Spins, Spiral Dives and Training

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

On Jul 2, 9:09*am, T8 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

One of the scariest experiences I ever had was an inadvertant spin in
a 2-place Fox. It's an aerobatic glider by design, with limited
washout and anhedral, so it's not exactly typical of your modern
racing gliders. The owner had asked me to fly with him to improve
his thermalling skills. We went up on a booming day, and "I got it"
at about 4,000. "Now, first thing we need to do is to slow it down a
little bit ... like this... Then, we increase the bank a little bit
like this.. Now, if we get a good bump we just wait for a one-
Mississippi, then tighten up the turn using whatever it takes like
th....... WOA, WHAT THE...." Sky and earth reversed and we're
spinning like a top. Now, at that time I was flying about 130-150
hrs per year including instructing at least every weekend. I was just
about as current and ready as you could be. Yet, it took me a good
couple of seconds to sort things out. In the Swift, it's no big
deal, since it has a VNE of something approaching Mach 1.0, but I'll
tell you that it wasn't pretty. The owner (a very experienced
aerobatic competitor) just sat there up front chuckling.

The message here isn't about the Swift and it's nasty spinning
habits. It's about the fact that we probably ALL get a little
complacent from time to time. When we change some variables (in the
case above, a new ship with very different handling
characteristics), we probably don't realize how unprepared we are
for the consequences. Whenever I fly my LS8, I'm always greatful
for what a wonderful handling airplane it is. However, add some
water, fly on a turbulent day, get a little too aggressive on thermal
entry, and it will remind you fairly forcefully, that you've exceeded
its limitations. I suspect that we all need to spend more time
CONSCIOUSLY practicing flight at the edges of the controllable regime
in various configurations on a much more frequent basis. Short
wings without water. Short wings with water. Long wings without
water. Divebrakes in. Divebrakes out. Flaps positive. Flaps
negative. Whatever. In some regimes, our pussycats are more like a
wildcat, and we need to be able to recognize the onset of bad behavior
before it gets out of control.

P3

http://news.bbc.co.uk/2/hi/uk_news/e...et/6905327.stm

On Jul 2, 7:09*am, T8 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

Getting a glider to transition to spinning starting from normal flight
with the airflow fully attached to the upper wing surface is difficult
- it just doesn't want to spin. The trick in getting realistic spin
departures is to set up an unstable flow with the glider already near
a stall.

The flow detachment/re-attachment phenomena can have some hysteresis
effects where the flow will momentarily 'hang on' beyond the stalling
AOA. Setting up a situation where the flow is just barely 'hanging
on' can take a few tens of seconds.

That's why I ask the student for a long 30 seconds plus of 'slow
flight'. While the student is doing this, I'm watching for an
increase in sink rate. If I can talk the student into this situation
of flying very slowly with abnormally high sink rate, any attempt to
turn will result in a sudden, and usually unexpected, spin departure.
The key is timing. The turn has to begin before the airspeed
increases again and the flow returns to stability.

I actually think this is the real killer spin. The pilot gets
distracted, perhaps the trim is still set for thermalling, the
airspeed drifts lower and lower. The glider begins to mush in a semi-
stalled state until the pilot attempts a sharp turn....

On Jul 2, 9:35*am, bildan wrote:
snip

I actually think this is the real killer spin. *The pilot gets
distracted, perhaps the trim is still set for thermalling, the
airspeed drifts lower and lower. *The glider begins to mush in a semi-
stalled state until the pilot attempts a sharp turn....- Hide quoted text -

- Show quoted text -

I think you have hit it here. I have see this many times when doing
stalls with students and even some fairly experienced pilots.
It is one thing to be on the trigger ready to recover from a spin. It
is totally another to be wondering why the nose is dropping and the
ailerons are not working for no apparent reason.
I have even read an accident report where the pilot reported that he
thought the ailerons have became disconnected becuase they were
ineffective.

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.

Brian

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.

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

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.