Cable break recovery spin entry... as previously discussed

[[email protected]]

Pilots depend on simple, quickly applied remedies to any loss of
control. Since we are not always afforded the luxury of examination,
analysis, and consideration of options as a preamble to action, any
flight condition where these simple rules of recovery do not work
demands closer examination and appropriate training to recognize
symptoms and take appropriate actions.

Modern aircraft are designed to meet well-defined controllability
requirements. For example, in the United States, the recommended
recovery (generic) for any impending or developed stall is to move the
control column forward while applying coordinated aileron and rudder to
halt an un-commanded roll. The Flight Manual for my S-H Ventus 2bx
states on page 3.4:

--On stalling whilst flying straight ahead or in a banked turn, normal
flying attitude is regained by firmly easing the control stick forward
and, if necessary, applying opposite rudder and aileron.--

Page 3.5 (Spin Recovery) continues...

--Note: Spinning may be safely avoided by following the actions given
in section 3.4 "Stall Recovery"-

During the past several years, I have made it a point to experiment
with various applications of controls throughout the stall break (and
in a variety of makes and models). In all cases where I maintained
coordination, either paying attention to the yaw string or through
application of equal amounts of aileron and rudder, the aircraft did
not spin, even if I held the stick firmly against the rear stop.
Instead, it would transition from stall to spiral dive.

In a recent RAS thread (Nimbus 4DT accident 31 July 2000 in Spain), I
was introduced to a maneuver practiced by BGA instructors to
demonstrate that a quick transition from coordinated flight into a spin
can take place while recovering from a winch launch cable break. This
was pointed out to refute my comment in that thread that modern gliders
need to be "helped" into a spin (by either intentional or
inadvertent abuse of the controls).

Chris Reed described the following:

--One of my favourite exercises for my annual checkouts as a UK Basic
Instructor is the spin off a simulated winch launch (only try this at
height with an appropriate instructor with you!). Simulate a winch
launch by diving to 90 kt and then pulling up at 45 degrees. As the
speed drops to about 60 kt cry "BANG - cable break", and push over into

the normal flying attitude. The moment normal attitude is reached,
begin
a co-ordinated turn.
All will be fine for a second or so, as you are flying at reduced G.
However, once the G comes back on many gliders will roll smoothly (no
buffeting) into a spin so fast that there is little you can do about it

(though the purpose of the exercise is to show the spin entry and then
a
recovery, so I've not tried reducing back pressure as the wing drops).
The Puchacz is excellent for this.--

For me, this raised an immediate alarm. It indicates that there are
flight regimes (whether experienced during a cable break recovery,
during an aggressive thermal entry, or as a result of turbulence) where
normal control movements may result in an immediate and unannounced
spin entry.
Since such matters are best examined in the air, I put together an
informal flight test plan to measure just how sudden the spin entry is
and whether there might be mitigating factors.

To prepare for the test, I set up the following limits:

First, I would at no time during the maneuver bring the stick back all
the way to the stop. We must assume that all pilots meet a base level
of competency, and under no circumstance would any competent pilot
resort to full up elevator to maintain attitude during a cable break
recovery. I would consider such control usage an abuse of the controls.

Second, I would remain coordinated (as indicated by my yaw string)
throughout the maneuver per the instructions of my flight manual.

Third, at stall break, I would hold the controls firm and visually
verify their positions, then wait for the sailplane to assume its new
state (either spin or spiral dive) then clearly identify that state
before making an appropriate recovery.

I began the test sequence with a series of four dives and recoveries
just as Chris described, but without introducing a bank. At 60 knots, I
called out "Bang - cable break - recover!" I pushed the stick
firmly forward. Three out of the four, I briefly suspended loose dirt
in the cockpit. As soon as the nose passed through the horizon into a
normal flying attitude, I moved the stick quickly back to its normal
position for that attitude. Of course, this did not entirely halt the
downward pitch of the nose. However, it was clearly apparent through
the feel of the controls that the sailplane was either stalled or on
the edge of a stall as a result of my quick application of stick from
well forward to neutral. It was very clear that bringing the stick
straight back to the stop would result in a full stall.

I began the dives in flap position -1, moving the flaps to position +1
as I slowed through 70 knots, as I might if I were entering a thermal,
though my recovery (pitch over) was much more aggressive than any I
would use during cross-country flight. Once I was comfortable with my
ability to keep myself from making an immediate recovery from any
stall, I stopped to thermal, then found a clear patch of sky and warned
off others away, as I fully expected to spin the sailplane.

In order to force an immediate turn, I imagined that there was an
obstruction preventing a straight ahead landing. As soon as the nose
came down, I determined that I would have to make an immediate turn to
the right, which I did, without adverse results. The sailplane rolled
sluggishly and felt on the edge of stall, but there was no loss of
control, and certainly no sudden yaw and entry into a spin. I thought
perhaps I had waited too long to initiate the turn, so with the next
pull and recovery, I made the decision, before the nose came fully
over, that I would land to the left in an adjoining field. I rolled to
about 30 degrees, then as the nose reached normal flying attitude, I
brought the stick right back to neutral... and braced myself against
making an immediate recovery.

As before, there was a sense of mushing through the air, but no
tendency for the glider to yaw itself into a spin. For the next pull
and recovery, I delayed saying "Bang - cable break - recover!"
until 50 knots. Given the additional delay, I was much more aggressive
with the stick, both moving it forward and returning it to neutral once
I reach normal flying attitude. And once again, the sailplane
demonstrated a sluggish, heavy feel as the g force came back on, but
without any tendency to "fall" into the direction of the turn.

It was clear to me that I could have easily induced a spin during this
maneuver. A little too much rudder or stick against the turn coupled
with bringing the stick full aft would have tipped the sailplane right
over. But my intent was to produce an unanticipated spin, even though I
was, ostensibly, doing everything right.

I repeated this maneuver several more times, making slight adjustments
to angle of bank, but without adverse effects.

My conclusions:

This is an interesting flight regime. I suspect that it would prove
useful for producing spins in typically resistant aircraft, and require
significantly less control abuse among those gliders that are inclined
to spin. However, for my make and model (which can be easily coaxed to
incipiency), normal attention to stall warning signs and application of
coordinated aileron and rudder are adequate. There does not appear to
be any tendency for the glider to spin suddenly or unpredictably,
though I would caution that if the stick is used to catch a dropping
wing without appropriate application of rudder, the spin entry could be
significantly accelerated.

The greater the span, the more pronounced the effects of a tip stall
would be, but greater span is usually compensated for by a longer tail
boom and larger vertical stabilizer. Some designs may choose to
underpower the vertical stabilizer to increase glide performance, but
hopefully these would include appropriate warnings and recovery
procedures in their respective flight manuals.

As far as thermal entry is concerned, I would give the same warning: if
you delay your pushover on thermal entry to the point where G and
airspeed are significantly reduced below the norms (generally not the
most efficient way to enter a thermal), extra attention should be paid
to coordination. I wouldn't expect the glider to snap into a spin,
but it is entirely possible that the now underpowered vertical
stabilizer may not adequately compensate if you have any tendency
towards sloppiness.

I intend to experiment with this maneuver some more over the coming
weeks. As I discover anything interesting, I'll add my comments to
the thread. Also, I uploaded my FR trace to the OLC, but my sampling
was 4 seconds, hardly adequate for analysis. However, just in case you
are tempted to make an armchair assay, be my guest!

http://www2.onlinecontest.org/olcphp/2005/ausw_fluginfo.php?ref3=197828&ueb=N&olc=olc-usa&spr=en&dclp=c9701de37223903b6f823e438ec30ed8

The test run began at 1454 ET (UTC-4) and ended at 1503 ET.

[Mike Schumann]

It is not obvious to me, why, in a cable break scenario, you would be close
to stalling when you push the nose down to a normal attitude while you
maintain 60 knot airspeed. This sounds like you are flying significantly
above stall speed. Could you elaborate?

Thanks,
Mike Schumann

> wrote in message
oups.com...
> Pilots depend on simple, quickly applied remedies to any loss of
> control. Since we are not always afforded the luxury of examination,
> analysis, and consideration of options as a preamble to action, any
> flight condition where these simple rules of recovery do not work
> demands closer examination and appropriate training to recognize
> symptoms and take appropriate actions.
>
> Modern aircraft are designed to meet well-defined controllability
> requirements. For example, in the United States, the recommended
> recovery (generic) for any impending or developed stall is to move the
> control column forward while applying coordinated aileron and rudder to
> halt an un-commanded roll. The Flight Manual for my S-H Ventus 2bx
> states on page 3.4:
>
> --On stalling whilst flying straight ahead or in a banked turn, normal
> flying attitude is regained by firmly easing the control stick forward
> and, if necessary, applying opposite rudder and aileron.--
>
> Page 3.5 (Spin Recovery) continues...
>
> --Note: Spinning may be safely avoided by following the actions given
> in section 3.4 "Stall Recovery"-
>
> During the past several years, I have made it a point to experiment
> with various applications of controls throughout the stall break (and
> in a variety of makes and models). In all cases where I maintained
> coordination, either paying attention to the yaw string or through
> application of equal amounts of aileron and rudder, the aircraft did
> not spin, even if I held the stick firmly against the rear stop.
> Instead, it would transition from stall to spiral dive.
>
> In a recent RAS thread (Nimbus 4DT accident 31 July 2000 in Spain), I
> was introduced to a maneuver practiced by BGA instructors to
> demonstrate that a quick transition from coordinated flight into a spin
> can take place while recovering from a winch launch cable break. This
> was pointed out to refute my comment in that thread that modern gliders
> need to be "helped" into a spin (by either intentional or
> inadvertent abuse of the controls).
>
> Chris Reed described the following:
>
> --One of my favourite exercises for my annual checkouts as a UK Basic
> Instructor is the spin off a simulated winch launch (only try this at
> height with an appropriate instructor with you!). Simulate a winch
> launch by diving to 90 kt and then pulling up at 45 degrees. As the
> speed drops to about 60 kt cry "BANG - cable break", and push over into
>
> the normal flying attitude. The moment normal attitude is reached,
> begin
> a co-ordinated turn.
> All will be fine for a second or so, as you are flying at reduced G.
> However, once the G comes back on many gliders will roll smoothly (no
> buffeting) into a spin so fast that there is little you can do about it
>
> (though the purpose of the exercise is to show the spin entry and then
> a
> recovery, so I've not tried reducing back pressure as the wing drops).
> The Puchacz is excellent for this.--
>
> For me, this raised an immediate alarm. It indicates that there are
> flight regimes (whether experienced during a cable break recovery,
> during an aggressive thermal entry, or as a result of turbulence) where
> normal control movements may result in an immediate and unannounced
> spin entry.
> Since such matters are best examined in the air, I put together an
> informal flight test plan to measure just how sudden the spin entry is
> and whether there might be mitigating factors.
>
> To prepare for the test, I set up the following limits:
>
> First, I would at no time during the maneuver bring the stick back all
> the way to the stop. We must assume that all pilots meet a base level
> of competency, and under no circumstance would any competent pilot
> resort to full up elevator to maintain attitude during a cable break
> recovery. I would consider such control usage an abuse of the controls.
>
> Second, I would remain coordinated (as indicated by my yaw string)
> throughout the maneuver per the instructions of my flight manual.
>
> Third, at stall break, I would hold the controls firm and visually
> verify their positions, then wait for the sailplane to assume its new
> state (either spin or spiral dive) then clearly identify that state
> before making an appropriate recovery.
>
> I began the test sequence with a series of four dives and recoveries
> just as Chris described, but without introducing a bank. At 60 knots, I
> called out "Bang - cable break - recover!" I pushed the stick
> firmly forward. Three out of the four, I briefly suspended loose dirt
> in the cockpit. As soon as the nose passed through the horizon into a
> normal flying attitude, I moved the stick quickly back to its normal
> position for that attitude. Of course, this did not entirely halt the
> downward pitch of the nose. However, it was clearly apparent through
> the feel of the controls that the sailplane was either stalled or on
> the edge of a stall as a result of my quick application of stick from
> well forward to neutral. It was very clear that bringing the stick
> straight back to the stop would result in a full stall.
>
> I began the dives in flap position -1, moving the flaps to position +1
> as I slowed through 70 knots, as I might if I were entering a thermal,
> though my recovery (pitch over) was much more aggressive than any I
> would use during cross-country flight. Once I was comfortable with my
> ability to keep myself from making an immediate recovery from any
> stall, I stopped to thermal, then found a clear patch of sky and warned
> off others away, as I fully expected to spin the sailplane.
>
> In order to force an immediate turn, I imagined that there was an
> obstruction preventing a straight ahead landing. As soon as the nose
> came down, I determined that I would have to make an immediate turn to
> the right, which I did, without adverse results. The sailplane rolled
> sluggishly and felt on the edge of stall, but there was no loss of
> control, and certainly no sudden yaw and entry into a spin. I thought
> perhaps I had waited too long to initiate the turn, so with the next
> pull and recovery, I made the decision, before the nose came fully
> over, that I would land to the left in an adjoining field. I rolled to
> about 30 degrees, then as the nose reached normal flying attitude, I
> brought the stick right back to neutral... and braced myself against
> making an immediate recovery.
>
> As before, there was a sense of mushing through the air, but no
> tendency for the glider to yaw itself into a spin. For the next pull
> and recovery, I delayed saying "Bang - cable break - recover!"
> until 50 knots. Given the additional delay, I was much more aggressive
> with the stick, both moving it forward and returning it to neutral once
> I reach normal flying attitude. And once again, the sailplane
> demonstrated a sluggish, heavy feel as the g force came back on, but
> without any tendency to "fall" into the direction of the turn.
>
> It was clear to me that I could have easily induced a spin during this
> maneuver. A little too much rudder or stick against the turn coupled
> with bringing the stick full aft would have tipped the sailplane right
> over. But my intent was to produce an unanticipated spin, even though I
> was, ostensibly, doing everything right.
>
> I repeated this maneuver several more times, making slight adjustments
> to angle of bank, but without adverse effects.
>
> My conclusions:
>
> This is an interesting flight regime. I suspect that it would prove
> useful for producing spins in typically resistant aircraft, and require
> significantly less control abuse among those gliders that are inclined
> to spin. However, for my make and model (which can be easily coaxed to
> incipiency), normal attention to stall warning signs and application of
> coordinated aileron and rudder are adequate. There does not appear to
> be any tendency for the glider to spin suddenly or unpredictably,
> though I would caution that if the stick is used to catch a dropping
> wing without appropriate application of rudder, the spin entry could be
> significantly accelerated.
>
> The greater the span, the more pronounced the effects of a tip stall
> would be, but greater span is usually compensated for by a longer tail
> boom and larger vertical stabilizer. Some designs may choose to
> underpower the vertical stabilizer to increase glide performance, but
> hopefully these would include appropriate warnings and recovery
> procedures in their respective flight manuals.
>
> As far as thermal entry is concerned, I would give the same warning: if
> you delay your pushover on thermal entry to the point where G and
> airspeed are significantly reduced below the norms (generally not the
> most efficient way to enter a thermal), extra attention should be paid
> to coordination. I wouldn't expect the glider to snap into a spin,
> but it is entirely possible that the now underpowered vertical
> stabilizer may not adequately compensate if you have any tendency
> towards sloppiness.
>
> I intend to experiment with this maneuver some more over the coming
> weeks. As I discover anything interesting, I'll add my comments to
> the thread. Also, I uploaded my FR trace to the OLC, but my sampling
> was 4 seconds, hardly adequate for analysis. However, just in case you
> are tempted to make an armchair assay, be my guest!
>
> http://www2.onlinecontest.org/olcphp/2005/ausw_fluginfo.php?ref3=197828&ueb=N&olc=olc-usa&spr=en&dclp=c9701de37223903b6f823e438ec30ed8
>
> The test run began at 1454 ET (UTC-4) and ended at 1503 ET.
>

[Don Johnstone]

If you imagine that you are climbing at 55kts no probs
and the cable breaks. The glider starts to decelerate
so the immediate action is to push the stick forward
to pitch the nose down. The glider flies a parabolic
arc and while it's mass remains the same the weight
that the wing has to support is dramatically reduced
at the top of the arc. So the glider can be at 45kts
or less and the wing has not stalled, the AoA is still
below the stalling angle and the airspeed is sufficient
with the reduced G to keep the glider flying. The harder
the push the greater the reduction in G and effective
weight the wing has to support. Because of inertia
the glider will take time to accelerate to sufficient
speed to generate the lift necessary to support the
glider as the G increases to 1. If aileron is applied
to turn before this acceleration takes place the increasing
G can mean that in effect the wing is stalled and application
of aileron could initiate the spin. It is important
to remember that it is the attitude of the glider to
the relative airflow that determines the angle of attack,
not the relationship of the glider to the horizon.
The picture the pilot sees in these circumstances could
well be one where the nose is well below the horizon
(approach attitude) but acceleration has not taken
place and the wing is stalled. Once the glider accelerates
it is then safe to use the ailerons as normal. It is
a reversal of the situation where high G increases
the stalling speed, the further stalling exercise.
I have seen as little as 20 kts at the top of a push
over with no ill effect provided the ailerons remain
central. Try it sometime at a safe height, this will
be a far better way of seeing the problem than my explanation.

At 14:36 30 June 2005, Mike Schumann wrote:
>It is not obvious to me, why, in a cable break scenario,
>you would be close
>to stalling when you push the nose down to a normal
>attitude while you
>maintain 60 knot airspeed. This sounds like you are
>flying significantly
>above stall speed. Could you elaborate?
>
>Thanks,
>Mike Schumann
>
> wrote in message
oups.com...
>> Pilots depend on simple, quickly applied remedies
>>to any loss of
>> control. Since we are not always afforded the luxury
>>of examination,
>> analysis, and consideration of options as a preamble
>>to action, any
>> flight condition where these simple rules of recovery
>>do not work
>> demands closer examination and appropriate training
>>to recognize
>> symptoms and take appropriate actions.
>>
>> Modern aircraft are designed to meet well-defined
>>controllability
>> requirements. For example, in the United States, the
>>recommended
>> recovery (generic) for any impending or developed
>>stall is to move the
>> control column forward while applying coordinated
>>aileron and rudder to
>> halt an un-commanded roll. The Flight Manual for my
>>S-H Ventus 2bx
>> states on page 3.4:
>>
>> --On stalling whilst flying straight ahead or in a
>>banked turn, normal
>> flying attitude is regained by firmly easing the control
>>stick forward
>> and, if necessary, applying opposite rudder and aileron.--
>>
>> Page 3.5 (Spin Recovery) continues...
>>
>> --Note: Spinning may be safely avoided by following
>>the actions given
>> in section 3.4 'Stall Recovery'-
>>
>> During the past several years, I have made it a point
>>to experiment
>> with various applications of controls throughout the
>>stall break (and
>> in a variety of makes and models). In all cases where
>>I maintained
>> coordination, either paying attention to the yaw string
>>or through
>> application of equal amounts of aileron and rudder,
>>the aircraft did
>> not spin, even if I held the stick firmly against
>>the rear stop.
>> Instead, it would transition from stall to spiral
>>dive.
>>
>> In a recent RAS thread (Nimbus 4DT accident 31 July
>>2000 in Spain), I
>> was introduced to a maneuver practiced by BGA instructors
>>to
>> demonstrate that a quick transition from coordinated
>>flight into a spin
>> can take place while recovering from a winch launch
>>cable break. This
>> was pointed out to refute my comment in that thread
>>that modern gliders
>> need to be 'helped' into a spin (by either intentional
>>or
>> inadvertent abuse of the controls).
>>
>> Chris Reed described the following:
>>
>> --One of my favourite exercises for my annual checkouts
>>as a UK Basic
>> Instructor is the spin off a simulated winch launch
>>(only try this at
>> height with an appropriate instructor with you!).
>>Simulate a winch
>> launch by diving to 90 kt and then pulling up at 45
>>degrees. As the
>> speed drops to about 60 kt cry 'BANG - cable break',
>>and push over into
>>
>> the normal flying attitude. The moment normal attitude
>>is reached,
>> begin
>> a co-ordinated turn.
>> All will be fine for a second or so, as you are flying
>>at reduced G.
>> However, once the G comes back on many gliders will
>>roll smoothly (no
>> buffeting) into a spin so fast that there is little
>>you can do about it
>>
>> (though the purpose of the exercise is to show the
>>spin entry and then
>> a
>> recovery, so I've not tried reducing back pressure
>>as the wing drops).
>> The Puchacz is excellent for this.--
>>
>> For me, this raised an immediate alarm. It indicates
>>that there are
>> flight regimes (whether experienced during a cable
>>break recovery,
>> during an aggressive thermal entry, or as a result
>>of turbulence) where
>> normal control movements may result in an immediate
>>and unannounced
>> spin entry.
>> Since such matters are best examined in the air, I
>>put together an
>> informal flight test plan to measure just how sudden
>>the spin entry is
>> and whether there might be mitigating factors.
>>
>> To prepare for the test, I set up the following limits:
>>
>> First, I would at no time during the maneuver bring
>>the stick back all
>> the way to the stop. We must assume that all pilots
>>meet a base level
>> of competency, and under no circumstance would any
>>competent pilot
>> resort to full up elevator to maintain attitude during
>>a cable break
>> recovery. I would consider such control usage an abuse
>>of the controls.
>>
>> Second, I would remain coordinated (as indicated by
>>my yaw string)
>> throughout the maneuver per the instructions of my
>>flight manual.
>>
>> Third, at stall break, I would hold the controls firm
>>and visually
>> verify their positions, then wait for the sailplane
>>to assume its new
>> state (either spin or spiral dive) then clearly identify
>>that state
>> before making an appropriate recovery.
>>
>> I began the test sequence with a series of four dives
>>and recoveries
>> just as Chris described, but without introducing a
>>bank. At 60 knots, I
>> called out 'Bang - cable break - recover!' I pushed
>>the stick
>> firmly forward. Three out of the four, I briefly suspended
>>loose dirt
>> in the cockpit. As soon as the nose passed through
>>the horizon into a
>> normal flying attitude, I moved the stick quickly
>>back to its normal
>> position for that attitude. Of course, this did not
>>entirely halt the
>> downward pitch of the nose. However, it was clearly
>>apparent through
>> the feel of the controls that the sailplane was either
>>stalled or on
>> the edge of a stall as a result of my quick application
>>of stick from
>> well forward to neutral. It was very clear that bringing
>>the stick
>> straight back to the stop would result in a full stall.
>>
>> I began the dives in flap position -1, moving the
>>flaps to position +1
>> as I slowed through 70 knots, as I might if I were
>>entering a thermal,
>> though my recovery (pitch over) was much more aggressive
>>than any I
>> would use during cross-country flight. Once I was
>>comfortable with my
>> ability to keep myself from making an immediate recovery
>>from any
>> stall, I stopped to thermal, then found a clear patch
>>of sky and warned
>> off others away, as I fully expected to spin the sailplane.
>>
>> In order to force an immediate turn, I imagined that
>>there was an
>> obstruction preventing a straight ahead landing. As
>>soon as the nose
>> came down, I determined that I would have to make
>>an immediate turn to
>> the right, which I did, without adverse results. The
>>sailplane rolled
>> sluggishly and felt on the edge of stall, but there
>>was no loss of
>> control, and certainly no sudden yaw and entry into
>>a spin. I thought
>> perhaps I had waited too long to initiate the turn,
>>so with the next
>> pull and recovery, I made the decision, before the
>>nose came fully
>> over, that I would land to the left in an adjoining
>>field. I rolled to
>> about 30 degrees, then as the nose reached normal
>>flying attitude, I
>> brought the stick right back to neutral... and braced
>>myself against
>> making an immediate recovery.
>>
>> As before, there was a sense of mushing through the
>>air, but no
>> tendency for the glider to yaw itself into a spin.
>>For the next pull
>> and recovery, I delayed saying 'Bang - cable break
>>- recover!'
>> until 50 knots. Given the additional delay, I was
>>much more aggressive
>> with the stick, both moving it forward and returning
>>it to neutral once
>> I reach normal flying attitude. And once again, the
>>sailplane
>> demonstrated a sluggish, heavy feel as the g force
>>came back on, but
>> without any tendency to 'fall' into the direction
>>of the turn.
>>
>> It was clear to me that I could have easily induced
>>a spin during this
>> maneuver. A little too much rudder or stick against
>>the turn coupled
>> with bringing the stick full aft would have tipped
>>the sailplane right
>> over. But my intent was to produce an unanticipated
>>spin, even though I
>> was, ostensibly, doing everything right.
>>
>> I repeated this maneuver several more times, making
>>slight adjustments
>> to angle of bank, but without adverse effects.
>>
>> My conclusions:
>>
>> This is an interesting flight regime. I suspect that
>>it would prove
>> useful for producing spins in typically resistant
>>aircraft, and require
>> significantly less control abuse among those gliders
>>that are inclined
>> to spin. However, for my make and model (which can
>>be easily coaxed to
>> incipiency), normal attention to stall warning signs
>>and application of
>> coordinated aileron and rudder are adequate. There
>>does not appear to
>> be any tendency for the glider to spin suddenly or
>>unpredictably,
>> though I would caution that if the stick is used to
>>catch a dropping
>> wing without appropriate application of rudder, the
>>spin entry could be
>> significantly accelerated.
>>
>> The greater the span, the more pronounced the effects
>>of a tip stall
>> would be, but greater span is usually compensated
>>for by a longer tail
>> boom and larger vertical stabilizer. Some designs
>>may choose to
>> underpower the vertical stabilizer to increase glide
>>performance, but
>> hopefully these would include appropriate warnings
>>and recovery
>> procedures in their respective flight manuals.
>>
>> As far as thermal entry is concerned, I would give
>>the same warning: if
>> you delay your pushover on thermal entry to the point
>>where G and
>> airspeed are significantly reduced below the norms
>>(generally not the
>> most efficient way to enter a thermal), extra attention
>>should be paid
>> to coordination. I wouldn't expect the glider to snap
>>into a spin,
>> but it is entirely possible that the now underpowered
>>vertical
>> stabilizer may not adequately compensate if you have
>>any tendency
>> towards sloppiness.
>>
>> I intend to experiment with this maneuver some more
>>over the coming
>> weeks. As I discover anything interesting, I'll add
>>my comments to
>> the thread. Also, I uploaded my FR trace to the OLC,
>>but my sampling
>> was 4 seconds, hardly adequate for analysis. However,
>>just in case you
>> are tempted to make an armchair assay, be my guest!
>>
>> http://www2.onlinecontest.org/olcphp/2005/ausw_fluginfo.php?ref3=
>>>197828&ueb=N&olc=olc-usa&spr=en&dclp=c9701de37223903b6f823e438ec30
ed8
>>
>> The test run began at 1454 ET (UTC-4) and ended at
>>1503 ET.
>>
>
>
>

[jonnyboy]

Mike Schumann wrote:
> It is not obvious to me, why, in a cable break scenario, you would be close
> to stalling when you push the nose down to a normal attitude while you
> maintain 60 knot airspeed. This sounds like you are flying significantly
> above stall speed. Could you elaborate?
>
> Thanks,
> Mike Schumann

Mike;
I don't think Chris means he maintain 60 knots.
Starts at 60 knots, but with the nose up speed decays.....
Push the nose over to an *attitude* that in normal flight would give
around 60 knots and the trap is set....

Real speed is <~ Vs (say 40k) but attitude is good and she IS flying
(as G < 1)

once the G reverts to 1 you either have a good angle of attack/speed
and you are flying
or you don't and you arent.

thats my take - Vs increases in a tight turn as g>1.
so... when G<1 (bunt/top of loop etc.) Vs *reduces*


;-) Jonny.

[[email protected]]

Someone taught me a pretty effective way to put almost "all" the
gliders in a spin. It consist in just flying straight at a speed just a
little over the stall speed. Then use the ailerons only to slightly
bank the wings, say ten or fifteen degrees. At that moment if you push
the rudder on the side of the low wing you _will_ enter a spin.

I remember that during instruction we had to use the ASK13 for the
spins, because the Grob Twin Astir was not really spinning. Years after
I have then tried the Twin with this system, and geez down it goes...

[Chris Reed]

And I should add that I was explaining the exercise from memory and may
have got the speeds wrong. 90 kts is definitely over the top for
starting - pull up from 65 or 70 into a 45 degree climb so as not to
throw more height away at the outset.

In the case of a real cable break, climbing at 45 at 60 kt you *will*
take a second or two before you begin the pushover (and if you have
quick reactions pretend to be an out of practice, early solo pilot).
Then it will take the aircraft another second or two to complete the
pushover, which will mean the speed decays further. Performing this
exercise, I'd expect to see the normal gliding attitude with a speed of
perhaps 30kt or even as low as 20kt, but you're still flying because of
reduced G. Mike is quite right that the controls don't feel quite right,
but you're concerned to make the turn as early as possible because
you're just at that awkward height where you can't get in ahead but are
low for an abbreviated circuit (say 450ft at my airfield) so you turn,
the G comes back on, and the wing drops.

Whether you enter a spin will depend on the aircraft - our K21 won't
spin, even in this exercise, so falls out into a spiral dive. The
Puchacz rolls smoothly into the spin without any buffeting or other
warning, and I suspect most Polish gliders would do the same. Our K13
used to do the same, though in a more stately fashion, but since
re-covering seems more reluctant.

My point was not that a spin is inevitable, but that many gliders will
spin from this even though you are flying co-ordinated.

jonnyboy wrote:
> Mike Schumann wrote:
>
>>It is not obvious to me, why, in a cable break scenario, you would be close
>>to stalling when you push the nose down to a normal attitude while you
>>maintain 60 knot airspeed. This sounds like you are flying significantly
>>above stall speed. Could you elaborate?
>>
>>Thanks,
>>Mike Schumann
>
>
> Mike;
> I don't think Chris means he maintain 60 knots.
> Starts at 60 knots, but with the nose up speed decays.....
> Push the nose over to an *attitude* that in normal flight would give
> around 60 knots and the trap is set....
>
> Real speed is <~ Vs (say 40k) but attitude is good and she IS flying
> (as G < 1)
>
> once the G reverts to 1 you either have a good angle of attack/speed
> and you are flying
> or you don't and you arent.
>
> thats my take - Vs increases in a tight turn as g>1.
> so... when G<1 (bunt/top of loop etc.) Vs *reduces*
>
>
> ;-) Jonny.
>

[Stefan]

Chris Reed wrote:

> And I should add that I was explaining the exercise from memory and may
> have got the speeds wrong. 90 kts is definitely over the top for

Watch the limits: The LS 4 for example is limited to 77 knots on the winch.

> In the case of a real cable break, climbing at 45 at 60 kt you *will*
> take a second or two before you begin the pushover (and if you have

Two seconds? Never! If it takes you two seconds to react on the winch,
then you are not winch worthy. Hanging at the winch is not the place to
be dozing.

> quick reactions pretend to be an out of practice, early solo pilot).

An out of practice, early solo pilot isn't sent solo at the winch.
Never. In our club, even the most experienced pilots are required to do
the first winch launch of the year with an instructor. (Club rule. And
yes, before you ask, for the instructors it's a catch 22 situation. It
works for us.)

> reduced G. Mike is quite right that the controls don't feel quite right,
> but you're concerned to make the turn as early as possible because
> you're just at that awkward height where you can't get in ahead but are
> low for an abbreviated circuit (say 450ft at my airfield) so you turn,

Nothing awkward with this height: There's plenty of time for a safe
downwind landing. In fact, you *must* take your time for that downwind
landing. Turn too early, and you'll find yourself with the (now in fact
awkward) problem of 200 ft height over the runway with possibly a tailwind.

Stefan

[Andrew Warbrick]

At 20:54 30 June 2005, Stefan wrote:
>Chris Reed wrote:
>
>> And I should add that I was explaining the exercise
>>from memory and may
>> have got the speeds wrong. 90 kts is definitely over
>>the top for
>
>Watch the limits: The LS 4 for example is limited to
>77 knots on the winch.

As you are fond of pointing out, read the thread.

What Chris is describing is an upper air excercise
(no winch involved), Va and Vne are relevant, the max
winch speed is of no concern (personally I favour 70-75kts
as an entry speed, 60 isn't quite enough to get the
glider into the winch launch attitude, push over and
then stop the nose dropping on the horizon, 90 would
work but you'd be wasting height).

To simulate the situation which kills people (namely
spinning as a result of commencing a turn before flying
speed is regained after a cable break) you dive to
acquire speed, pull up into the winch launch attitude
then, at the appropriate moment, shout 'bang' and recover,
but check the pitch down at the normal gliding attitude
for 60kts, then immediately start a co-ordinated turn.
A Puchacz will immediately spin off this if you get
it right (the speeds are quite critical), too slow
you can't hold the nose up, too fast and it gets 'untidy'.
Trying to do this demo off a real winch launch would
hurt.

[Bill Daniels]

"Andrew Warbrick" > wrote in message
...
> At 20:54 30 June 2005, Stefan wrote:
> >Chris Reed wrote:
> >
> >> And I should add that I was explaining the exercise
> >>from memory and may
> >> have got the speeds wrong. 90 kts is definitely over
> >>the top for
> >
> >Watch the limits: The LS 4 for example is limited to
> >77 knots on the winch.
>
> As you are fond of pointing out, read the thread.
>
> What Chris is describing is an upper air excercise
> (no winch involved), Va and Vne are relevant, the max
> winch speed is of no concern (personally I favour 70-75kts
> as an entry speed, 60 isn't quite enough to get the
> glider into the winch launch attitude, push over and
> then stop the nose dropping on the horizon, 90 would
> work but you'd be wasting height).
>
> To simulate the situation which kills people (namely
> spinning as a result of commencing a turn before flying
> speed is regained after a cable break) you dive to
> acquire speed, pull up into the winch launch attitude
> then, at the appropriate moment, shout 'bang' and recover,
> but check the pitch down at the normal gliding attitude
> for 60kts, then immediately start a co-ordinated turn.
> A Puchacz will immediately spin off this if you get
> it right (the speeds are quite critical), too slow
> you can't hold the nose up, too fast and it gets 'untidy'.
> Trying to do this demo off a real winch launch would
> hurt.
>
You guys do this a little bit more subtly than I did it. I just asked the
student to deliberately botch the simulated wire break by doing nothing at
first. Just leave the glider pointed at the sky until it runs out of energy
and the nose falls through on it own and THEN, just as the nose falls
through the horizon, yank hard back on the stick while attempting a turn.
Almost any spinable glider will spin with enthusiasm under those conditions.
Of course, I'm talking about doing this at a safe altitude.

Fiveniner's point that this is abnormal use of controls is a fact but a
rusty or inexperienced pilot already unnerved by a wire break and now seeing
the nose fall toward the earth may just do it this way if not for this sort
of explicit training. It would appear that there are several cases in the
BGA accident database where this might have happened.

Just in case there are lurkers reading this who are getting the impression
that this is a sort of trap for the unwary should carefully read fiveniner's
flight test report. It DOES require the pilot to use very abnormal, in fact
illogical, control inputs. The training just reinforces the very basic idea
that the pilot must see a safe airspeed for the glider being flown before
establishing a normal glide or attempting a turn. No rocket science here,
just mind your airspeed and use smooth, logical control inputs.

Bill Daniels

[Don Johnstone]

At 00:48 01 July 2005, Bill Daniels wrote: (snip)
>Just in case there are lurkers reading this who are
>getting the impression
>that this is a sort of trap for the unwary should carefully
>read fiveniner's
>flight test report. It DOES require the pilot to use
>very abnormal, in fact
>illogical, control inputs. The training just reinforces
>the very basic idea
>that the pilot must see a safe airspeed for the glider
>being flown before
>establishing a normal glide or attempting a turn.
>No rocket science here,
>just mind your airspeed and use smooth, logical control
>inputs.

Unfortunately Bill that is just what it is, a trap
for the unwary. You can be in a situation where everything
looks normal, the nose is down in the approach attitude
you put in aileron and rudder and voila, spin/spiral
dive.

I have always taught that the decision whether to land
ahead or turn should never be made until both conditions
are met, attitude and airspeed. You cannot rely on
attitude in the same way as we do for 'normal' flying.
It is a trap easily avoided by thinking rather than
acting instictively. It's a bit like the turn on finals
- open the airbrake syndrome, people do it until it
bites.

[[email protected]]

What this exercise really does is demonstrate how angle of attack is
decoupled from attitude. It's unfortunate that the concept of pitch
control by reference to angle attack is only taught at a basic
theoretical level in most gliding instruction - undoubtedly due to the
lack of any angle of attack indicator on gliders! (unless you count the
pitot mast -mounted yaw string on a 2-33).

I really wish there was a simple, reliable and easy to read angle of
attack (AOA) gauge available for gliders, optimized for efficient
thermalling (no adjustment needed for water ballast or bank angle -
unlike airspeed) and safe pattern speeds (instant response to wind
gradient and shear; and again automatically adjusts for landing right
off tow while still full of water).

Then you could use this exercise to show how to drive the AOA way past
the stalling AOA while still appearing to be in a level "flying"
attitude.

Kirk

[John Sinclair]

At 12:00 01 July 2005, wrote:
>What this exercise really does is demonstrate how angle
>of attack is
>decoupled from attitude. It's unfortunate that the
>concept of pitch
>control by reference to angle attack is only taught
>at a basic
>theoretical level in most gliding instruction - undoubtedly
>due to the
>lack of any angle of attack indicator on gliders! (unless
>you count the
>pitot mast -mounted yaw string on a 2-33).
>
>I really wish there was a simple, reliable and easy
>to read angle of
>attack (AOA) gauge available for gliders, optimized
>for efficient
>thermalling (no adjustment needed for water ballast
>or bank angle -
>unlike airspeed) and safe pattern speeds (instant response
>to wind
>gradient and shear; and again automatically adjusts
>for landing right
>off tow while still full of water).
>
>Then you could use this exercise to show how to drive
>the AOA way past
>the stalling AOA while still appearing to be in a level
>'flying'
>attitude.
>
>Kirk
What you really want, Kirt, is an F-4 with long wings.
What was the recovery, 8 to 10 units and don't look
outside?
JJ

[Bill Daniels]

> wrote in message
oups.com...

> I really wish there was a simple, reliable and easy to read angle of
> attack (AOA) gauge available for gliders, optimized for efficient
> thermalling (no adjustment needed for water ballast or bank angle -
> unlike airspeed) and safe pattern speeds (instant response to wind
> gradient and shear; and again automatically adjusts for landing right
> off tow while still full of water).
>
> Then you could use this exercise to show how to drive the AOA way past
> the stalling AOA while still appearing to be in a level "flying"
> attitude.
>
> Kirk
>

I agree that an AoA indicator would be very useful in general and in winch
launch in particular.

A VERY cheap AoA indicator can be made with two red yarns taped to the sides
of the canopy as far forward and as low a possible yet where the pilot can
still see them. You need two yarns to insure that the pitch angle is not
affected by a yaw angle. Calibrate the yarns with a flight at best L/D, Min
Sink and stall. Those are the only AoA you are interested in.

The $99 Dynon AoA probe looks like it might work in gliders. It's just a
pitot probe with a 45 degree angled flat face below the pitot opening with a
pressure port in the middle of the flat face. Some clever electronics
convert the pressure differential into an AoA display. If you have a
flapped glider, the electronic smarts will need to know the flap position.
If the electronics have the correct AoA, then the best flap setting for that
AoA is also known and can be displayed too.

Bill Daniels

[Kilo Charlie]

> wrote in message
oups.com...
> What this exercise really does is demonstrate how angle of attack is
> decoupled from attitude. It's unfortunate that the concept of pitch
> control by reference to angle attack is only taught at a basic
> theoretical level in most gliding instruction - undoubtedly due to the
> lack of any angle of attack indicator on gliders! (unless you count the
> pitot mast -mounted yaw string on a 2-33).
>
> I really wish there was a simple, reliable and easy to read angle of
> attack (AOA) gauge available for gliders, optimized for efficient
> thermalling (no adjustment needed for water ballast or bank angle -
> unlike airspeed) and safe pattern speeds (instant response to wind
> gradient and shear; and again automatically adjusts for landing right
> off tow while still full of water).
>
> Then you could use this exercise to show how to drive the AOA way past
> the stalling AOA while still appearing to be in a level "flying"
> attitude.
>
> Kirk

Hey Kirk.....I thought that you had experimented with placing "yaw strings"
on the sides of the canopy at one point....any input re how that went for a
poor man's AOA?

Casey

[[email protected]]

Yeah, I tried a "yaw string" AoA setup, and while it did show AoA, it
was extremely sensitive to yaw, and wasn't really in the correct
position to help a pilot while thermalling or during landing. Plus the
range from "cruise" to "min sink" to "too slow" wasn't very big (on my
LS6, using about 8 inch long "AoA strings") - less than 2 inches, if I
remember right, and the ends are always moving making holding a
particular AoA a bit problematical.

Plus one of the strings (the upwind one, obviously) was always getting
caught in the canopy...

Heck, JJ, I figure that since the F-4 came equipped with both a real
live mil-spec yaw string (there is actually a hole in front of the
windscreen for the string to exit after being tied off inside the nose
- and a black stripe painted in front of the canopy for reference) and
a really nice visual and aural AoA system, we should have the same
thing in a glider.

An aural "fast - on speed - SLOW" AoA tone that would replace the audio
vario when the gear is down would be nice...

JJ, it was 3 to 8 units until the jet started to fly again - pointy end
first. Otherwise, the F-4 departure bold face was (I think...) "STICK
- FORWARD, AILERONS AND RUDDER - NEUTRAL, IF NOT RECOVERED MAINTAIN
FULL FORWARD STICK AND DEPLOY DRAG CHUTE"

And I think the the spin recovery bold face was: "STICK - MAINTAIN FULL
FORWARD, AILERONS - FULL WITH SPIN (TURN NEEDLE), AIRCRAFT UNLOADED -
AILERONS NEUTRAL"

Departures were interesting, but spins were a bad thing!

Off to fly!

Kirk

[Don Johnstone]

At 21:06 01 July 2005, wrote:
>Yeah, I tried a 'yaw string' AoA setup, and while it
>did show AoA, it
>was extremely sensitive to yaw, and wasn't really in
>the correct
>position to help a pilot while thermalling or during
>landing. Plus the
>range from 'cruise' to 'min sink' to 'too slow' wasn't
>very big (on my
>LS6, using about 8 inch long 'AoA strings') - less
>than 2 inches, if I
>remember right, and the ends are always moving making
>holding a
>particular AoA a bit problematical.
>
>Plus one of the strings (the upwind one, obviously)
>was always getting
>caught in the canopy...
>
>Heck, JJ, I figure that since the F-4 came equipped
>with both a real
>live mil-spec yaw string (there is actually a hole
>in front of the
>windscreen for the string to exit after being tied
>off inside the nose
>- and a black stripe painted in front of the canopy
>for reference) and
>a really nice visual and aural AoA system, we should
>have the same
>thing in a glider.
>
>An aural 'fast - on speed - SLOW' AoA tone that would
>replace the audio
>vario when the gear is down would be nice...
>
>JJ, it was 3 to 8 units until the jet started to fly
>again - pointy end
>first. Otherwise, the F-4 departure bold face was
>(I think...) 'STICK
>- FORWARD, AILERONS AND RUDDER - NEUTRAL, IF NOT RECOVERED
>MAINTAIN
>FULL FORWARD STICK AND DEPLOY DRAG CHUTE'
>
>And I think the the spin recovery bold face was: 'STICK
>- MAINTAIN FULL
>FORWARD, AILERONS - FULL WITH SPIN (TURN NEEDLE), AIRCRAFT
>UNLOADED -
>AILERONS NEUTRAL'
>
>Departures were interesting, but spins were a bad thing!
>
>Off to fly!
>
>Kirk

Differs from the SEPECAT Jaguar where the action is
much simpler. SEIZE BLACK AND YELLOW HANDLE, PULL HARD
:-)

[soarski]

I have never been in that predicament. Never seen a cable break
or lost power at below 200 ft or the tow rope on aero tow.
I do have 1000s of hours and acro time.

If I would want to land downwind on the runway I was taking off
I could be inclined to just kick in full rudder, and make the 180 Turn
via a "Hammerhead" I think it is called a "Kehre" in German, or a
"Turn? There would be mostly rudder work required, some back preasure
on coming out of a dive following the wingover, which is really half a
spin. Has anyone ever seen that done? Actually, come to think of it, I
have, in an airshow, a long time ago in a clipped wing Cub.

I will have to try at altitude, what will need more altitude to
recover.

DB

Pushing over forward very hard after cable break, you could get into a
negative flight regime, possibly into an inverted spin?



Don Johnstone wrote:
> At 21:06 01 July 2005, wrote:
> >Yeah, I tried a 'yaw string' AoA setup, and while it
> >did show AoA, it
> >was extremely sensitive to yaw, and wasn't really in
> >the correct
> >position to help a pilot while thermalling or during
> >landing. Plus the
> >range from 'cruise' to 'min sink' to 'too slow' wasn't
> >very big (on my
> >LS6, using about 8 inch long 'AoA strings') - less
> >than 2 inches, if I
> >remember right, and the ends are always moving making
> >holding a
> >particular AoA a bit problematical.
> >
> >Plus one of the strings (the upwind one, obviously)
> >was always getting
> >caught in the canopy...
> >
> >Heck, JJ, I figure that since the F-4 came equipped
> >with both a real
> >live mil-spec yaw string (there is actually a hole
> >in front of the
> >windscreen for the string to exit after being tied
> >off inside the nose
> >- and a black stripe painted in front of the canopy
> >for reference) and
> >a really nice visual and aural AoA system, we should
> >have the same
> >thing in a glider.
> >
> >An aural 'fast - on speed - SLOW' AoA tone that would
> >replace the audio
> >vario when the gear is down would be nice...
> >
> >JJ, it was 3 to 8 units until the jet started to fly
> >again - pointy end
> >first. Otherwise, the F-4 departure bold face was
> >(I think...) 'STICK
> >- FORWARD, AILERONS AND RUDDER - NEUTRAL, IF NOT RECOVERED
> >MAINTAIN
> >FULL FORWARD STICK AND DEPLOY DRAG CHUTE'
> >
> >And I think the the spin recovery bold face was: 'STICK
> >- MAINTAIN FULL
> >FORWARD, AILERONS - FULL WITH SPIN (TURN NEEDLE), AIRCRAFT
> >UNLOADED -
> >AILERONS NEUTRAL'
> >
> >Departures were interesting, but spins were a bad thing!
> >
> >Off to fly!
> >
> >Kirk
>
> Differs from the SEPECAT Jaguar where the action is
> much simpler. SEIZE BLACK AND YELLOW HANDLE, PULL HARD
> :-)

[Derek Copeland]

Dear Mr (or Mrs or Ms or Miss) Soarski,

Whoever you are, please remind me not to stand on or near any airfield where
you are flying, as I don't want a glider falling on top of me. Feeding in
full rudder after a rope or cable break almost guarantees a spin and once
you are in one you will lose at least 150 ft per turn plus another 300ft to
recover. I do hope you were not being serious!

The correct recovery from a winch launch cable break is to lower the nose
fairly rapidly to slightly below the normal approach attitude, allow the
speed to build up to the correct approach speed for the day and then decide
what to do, depending on your height and landing options ahead. It is
usually safer to land ahead if you can. While you are waiting for the nose
to come down it is also a good idea to pull the cable release twice to get
rid of any remaining broken cable, so it can't get caught round any trees,
power lines, etc.

From aerotow you are usually in a more level attitude and usually have
plenty of speed. If the rope breaks just lower the nose slightly and monitor
your airspeed. If you are low you have to land more or less straight ahead.
With a bit more height - say 200 ft or more, a 180 degree turn is possible,
but must be flown accurately - not skidded round on the rudder.

Regards
Derek C (UK Instructor)

05:18 02 July 2005 'Soarski' wrote:
I have never been in that predicament. Never seen a cable break
or lost power at below 200 ft or the tow rope on aero tow.
I do have 1000s of hours and acro time.

If I would want to land downwind on the runway I was taking off
I could be inclined to just kick in full rudder, and make the 180 Turn
via a "Hammerhead" I think it is called a "Kehre" in German, or a
"Turn? There would be mostly rudder work required, some back preasure
on coming out of a dive following the wingover, which is really half a
spin. Has anyone ever seen that done? Actually, come to think of it, I
have, in an airshow, a long time ago in a clipped wing Cub.

I will have to try at altitude, what will need more altitude to
recover

[Andreas Maurer]

On 1 Jul 2005 22:00:34 -0700, "soarski" > wrote:


>If I would want to land downwind on the runway I was taking off
>I could be inclined to just kick in full rudder, and make the 180 Turn
>via a "Hammerhead" I think it is called a "Kehre" in German, or a
>"Turn? There would be mostly rudder work required, some back preasure
>on coming out of a dive following the wingover, which is really half a
>spin. Has anyone ever seen that done? Actually, come to think of it, I
>have, in an airshow, a long time ago in a clipped wing Cub.

Jmmm... I never ever heard of such a maneuvre. The closer to the
ground, the more important it is to keep the yaw string centered.
Kicking in full rudder is regarded as <censored>.

We simply fly a 180 degrees turn at the end of the runway.



>Pushing over forward very hard after cable break, you could get into a
>negative flight regime, possibly into an inverted spin?

No. Not even if you puished the stick to the forward stop.

Bye
Andreas

[Bruce]

Hi Tom

Just because the gilder is at a 40 to 50 degree nose up attitude with respect to
the ground does not mean it has the energy for a stall turn.

There was a recent fatality in New Zealand where someone inadvertently tried
this. Assume you were joking, but in case you were serious, please feel free to
try it - the outcome would be merely predictable, if a little sad. Since I live
nearly 9 000 miles away I am confident you will not impact on my personal safety...

Bruce

soarski wrote:
> I have never been in that predicament. Never seen a cable break
> or lost power at below 200 ft or the tow rope on aero tow.
> I do have 1000s of hours and acro time.
>
<SNIP>

>MAINTAIN
>>>FULL FORWARD STICK AND DEPLOY DRAG CHUTE'
>>>
>>>And I think the the spin recovery bold face was: 'STICK
>>>- MAINTAIN FULL
>>>FORWARD, AILERONS - FULL WITH SPIN (TURN NEEDLE), AIRCRAFT
>>>UNLOADED -
>>>AILERONS NEUTRAL'
>>>
>>>Departures were interesting, but spins were a bad thing!
>>>
>>>Off to fly!
>>>
>>>Kirk
>>
>>Differs from the SEPECAT Jaguar where the action is
>>much simpler. SEIZE BLACK AND YELLOW HANDLE, PULL HARD
>>:-)
>
>


--
Bruce Greeff
Std Cirrus #57
I'm no-T at the address above.

[Edward Lockhart]

At 05:18 02 July 2005, Soarski wrote:

>If I would want to land downwind on the runway I was
>taking off
>I could be inclined to just kick in full rudder, and
>make the 180 Turn
>via a 'Hammerhead' I think it is called a 'Kehre' in
>German, or a
>'Turn? There would be mostly rudder work required,
>some back preasure
>on coming out of a dive following the wingover, which
>is really half a
>spin. Has anyone ever seen that done? Actually, come
>to think of it, I
>have, in an airshow, a long time ago in a clipped wing
>Cub.
>
>I will have to try at altitude, what will need more
>altitude to
>recover.
>
>DB

So you're talking about some sort of stall turn at
low speed off a 45 degree upline. I think the speed
would be too slow to get any significant yaw. At slow
speed, high AoA you'll get a lot of roll with some
nose drop, almost a low energy flick/snap roll to a
very steep (inverted?) downline.

If you're high enough, you can recover.

The steep climb rate of a winch launch means that you
will then be passing the launch point at low level,
heading downwind at high speed through any landing
traffic, needing to do a smart 180 to land back on
the airfield; not really possible in a K13.

This all sounds like a lot of fun but I'm not sure
we should be teaching it to pre-solo pilots

>
>Pushing over forward very hard after cable break, you
>could get into a
>negative flight regime, possibly into an inverted spin?

With the typical soaring/training aerofoils used, and
at low speed, that would need an incredibly rapid push.
Even then, so long as the pilot keeps the rudder centralised,
there's no chance of an inverted spin.

Winch techniques have evolved over decades with safety
as the first priority. There's nothing wrong with a
bit of imagination but Soarski, that's a bit too much.

Ed

[F.L. Whiteley]

Edward Lockhart wrote:

> At 05:18 02 July 2005, Soarski wrote:
>
>>If I would want to land downwind on the runway I was
>>taking off
>>I could be inclined to just kick in full rudder, and
>>make the 180 Turn
>>via a 'Hammerhead' I think it is called a 'Kehre' in
>>German, or a
>>'Turn? There would be mostly rudder work required,
>>some back preasure
>>on coming out of a dive following the wingover, which
>>is really half a
>>spin. Has anyone ever seen that done? Actually, come
>>to think of it, I
>>have, in an airshow, a long time ago in a clipped wing
>>Cub.
>>
>>I will have to try at altitude, what will need more
>>altitude to
>>recover.
>>
>>DB
>
> So you're talking about some sort of stall turn at
> low speed off a 45 degree upline. I think the speed
> would be too slow to get any significant yaw. At slow
> speed, high AoA you'll get a lot of roll with some
> nose drop, almost a low energy flick/snap roll to a
> very steep (inverted?) downline.
>
> If you're high enough, you can recover.
>
> The steep climb rate of a winch launch means that you
> will then be passing the launch point at low level,
> heading downwind at high speed through any landing
> traffic, needing to do a smart 180 to land back on
> the airfield; not really possible in a K13.
>
> This all sounds like a lot of fun but I'm not sure
> we should be teaching it to pre-solo pilots
>
>>
>>Pushing over forward very hard after cable break, you
>>could get into a
>>negative flight regime, possibly into an inverted spin?
>
> With the typical soaring/training aerofoils used, and
> at low speed, that would need an incredibly rapid push.
> Even then, so long as the pilot keeps the rudder centralised,
> there's no chance of an inverted spin.
>
> Winch techniques have evolved over decades with safety
> as the first priority. There's nothing wrong with a
> bit of imagination but Soarski, that's a bit too much.
>
> Ed
Speaking of over the top.

Slingby Swallow takes winch launch to 1100agl.
Rolls inverted.
Dives out.
Loops.
Chandelles.
Lands.

You had to be there.

Frank

[Don Johnstone]

At 20:30 02 July 2005, F.L. Whiteley wrote:
>Speaking of over the top.
>
>Slingby Swallow takes winch launch to 1100agl.
>Rolls inverted.
>Dives out.
>Loops.
>Chandelles.
>Lands.
>
>You had to be there.
>
>Frank

Pilot by the name of Doug Ross, No 2 GC UK? Before
they put the elevator stops on to prevent you doing
it. Spoilsports.
>

[Capt. Geoffry Thorpe]

"soarski" > wrote in message
oups.com...
>I have never been in that predicament. Never seen a cable break
> or lost power at below 200 ft or the tow rope on aero tow.

Been lucky so far?

> I do have 1000s of hours and acro time.
>
> If I would want to land downwind on the runway I was taking off
> I could be inclined to just kick in full rudder, and make the 180 Turn
> via a "Hammerhead" I think it is called a "Kehre" in German, or a
> "Turn? There would be mostly rudder work required, some back preasure
> on coming out of a dive following the wingover, which is really half a
> spin. Has anyone ever seen that done? Actually, come to think of it, I
> have, in an airshow, a long time ago in a clipped wing Cub.

D00d. A hammerhead works on a verticle up / down line at zero G. Coming of a
cable break you are still only at about 30-40 degrees nose up. Do you think
you would have enough speed to make it to a verticle up? I doubt it, usually
the entry speed for a hammerhead is fairly high, right? If you try to do a
hammerhead on a, say 45 degree up, I'm not sure how /if it could work - I've
never seen it done, I assume there is a reason. You would have to keep
pushing to stay at 0 G I think. I guess it could be entertaining to try if
you have some altitude under your butt.

You could attempt a kinda chandelle like turn, but you are starting out nose
high, low speed, and straight ahead. It would take a lot of forward stick to
keep the G loading below 1 throughout the manouver I would think. Buy the
time you get turned around, you would likely end up pointing way down. eh?

>
> I will have to try at altitude, what will need more altitude to
> recover.
>

That sounds like a good idea. Don't forget the 'chute.

--
Geoff
the sea hawk at wow way d0t com
remove the spaces and do the obvious substitutions to reply by mail
Spell checking is left as an excersise for the reader.

[F.L. Whiteley]

Don Johnstone wrote:

> At 20:30 02 July 2005, F.L. Whiteley wrote:
>>Speaking of over the top.
>>
>>Slingby Swallow takes winch launch to 1100agl.
>>Rolls inverted.
>>Dives out.
>>Loops.
>>Chandelles.
>>Lands.
>>
>>You had to be there.
>>
>>Frank
>
> Pilot by the name of Doug Ross, No 2 GC UK? Before
> they put the elevator stops on to prevent you doing
> it. Spoilsports.
>>
No, the inimitable Mick Boyden.

The tricky bit is that twist is such that all the flying load is on the tips
while inverted. Gotta hope for good glue and no bumps.

[soarski]

Ahhh, stepped into a hornet's nest here? The thought came to me after
seeing the rather lengthy
tales in the beginning of this thread. I am against yanking the stick
forward and then back, hard or fully. So the thought of mostly rudder
work, like entering or coming out of a spin or half a spin came to me.
Naturally one would not teach that, but on the other hand, some of you
might have a "Hammerhead " demonstrated to you, or take some Acro
instruction? Edward aparently understood what I was thinking. He is
right, one would come out of that half spin recovery too fast which
would not work on a tight airfield.

What Frank saw after the loop and before the landing with that Swallow
might have been a hammerhead rather than a Chandelle, which would have
taken too long. Spin entry is faster. Of course, the Swallow is a very
light aircraft and can do those manouvers much slower than the glass
slippers.

In the late 50s a former Luftwaffe Pilot named Karlie Marsen did Acro
work out of a winch launch regularly at Flugplatzfests same what Frank
saw,.. in a Lo 100.......He was a skier too!

Soarski

[Bruce Hoult]

In article >,
"Capt. Geoffry Thorpe" <The Sea Hawk at wow way d0t com> wrote:

> You could attempt a kinda chandelle like turn, but you are starting out nose
> high, low speed, and straight ahead. It would take a lot of forward stick to
> keep the G loading below 1 throughout the manouver I would think.

This doesn't make sense. The G loading will stay appropriate to your
current speed at all times as long as the stick is anywhere except hard
back. Above 1, below 1, doesn't matter. Angle of attack is what
matters, and the AoA is fine as long as the stick is somewhere near the
middle. Right forward is completely unnecessary.

I don't think I'd try a chandelle from that position, but the limiting
factor would be roll rate and getting in sufficient bank to be useful
before you ran out of speed. Slow over the top banked 90 degrees and
pulling half a G aroudn the corner would be useful in getting turned
around, if you kept the string straight and the stick back not too far.
Slow over the top and banked 30 degrees would do you very little good
(though I don't think it would hurt).

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------