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

On Saturday, November 26, 2016 at 6:50:46 AM UTC+3, Eric Greenwell wrote:
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.

Stick quickly a little bit forward restored aileron authority?

Bruce Hoult wrote on 11/26/2016 12:40 AM:
On Saturday, November 26, 2016 at 6:50:46 AM UTC+3, Eric Greenwell wrote:
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.

Stick quickly a little bit forward restored aileron authority?

The normal spin recovery works fine; even quicker was moving the flap
lever forward to the first negative flap position. I don't recall if
only stick forward was enough.

--
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 Sat, 26 Nov 2016 21:16:47 -0800, Eric Greenwell wrote:

Bruce Hoult wrote on 11/26/2016 12:40 AM:
On Saturday, November 26, 2016 at 6:50:46 AM UTC+3, Eric Greenwell
wrote:
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.

Stick quickly a little bit forward restored aileron authority?

The normal spin recovery works fine; even quicker was moving the flap
lever forward to the first negative flap position. I don't recall if
only stick forward was enough.

The ASW 20 manual says applying full negative flap should be the first
spin recovery action and will often be sufficient for recovery. IME that
worked well and since, also IME, immediate recovery from an incipient
could cost 300 ft and add 40kts, full negative flap is always a good idea
since that also gives you the greatest Vne.

In case you're wondering, mine departed twice from a thermal turn with no
warning I could detect. Both times I was thermalling at a bit over 45 kts
in flap 3 (zero flap) in a well-banked turn. It was something I couldn't
replicate intentionally: I wonder if it could be connected with
microturbulence in the thermal.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

I had a Nimbus 4 depart with no warning. Was flying dry and being how slow it would thermal. A wing dropped and a quarter turn before recovery. I remember thinking there was no sign of impending stall had full roll control up to departure.

On Sunday, November 27, 2016 at 4:32:32 AM UTC-8, Martin Gregorie wrote:
On Sat, 26 Nov 2016 21:16:47 -0800, Eric Greenwell wrote:

Bruce Hoult wrote on 11/26/2016 12:40 AM:
On Saturday, November 26, 2016 at 6:50:46 AM UTC+3, Eric Greenwell
wrote:
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.

Stick quickly a little bit forward restored aileron authority?

The normal spin recovery works fine; even quicker was moving the flap
lever forward to the first negative flap position. I don't recall if
only stick forward was enough.

The ASW 20 manual says applying full negative flap should be the first
spin recovery action and will often be sufficient for recovery. IME that
worked well and since, also IME, immediate recovery from an incipient
could cost 300 ft and add 40kts, full negative flap is always a good idea
since that also gives you the greatest Vne.

In case you're wondering, mine departed twice from a thermal turn with no
warning I could detect. Both times I was thermalling at a bit over 45 kts
in flap 3 (zero flap) in a well-banked turn. It was something I couldn't
replicate intentionally: I wonder if it could be connected with
microturbulence in the thermal.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |