Another stall spin

My $0.20c worth:
Practice at altitude in your glider. Some new gliders are "interesting" in
a full spin.
You will most likely find that the standard recovery is best.
Do not put yourself in the low save situation, especially when windy. Look
at the winners IGC files from Uvalde [or any other contest], you will find
the winners used lesser thermals at times to stay high, smarter flying.
If you do get below your safe level then do a safe outlanding, [this also
needs a little spare altitude to set up!].
Tom


At 20:19 30 August 2012, Sean F F2 wrote:
Great post. I should spin more. We all should. It might sound wimpy
but
=
my personal limit (post Ionia R6N and Tim's accident) is 800ft (see last
da=
y trace). I have not been below 1100 AGL since except at Parowan which
it
=
was unavoidable. Im just not that good and to fight lower, even in
competi=
tion, is simply not worth it to me any longer (as has been aptly
demonstrat=
ed this summer). I actually figure eighted alot in Parowon near the
hills
=
in turbulent gusty thermals during the contest (my first flying ever in
the=
mountains...) and didn't lose much. It was much more comfortable. I
actu=
ally felt great about being cautious.

I also pulled aside from launching in 20-35+ kts of wind. Just too much
wi=
nd for me knowing the drop off was going to be 200 ft over the mountains
in=
most cases.

Sure has been a tough year...and unfortunately I see little real change
(pe=
rsonally with pilots or in rules or regulation or procedure). Lots of
pilo=
ts regularly down to and below 500 ft (the red zone). =20

Simply put, we are each are 100% responsible for ourselves and our
passenge=
rs whenever we waggle the rudder and start to roll. That's all there is
to=
o it. If you choose to circle below the altitude by which you can
recover
=
100% of the time (if you really know this altitude as UH seems too) the
ris=
ks are suddenly EXTREME. You are in the "red zone" and mistakes are
potent=
ially absolutely deadly. We have all gone into the red zone. We are
there=
every time we launch and land. We are there every time we get low and
fig=
ht. Some of us well into it...200ft or so circling... I have done this
se=
veral times... And I was stupid.=20

Ridge pilots often spend the whole damn day in the red zone. Many of us
ta=
ke huge risk so regularly we seem to get used to it. Some thrive on it.

The problem might be that the soaring culture (has/had/did/does?)
respects
=
low saves more than sensible land outs. This has been my experience.
Not
=
alot of atta boys for landing out. At least a few for "digging out" at
400=
ft.

Unless rules are put in place to penalize low flying (in clubs, contests,
e=
tc) expect these accidents to continue... The stick is a useful tool but
w=
ill it be used? Can it be used?

F2

On Monday, August 27, 2012 7:08:30 PM UTC-4, (unknown) wrote:
On Monday, August 27, 2012 6:40:42 PM UTC-4, Ramy wrote:
=20
On Monday, August 27, 2012 1:08:49 PM UTC-7, Brian wrote: So I am
see=
ing the why do we still thermal low comment, but no one is says how low.
I
=
suspect these accidents may not be a low as some of us think. But have no
d=
ata to back it up. With so many of us using flight recorders it
should
=
be pretty easy to look a few of these accidents and see, but somehow this
d=
ata never seems to reach us. I can understand some liability issues but
it
=
seems like it would be pretty easy to reproduce the data into a generic
for=
mat that didn't give away the location or ID of what happened but would
sti=
ll allow us to review the flight path of an actual flight that led to the
a=
ccident. Brian My thoughts exactly. we need the actual data to
lear=
n something from those accidents, but it is almost never provided. We
shoul=
d have enough statistics to be able to determine how low is too low to
reco=
ver, so we can adjust our threshold. This is what safety culture is all
abo=
ut. If we keep this info to ourselves, no much can be learned. Ramy
=20
=20
=20
I do not agree.
=20
There is nothing new to learn from Jim's accident.
=20
People just keep repeating the same stupid stuff they know better than
to=
do.
=20
A handful of folks on this forum seem to want to study the crap out of
ac=
cidents like this in the hope that they will learn something new.
=20
There are no new lessons to be learned here guys. It is very simple.
You
=
can't circle at low altitude without an unaceptable risk of a(commonly
gust=
induced) stall spin. And these spins do NOT happen like the ones we
practi=
ce. They happen much more quickly and violently. I have a personal hard
dec=
k of 500 feet where circling is cancelled. The only exception is ridge
flyi=
ng where a whole group of additional variables come into play.
=20
If you want data, go spin your glider in the configuration you fly it
all=
the time. Let it start to spin, not just catch it when it departs. See
how=
much altitude you lose, then throw in another 1-200 feet for the
surprise
=
factor.
=20
I spin sailpalnes probably 60-80 times a year and my contest gliders a
do=
zen time a year. From that, I've developed my personal limits. =20
=20
Note that gliders with winglets commonly may be more benign in stall
than=
ones without, but may well be uglier in a true spin.
=20
As instructors, mentors, and friends, we need to embrace and promote
the
=
concept that we all need a limit where we STOP SOARING AND START LANDING
wi=
th NO exceptions.
=20
Sorry to rant, but I've lost 3 friends this year, all for the same damn
r=
eason and all knew better.
=20
UH

On Aug 30, 3:38*pm, Martin Gregorie
wrote:
On Thu, 30 Aug 2012 13:13:31 -0700, unclhank wrote:
The dumping of flaps seems to be well practiced in recovering from this
maneuver- I wonder who taught him this.

Its the recommended first action according to the ASW-20 POH, which goes
on to say that this action alone will often cause spin recovery, but that
if it doesn't, follow the standard procedure AFTER you've set the flaps
fully negative. The POH says the flap movement is to avoid exceeding VNE:
for positive flap settings VNE is quite low.

I'd also point out that sharply selecting fully negative flap reduces AOA
relative to the fuselage and airflow and so, as the POH says, may
initiate recovery by unstalling the wing.

Two points for those who haven't flown an ASW-20:

- ailerons and flaps are interconnected so that ailerons deflect with
* the flaps as the flap lever is moved except when selecting landing
* flap, when the ailerons go to a negative setting. This "crow mode"
* increases drag and helps to prevent tip stalling.

- the POH recommends always starting an aerotow with the flaps in
* position #2 (-6 degrees) for better low-speed control.

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

.....hmm, if we're talking about recovering from a low/slow spin, I'm
not sure if I'd be overly concerned with exceeding Vne. Good point
that in landing configuration, the ailerons go negative in the 20. My
question (hypothesis), however, was how did Bruno's spin recovery work
if the only thing he did was to dump his flaps (or go negative)? My
uneducated quess was that by doing so, either the full-opposite
ailerons became unloaded and/or the AOA was reduced. If I have this
right, Bruno's spin recovery wasn't an attempt to save his life as
much as it was to stay in the strong, gusting thermal somewhere at
stratospheric altitude, which he did with good skill. He knew his
ship's behavioral characteristics well from experience, even if the
glider may not have been in factory-tune (and he did mention
somewhere about adjusting its CG).

From the Soaring Safety Foundation website it looks like at one time
they were trying to implement Condor-based videos that simulated
safety-related issues like these. Perhaps a most effective/safe way of
visualizing what the ground looks like in a low-spin.

My Monday morning quarterbacking: It appears to me that Bruno's yaw string also indicates he may have a heavy left foot and thus somewhat uncoordinated inputs too. None of us are perfect but we need to strive to be...

-Jim

On Friday, August 31, 2012 4:25:27 PM UTC-5, Jim wrote:
My Monday morning quarterbacking: It appears to me that Bruno's yaw string also indicates he may have a heavy left foot and thus somewhat uncoordinated inputs too. None of us are perfect but we need to strive to be...



-Jim

I disagree - to me it looks like Bruno's yaw string is centered or indicates a slight slip - hard to tell from the camera angle. I know my LS6 likes to thermal with some slip - and theoretically, since the yaw string is in front of the CG, a slip indication is actually correct - a perfectly centered yaw string during a turn actually indicates a slight skid.

Bruno did exactly the right thing - recovered per the POH from a departure
BEFORE it became a spin, then continued to thermal. If you can't do that when you are thermalling your ship, please don't join me in my thermal - go practice until you can post a video on Youtube!

Kirk
66

There seems to be some confusion in this thread about spins. A spin is a stable autorotation with the wings stalled and fairly constant airspeed. A departure is when the your glider starts to do something that you didn't tell it to do or want it to do, either because you got too slow and stalled it, or a gust upset it, whatever. A spin entry, in a glider that will actually spin (not all will), is a controlled departure held long enough to stabilize into a spin.

But a departure doesn't have to result in a spin. If corrective action is done promptly and correctly (almost always involving unloading the wing by reducing AOA), the glider will resume flying and will never get to the autorotation state. Many (most?) glass ships, unless the CG is way aft or flaps are in landing configuration, are reluctant to spin, probably due to limited elevator authority. They may depart, and if you sit there like a bump on a log and don't apply corrective action, may progress to a spin, or a spiral dive, or just recover on their own.

But if you experiment (at safe altitude) with the glider you fly, trying all it's configurations and finding out how it reacts to a departure, you will be prepared (like Bruno) to safely recover from a departure with minimum loss of altitude (or danger to your gaggle mates).

This is BASIC stuff, guys. If I'm just telling all of you what you already know, I apologize. But if you really don't understand this (and some of the discussions on RAS about AOA makes me think many don't) then please get with an acro/spin instructor and brush up.

Cheers,

Kirk
66

On Friday, August 31, 2012 6:11:41 PM UTC-4, kirk.stant wrote:
There seems to be some confusion in this thread about spins. A spin is a stable autorotation with the wings stalled and fairly constant airspeed. A departure is when the your glider starts to do something that you didn't tell it to do or want it to do, either because you got too slow and stalled it, or a gust upset it, whatever. A spin entry, in a glider that will actually spin (not all will), is a controlled departure held long enough to stabilize into a spin.



But a departure doesn't have to result in a spin. If corrective action is done promptly and correctly (almost always involving unloading the wing by reducing AOA), the glider will resume flying and will never get to the autorotation state. Many (most?) glass ships, unless the CG is way aft or flaps are in landing configuration, are reluctant to spin, probably due to limited elevator authority. They may depart, and if you sit there like a bump on a log and don't apply corrective action, may progress to a spin, or a spiral dive, or just recover on their own.



But if you experiment (at safe altitude) with the glider you fly, trying all it's configurations and finding out how it reacts to a departure, you will be prepared (like Bruno) to safely recover from a departure with minimum loss of altitude (or danger to your gaggle mates).



This is BASIC stuff, guys. If I'm just telling all of you what you already know, I apologize. But if you really don't understand this (and some of the discussions on RAS about AOA makes me think many don't) then please get with an acro/spin instructor and brush up.



Cheers,



Kirk

66

Maybe its not so basic, but then what do I know. If both wings are stalled, then you just have a stall, the nose drops and recovery is easily accomplished. If you stall in turning flight or uncoordinated use of controls, then the slower wing will stall and an autorotation will commence. The outer wing is not stalled. Correct me if I'm wrong.

Tom

On Aug 31, 9:44*pm, wrote:
On Friday, August 31, 2012 6:11:41 PM UTC-4, kirk.stant wrote:
There seems to be some confusion in this thread about spins. *A spin is a stable autorotation with the wings stalled and fairly constant airspeed. A departure is when the your glider starts to do something that you didn't tell it to do or want it to do, either because you got too slow and stalled it, or a gust upset it, whatever. *A spin entry, in a glider that will actually spin (not all will), is a controlled departure held long enough to stabilize into a spin.

But a departure doesn't have to result in a spin. *If corrective action is done promptly and correctly (almost always involving unloading the wing by reducing AOA), the glider will resume flying and will never get to the autorotation state. *Many (most?) glass ships, unless the CG is way aft or flaps are in landing configuration, are reluctant to spin, probably due to limited elevator authority. *They may depart, and if you sit there like a bump on a log and don't apply corrective action, may progress to a spin, or a spiral dive, or just recover on their own.

But if you experiment (at safe altitude) with the glider you fly, trying all it's configurations and finding out how it reacts to a departure, you will be prepared (like Bruno) to safely recover from a departure with minimum loss of altitude (or danger to your gaggle mates).

This is BASIC stuff, guys. *If I'm just telling all of you what you already know, I apologize. But if you really don't understand this (and some of the discussions on RAS about AOA makes me think many don't) then please get with an acro/spin instructor and brush up.

Cheers,

Kirk

66

Maybe its not so basic, but then what do I know. If both wings are stalled, then you just have a stall, the nose drops and recovery is easily accomplished. If you stall in turning flight or uncoordinated use of controls, then the slower wing will stall and an autorotation will commence. The outer wing is not stalled. Correct me if I'm wrong.

Tom- Hide quoted text -

- Show quoted text -http://www.youtube.com/watch?v=PpJA53LjarM

Yes and no. I was repeatedly taught the same spin theory (i.e., one
stalled; one not), but in a spin both wings are apparently stalled but
with one wing deeper than the other. During the incipient phase in a
controlled turn, I have read where both wings stall simulaneously,
while if uncoordinated the inboard wing stalls first before the
outboard. Back on topic, from what I read in the flaps-out landing
configuration the ASW-20's interconnecting flap/aileron system moves
the ailerons to -8deg, a design intended to reduce the chance of a tip-
stall at low altitude. Where I disagree with "66" in the ASW-20 video
is that the pilot applied the POH-recommended spin recovery at high
altitude (according to the pilot's own words). He's in a tight turn,
near or below the slowest part of the ASI white-arc range when he
encounters a gust (increasing AOA). As the incipient phase begins and
the wing drops hard, he first rapidly moves the stick further towards
the outboard wing (opposite aileron) with no opposite rudder input.
His reflexive move is to reduce flaps to full negative (per the POH)
while still holding opp aileron.. The resulting decrease in AOA is
what presumably unstalls the wings. I think this is right. When low,
the POH recommends not reduceing flaps, but rather to carry extra
speed. Good lesson.

On Saturday, September 1, 2012 6:08:52 AM UTC-4, Duster wrote:
Good lesson.

You'd be smarter to take UH's advice. I think he has around 1500 hours in 20s. I've got about a third of that. How much did the factory have when they wrote the book? As much as 50? We can speculate why they wrote it that way. It is a bit puzzling. The rest of the POH is excellent.

T8

On Saturday, September 1, 2012 5:08:52 AM UTC-5, Duster wrote:
Where I disagree with "66" in the ASW-20 video

is that the pilot applied the POH-recommended spin recovery at high

altitude (according to the pilot's own words). He's in a tight turn,

near or below the slowest part of the ASI white-arc range when he

encounters a gust (increasing AOA). As the incipient phase begins and

the wing drops hard, he first rapidly moves the stick further towards

the outboard wing (opposite aileron) with no opposite rudder input.

His reflexive move is to reduce flaps to full negative (per the POH)

while still holding opp aileron.. The resulting decrease in AOA is

what presumably unstalls the wings. I think this is right. When low,

the POH recommends not reduceing flaps, but rather to carry extra

speed. Good lesson.

Ok, lets think about this. Steep turn, so possibly some top aileron prevent overbanking. Wing drops (bottom wing starting to stall?) first action is to use top aileron to stop the roll (top wing is presumably not stalled), then when the lower wing didn't come back up, recognize the departure and reduce angle of attack by first raising the flaps, then if necessary, forward stick. Recovery was too fast to allow a yaw rate to develop, so coarse use of rudder not really needed.

Not an expert on 20s, but I know my LS6 will recover by releasing back pressure. but manual also says to put flaps at 0 to prevent overspeeding in the recovery, should the departure end up in a full spin or spiral dive situation. Really, the response is the same - slight easing of the stick (probably not even visible in a video) and flaps up if the nose starts to drop much.

Of course, at low altitude, speed is life - when you are scratching out a save you absolutely cannot afford to depart or spin - and again now we are doing steep turns in tight, turbulent lift: quick, what's your stall speed at 60 degrees of bank? With half water? It's not in the POH, probably, so what speed do you use? AOA sure would be nice to have!

As far as only one wing being stalled in a spin - if one wing is still flying (below stall AOA), the other is just barely at stall AOA (due to yaw, gust, whatever) and the flying wing will roll you over until it too stalls (now you are spinning, via an over the top entry, or once the nose goes down you will accelerate until the stalled wing is under stalling AOA. If you fully stall the glider in a yaw, both wings are above stall AOA, but one will still produce more lift than the other, that is what causes the autorotation/spin.

Kirk
66

On Saturday, September 1, 2012 9:44:12 AM UTC-5, kirk.stant wrote:

As far as only one wing being stalled in a spin - if one wing is still flying (below stall AOA), the other is just barely at stall AOA (due to yaw, gust, whatever) and the flying wing will roll you over until it too stalls (now you are spinning, via an over the top entry, or once the nose goes down you will accelerate until the stalled wing is under stalling AOA. If you fully stall the glider in a yaw, both wings are above stall AOA, but one will still produce more lift than the other, that is what causes the autorotation/spin.

I spoke too soon without refreshing myself on spin dynamics:

Depending on spin mode, the inner wing is always stalled, but the outer wing may or may not be stalled.

Good explanation of spins at: http://www.av8n.com/how/htm/spins.html

Kirk
66