Unintentional fully-developed spins...

[Marc Ramsey]

OK, I'm curious. How many of you have had to recover from a fully
developed (greater than one turn), unintentional spin that occurred
during normal non-aerobatic flight?

I've got close to 1000 hours in roughly 25 different types of single
seat and higher performance two seat gliders, with stall/spin
characteristics ranging from "benign" to "interesting", and while I've
had my share of accidental spin entries (all while thermaling in
turbulent conditions), I can't remember a single one that went beyond a
quarter turn before recovery.

Where I first learned to fly gliders, everyone went up in for a single
flight in a 2-32 to do their "spin training" prior to solo. The 2-32
spins quite nicely, but the whole thing was such a bizarrely alien
experience, that was seemingly irrelevant to "normal" flying.

I experienced much more relevant spin training when I was being checked
out in a K-13 a few years later. We had about 8000 feet to waste, so
the instructor had me to set up a moderately banked turn, feed in a bit
of extra bottom rudder, then asked me to see how slowly I could fly.
After the "what the f*ck" moment as the ground and sky swapped places, I
managed to recover in a turn or so. He spent the rest of the flight
showing me how to induce and recognize different kinds of spin entries,
and how to recover from them as quickly as possible.

These days, at the beginning of each season, I make sure I have the spin
recovery procedure in the manual memorized, and try various types of
spin entries with slightly delayed recovery (roughly one quarter to one
half turn). When I first fly with water, I do the same. I have not
tried fully developed spins in any glider I've owned, other than my
DG-303 Acro. Some have been placarded against spins, in the others, I
just haven't felt it to be necessary or appropriate.

Marc

[Chris Nicholas]

Marc Ramsey wrote "OK, I'm curious. How many of you have had to recover
from a fully
developed (greater than one turn), unintentional spin that occurred
during normal non-aerobatic flight?" [snip]

Not me personally, but I have known, or known of, several pilots who
did. Most died, after cable breaks, mismanaged aftermath, and spins
into the ground from about 600 feet. Of two who survived, one couldn't
explain why he didn't effect prompt recovery - has since given up
gliding. The other I referred to earlier - didn't realise it was a
spin, thought tail had come off.

You may not get many first person replies, because those who did are
mostly no longer with us. I would hope our training regimes strive to
prevent too many more, not only by Eric Greenwell's 4, 3 and 2 (which I
entirely support) but also by 1, time and again, until people no longer
fail to realise what they have done when they somehow skip over 4, 3,
and 2, stop panicking, and can recover.

Chris N.

[Marc Ramsey]

Chris Nicholas wrote:

> Marc Ramsey wrote:
> "OK, I'm curious. How many of you have had to recover
> from a fully developed (greater than one turn), unintentional
> spin that occurred during normal non-aerobatic flight?" [snip]
>
> Not me personally, but I have known, or known of, several pilots who
> did. Most died, after cable breaks, mismanaged aftermath, and spins
> into the ground from about 600 feet. Of two who survived, one couldn't
> explain why he didn't effect prompt recovery - has since given up
> gliding. The other I referred to earlier - didn't realise it was a
> spin, thought tail had come off.

What I asked is if anyone here has properly recognized a spin entry,
immediately attempted recovery, and not been able to do so in well under
a turn. For my own education, I would like to know the circumstances.

> You may not get many first person replies, because those who did are
> mostly no longer with us. I would hope our training regimes strive to
> prevent too many more, not only by Eric Greenwell's 4, 3 and 2 (which
> I entirely support) but also by 1, time and again, until people no
> longer fail to realise what they have done when they somehow skip over
> 4, 3, and 2, stop panicking, and can recover.

I feel that I, personally, benefit a great deal more from practicing to
properly recognize and recover from a spin entry immediately, than I do
from practicing initiating a spin, holding it for a few turns, then
recovering.

Marc

[Richard Brisbourne]

Marc Ramsey wrote:

> OK, I'm curious. How many of you have had to recover from a fully
> developed (greater than one turn), unintentional spin that occurred
> during normal non-aerobatic flight?
>

Well I haven't.

An interesting aside, especially in view of the comments about spinning (or
not) ballasted.

I still have on my shelf a copy of George Moffat's "Winning on the Wind"
which includes his account of the 1970 Worlds at Marfa (which he won). He
mentions a hair-raising inadvertent spin in the (presumably ballasted)
Nimbus 1 in which he lost 1500 ft and recovered by "flexing the floppy
wings by yanking on the stick". Don't try this at home.

--
Soar the big sky
The real name on the left is richard

[Wallace Berry]

In article >,
Marc Ramsey > wrote:

> Chris Nicholas wrote:
>
> > Marc Ramsey wrote:
> > "OK, I'm curious. How many of you have had to recover
> > from a fully developed (greater than one turn), unintentional
> > spin that occurred during normal non-aerobatic flight?" [snip]


In slightly more than 1000 hours in all types of soaring, in ships
ranging from old wood, old metal, old glass, and new glass, I have never
had any inadvertant spin go more than 1/2 turn. That was in a 1-26 that
went "over the top" with me due to a terrrifically strong gust in a
turbulent thermal. Took me a sec to realize it was a spin entry and not
just the gust overpowering my aileron control.

I have witnessed two fully developed unintentional spins. Both by the
same pilot in two different ships. First was in a Ka-6 at altitude. I
was cruising over to join this fellow in a thermal when he just tucked
and spun two rotations before affecting recovery. He made a rather
excited radio call about the glider "spinning out from under him". I
chose not to join him in that or any other thermal. The second I saw
from the ground. The same guy was returning to the airport too low in an
SGS 1-23D. On entry to downwind (estimated to be about 700 agl), the
nose dropped sharply and the glider rotated a bit more than one full
rotation. We all thought he was going to buy the farm on that one.
Fortunately, he recovered and pulled back to wings level with about 200
feet to spare (we lost him behind the trees from our viewing angle). He
managed to land on the airport but didn't make the runway. He stopped
flying gliders after that.

[Bob Kuykendall]

Earlier, Marc Ramsey wrote:

> OK, I'm curious. How many of you have
> had to recover from a fully developed
> (greater than one turn), unintentional
> spin that occurred during normal non-
> aerobatic flight?

I've watched an ASW-20, flown by a well-respected pilot,
flick into a spin while thermalling. Including the
recovery, it went about a turn and a half. The thing
that impressed me about it was the dynamic and asymmetric
flexing of the wings in the entry. I seem to recall
that it was an over-the-top entry, but I could be wrong
on that. I have no idea what precipitated the entry,
but I can say that it made more of an impression on
my opinion of the ship than on my opinion of the pilot.

I came away from that incident wondering to what degree
the limber structures of second-generation composite
wings might interact with hard-to-predict post-stall
aerodynamic behaviors to incite spin entries and perhaps
inhibit recovery.

Thanks, and best regards to all

Bob K.

[K.P. Termaat]

During the Dutch Nationals quite a few years ago I was flying a Pik-20D. My
experience with this glider was that it was very reluctant to enter a spin.
My son flew an asw-20 borrowed from a friend at the same occasion. While
seriously banking at a turnpoint in order to take a photo the glider started
a steep turn. After about one full rotation my son managed to stop the spin,
but guess what the asw-20 dove straight away in rotation again but now in
the other direction. He recovered within one rotation again and came out
with the nose of the glider pointing vertically to the ground. Luckely high
enough to return to the normal flying mode. We decided that he would fly the
PIK-20D in following competitions.

Karel, NL
"Bob Kuykendall" > schreef in bericht
...
> Earlier, Marc Ramsey wrote:
>
> > OK, I'm curious. How many of you have
> > had to recover from a fully developed
> > (greater than one turn), unintentional
> > spin that occurred during normal non-
> > aerobatic flight?
>
> I've watched an ASW-20, flown by a well-respected pilot,
> flick into a spin while thermalling. Including the
> recovery, it went about a turn and a half. The thing
> that impressed me about it was the dynamic and asymmetric
> flexing of the wings in the entry. I seem to recall
> that it was an over-the-top entry, but I could be wrong
> on that. I have no idea what precipitated the entry,
> but I can say that it made more of an impression on
> my opinion of the ship than on my opinion of the pilot.
>
> I came away from that incident wondering to what degree
> the limber structures of second-generation composite
> wings might interact with hard-to-predict post-stall
> aerodynamic behaviors to incite spin entries and perhaps
> inhibit recovery.
>
> Thanks, and best regards to all
>
> Bob K.
>
>
>

[Andreas Maurer]

On 29 Jan 2004 21:46:51 GMT, Bob Kuykendall
> wrote:

>I've watched an ASW-20, flown by a well-respected pilot,
>flick into a spin while thermalling. Including the
>recovery, it went about a turn and a half. The thing
>that impressed me about it was the dynamic and asymmetric
>flexing of the wings in the entry. I seem to recall
>that it was an over-the-top entry, but I could be wrong
>on that. I have no idea what precipitated the entry,
>but I can say that it made more of an impression on
>my opinion of the ship than on my opinion of the pilot.

Typical for an ASW-20 in flap setting 4.

My only unintentional spin also happened in a 20. At flap setting 4
the 20's departure can be aprupt and if the CG is halfways backwards
it immediately enters a spin with an over-the-top entry if not
immediate corrective measures (anti-spinwise rudder, flaps to neutral
or even negative) are applied. Time from stall to spin less than two
seconds. Really impressive.

My spin happened when I was hit by strong lift while flying along a
cloud street at very low speed (below 75 kp/h) and flap setting 4.
I consciously delayed my correction with the rudder when the 20 began
to turn towards one wing because I wanted to see what would happen,
and was amazed how quickly I was going trough inverted into a
fully-developed spin.

Immediate application of rudder had prevented that, and at neutral or
even flaps the 20 has very docile stall manners.

Bye
Andreas

[Raphael Warshaw]

Marc:

I had an unintentional spin from a thermalling turn in a Baby Lark.
There was no warning (at least that I noticed), the entry was over the
top and the glider ended up spinning oposite the direction I had been
thermalling. Once I realized that it was spinning, it recovered
normally but I lost a lot of altitude before I figured it out. At
12,000 feet where it happened, it was a non-event. At 1,000 feet it
most likely would have killed me.

In turning stalls, this particular Baby Lark ALWAYS dropped a wing,
but this was quite different. In a turning stall, my own ship just
mushes until the nose drops. It will spin, but it has to be put there.

The Lark was, BTW, a rental ship and I don't remember any special
emphasis on its spin characteristics during my checkout. I continued
to fly it afterwards until it was destroyed by someone who tried to
land it perpendicular to a road. I never let it get slow near the
ground or unintentionally again, though.

Ray Warshaw

Marc Ramsey > wrote in message >...

[Slingsby]

Bob Kuykendall > wrote in message >...
> Earlier, Marc Ramsey wrote:
>
> > OK, I'm curious. How many of you have
> > had to recover from a fully developed
> > (greater than one turn), unintentional
> > spin that occurred during normal non-
> > aerobatic flight?
>
> I've watched an ASW-20, flown by a well-respected pilot,
> flick into a spin while thermalling. Including the
> recovery, it went about a turn and a half. The thing
> that impressed me about it was the dynamic and asymmetric
> flexing of the wings in the entry. I seem to recall
> that it was an over-the-top entry, but I could be wrong
> on that. I have no idea what precipitated the entry,
> but I can say that it made more of an impression on
> my opinion of the ship than on my opinion of the pilot.
>
> I came away from that incident wondering to what degree
> the limber structures of second-generation composite
> wings might interact with hard-to-predict post-stall
> aerodynamic behaviors to incite spin entries and perhaps
> inhibit recovery.
>
> Thanks, and best regards to all
>
> Bob K.

Do you also mean high aspect ratio wings with poorly glued spar caps?

[JJ Sinclair]

Mark,
I have owned over 40 sailplanes and flown over 50 types while logging 4110 hrs
in sailplanes. I have never entered an unintentional spin and "get this" I have
never even had a full unintentional stall in any sailplane. Once turning final
for a rocky, up hill, landing, I got pre-stall buffet in my H-301 libelle,
eased off a bit on the back stick and landed OK. On another occasion I was
stretching the glide to a duster strip in the Sierras (Sunrise) and arrived
there with 500 feet, flew an abbreviated down wind, lowered the flaps, lowered
the gear, cracked the spoilers and turned left, all from about 45 knots. The
LS-6 just shook its head and said, "I don't think so". Shoved the stick forward
and landed OK. I think its all about feeling the ship. Most pilots have the
feel of what's going on, a few don't and they never will.
I believe we should be doing spin entry followed by emmediate recovery, just in
case, but a well flown sailplane won't be in need of any spin recovery.
JJ Sinclair

[Bill Daniels]

"Marc Ramsey" > wrote in message
m...
> OK, I'm curious. How many of you have had to recover from a fully
> developed (greater than one turn), unintentional spin that occurred
> during normal non-aerobatic flight?
>
> I've got close to 1000 hours in roughly 25 different types of single
> seat and higher performance two seat gliders, with stall/spin
> characteristics ranging from "benign" to "interesting", and while I've
> had my share of accidental spin entries (all while thermaling in
> turbulent conditions), I can't remember a single one that went beyond a
> quarter turn before recovery.
>
> Where I first learned to fly gliders, everyone went up in for a single
> flight in a 2-32 to do their "spin training" prior to solo. The 2-32
> spins quite nicely, but the whole thing was such a bizarrely alien
> experience, that was seemingly irrelevant to "normal" flying.
>
> I experienced much more relevant spin training when I was being checked
> out in a K-13 a few years later. We had about 8000 feet to waste, so
> the instructor had me to set up a moderately banked turn, feed in a bit
> of extra bottom rudder, then asked me to see how slowly I could fly.
> After the "what the f*ck" moment as the ground and sky swapped places, I
> managed to recover in a turn or so. He spent the rest of the flight
> showing me how to induce and recognize different kinds of spin entries,
> and how to recover from them as quickly as possible.
>
> These days, at the beginning of each season, I make sure I have the spin
> recovery procedure in the manual memorized, and try various types of
> spin entries with slightly delayed recovery (roughly one quarter to one
> half turn). When I first fly with water, I do the same. I have not
> tried fully developed spins in any glider I've owned, other than my
> DG-303 Acro. Some have been placarded against spins, in the others, I
> just haven't felt it to be necessary or appropriate.
>
> Marc

It's never happened to me, but I have observed two spins all the way to the
ground. In neither case was it obvious that the pilots were making any
attempt to stop the spin.

One was a Stan Hall Cherokee - a wood and fabric homebuilt single seater.
It made at least 20 turns before impact. The spin looked normal to me but
some people speculated that the CG was too far aft. The pilot survived with
serious injuries. He said that, "it just got away from me while
thermalling".

The other was a LK-10 (Wood and fabric two seater built for the US military
during WWII). It spun off the top of a winch launch at Torry Pines and went
at least 6 normal looking turns to impact. Neither occupant survived.

Bill Daniels

[Geir Raudsandmoen]

At 03:18 30 January 2004, Jj Sinclair wrote:
>Mark,
>I have owned over 40 sailplanes and flown over 50 types
>while logging 4110 hrs
>in sailplanes. I have never entered an unintentional
>spin and 'get this' I have
>never even had a full unintentional stall in any sailplane.
>Once turning final
>for a rocky, up hill, landing, I got pre-stall buffet
>in my H-301 libelle,
>eased off a bit on the back stick and landed OK. On
>another occasion I was
>stretching the glide to a duster strip in the Sierras
>(Sunrise) and arrived
>there with 500 feet, flew an abbreviated down wind,
>lowered the flaps, lowered
>the gear, cracked the spoilers and turned left, all
>from about 45 knots. The
>LS-6 just shook its head and said, 'I don't think so'.
>Shoved the stick forward
>and landed OK. I think its all about feeling the ship.
>Most pilots have the
>feel of what's going on, a few don't and they never
>will.
>I believe we should be doing spin entry followed by
>emmediate recovery, just in
>case, but a well flown sailplane won't be in need of
>any spin recovery.
>JJ Sinclair

But a sailplane ain't always flown well.
Nobody is perfect, not even you.

Geir
>

[Buck Wild]

(JJ Sinclair) wrote in message >...
> Mark,

> I have owned <snip>...
I think its all about feeling the ship. Most pilots have the
feel of what's going on, a few don't and they never will.

> JJ Sinclair

JJ, that says it all.

(except you got the "most" and the "a few" mixed up.)

-Dan

[F.L. Whiteley]

"Marc Ramsey" > wrote in message
om...
> Chris Nicholas wrote:
>
> > Marc Ramsey wrote:
> > "OK, I'm curious. How many of you have had to recover
> > from a fully developed (greater than one turn), unintentional
> > spin that occurred during normal non-aerobatic flight?" [snip]
> >
> > Not me personally, but I have known, or known of, several pilots who
> > did. Most died, after cable breaks, mismanaged aftermath, and spins
> > into the ground from about 600 feet. Of two who survived, one couldn't
> > explain why he didn't effect prompt recovery - has since given up
> > gliding. The other I referred to earlier - didn't realise it was a
> > spin, thought tail had come off.
>
> What I asked is if anyone here has properly recognized a spin entry,
> immediately attempted recovery, and not been able to do so in well under
> a turn. For my own education, I would like to know the circumstances.
>
Not yet

> > You may not get many first person replies, because those who did are
> > mostly no longer with us. I would hope our training regimes strive to
> > prevent too many more, not only by Eric Greenwell's 4, 3 and 2 (which
> > I entirely support) but also by 1, time and again, until people no
> > longer fail to realise what they have done when they somehow skip over
> > 4, 3, and 2, stop panicking, and can recover.
>
> I feel that I, personally, benefit a great deal more from practicing to
> properly recognize and recover from a spin entry immediately, than I do
> from practicing initiating a spin, holding it for a few turns, then
> recovering.
>
I get occasional incipient entries while thermaling, but was, I believe,
properly trained to recognize and respond appropriately, so none have
developed into full spins inadvertantly. I do practice this regularly also
and do a 1-2 turn spin from time to time.

The Brits had a training concept when I initially learned to soar, 'recovery
from unusual attitudes'. The instructor would but the glider in an awkward
attitude and allow the student to recover to straight and level. Could be
nose up, down, cross controls, whatever. The important part was the proper
input to get things back in control.

I recall one odd day when flying my SHK not too far off the Anglia coast. I
think the air had a bit of shear. I went to turn to the left, but the
glider definitely wanted to roll right. Speed was fine, but I had the
distinct impression that the air was rolling or in vertical shear in a
clockwise direction. After a few seconds things went back to normal, but
for a bit I thought I'd flick over the top of the turn and I really wasn't
looking forward to it.

Frank Whiteley


Frank

[F.L. Whiteley]

IS 28 and IS 29 both have relatively large cordwise ailerons. Using too
much aileron for incipient recovery may result in a full spin, but
especially in where the aileron is a large percentage of the chord.. Our
club chairman test flew an IS 29 that our club (1979?) was considering at
one point and rejected it for this very reason. I personally found the IS
28 a nice platform but know that others were cautious or critical. I recall
comments, a la Puchaz, from around 1980, after a few spin-ins, including two
UK instructors in one instance.

You are invited to google this thread from 1995, http://tinyurl.com/2gg7r

Frank Whiteley


"Raphael Warshaw" > wrote in message
m...
> Marc:
>
> I had an unintentional spin from a thermalling turn in a Baby Lark.
> There was no warning (at least that I noticed), the entry was over the
> top and the glider ended up spinning oposite the direction I had been
> thermalling. Once I realized that it was spinning, it recovered
> normally but I lost a lot of altitude before I figured it out. At
> 12,000 feet where it happened, it was a non-event. At 1,000 feet it
> most likely would have killed me.
>
> In turning stalls, this particular Baby Lark ALWAYS dropped a wing,
> but this was quite different. In a turning stall, my own ship just
> mushes until the nose drops. It will spin, but it has to be put there.
>
> The Lark was, BTW, a rental ship and I don't remember any special
> emphasis on its spin characteristics during my checkout. I continued
> to fly it afterwards until it was destroyed by someone who tried to
> land it perpendicular to a road. I never let it get slow near the
> ground or unintentionally again, though.
>
> Ray Warshaw
>
> Marc Ramsey > wrote in message
>...

[Robert Ehrlich]

JJ Sinclair wrote:
> ...
> The LS-6 just shook its head and said, "I don't think so". Shoved the stick forward
> and landed OK. I think its all about feeling the ship. Most pilots have the
> feel of what's going on, a few don't and they never will.
> ...

I compeletely agree. I remember some occasions where this was exactly my
feeling (the glider saying "I don't think so"). Maybe one thing which
contributed to develop this feeling is my previous practice of windsurfing.
When your weigth is just balanced by the lift of the sail (or rather by
a component of this force) and a loss of lift ends in a dive into cold
water, you quickly become very sensitive to any kind of loss of lift.
I had least year a discussion with a German pilot who also was windsurfing,
and he said he had exacltly the same feelings.

[nafod40]

Bob Kuykendall wrote:
>
> I've watched an ASW-20, flown by a well-respected pilot,
> flick into a spin while thermalling. Including the
> recovery, it went about a turn and a half.

I haven't spun gliders, but I have hundreds of hours spinning Navy jets.
In the larger planes, there was a period of post stall gyration (PSG)
before entering a spin proper, with a spin defined as steady state yaw
rate, pitch attitude, and AOA (or not too big oscillations about a
state). PSG could last a fair number of turns.

So was the ASW-20 really in a spin? Steady state?

[JJ Sinclair]

Geir wrote>>>>>>>>>>>>>>>>>>>
>But a sailplane ain't always flown well.
>Nobody is perfect, not even you.
>

I don't claim to be perfect, but I do think too much emphasis is being spent on
spin training by some contries. For what its worth, I think we got it just
about right here in the US. Spins are demonstrated to the student and the rest
is up to the instructor. Most, I believe have the student show profiency in
immediate spin recovery (less than 1 turn). Reoccuring training (biennials) are
again, up to the instructor.

The brits, on the other hand, went out looking for a 2-seater that was easy to
spin and they found a GOOD one in the Puch. Mike believes that 15 have spun-in,
world wide and the Brits are investigating their 4th Puch-in.

Modern German sailplanes are quite well behaved and some won't spin at all. Why
are we continuing to overemphasize full blown spins? Purchase trainers that are
dificult to spin and teach spin avoidance. Sure, we should be comfortable with
a spin entry and immediate recovery, but some contries are making the cure more
deadly than the disease.

BTW, I'm talking about modern German gliders, If yiu fly the Puch, Lark (single
or 2-place) or the SZD 69, I would recommend extensive and recurring spin
training.
JJ Sinclair

[Bob Kuykendall]

Earlier, (Slingsby) wrote:

> Do you also mean high aspect ratio
> wings with poorly glued spar caps?

Geez, there you go again.

No, I don't.

[Bob Kuykendall]

Earlier, nafod40 > wrote:

> ...So was the ASW-20 really in a
> spin? Steady state?

I saw it go thundering down out of the thermal, a-whirling and
a-waggling. I don't think it ever arrived at a steady state, but I
wasn't in a situation that allowed much attention to it.

Bob K.

[Kilo Charlie]

I have over 2000 hours in gliders including many types of glass. I also
have extensive experience in powered and glider aerobatics. Not long after
the purchase of my first fiberglass glider (Pegasus) I was thermaling around
400' over a mountain (US east coast variety) and attempted the hang glider
maneuver (which I had also been flying a lot of lately) of horsing the
aircraft into the center of a turbulent rotor type thermal. Retrospectively
the fact that it meant cross controlling while in a 60 degree bank made it a
no brainer re what resulted.....in a heartbeat I was looking at the mountain
through the top of the canopy. My first thought was "Hmmm....I've been here
before" and made immediate corrections with little more than a couple
hundred feet and an increased heart rate to show for it. Luckily the only
other pilots were above me. Take home message.....what they teach you re
spin entry is real and aerobatic training is a definite help if you get in
that situation, or at least spin training is.

As a sidebar to this discussion I noticed one person posted that he is
constantly on the edge of stalling his glider during thermaling. I would
argue that he is flying very inefficiently if that is in fact the case. To
convince yourself try thermaling (when alone) at the buffet speed vs adding
5-10 kts at differing angles of bank and focus on the VSI and see what the
results are. Look at any polar as well. Also if you try this out here in
the turbulent wild west let me know when you go flying 'cause I don't want
to be below you!

Casey Lenox
KC
Phoenix

[Caracole]

(JJ Sinclair) wrote in message >...
SNIPPED A BIT
>
> The brits, on the other hand, went out looking for a 2-seater that was easy to
> spin and they found a GOOD one in the Puch. Mike believes that 15 have spun-
>in, world wide and the Brits are investigating their 4th Puch-in.

Hate to tell you this boys and girls,
my list,
confirmed by direct contacts, of spinning Puch impacts is now up to
23 whacks worldwide.
And I am now chasing down a story about a 24th ... which is an 'old'
one, not the January English tragedy. The unveiling of #24 came about
through these threads....

On a production run of about 200 gliders, we only have a few more low
spinning fatalities to go, to remove the fleet from service.
Macabre enough yet?

Many of these wretched losses could have been avoided, had there been
a requirement for a hard deck for recovery that would allow egress and
use of parachutes. I know I won't get the Puchacz retired from
service, but possibly, maybe, by the grace of a higher power,

I might get people to STOP spin training in the Puchacz (at the least)
at low altitudes.

With a prayer,

Cindy B
Caracole Soaring

[Greg Arnold]

1/8 of the fleet has been destroyed by spinning crashes? Yikes!

My first glider ride was in a Puch that was subsequently destroyed in a
spinning wreck (two fatalities).


Caracole wrote:

> (JJ Sinclair) wrote in message >...
> SNIPPED A BIT
>
>>The brits, on the other hand, went out looking for a 2-seater that was easy to
>>spin and they found a GOOD one in the Puch. Mike believes that 15 have spun-
>>in, world wide and the Brits are investigating their 4th Puch-in.
>
>
> Hate to tell you this boys and girls,
> my list,
> confirmed by direct contacts, of spinning Puch impacts is now up to
> 23 whacks worldwide.
> And I am now chasing down a story about a 24th ... which is an 'old'
> one, not the January English tragedy. The unveiling of #24 came about
> through these threads....
>
> On a production run of about 200 gliders, we only have a few more low
> spinning fatalities to go, to remove the fleet from service.
> Macabre enough yet?
>
> Many of these wretched losses could have been avoided, had there been
> a requirement for a hard deck for recovery that would allow egress and
> use of parachutes. I know I won't get the Puchacz retired from
> service, but possibly, maybe, by the grace of a higher power,
>
> I might get people to STOP spin training in the Puchacz (at the least)
> at low altitudes.
>
> With a prayer,
>
> Cindy B
> Caracole Soaring

[Ian Forbes]

Richard Brisbourne wrote:

> I still have on my shelf a copy of George Moffat's "Winning on the
> Wind"
> which includes his account of the 1970 Worlds at Marfa (which he won).
> He mentions a hair-raising inadvertent spin in the (presumably
> ballasted) Nimbus 1 in which he lost 1500 ft and recovered by "flexing
> the floppy
> wings by yanking on the stick". Don't try this at home.

I have twice spun a Nimbus II. Both occasions it was fully ballasted.
Both followed the same sequence of events.

A pull up from high cruise speed to enter a thermal - about 3 G's,
followed by lots of aleron and rudder to get the big wings into a turn
before flying out the other side of the thermal - simultaneously with a
push over at the top of the zoom climb. Got the nose below the horizon
with a little less airspeed on the clock than I would have liked but in
a turn and in the thermal. But both times I neglected to set the flaps
from full negative to full thermal ...

The glider dropped a wing and went straight into a spin. But it
recovered equally quickly with appropriate procedures. Nothing dramatic
like Moffat Nimbus I story.

With positive flaps, it would just mush, it never dropped a wing.

I would not recommend thermal entries like that from low altitude, or
with other gliders anywhere nearby, either below or above. I never
intentionally spun the Nimbus, either with or without ballast.

Ian

[Eric Greenwell]

Ian Forbes wrote:
> I have twice spun a Nimbus II. Both occasions it was fully ballasted.
> Both followed the same sequence of events.
>
> A pull up from high cruise speed to enter a thermal - about 3 G's,
> followed by lots of aleron and rudder to get the big wings into a turn
> before flying out the other side of the thermal - simultaneously with a
> push over at the top of the zoom climb. Got the nose below the horizon
> with a little less airspeed on the clock than I would have liked but in
> a turn and in the thermal. But both times I neglected to set the flaps
> from full negative to full thermal ...
>
> The glider dropped a wing and went straight into a spin. But it
> recovered equally quickly with appropriate procedures. Nothing dramatic
> like Moffat Nimbus I story.
>
> With positive flaps, it would just mush, it never dropped a wing.

Generally flapped gliders are much more reluctant to spin with negative
flaps, and for my ASW 20 and ASH 26, going to negative flap per the
manual quickens the recovery. Is this not true for the Nimbus II?

--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[Janos Bauer]

Raphael Warshaw wrote:

> The Lark was, BTW, a rental ship and I don't remember any special
> emphasis on its spin characteristics during my checkout.

Hmm, it's strange. This glider is "famous" for it's stall
characteristics. Lot of pilot died in small IS...

/Janos

[Ian Forbes]

Caracole wrote:

> (JJ Sinclair) wrote in message
> >... SNIPPED A BIT
>>
>> The brits, on the other hand, went out looking for a 2-seater that
>> was easy to spin and they found a GOOD one in the Puch. Mike believes
>> that 15 have spun-
>>in, world wide and the Brits are investigating their 4th Puch-in.
>
> Hate to tell you this boys and girls,
> my list,
> confirmed by direct contacts, of spinning Puch impacts is now up to
> 23 whacks worldwide.
> And I am now chasing down a story about a 24th ... which is an 'old'
> one, not the January English tragedy. The unveiling of #24 came about
> through these threads....
>
> On a production run of about 200 gliders, we only have a few more low
> spinning fatalities to go, to remove the fleet from service.
> Macabre enough yet?
>
> Many of these wretched losses could have been avoided, had there been
> a requirement for a hard deck for recovery that would allow egress and
> use of parachutes. I know I won't get the Puchacz retired from
> service, but possibly, maybe, by the grace of a higher power,
>
> I might get people to STOP spin training in the Puchacz (at the least)
> at low altitudes.
>
> With a prayer,
>
> Cindy B
> Caracole Soaring

I read this a couple of days ago and I have seen little follow-up. The
information is far more relevant to our sport than most of what is said
on RAS. It was under a thread "Unintentional fully-developed spins"
that has since died, I suspect many readers missed it. So have taken
the liberty of reserecting it under a new subject.

If it is true, it is pretty damming. It also shows that the Brits record
is not out of proportion with the world fleet - so this is not due to
anything specific in their training.

Ian

[Mark James Boyd]

>As a sidebar to this discussion I noticed one person posted that he is
>constantly on the edge of stalling his glider during thermaling. I would
>argue that he is flying very inefficiently if that is in fact the case. To
>convince yourself try thermaling (when alone) at the buffet speed vs adding
>5-10 kts at differing angles of bank and focus on the VSI and see what the
>results are. Look at any polar as well.

>Casey Lenox
>KC
>Phoenix

I haven't seen polars that take into effect bank angle, but
from doing the calculations of turn radius and angles of
bank, I'm convinced that in very long wing gliders at
high angles of bank and slow speeds (and ergo light weights too),
the inner wing is significantly slower than the
outer wing, and tacking on some knots is most
efficient (to keep the length of the inner wing nicely above stall)...

Mark Boyd

[Mike Borgelt]

On Thu, 29 Jan 2004 18:28:59 GMT, Marc Ramsey >
wrote:

>OK, I'm curious. How many of you have had to recover from a fully
>developed (greater than one turn), unintentional spin that occurred
>during normal non-aerobatic flight?
I was going to say once but on thinking about it I doubt that it got
to even one turn.
Late 1968 on my first flight in a Schneider ES57 Kingfisher(look it up
in a Directory of World's Crummy Old Gliders) .
I was thermalling at 4000 feet and kept pulling in tighter and all of
a sudden it snapped in to a spin. I took full recovery action and it
recovered instantly. Did it twice more that flight while exploring the
boundary. I had about 50 hours at the time and only one spin training
session 18 months before.

The ES57 is a very small lightweight glider of about Grunau Baby
performance but without struts. Very low inertia about all axes hence
the quick entry once it let go and there weren't any great
oscillations on spin entry.

Since then the only times a glider has gone even a quarter turn on me
is during deliberate spinning.

I used to spin my Salto a bit at first(fairly exciting oscillating
entry), I spun my Mini Nimbus a couple of times at first to find out
what would happen(rolls upside down on entry), I never bothered to
spin my ASW20B and incipient spins is all I've done in the Ventus C.

I once had the Nimbus 3DM we owned roll wings level and pitch down
maybe 20 degrees in a turbulent narrow thermal at 5000 feet over
Kingaroy airfield. No problem to reduce AOA and continue in the
thermal.

I think it is fair to say that full spin recovery training is of
little to no use for the failed winch launch/base/final turn/low
thermalling cases. In all these cases departures from controlled
flight are to be avoided at all times. Likewise I would hope that
nobody ever gets into a full spin accidently while thermalling. There
may be gliders below you.

Maybe I'm a little hard on the Kingfisher. I did get my Silver C in
it.

Mike Borgelt

[Mike Borgelt]

On Mon, 02 Feb 2004 22:39:28 +0200, Ian Forbes
> wrote:

>Caracole wrote:
>
>> (JJ Sinclair) wrote in message
>> >... SNIPPED A BIT
>>>
>>> The brits, on the other hand, went out looking for a 2-seater that
>>> was easy to spin and they found a GOOD one in the Puch. Mike believes
>>> that 15 have spun-
>>>in, world wide and the Brits are investigating their 4th Puch-in.
>>
>> Hate to tell you this boys and girls,
>> my list,
>> confirmed by direct contacts, of spinning Puch impacts is now up to
>> 23 whacks worldwide.
>> And I am now chasing down a story about a 24th ... which is an 'old'
>> one, not the January English tragedy. The unveiling of #24 came about
>> through these threads....
>>
>> On a production run of about 200 gliders, we only have a few more low
>> spinning fatalities to go, to remove the fleet from service.
>> Macabre enough yet?
>>
>> Many of these wretched losses could have been avoided, had there been
>> a requirement for a hard deck for recovery that would allow egress and
>> use of parachutes. I know I won't get the Puchacz retired from
>> service, but possibly, maybe, by the grace of a higher power,
>>
>> I might get people to STOP spin training in the Puchacz (at the least)
>> at low altitudes.
>>
>> With a prayer,
>>
>> Cindy B
>> Caracole Soaring
>

>If it is true, it is pretty damming. It also shows that the Brits record
>is not out of proportion with the world fleet - so this is not due to
>anything specific in their training.
>
>Ian
>
Or it means the stupidity and ignorance is pandemic.
Thanks to Cindy for bringing this interesting statistic to light.
Now can we placard the damn things against intentional spins?
Research modifications?
Burn them?
I'm actually a fan of Polish gliders for their nice handling generally
but is there an excuse for this one?

Mike Borgelt

[Ian Johnston]

On Mon, 2 Feb 2004 20:39:28 UTC, Ian Forbes >
wrote:

: If it is true, it is pretty damming. It also shows that the Brits record
: is not out of proportion with the world fleet - so this is not due to
: anything specific in their training.

I am still not sure quite what is so odd about the majority of
spinning accidents happening in a spinnable glider.

Ian

--

[Mike Borgelt]

On 4 Feb 2004 18:48:21 GMT, "Ian Johnston" >
wrote:

>On Mon, 2 Feb 2004 20:39:28 UTC, Ian Forbes >
>wrote:
>
>: If it is true, it is pretty damming. It also shows that the Brits record
>: is not out of proportion with the world fleet - so this is not due to
>: anything specific in their training.
>
>I am still not sure quite what is so odd about the majority of
>spinning accidents happening in a spinnable glider.
>
>Ian


It isn't odd. What is odd is that people still insist on spinning the
damn things despite the horrendous statistics.


Mike Borgelt

[Bill Daniels]

"Mike Borgelt" > wrote in message
...
> On 4 Feb 2004 18:48:21 GMT, "Ian Johnston" >
> wrote:
>
> >On Mon, 2 Feb 2004 20:39:28 UTC, Ian Forbes >
> >wrote:
> >
> >: If it is true, it is pretty damming. It also shows that the Brits
record
> >: is not out of proportion with the world fleet - so this is not due to
> >: anything specific in their training.
> >
> >I am still not sure quite what is so odd about the majority of
> >spinning accidents happening in a spinnable glider.
> >
> >Ian
>
>
> It isn't odd. What is odd is that people still insist on spinning the
> damn things despite the horrendous statistics.
>
>
> Mike Borgelt

It would be hard to put reliable data together, but I suspect there are
other glider types whose numbers have been depleted by fatal spins to an
even larger percentage than the Puchacz. The 2-32 and LK-10 come to mind.
I seem to recall it being said that 75% of the LK-10's original numbers were
lost in spins that killed the pilot. I also remember the IDENTICAL
discussion about the LK-10 as we are having about the Owl.

Rather than blame the glider, I would point the finger at training that
doesn't equip pilots with the skills needed to fly these gliders.

Bill Daniels

[Mike Borgelt]

On Wed, 4 Feb 2004 15:17:07 -0700, "Bill Daniels" >
wrote:


>> It isn't odd. What is odd is that people still insist on spinning the
>> damn things despite the horrendous statistics.
>>
>>
>> Mike Borgelt
>
>It would be hard to put reliable data together, but I suspect there are
>other glider types whose numbers have been depleted by fatal spins to an
>even larger percentage than the Puchacz. The 2-32 and LK-10 come to mind.
>I seem to recall it being said that 75% of the LK-10's original numbers were
>lost in spins that killed the pilot. I also remember the IDENTICAL
>discussion about the LK-10 as we are having about the Owl.
>
>Rather than blame the glider, I would point the finger at training that
>doesn't equip pilots with the skills needed to fly these gliders.
>
>Bill Daniels


I have quite a few hours in a flat topped LK-10. It was the second
glider type I flew and the first I flew in a contest. Yes, there were
concerns about the LK-10 spinning/recovery. It was never deliberately
spun and I think all were so concerned nobody ever even let it get to
the incipient stage.
I think it met its end on an outlanding, something to do with a fence
and a ditch, no injuries, not worth repairing.

As the LK-10 was designed as a military training glider in wartime I
can believe it may have had less than ideal flight characteristics
and it may well have killed many inexperienced, hastily trained
cadets. This may be regarded as acceptable by the military in wartime.

Is this acceptable for civilians in peacetime?

I just re-read the chapter by Leighton Collins at the back of "Stick
and Rudder". It is called "The Dangers of the Air". Highly relevant to
these spin threads and training. It was written in 1946 and we seem to
have learned little.

Given that the dangers of spinning from a failed launch, on base or
final, from low thermalling or in a gaggle are all well known and
understood and we all agree that this shouldn't be done ever then the
problem becomes not spin recovery but absolute prevention of
unintentional spins.

Most pilots seem to manage this at least with most modern gliders.
What is it about either some gliders or the training that results in
some not "getting it"?

Mike Borgelt

[Bill Daniels]

"Mike Borgelt" > wrote in message
...
> On Wed, 4 Feb 2004 15:17:07 -0700, "Bill Daniels" >
> wrote:
>
>
> >> It isn't odd. What is odd is that people still insist on spinning the
> >> damn things despite the horrendous statistics.
> >>
> >>
> >> Mike Borgelt
> >
> >It would be hard to put reliable data together, but I suspect there are
> >other glider types whose numbers have been depleted by fatal spins to an
> >even larger percentage than the Puchacz. The 2-32 and LK-10 come to
mind.
> >I seem to recall it being said that 75% of the LK-10's original numbers
were
> >lost in spins that killed the pilot. I also remember the IDENTICAL
> >discussion about the LK-10 as we are having about the Owl.
> >
> >Rather than blame the glider, I would point the finger at training that
> >doesn't equip pilots with the skills needed to fly these gliders.
> >
> >Bill Daniels
>
>
> I have quite a few hours in a flat topped LK-10. It was the second
> glider type I flew and the first I flew in a contest. Yes, there were
> concerns about the LK-10 spinning/recovery. It was never deliberately
> spun and I think all were so concerned nobody ever even let it get to
> the incipient stage.
> I think it met its end on an outlanding, something to do with a fence
> and a ditch, no injuries, not worth repairing.
>
> As the LK-10 was designed as a military training glider in wartime I
> can believe it may have had less than ideal flight characteristics
> and it may well have killed many inexperienced, hastily trained
> cadets. This may be regarded as acceptable by the military in wartime.
>
> Is this acceptable for civilians in peacetime?
>
> I just re-read the chapter by Leighton Collins at the back of "Stick
> and Rudder". It is called "The Dangers of the Air". Highly relevant to
> these spin threads and training. It was written in 1946 and we seem to
> have learned little.
>
> Given that the dangers of spinning from a failed launch, on base or
> final, from low thermalling or in a gaggle are all well known and
> understood and we all agree that this shouldn't be done ever then the
> problem becomes not spin recovery but absolute prevention of
> unintentional spins.
>
> Most pilots seem to manage this at least with most modern gliders.
> What is it about either some gliders or the training that results in
> some not "getting it"?
>
> Mike Borgelt
>

Interesting. There aren't many of us left who flew the LK-10. Did you fly
one in OZ or in the US? My primary trainer was a "double-bubble" flat
topped LK-10. N22U once graced the cover of the cross country chapter of
the SSA soaring handbook.

I once heard Jack Laister tell that the LK-10 was itself a modification of
his "Yankee Doodle" single place competition glider designed while he was a
teenager. The US military asked him to design a two-place trainer in the
early 1940's. Jack said he just straightened out the gull wings and
stretched the fuselage behind the wing to make room for a rear cockpit and
the Yankee Doodle became the military LK-10 or TG-4.

I spun both N22U and another LK-10 still in the original configuration.
Both left no doubt that mis-handling them would kill. I sometimes had the
hair-raising feeling that the glider was actively trying to kill me. That
experience left me with a wariness of low and slow flying that is still with
me. I'd like to see that wariness passed along to a new generation of
pilots. I think it saved my life on several occasions and might save some
of theirs too.

Bill Daniels

[Liam Finley]

"Bill Daniels" > wrote in message >...
> It would be hard to put reliable data together, but I suspect there are
> other glider types whose numbers have been depleted by fatal spins to an
> even larger percentage than the Puchacz. The 2-32 and LK-10 come to mind.
> I seem to recall it being said that 75% of the LK-10's original numbers were
> lost in spins that killed the pilot. I also remember the IDENTICAL
> discussion about the LK-10 as we are having about the Owl.
>
> Rather than blame the glider, I would point the finger at training that
> doesn't equip pilots with the skills needed to fly these gliders.
>
> Bill Daniels

Interesting. I did a little research with the NTSB accident database.
I found 7 fatal spin-related 2-32 crashes. With a production run of
87, 8% of aircraft produced were taken out by fatal spins.

Also, according the the sailplane directory online, the production run
for the Puchacz was 300, not 200. If true, that means a fatal spin
rate of 24/300= 8%, exactly the same rate as the 2-32.

That assumes all fatal 2-32 crashes were in the US, which is probably
a fair assumption. Otherwise the 2-32 rate would be even higher than
the Puch.

Of course, the 2-32 has been around alot longer than the Puchacz. The
interesting thing is, the 2-32 spins were all in a period from the
late 60's to early 80's, last one in 1982. Then they all stopped. If
this were 1982, we'd presumably be calling for the 2-32 to be taken
out of service.

What happened that we have gone 22 years without any additional 2-32
spin fatalities?

[Andrew Nairn]

I too am astounded that more is not done by the worthy's in our sport.
Between 1987 and 1997 there were 34 fatal accidents in the UK. 4 in Puch's
and 3 in Pirats. That's one in five! There are many ways to dismiss the
figures but like it or not, these airplanes are killing people and out of
all proportion.

"Caracole" > wrote in message
om...
> (JJ Sinclair) wrote in message
>...
> SNIPPED A BIT
> >
> > The brits, on the other hand, went out looking for a 2-seater that was
easy to
> > spin and they found a GOOD one in the Puch. Mike believes that 15 have
spun-
> >in, world wide and the Brits are investigating their 4th Puch-in.
>
> Hate to tell you this boys and girls,
> my list,
> confirmed by direct contacts, of spinning Puch impacts is now up to
> 23 whacks worldwide.
> And I am now chasing down a story about a 24th ... which is an 'old'
> one, not the January English tragedy. The unveiling of #24 came about
> through these threads....
>
> On a production run of about 200 gliders, we only have a few more low
> spinning fatalities to go, to remove the fleet from service.
> Macabre enough yet?
>
> Many of these wretched losses could have been avoided, had there been
> a requirement for a hard deck for recovery that would allow egress and
> use of parachutes. I know I won't get the Puchacz retired from
> service, but possibly, maybe, by the grace of a higher power,
>
> I might get people to STOP spin training in the Puchacz (at the least)
> at low altitudes.
>
> With a prayer,
>
> Cindy B
> Caracole Soaring

[Andrew Nairn]

I too am astounded that more is not done by the worthy's in our sport.
Between 1987 and 1997 there were 34 fatal accidents in the UK. 4 in Puch's
and 3 in Pirats. That's one in five! There are many ways to dismiss the
figures but like it or not, these airplanes are killing people and out of
all proportion.

"Caracole" > wrote in message
om...
> (JJ Sinclair) wrote in message
>...
> SNIPPED A BIT
> >
> > The brits, on the other hand, went out looking for a 2-seater that was
easy to
> > spin and they found a GOOD one in the Puch. Mike believes that 15 have
spun-
> >in, world wide and the Brits are investigating their 4th Puch-in.
>
> Hate to tell you this boys and girls,
> my list,
> confirmed by direct contacts, of spinning Puch impacts is now up to
> 23 whacks worldwide.
> And I am now chasing down a story about a 24th ... which is an 'old'
> one, not the January English tragedy. The unveiling of #24 came about
> through these threads....
>
> On a production run of about 200 gliders, we only have a few more low
> spinning fatalities to go, to remove the fleet from service.
> Macabre enough yet?
>
> Many of these wretched losses could have been avoided, had there been
> a requirement for a hard deck for recovery that would allow egress and
> use of parachutes. I know I won't get the Puchacz retired from
> service, but possibly, maybe, by the grace of a higher power,
>
> I might get people to STOP spin training in the Puchacz (at the least)
> at low altitudes.
>
> With a prayer,
>
> Cindy B
> Caracole Soaring

[F1y1n]

(Mark James Boyd) wrote in message news:<401ec4d0$1@darkstar>...
> >As a sidebar to this discussion I noticed one person posted that he is
> >constantly on the edge of stalling his glider during thermaling. I would
> >argue that he is flying very inefficiently if that is in fact the case. To
> >convince yourself try thermaling (when alone) at the buffet speed vs adding
> >5-10 kts at differing angles of bank and focus on the VSI and see what the
> >results are. Look at any polar as well.
>
> >Casey Lenox
> >KC
> >Phoenix
>
> I haven't seen polars that take into effect bank angle, but
> from doing the calculations of turn radius and angles of
> bank, I'm convinced that in very long wing gliders at
> high angles of bank and slow speeds (and ergo light weights too),
> the inner wing is significantly slower than the
> outer wing, and tacking on some knots is most
> efficient (to keep the length of the inner wing nicely above stall)...
>
> Mark Boyd

I don't believe your argument is correct. What determines the lift and
drag coefficients is angle of attact, NOT airspeed. The inner wing is
flying at the same angle of attack as the outer wing, think about it.
Speeding up won't make you climb better.

[Mark James Boyd]

F1y1n > wrote:
>> high angles of bank and slow speeds (and ergo light weights too),
>> the inner wing is significantly slower than the
>> outer wing, and tacking on some knots is most
>> efficient (to keep the length of the inner wing nicely above stall)...
>>
>> Mark Boyd
>

>I don't believe your argument is correct. What determines the lift and
>drag coefficients is angle of attact, NOT airspeed.

This is true, and if the glider is at a certain pitch angle straight,
level, and coordinated in still air, both wings are at the
same AOA. If the two wings are at different airspeeds,
like in a turn or skid, the two wings are at different angles of attack.

>The inner wing is
>flying at the same angle of attack as the outer wing, think about it.

Not if the wings are at different airspeeds. This is how we
do a spin. One wing is "more" stalled than the other wing
(i.e. has a higher AOA because it is the inside wing, and has less
airspeed). A turn is similar in the sense the wings are at
different airspeeds (but the same pitch angle), but in a turn,
it isn't true that both wings are stalled (that is the difference
between a turn and a spin).

>Speeding up won't make you climb better.

Err...well, we are trying to sink less. If the wingspan is very
short, the point on the polar is the same for every part of
the wing. If the wingspan is long and in a turn, different
parts along the wings are flying at different airspeeds, and
are at different "efficiencies" and points along the polar.

The goal is to minimize the average sink rate along the
wing. The best way to do this is to strongly avoid the
back side of the polar (which drops off steeply), which
is the inner wing in the turn. If we fly a little faster
than recommended IAS (from the "G" table for bank) then
a larger portion of the long inner wing is near the
min-sink point, and the outer wing, although not optimally
efficient, is just displaced a little way along the front side of
the min-sink curve (which is a little flatter).

The amount of extra speed that is optimal should be based on
wingspan, the polar, and the bank angle. The
magnitude of this speed "correction" is something I have yet
to calculate, but thank you to the folks who have corrected
some of the previous attempts to calculate it...

[Chris OCallaghan]

> I don't believe your argument is correct. What determines the lift and
> drag coefficients is angle of attact, NOT airspeed. The inner wing is
> flying at the same angle of attack as the outer wing, think about it.
> Speeding up won't make you climb better.

In fact, the inner wing is not flying at the same airspeed. It has the
same angular speed, but it is transribing a smaller circle than the
outer wing and thus going a shorter distance in the same amount of
time. Both wings are sinking at the same rate, therefore, since the
tangential (straight line) speed of the inner wing is lower, its angle
of attack is higher. Same thing happens at the wheels of your car,
which is why you need a differential gear, to accomodate the
difference in speed between the inside and outside wheels during a
turn. The outside wheel travels a greater distance, though both have
the same angular speed.

[F1y1n]

(Chris OCallaghan) wrote in message >...
> > I don't believe your argument is correct. What determines the lift and
> > drag coefficients is angle of attact, NOT airspeed. The inner wing is
> > flying at the same angle of attack as the outer wing, think about it.
> > Speeding up won't make you climb better.
>
> In fact, the inner wing is not flying at the same airspeed.

Agreed. I didn't say it did.


> It has the
> same angular speed, but it is transribing a smaller circle than the
> outer wing and thus going a shorter distance in the same amount of
> time. Both wings are sinking at the same rate, therefore, since the
> tangential (straight line) speed of the inner wing is lower, its angle
> of attack is higher.

This I do not agree with. The angle of attack of both wings is the
same. The air is impacting both wings from exactly the same angle -
the wings are connected by the fuselage. The inner wing is flying
slower, and thus producing less lift, while the outer wing is flying
faster, and thus producing more lift. The angle of attack and hence
the position on the polar is the same for both wings. You are correct
that both wings are sinking at the same rate, but this does imply that
the both create the same amount of lift.

Incidentally, the reason why you need some contra-aileron in a steep
turn is precisely for this reason - to correct for the net torque
trying to lift the outer, faster, wing!

[F1y1n]

(Mark James Boyd) wrote in message news:<40252a00$1@darkstar>...
> F1y1n > wrote:
> >> high angles of bank and slow speeds (and ergo light weights too),
> >> the inner wing is significantly slower than the
> >> outer wing, and tacking on some knots is most
> >> efficient (to keep the length of the inner wing nicely above stall)...
> >>
> >> Mark Boyd
> >
>
> >I don't believe your argument is correct. What determines the lift and
> >drag coefficients is angle of attact, NOT airspeed.
>
> This is true, and if the glider is at a certain pitch angle straight,
> level, and coordinated in still air, both wings are at the
> same AOA. If the two wings are at different airspeeds,
> like in a turn or skid, the two wings are at different angles of attack.

In a coordinated turn both wings are at the same AOA (please see my
reply to the other post in this thread). In an uncoordinated turn this
is not the case. Think of the direction of the airflow over the wing -
in a coordinated turn the airflow is always from the same direction
regardless of position on the wings; in an uncoordinated turn this is
not so, hence the AOA will be different. I was talking about
coordinated turns only (and I presume you were too in your original
post).

> >The inner wing is
> >flying at the same angle of attack as the outer wing, think about it.
>
> Not if the wings are at different airspeeds. This is how we
> do a spin. One wing is "more" stalled than the other wing
> (i.e. has a higher AOA because it is the inside wing, and has less
> airspeed).

Yes, in a spin the inner wing is flying at a higher AOA. But spin is
not a coordinated maneuver - see above. This analogy is moot.

> >Speeding up won't make you climb better.
>
> Err...well, we are trying to sink less.

Well, it's half-full for me.

[Chris OCallaghan]

You are confusing AOA with sink rate. The sink rate is the same across
the airfoil, but AOA is dependent on sink rate and forward speed, so:

If an airfoil has a forward motion of 10 and sink rate of one, then
its angle of attack can be measured -- about 5.7 degrees. If we then
slowed its forward speed to 9 while maintaining a sink rate of 1, the
angle of attack would be higher: 6.3 degrees.

We agree that the angular speed is the same across the span. We agree
"that the inner wing is flying slower." The sink rate is the same
across the span. As you've stated, this is a given: the wings are
fixed to one another. Since AOA is dependent on both sink rate and
forward speed, then the inside wingtip must have a higher AOA.

Inner wing slower, higher AOA. Outer wing faster, lower AOA. Lift is
dependent on both AOA and speed. So even though the outer wing is at a
lower angle of attack, it is moving through the air more rapidly, and
producing slightly more lift than the inner wing. With resulting
overbanking tendency.

Balance this knowledge against the sailplane's response to a turning
stall. Inner wingtip typically drops first. Why? Because it has a
higher AOA. No aggrevation from the aileron required.

[Mark James Boyd]

F1y1n > wrote:
(Mark James Boyd) wrote in message news:<40252a00$1@darkstar>...
>
>In a coordinated turn both wings are at the same AOA (please see my
>reply to the other post in this thread). In an uncoordinated turn this
>is not the case. Think of the direction of the airflow over the wing -
>in a coordinated turn the airflow is always from the same direction
>regardless of position on the wings; in an uncoordinated turn this is
>not so, hence the AOA will be different. I was talking about
>coordinated turns only (and I presume you were too in your original
>post).

Hmmm...a little history. All of this argument came up
because we were discussing spins, and a bunch of posters
were talking about skids being the cause, and some of
us (the other posters) thought it was more due to
aileron stall and different airspeeds of different
wings in steep banks.

So we're trying to calculate the magnitude of the
airspeed difference caused by bank angles in steep turns
with long wings, vs. that caused by skids. How significant
is a skid vs. bank? Is it a skid or an accelerated skid (coarse use of
rudder) that's causes these spins?

Clearly the effect of bank on precipitating a skid
is a little surprising to other posters as well. It
was interesting and novel to me as well a few days ago...

[nafod40]

F1y1n wrote:
>
> This I do not agree with. The angle of attack of both wings is the
> same.

It always helps my understanding to look at limiting cases.

If you take the wingspan to an extreme, the inner wing would reach all
of the way to the center of the circle, and its airspeed would be zero.
It would be descending, though, so its AOA would be 90 degrees.
Certainly different from the outer wing.

[Mike Borgelt]

On Thu, 5 Feb 2004 14:44:54 -0700, "Bill Daniels" >
wrote:


>Interesting. There aren't many of us left who flew the LK-10. Did you fly
>one in OZ or in the US? My primary trainer was a "double-bubble" flat
>topped LK-10. N22U once graced the cover of the cross country chapter of
>the SSA soaring handbook.
>

The one I flew was the only one imported into Oz. I think it was
imported in about 1954 or so by the late Ric New. He flat topped it
and put on the double bubble in consultation with Dr Raspet. The rear
seat bubble could be replaced by a flat plate without bubble for solo
flight.
The Gliding Club of Western Australia bought it in 1964 or so and the
write off was in 1971.
I flew my first contest in it in 1969 when I was just 21.



>I once heard Jack Laister tell that the LK-10 was itself a modification of
>his "Yankee Doodle" single place competition glider designed while he was a
>teenager. The US military asked him to design a two-place trainer in the
>early 1940's. Jack said he just straightened out the gull wings and
>stretched the fuselage behind the wing to make room for a rear cockpit and
>the Yankee Doodle became the military LK-10 or TG-4.
>
>I spun both N22U and another LK-10 still in the original configuration.
>Both left no doubt that mis-handling them would kill. I sometimes had the
>hair-raising feeling that the glider was actively trying to kill me. That
>experience left me with a wariness of low and slow flying that is still with
>me. I'd like to see that wariness passed along to a new generation of
>pilots. I think it saved my life on several occasions and might save some
>of theirs too.
>

We sure were wary about it and maybe that is what needs to be passed
on.

For all the full spin training that is done in the UK there still seem
to be stall/spin accidents. I suspect that just like in Oz the full
spin training tends to substitute for departure avoidance training.

Mike Borgelt

[Chris Ashburn]

Trouble is we don't know how many general spin accidents there would have
been if no instruction were given in full spin recovery.

There are many (many) more private/club single seat gliders that we
might assume are not used for spin TRAINING.

Is there any data to provide an idea of the ratio of training vs
single seat spin incidents relative to the number of flights?

Even this isn't the answer, since the training mission is spinning,
vs the unintended end of a flight with a spin.

Yes, solid spin avoidance training is critical, but if that habit fails
to prevent one,
where's the experience to get out of it quickly?

Overall, I think a good measure would be training related spin-ins
per 1,000 training flights vs spin accidents per 1,000 solo flights.

(You could argue ~ x10 factor for the training since maybe 1 in 10
training flight involve spinning.)


Andrew Nairn wrote:
> I too am astounded that more is not done by the worthy's in our sport.
> Between 1987 and 1997 there were 34 fatal accidents in the UK. 4 in Puch's
> and 3 in Pirats. That's one in five! There are many ways to dismiss the
> figures but like it or not, these airplanes are killing people and out of
> all proportion.
>

[F1y1n]

The point I'm replying to is:

> I'm convinced that in very long wing gliders at
> high angles of bank and slow speeds (and ergo light weights too),
> the inner wing is significantly slower than the
> outer wing, and tacking on some knots is most
> efficient (to keep the length of the inner wing nicely above stall)...

I grant you that the AOA is slightly higher for the inner wing due to
the contribution from the sink, but this is negligible. Consider a
45deg bank, 45 knots. The turn radius (at the fuselage) is about 50
meters, so for a 15-m glider the speed of the outer wingtip is about
50knots, and the speed of the inner wingtip is about 40knots. If the
sink rate in this configuration is 1.5 knots, the difference in AOA
for the two wingtips is about 0.4 degrees. You will notice that (for a
good reason!) this is much less than the typical twist of a wing. You
cannot stall the inner wingtip in a steep turn without stalling both
wing roots first! For the same reason, the inner wingtip is NEVER on
the back side of the polar when thermaling. If it was the wing roots
would already be stalled.

To answer the original question - should one speed up when thermalling
with a steep bank - the answer is no. There are too many factors that
come into play - the twist of the wing as a function of position, the
wing profile as a function of position, the drag produced by the
aileron deflection needed to correct for the overbanking tendency as a
function of speed, and so on. In the end, these effects will tend to
cancel each other: if you speed up a little to bring the wing roots to
the front side of the polar you will a) create more drag on the wing
tips and b) need more aileron input to correct for the overbanking
torque and hence create more drag. I suspect that amount by which one
should speed up or slow down to optimize the sink rate in theory will
be much smaller than the speed of the turbulent currents in the
thermal, and thus utterly irrelevant in practice. Your time will be
better spent flying cleanly and in the core of the thermal rather than
trying to nail the speed to within 0.2 knots.


(Chris OCallaghan) wrote in message >...
> You are confusing AOA with sink rate. The sink rate is the same across
> the airfoil, but AOA is dependent on sink rate and forward speed, so:
>
> If an airfoil has a forward motion of 10 and sink rate of one, then
> its angle of attack can be measured -- about 5.7 degrees. If we then
> slowed its forward speed to 9 while maintaining a sink rate of 1, the
> angle of attack would be higher: 6.3 degrees.
>
> We agree that the angular speed is the same across the span. We agree
> "that the inner wing is flying slower." The sink rate is the same
> across the span. As you've stated, this is a given: the wings are
> fixed to one another. Since AOA is dependent on both sink rate and
> forward speed, then the inside wingtip must have a higher AOA.
>
> Inner wing slower, higher AOA. Outer wing faster, lower AOA. Lift is
> dependent on both AOA and speed. So even though the outer wing is at a
> lower angle of attack, it is moving through the air more rapidly, and
> producing slightly more lift than the inner wing. With resulting
> overbanking tendency.
>
> Balance this knowledge against the sailplane's response to a turning
> stall. Inner wingtip typically drops first. Why? Because it has a
> higher AOA. No aggrevation from the aileron required.

[K.P. Termaat]

Convincing story "F1y1n" and I agree with most of it.

However when banking, the loadfactor of the glider increases. E.g. at a bank
angle of 45° the loadfactor is 1.41. The result of this is that the polar
diagram of the glider moves with a factor sqrt(1.41) = 1.19 to the right and
down. So when one likes to stay clear of stalling speeds for what ever part
of the glider, flying speed should go up by 19% when banking 45° compared to
the "normal" flying speed without banking. "Normal" meaning something like
flying with an IAS where sink rate is minimum or may be a little faster to
ease control of the glider.

Karel, NL
Ventus-2cxT


"F1y1n" > schreef in bericht
om...
> The point I'm replying to is:
>
> > I'm convinced that in very long wing gliders at
> > high angles of bank and slow speeds (and ergo light weights too),
> > the inner wing is significantly slower than the
> > outer wing, and tacking on some knots is most
> > efficient (to keep the length of the inner wing nicely above stall)...
>
> I grant you that the AOA is slightly higher for the inner wing due to
> the contribution from the sink, but this is negligible. Consider a
> 45deg bank, 45 knots. The turn radius (at the fuselage) is about 50
> meters, so for a 15-m glider the speed of the outer wingtip is about
> 50knots, and the speed of the inner wingtip is about 40knots. If the
> sink rate in this configuration is 1.5 knots, the difference in AOA
> for the two wingtips is about 0.4 degrees. You will notice that (for a
> good reason!) this is much less than the typical twist of a wing. You
> cannot stall the inner wingtip in a steep turn without stalling both
> wing roots first! For the same reason, the inner wingtip is NEVER on
> the back side of the polar when thermaling. If it was the wing roots
> would already be stalled.
>
> To answer the original question - should one speed up when thermalling
> with a steep bank - the answer is no. There are too many factors that
> come into play - the twist of the wing as a function of position, the
> wing profile as a function of position, the drag produced by the
> aileron deflection needed to correct for the overbanking tendency as a
> function of speed, and so on. In the end, these effects will tend to
> cancel each other: if you speed up a little to bring the wing roots to
> the front side of the polar you will a) create more drag on the wing
> tips and b) need more aileron input to correct for the overbanking
> torque and hence create more drag. I suspect that amount by which one
> should speed up or slow down to optimize the sink rate in theory will
> be much smaller than the speed of the turbulent currents in the
> thermal, and thus utterly irrelevant in practice. Your time will be
> better spent flying cleanly and in the core of the thermal rather than
> trying to nail the speed to within 0.2 knots.
>
>
> (Chris OCallaghan) wrote in message
>...
> > You are confusing AOA with sink rate. The sink rate is the same across
> > the airfoil, but AOA is dependent on sink rate and forward speed, so:
> >
> > If an airfoil has a forward motion of 10 and sink rate of one, then
> > its angle of attack can be measured -- about 5.7 degrees. If we then
> > slowed its forward speed to 9 while maintaining a sink rate of 1, the
> > angle of attack would be higher: 6.3 degrees.
> >
> > We agree that the angular speed is the same across the span. We agree
> > "that the inner wing is flying slower." The sink rate is the same
> > across the span. As you've stated, this is a given: the wings are
> > fixed to one another. Since AOA is dependent on both sink rate and
> > forward speed, then the inside wingtip must have a higher AOA.
> >
> > Inner wing slower, higher AOA. Outer wing faster, lower AOA. Lift is
> > dependent on both AOA and speed. So even though the outer wing is at a
> > lower angle of attack, it is moving through the air more rapidly, and
> > producing slightly more lift than the inner wing. With resulting
> > overbanking tendency.
> >
> > Balance this knowledge against the sailplane's response to a turning
> > stall. Inner wingtip typically drops first. Why? Because it has a
> > higher AOA. No aggrevation from the aileron required.

[Chris OCallaghan]

I was taking issue with an oversimplification, one you made for the
sake of convenience, I'm sure. Pet peeve of mine.

In an earlier thread on slips, I asked whether anyone had thought
through the notion of using a slip (dihedral rolling moment)to
counteract the overbanking tendency . I didn't note any responses,
though it might prove interesting to develop the idea in the context
of this thread.

Dodging the math, I'll also add that a few extra knots while circling
gives a great deal more aileron and rudder authority. Since smooth,
elevator cores are the exception rather than the rule, the more
effective your controls, the quicker you can correct for or take
advantage of turbulence, then get the controls streamlined (or as
close a practical) to minimize drag. The lower the speed, the greater
the drag for a given control input, and the longer you'll have to
leave it in to achieve the desired change in direction.

Cheers,

Chris

[Mark James Boyd]

F1y1n > wrote:
>The point I'm replying to is:
>
>> I'm convinced that in very long wing gliders at
>> high angles of bank and slow speeds (and ergo light weights too),
>> the inner wing is significantly slower than the
>> outer wing, and tacking on some knots is most
>> efficient (to keep the length of the inner wing nicely above stall)...
>
>I grant you that the AOA is slightly higher for the inner wing due to
>the contribution from the sink, but this is negligible. Consider a
>45deg bank, 45 knots. The turn radius (at the fuselage) is about 50
>meters, so for a 15-m glider the speed of the outer wingtip is about
>50knots, and the speed of the inner wingtip is about 40knots. If the

snip

>thermal, and thus utterly irrelevant in practice. Your time will be
>better spent flying cleanly and in the core of the thermal rather than
>trying to nail the speed to within 0.2 knots.

I thank you for taking the time to do some math, but
unfortunately I don't have quite the time to verify it,
and I've two references (Carl Herold and Dick Johnson)
who seem to encourage what I've suggested.

And my math must be poor. If a glider has 2 knots of sink
near stall, and stalls at about 40 knots, then straight it has
an AOA of 3 degrees (sin 3 deg = .05...)? Ahhh...that can't
be right...

I'll need to look closer at this, but I certainly hope at least
you gained something for yourself from this discussion too...

[Bruce Hoult]

In article <40289ab7@darkstar>, (Mark James Boyd)
wrote:

> And my math must be poor. If a glider has 2 knots of sink
> near stall, and stalls at about 40 knots, then straight it has
> an AOA of 3 degrees (sin 3 deg = .05...)? Ahhh...that can't
> be right...

No, 3 degrees (down) is its flight path. The AOA could be anything at
all, depending on how far up the nose is (and the rigging incidence).

-- Bruce

[Bob Kuykendall]

Earlier, (F1y1n) wrote:

> ...The angle of attack of both wings is the
> same. The air is impacting both wings from
> exactly the same angle - the wings are
> connected by the fuselage....

I think I disagree on what might appear to be a technicality: The
wings are connected not only by the fuselage, but also by the control
system that the pilot uses to balance the lift distribution between
the two wings.

Since the inner wing is going substantially slower, and as you point
out later has only a slightly greater angle of attack, something has
to increase the Cl on the inner wing in order to keep from rolling
into the turn (the overbanking tendency). That something is the pilot
applying slight opposite aileron, increasing the inner wing's
effective angle of attack.

That may only be a couple of degrees of deflection down on the inner
wing, but its also the same or more up on the outer wing, decreasing
its effective angle of attack. The deflected surface has a substantial
effect on the pressure distribution of the airfoil in front of it, and
can make a big difference on its stall characteristics.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

[Chris OCallaghan]

You'll want to add the angle of incidence of the wing. Assume it is 15
degrees to the fuselage center line and you're getting close to
typical critical AOA. The math, in fact is a little more tenuous, but
not much. Just assume your airspeed is the path through the air. You
also have vertical speed, so you have the hypotenuse and one side.
Some trig yields horizontal speed, a little more yields AOA at the
fuselage centerline, then add AOI for AOA of the airfoil. A bit psuedo
scientific, but perfectly acceptable for the sake of the discussion.
At least it gets us numbers that look more like the stuff we see in
tables.

[Mark James Boyd]

Robert Ehrlich > wrote:
>Mark James Boyd wrote:
>> ...
>> And my math must be poor. If a glider has 2 knots of sink
>> near stall, and stalls at about 40 knots, then straight it has
>> an AOA of 3 degrees (sin 3 deg = .05...)? Ahhh...that can't
>> be right...

>call this last one incidence while in France we call this "calage"
>because we use "incidence" for what you call AOA :-)

In the US, "calage" is where I would go to learn math and franch,
and how to spell patato.

By the way, I love the bread, fries, and kissing. You can keep
the dressing, horn, doors, and braids. :P

But thanks for the Statue of Liberty!

[Robert Ehrlich]

Mark James Boyd wrote:
> ...
> And my math must be poor. If a glider has 2 knots of sink
> near stall, and stalls at about 40 knots, then straight it has
> an AOA of 3 degrees (sin 3 deg = .05...)? Ahhh...that can't
> be right...
> ...

No, 3 degrees is the angle between the airflow and an horizontal line.
In order to obtain the AOA you have to add the angle of the fuselage
axis with this horizontal line (nose up attitude) and the angle of
the wing chord with the fuselage axis, you english speaking people
call this last one incidence while in France we call this "calage"
because we use "incidence" for what you call AOA :-)

[Robert Ehrlich]

nafod40 wrote:
>
> F1y1n wrote:
> >
> > This I do not agree with. The angle of attack of both wings is the
> > same.
>
> It always helps my understanding to look at limiting cases.
>
> If you take the wingspan to an extreme, the inner wing would reach all
> of the way to the center of the circle, and its airspeed would be zero.
> It would be descending, though, so its AOA would be 90 degrees.
> Certainly different from the outer wing.

Yes, but we are far from this limiting case. As someone else pointed,
in the case of a typical glider making a typical turn the difference
is a few tenth of degrees. This explains why it can't counteract the
effect of the speed difference and we all have experienced this
overbanking tendancy that we must counter with outside stick.

So the speed difference make a little difference in AOA but a much more
noticeable difference in lift. We cancel this difference by using
outside stick, i.e. introducing a difference in lift coefficient by
changing airfoil and AOA. But when we are sufficently close to stall AOA,
i.e. maximum lift coefficient, this change is of no help and may even have
the opposite effect if this brings the inner wing tip to a lower lift coefficient.
Then the inner wing will drop, and then, as now both wing have a significative
difference in their sink speed, this introduces a significative difference
in their AOA.

[ADP]

I'm with Bob on this one.

From an aerodynamics manual:

"However, many other parameters influence the lift that a wing produces. The
most basic is the configuration of the wing, specifically the position of
the trailing-edge flaps, leading-edge flaps or slats, and spoilers. As the
trailing-edge flaps are extended, the curvature (or camber) and area of the
wing are increased, and the wing will produce more lift at the same AOA
(fig. 2). Note that although the maximum lift is increased, the AOA at which
stall occurs is actually less because the wing cannot sustain the higher
lift levels up to the same AOA. The airflow separates earlier.
Wing-mounted speed brakes or spoilers have the opposite effect. They reduce
the lift at a given AOA; they also reduce the maximum lift achievable but,
surprisingly, increase the AOA at which stall occurs."

Note that, on a long winged glider with ailerons near the tips, a deflected
aileron on the down wing changes the camber of the wing in that area. With
the overbanking tendency of the down wing, there is inevitably some down
aileron on that wing (to stop the bank) and the above aerodynamics apply.

Allan


"Bob Kuykendall" > wrote in message
om...
> Earlier, (F1y1n) wrote:
>
> > ...The angle of attack of both wings is the
> > same. The air is impacting both wings from
> > exactly the same angle - the wings are
> > connected by the fuselage....
>
> I think I disagree on what might appear to be a technicality: The
> wings are connected not only by the fuselage, but also by the control
> system that the pilot uses to balance the lift distribution between
> the two wings.
>
> Since the inner wing is going substantially slower, and as you point
> out later has only a slightly greater angle of attack, something has
> to increase the Cl on the inner wing in order to keep from rolling
> into the turn (the overbanking tendency). That something is the pilot
> applying slight opposite aileron, increasing the inner wing's
> effective angle of attack.
>
> That may only be a couple of degrees of deflection down on the inner
> wing, but its also the same or more up on the outer wing, decreasing
> its effective angle of attack. The deflected surface has a substantial
> effect on the pressure distribution of the airfoil in front of it, and
> can make a big difference on its stall characteristics.
>
> Thanks, and best regards to all
>
> Bob K.
> http://www.hpaircraft.com/hp-24

[John Firth]

Chris OCallaghan ) writes:
> I was taking issue with an oversimplification, one you made for the
> sake of convenience, I'm sure. Pet peeve of mine.
>
> In an earlier thread on slips, I asked whether anyone had thought
> through the notion of using a slip (dihedral rolling moment)to
> counteract the overbanking tendency . I didn't note any responses,
> though it might prove interesting to develop the idea in the context
> of this thread.

I think experienced contest pilots have been doing this for a long time;
in '74 in Oz, I found in the first practice days that the Std Cirrus was
outclimbing my Libelle quite depressingly; I was used to flying string in
the middle.
First action, was to get the CG on the aft limit with lead; removed the
tail down force and the control surface drag; then to counter the sprial
instability and keep the flow attached at the inner wing root, I used
slip and was able to leave the ailerons nearly neutral; climbed with
the Cirrus just fine and when they had full water, i could go up the inside.
winglets now change the whole thing; you must keep the string in the middle
or one winglet stalls.
John Firth
Old but no longer bold pilot.>
> Dodging the math, I'll also add that a few extra knots while circling
> gives a great deal more aileron and rudder authority. Since smooth,
> elevator cores are the exception rather than the rule, the more
> effective your controls, the quicker you can correct for or take
> advantage of turbulence, then get the controls streamlined (or as
> close a practical) to minimize drag. The lower the speed, the greater
> the drag for a given control input, and the longer you'll have to
> leave it in to achieve the desired change in direction.
>
> Cheers,
>
> Chris


--


What is the meaning of life? Life is trial by computer

[Robert Ehrlich]

Mark James Boyd wrote:
> ...
> In the US, "calage" is where I would go to learn math and franch,
> and how to spell patato.
> ...

Took some time to understand this. I presume you pronounce "calage"
in the same way as "college", which is far from the way it is pronounced
in France.

[Mark James Boyd]

In article >,
Robert Ehrlich > wrote:
>Mark James Boyd wrote:
>> ...
>> In the US, "calage" is where I would go to learn math and franch,
>> and how to spell patato.
>> ...
>
>Took some time to understand this. I presume you pronounce "calage"
>in the same way as "college", which is far from the way it is pronounced
>in France.

Makes it even funier, no? :P