I'm also a big fan of "If it happens, it must be possible,"...which is
why I included the "experience-based" info leading into "the rest of my post."

And as I'm sure you grasped, I was less commenting/suggesting anything about
an ASW 20C's specific flying characteristics than I was about "the general
nature" of low-speed, essentially-one-g, stalls as a PIC concept. FWIW, every
"general aviation-like" plane (glider/single-engine-piston) in which I've been
able to "play around with those types of stalls" have always presented other
cues that Joe Pilot might be on the edge of playing with fire.

As always, when discussing things of any nuance whatsoever, YMMV.

Bob W.

I did grasp that, but you might play around a bit more and learn things which will make general statements like yours look, well, not quite intelligent.

No reason for me to continue this discussion.

On 11/23/2016 11:11 AM, Tango Whisky wrote:
I did grasp that, but you might play around a bit more and learn things
which will make general statements like yours look, well, not quite
intelligent.
Well-intended advice noted, thanks. For the record (and no sarcasm intended),
I stopped worrying about that aspect of "general statements" upon encountering
the contention, "All generalizations are false, including this one." Everyone
encountering a generality is free to individually decide if there is - or
isn't - some kernel of "reality-based wisdom" in it.

No reason for me to continue this discussion.


Bob W.

Bob Whelan wrote on 11/22/2016 9:06 PM:
True, before the wing "let go" there was (almost always) an absence of
aerodynamic burble felt through the stick or one's butt or merely
"drummed" through the metal fuselage, but by the time the wing did let
go, "all the other usual suspects" had put in their appearances: low
wind noise; nose noticeably high; controls (especially stick) getting
sloppy; etc. Subsequent to checking out in the ship, I found it
"intellectual fun" to mess around with it in slow flight "trying to find
the burble." Abrupt departure from controlled flight - yes, indeed! "No
warning?" - not by a long shot.

The nose was not noticeably high in either glider (20 C or 26E); the
wind noise was subdued, but both gliders were very quiet, and the change
in noise was very small; there was no burble or "butt feel"; the
controls were light but not unusually so; and the wing "departure" was
not abrupt - I simply ran out aileron, and the wing would start
downward. I'm guessing the inside wing tip doesn't stall, but can't be
sure about that.

But that scenario is with a shallow turn - 20 degree bank? - and at
30-40 degrees bank, it was harder to provoke the incipient spin. Much
harder, as I recall.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"

https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf