Spins, Spiral Dives and Training

On Jul 3, 7:38*am, Surfer! wrote:
In message
, Ian
writes

On 2 July, 20:21, Brian wrote:

I totally believe most stall spin accident soccur because the pilot is
not thinking about a stall spin and is not on the hair trigger ready
to recover, .i.e. they are distracted from this issue.

I believe that many of the spin accidents in the UK occur because most
pilots are trained ab initio in unspinnable gliders and, whatever
their instructors say, end up believing deep down that spins have to
be specially provoked in specially prepared or chosen aircraft.

What glider has killed most pilots in spins? The K21.

However the two recent accidents both involved US pilots, presumably
trained in the US. *Is the K21 so ubiquitous over there?

BTW have seen folks allowed to fly the K21 solo without spin training,
but *not* the Juniors.

--
Surfer!
Email to: ramwater at uk2 dot net

Don't think the accidents had anything to do with training and
certainly nothing to do with the K21 or whatever other ships they may
have trained in. These were experienced competition pilots.

-T8

On 3 July, 12:38, Surfer! wrote:

BTW have seen folks allowed to fly the K21 solo without spin training,
but *not* the Juniors.

Juniors have a complicated spin mode which is generally three turns
nose down and recoverable, three flat and unrecoverable, rinse,
repeat. If you don't recover in the first three turns (Turn 1: ****,
better get the nose up. Turn 2: why didn't that work? Turn 3: What's
spin recovery again?) you just have to sweat it out for a few hundred
feet or your current altitude, whichever is less.

Ian

We changed our spin training approach based on this thought.
We now have the student enter a thermaling turn at slow speed with about 30
degrees of bank.
Keep coaching them to get it slower, sometimes on their own they use a
little too much inside rudder and zippity do dah.. spin entry.

I had one Grob 103 check out, doing cross controlled stalls at about 15
degrees of bank and it got very slightly uncoordinated. The inside wing
started to drop, and the student applied correcting aileron. I saw the nose
starting to track to the inside of the very quickly and I just as quickly
took the controls and applied spin recovery procedure. The student also saw
it and asked if we could do that again... ahh... not intentionally and not
this low.
We were high enough per FAR for Stalls, but not above for my personal floor
for spin recognition / recovery practice.
BT

"T8" wrote in message
...
Okay guys, here's your new thread. Please...

Del asks "how well will pilots react if they unexpectedly get into a
spin or a spiral dive? Normally you gird your loins up first before
doing a deliberate spin!"

Answer: this depends on the pilot, of course. By the time you are
gaggle flying, thermaling up off ridges or flying in competition it
damned well better be automatic, reflexive.

The only point to doing deliberate spins by stalling straight ahead
and kicking rudder is to get some sense of how the sailplane behaves
and what it takes to recover from a fully developed spin. It might
also help you develop some sense of spin entry feel, but unintentional
spins normally come from some combination of turning, skidding flight,
gusts, etc. Oh, there's also the famous pilot who transitioned from
15m to std class and early on charged into a gaggle, pulled up,
reached for the "flap" handle and spun out of the gaggle with spoilers
deployed. UH, hUH! But I won't mention any names :-). I love that
story.

What you should practice is realistic spin entries from thermaling
turns and simulated pattern turns gone bad. Do 'em in all aircraft
configurations. In flapped ships the behavior changes quite a lot.
If you are fooling with CG location, check that out too. Your
responses can and should become fast and accurate. You should do this
until you aren't "girding your loins", you aren't tense. No panic.
Aircraft departs controlled flight: so what, you deal with it, get it
back.

regards,

Evan Ludeman / T8

I personally am of the opinion that a lot of people thermal too slowly
and put themselves in a position to have an inadvertent stall/spin
accident.

Most of us are aware that stall speed goes up in a banked turn. But
the desire to fly slowly and stay in the thermal keeps us down in the
"danger-zone", just above the stall speed. This is unnecessary and
can actually be a big hinderance! Why?

1) There's no reason to fly below min-sink speed, as any good glider
handbook will tell you. What they don't usually mention is that your
min-sink speed is higher in a banked turn than straight-and-level
flight! The same G-loading that affects your stall speed also affects
your whole glide polar - just as added wing-loading does when you use
water ballast. So in a thermal you should already be flying a bit
faster than the POH indicates for min-sink. How much faster depends
on your bank angle, and the same calculations for stall speed in a
banked turn should be applicable to your aircraft.

2) The slower you go, the less control authority you have. This means
upsets are tougher to avoid, recovery from an unusual attitude is
harder to achieve, and control deflections have to be bigger in order
to make normal corrections to maintain your bank & pitch angles.
Remember - bigger control deflections equal more drag!

3) Remember that your airframe and wings start to experience localized
areas of separated airflow long before you get down to true stall
speed. _Any_ dirty or separated airflow is extra drag and can result
in a slower overall climb-rate (as you burn some of your energy
maintaining speed and countering the drag forces). You want the
entire aircraft to be sliding through the air as cleanly as possible
to maximize the lift in the thermal!

4) Thermals contain unstable air - turbulence and wind gusts and the
shear around the edges of the thermal can all create assymetrical lift
conditions across the wings; or cause airflow separation on parts of
the wing (if the boundary layer is already close to seaparating). The
closer you are to stall speed, the more likely this is to suddenly
occur due to gusts or shear effects.

(For those of you who are trying to fly fast, add in the effects of
your water-ballast to all of this, too)

Just some food for thought,

--Noel

On Jul 2, 3:27*pm, "noel.wade" wrote:
I personally am of the opinion that a lot of people thermal too slowly
and put themselves in a position to have an inadvertent stall/spin
accident.

Most of us are aware that stall speed goes up in a banked turn. *But
the desire to fly slowly and stay in the thermal keeps us down in the
"danger-zone", just above the stall speed. *This is unnecessary and
can actually be a big hinderance! *Why?

1) There's no reason to fly below min-sink speed, as any good glider
handbook will tell you. *What they don't usually mention is that your
min-sink speed is higher in a banked turn than straight-and-level
flight! *The same G-loading that affects your stall speed also affects
your whole glide polar - just as added wing-loading does when you use
water ballast. *So in a thermal you should already be flying a bit
faster than the POH indicates for min-sink. *How much faster depends
on your bank angle, and the same calculations for stall speed in a
banked turn should be applicable to your aircraft.

2) The slower you go, the less control authority you have. *This means
upsets are tougher to avoid, recovery from an unusual attitude is
harder to achieve, and control deflections have to be bigger in order
to make normal corrections to maintain your bank & pitch angles.
Remember - bigger control deflections equal more drag!

3) Remember that your airframe and wings start to experience localized
areas of separated airflow long before you get down to true stall
speed. *_Any_ dirty or separated airflow is extra drag and can result
in a slower overall climb-rate (as you burn some of your energy
maintaining speed and countering the drag forces). *You want the
entire aircraft to be sliding through the air as cleanly as possible
to maximize the lift in the thermal!

4) Thermals contain unstable air - turbulence and wind gusts and the
shear around the edges of the thermal can all create assymetrical lift
conditions across the wings; or cause airflow separation on parts of
the wing (if the boundary layer is already close to seaparating). *The
closer you are to stall speed, the more likely this is to suddenly
occur due to gusts or shear effects.

(For those of you who are trying to fly fast, add in the effects of
your water-ballast to all of this, too)

Just some food for thought,

--Noel

For this reason and for safety is why I advocate an angle of attack
indicator. The AOA indicator will help determine the exact airspeed
for minimum sink for your wing loading and bank angle. Then, you can
use either instrument as your guide.

There's actually quite a large range of AOA between min sink and stall
so flying min sink AOA will keep you a safe distance from a stall.

I have to think that an AOA indicator 'might' have saved at least one
life this summer.

Our club's DG1000T has a stall warning device that sounds when a certain
angle of attack is reached. However I find the thing a distaction, as it
goes off every time you hit a gust (thermals tend to be gusty) and I can
comfortably circle at a speed where it is sounding all the time.

If Noel Wade came to visit the UK, he would probably not be able to climb
at all in our often tiny little thermals using the techniques he suggests.
The necessary skill is to be able to fly in accurate well banked turns at
not more than about 5 knots over the turning stall speed. Otherwise he
will be going round in the sink surrounding the thermal.

However I agree that you should not fly so slowly that the glider is
buffeting, as that is inefficient and dangerous.

By the way, my favourite spin entry for annual checks on our members is
out of a well banked turn. All you have to is slow the glider down in a
typical thermalling turn until it is just starting to buffet and then feed
in a bit of bottom rudder. The glider will depart instantly into a fully
developed spin. This demonstrates the need for accurate flying and for not
using too much rudder into the turn. If you put in a bit of top rudder it
is almost impossible to make the glider spin, however slowly you fly it.

Del Copeland


At 22:27 02 July 2009, bildan wrote:
On Jul 2, 3:27=A0pm, "noel.wade" wrote:
I personally am of the opinion that a lot of people thermal too slowly
and put themselves in a position to have an inadvertent stall/spin
accident.

Most of us are aware that stall speed goes up in a banked turn. =A0But
the desire to fly slowly and stay in the thermal keeps us down in the
"danger-zone", just above the stall speed. =A0This is unnecessary
and
can actually be a big hinderance! =A0Why?

1) There's no reason to fly below min-sink speed, as any good glider
handbook will tell you. =A0What they don't usually mention is that
your
min-sink speed is higher in a banked turn than straight-and-level
flight! =A0The same G-loading that affects your stall speed also
affects
your whole glide polar - just as added wing-loading does when you use
water ballast. =A0So in a thermal you should already be flying a bit
faster than the POH indicates for min-sink. =A0How much faster depends
on your bank angle, and the same calculations for stall speed in a
banked turn should be applicable to your aircraft.

2) The slower you go, the less control authority you have. =A0This
means
upsets are tougher to avoid, recovery from an unusual attitude is
harder to achieve, and control deflections have to be bigger in order
to make normal corrections to maintain your bank & pitch angles.
Remember - bigger control deflections equal more drag!

3) Remember that your airframe and wings start to experience localized
areas of separated airflow long before you get down to true stall
speed. =A0_Any_ dirty or separated airflow is extra drag and can
result
in a slower overall climb-rate (as you burn some of your energy
maintaining speed and countering the drag forces). =A0You want the
entire aircraft to be sliding through the air as cleanly as possible
to maximize the lift in the thermal!

4) Thermals contain unstable air - turbulence and wind gusts and the
shear around the edges of the thermal can all create assymetrical lift
conditions across the wings; or cause airflow separation on parts of
the wing (if the boundary layer is already close to seaparating).
=A0The
closer you are to stall speed, the more likely this is to suddenly
occur due to gusts or shear effects.

(For those of you who are trying to fly fast, add in the effects of
your water-ballast to all of this, too)

Just some food for thought,

--Noel

For this reason and for safety is why I advocate an angle of attack
indicator. The AOA indicator will help determine the exact airspeed
for minimum sink for your wing loading and bank angle. Then, you can
use either instrument as your guide.

There's actually quite a large range of AOA between min sink and stall
so flying min sink AOA will keep you a safe distance from a stall.

I have to think that an AOA indicator 'might' have saved at least one
life this summer.

On Jul 3, 12:00*am, Derek Copeland wrote:

If Noel Wade came to visit the UK, he would probably not be able to climb
at all in our often tiny little thermals using the techniques he suggests..
The necessary skill is to be able to fly in accurate well banked turns at
not more than about 5 knots over the turning stall speed. Otherwise he
will be going round in thesinksurrounding the thermal.

Derek -

Thanks for attacking my skills rather than arguing the point from a
logical perspective... I trained and fly in places that have both
weak lift and narrow lift, and I stay in them just fine - for the
record.

Now, to actually defend the point:

If your argument is that you have to fly slowly in order to stay in a
small thermal, you're ignoring an alternate solution: tighten your
bank angle. It is true that a slower speed gives you a smaller
turning radius at the same bank-angle, but it has a number of
drawbacks (many of which I touched on with my post - you're closer to
stall speed, you're possibly below min-sink - and therefore not flying
the glider as cleanly or efficiently as you could be). If you simply
keep your speed up and tighten your bank angle, you'll achieve a
smaller turning radius and you won't be in danger of stalling.

I urge you to do the math, as I have done (or at least look it up
online, there are webpages that illustrate this - such as:
http://www.soarns.ca/crclmotn.html)... Down around the speeds we're
talking about, you will have a _smaller_ turn radius at a 45-degree
bank-angle than at a 30-degree bank-angle, EVEN if you add 5 - 7 knots
of speed in the higher bank-angle turn. AND the additional G-loading
does not increase your sink rate by that much (around 20 ft/min in my
DG-300). Even in a small 2-knot thermal you're really only giving up
a small percentage of performance in order to be a lot safer. And
there are plenty of ways that the average pilot can "make up" that
performance, by flying more cleanly in other phases of flight.
Finally, if you _have_ been flying below min-sink speed (for a given
bank-angle), you may actually find _improved_ climb performance by
keeping your speed up and tightening your bank-angle.

Take care,

--Noel

yes.. but the idea is to train spin recognition and recovery..
and why it is not good to thermal too slowly..
but how if the pilot is not attentive to his speed..
he can get into trouble..
not fun in a thermal with others below
BT

"noel.wade" wrote in message
...
I personally am of the opinion that a lot of people thermal too slowly
and put themselves in a position to have an inadvertent stall/spin
accident.

Most of us are aware that stall speed goes up in a banked turn. But
the desire to fly slowly and stay in the thermal keeps us down in the
"danger-zone", just above the stall speed. This is unnecessary and
can actually be a big hinderance! Why?

1) There's no reason to fly below min-sink speed, as any good glider
handbook will tell you. What they don't usually mention is that your
min-sink speed is higher in a banked turn than straight-and-level
flight! The same G-loading that affects your stall speed also affects
your whole glide polar - just as added wing-loading does when you use
water ballast. So in a thermal you should already be flying a bit
faster than the POH indicates for min-sink. How much faster depends
on your bank angle, and the same calculations for stall speed in a
banked turn should be applicable to your aircraft.

2) The slower you go, the less control authority you have. This means
upsets are tougher to avoid, recovery from an unusual attitude is
harder to achieve, and control deflections have to be bigger in order
to make normal corrections to maintain your bank & pitch angles.
Remember - bigger control deflections equal more drag!

3) Remember that your airframe and wings start to experience localized
areas of separated airflow long before you get down to true stall
speed. _Any_ dirty or separated airflow is extra drag and can result
in a slower overall climb-rate (as you burn some of your energy
maintaining speed and countering the drag forces). You want the
entire aircraft to be sliding through the air as cleanly as possible
to maximize the lift in the thermal!

4) Thermals contain unstable air - turbulence and wind gusts and the
shear around the edges of the thermal can all create assymetrical lift
conditions across the wings; or cause airflow separation on parts of
the wing (if the boundary layer is already close to seaparating). The
closer you are to stall speed, the more likely this is to suddenly
occur due to gusts or shear effects.

(For those of you who are trying to fly fast, add in the effects of
your water-ballast to all of this, too)

Just some food for thought,

--Noel

If may, I would like to get off on a bit of a tangent, i.e. the
original subject stated in the title of this thread.

One of the problems that I have observed with students and a few high
time pilots alike is the following: when presented with a spin or a
spiral dive, mis-diagnosing the problem and applying the wrong recovery.
To some who experience these maneuvers infrequently, they appear similar
enough to bring about confusion and as you know, applying the wrong
recovery can get grim.

I believe airspeed, sound and G are the keys with the latter two very
important. Some are so confused by the ground spinning around that they
don't think about looking at the airspeed indicator. But they do seem to
sense if it is relatively quiet or loud and if they are experiencing
more than 1G. A thorough ground briefing on the differences and then
demonstrating both on the same flight really helps. Then follow that
with a lesson where they must make the diagnosis and apply the proper
recovery. This has worked for me. I would enjoy hearing from others who
have thoughts on this very important subject.

Paul
ZZ









8 wrote:
Okay guys, here's your new thread. Please...

Del asks "how well will pilots react if they unexpectedly get into a
spin or a spiral dive? Normally you gird your loins up first before
doing a deliberate spin!"

Answer: this depends on the pilot, of course. By the time you are
gaggle flying, thermaling up off ridges or flying in competition it
damned well better be automatic, reflexive.

The only point to doing deliberate spins by stalling straight ahead
and kicking rudder is to get some sense of how the sailplane behaves
and what it takes to recover from a fully developed spin. It might
also help you develop some sense of spin entry feel, but unintentional
spins normally come from some combination of turning, skidding flight,
gusts, etc. Oh, there's also the famous pilot who transitioned from
15m to std class and early on charged into a gaggle, pulled up,
reached for the "flap" handle and spun out of the gaggle with spoilers
deployed. UH, hUH! But I won't mention any names :-). I love that
story.

What you should practice is realistic spin entries from thermaling
turns and simulated pattern turns gone bad. Do 'em in all aircraft
configurations. In flapped ships the behavior changes quite a lot.
If you are fooling with CG location, check that out too. Your
responses can and should become fast and accurate. You should do this
until you aren't "girding your loins", you aren't tense. No panic.
Aircraft departs controlled flight: so what, you deal with it, get it
back.

regards,

Evan Ludeman / T8

I have already been flamed once for bringing up this subject in the
original Parowan accident thread, as being irrelevant to highly
experienced competition pilots!

However for those of them who are not also instructors, that experience
consists of many hundreds or thousands of hours of either flying straight
or circling in thermals! How well would they cope in the event of a sudden
and unexpected upset?

It is important to be able to differentiate between a spin and a spiral
dive because the recovery actions are quite different.

In a spin, the nose will often go well down, despite the fact you are
stalled, the ground will rotate in front of you, and there will be very
little build up of g. The ASI is likely to totally misread due to the
amount of yaw present; it may even go back though zero and show a very
high reading.

In a spiral dive, the nose may remain fairly well up, despite the fact you
are not stalled, and airspeed and g will build up rapidly and continue to
do so. In many ways spiral dives are more dangerous as you risk going
through Vne and breaking up the glider. Spins in themselves are not
dangerous at all, at least as long as you recover before hitting the
deck.

Just a quick reminder of the standard recovery actions:

Spin:

1) Centralise the ailerons
2) Apply full outspin rudder
3) Move the stick steadily and progressively forward until the spin stops
4) Centralise the rudder and ease out of the dive

Spiral dive:

1) Keep the stick fairly well back and use the controls normally to reduce
the angle of bank - a spiral dive is just a very overbanked turn.

IMHO spins and spiral dives should be a part of periodic check flights.

Derek Copeland (UK Gliding Instructor)



At 04:15 04 July 2009, ZZ wrote:
If may, I would like to get off on a bit of a tangent, i.e. the
original subject stated in the title of this thread.

One of the problems that I have observed with students and a few high
time pilots alike is the following: when presented with a spin or a
spiral dive, mis-diagnosing the problem and applying the wrong recovery.

To some who experience these maneuvers infrequently, they appear similar

enough to bring about confusion and as you know, applying the wrong
recovery can get grim.

I believe airspeed, sound and G are the keys with the latter two very
important. Some are so confused by the ground spinning around that they
don't think about looking at the airspeed indicator. But they do seem to

sense if it is relatively quiet or loud and if they are experiencing
more than 1G. A thorough ground briefing on the differences and then
demonstrating both on the same flight really helps. Then follow that
with a lesson where they must make the diagnosis and apply the proper
recovery. This has worked for me. I would enjoy hearing from others who
have thoughts on this very important subject.

Paul
ZZ









8 wrote:
Okay guys, here's your new thread. Please...

Del asks "how well will pilots react if they unexpectedly get into a
spin or a spiral dive? Normally you gird your loins up first before
doing a deliberate spin!"

Answer: this depends on the pilot, of course. By the time you are
gaggle flying, thermaling up off ridges or flying in competition it
damned well better be automatic, reflexive.

The only point to doing deliberate spins by stalling straight ahead
and kicking rudder is to get some sense of how the sailplane behaves
and what it takes to recover from a fully developed spin. It might
also help you develop some sense of spin entry feel, but unintentional
spins normally come from some combination of turning, skidding flight,
gusts, etc. Oh, there's also the famous pilot who transitioned from
15m to std class and early on charged into a gaggle, pulled up,
reached for the "flap" handle and spun out of the gaggle with
spoilers
deployed. UH, hUH! But I won't mention any names :-). I love that
story.

What you should practice is realistic spin entries from thermaling
turns and simulated pattern turns gone bad. Do 'em in all aircraft
configurations. In flapped ships the behavior changes quite a lot.
If you are fooling with CG location, check that out too. Your
responses can and should become fast and accurate. You should do this
until you aren't "girding your loins", you aren't tense. No
panic.
Aircraft departs controlled flight: so what, you deal with it, get it
back.

regards,

Evan Ludeman / T8