Spinning (mis)concepts

[Arnold Pieper]

1) "The spin is caused primarily by the position of the controls" - True,
but spins can also be cause by external factors.
2) "...Stick in the aft stop is the 'Stall' position" - Not exactly true. It
is true only with the wings level.
It is possible to fly regularly in a thermal with the stick against the full
aft position, as long as there is some angle of bank (15-20 degrees,
depending on the aircraft).
With the wings level, it will always produce a stall, that's what it is
designed to do.
Any competent flight instructor can demonstrate this if you're too affraid
to try it yourself.

3) "Always fly flatter close to the ground" - Now here is one that REALLY
bothers me.
This is probably the WORST misconception that insists in lingering around
hangar talk, internet talk and in other media with many "experts".
It should be replaced with "Always fly coordinated !" or "Fly with the right
amount of bank for the turn you want to make".
That's the simple, naked, honest truth.

Instilling fear of banking close to the ground is one of the worst things
you can do to your students.
I really hate people who insist on this one.
Gliders will not Stall or Spin due to bank angles. They will do so because
of angle of attack (pitch) not angle of bank.
Since most of us don't have an AOA indicator in our gliders, we use Speed as
an easy way to determine it.

Therefore, if you're maintaining the correct Speed in the traffic pattern,
you can (and SHOULD) bank the glider as appropriate for the turn. ALWAYS.
There is no exception.

A glider will not Stall/Spin from a coordinated turn with the proper speed.

It will do so always from an uncoordinated turn, usually with the Wings
close to level in a skidding turn and the stick aft.
Remember what I said about Wings level and the stick full aft.


Tom Knauff has some excellent material on the subject, published in many
different places, internet, SOARING Magazine, articles, etc.

[Owain Walters]

Arnold,

I agree. It is quite clear, and frightening to be honest,
that there are many 'Experienced' people on this site
that need to seek remidial spin training immediately.
Before they fly again and certainly before they fly
with students!

The misinformation on this site, particularly on this
subject (not to mention others) should be regarded
as criminal.

Owain

[Mike Lindsay]

>
>3) "Always fly flatter close to the ground" - Now here is one that REALLY
>bothers me.
>This is probably the WORST misconception that insists in lingering around
>hangar talk, internet talk and in other media with many "experts".
>It should be replaced with "Always fly coordinated !" or "Fly with the right
>amount of bank for the turn you want to make".
>That's the simple, naked, honest truth.
>
>Instilling fear of banking close to the ground is one of the worst things
>you can do to your students.
>I really hate people who insist on this one.
>Gliders will not Stall or Spin due to bank angles. They will do so because
>of angle of attack (pitch) not angle of bank.
>Since most of us don't have an AOA indicator in our gliders, we use Speed as
>an easy way to determine it.
>
OTOH if you do a well banked turn close to the ground and there is a
steepish wind gradient, its liable to be the last one you ever do.
>
>

--
Mike Lindsay

[Michel Talon]

Arnold Pieper > wrote:
>
> Therefore, if you're maintaining the correct Speed in the traffic pattern,
> you can (and SHOULD) bank the glider as appropriate for the turn. ALWAYS.
> There is no exception.
>
> A glider will not Stall/Spin from a coordinated turn with the proper speed.
>
> It will do so always from an uncoordinated turn, usually with the Wings
> close to level in a skidding turn and the stick aft.
> Remember what I said about Wings level and the stick full aft.

How true! I have NEVER spun unintentionally in many years of practising
gliding doing that. Learning how to recover from spin will not save a
single life when 99% of accidents are close to the ground, either
landing or ridge flying. Learning to fly perfectly coordinated in ALL
circumstances will save lifes. Learning to keep speed and not stupidly
thermalling at slower speed than necessary will both increase climb rate
and save lifes. I can unfortunately say that i have seen instructors
learning to fly both too slow and with the rudder inside the turn,
on a ridge. This is criminal. The argument was that the aileron produces
more drag, that inverse effects suffice to bank the glider and other
bull****. I always wondered how the instructor didn't kill himself.
When i became more proficient, i discovered i could exploit small lift
exactly as efficiently flying a little faster and with correct banking
of the glider than he was doing with these dangerous techniques.


--

Michel TALON

[CV]

Arnold Pieper wrote:
> 3) "Always fly flatter close to the ground" - Now here is one that REALLY
> bothers me.
> This is probably the WORST misconception that insists in lingering around
> hangar talk, internet talk and in other media with many "experts".
> It should be replaced with "Always fly coordinated !" or "Fly with the right
> amount of bank for the turn you want to make".
> That's the simple, naked, honest truth.
>
> Instilling fear of banking close to the ground is one of the worst things
> you can do to your students.
> I really hate people who insist on this one.

I was actually taught from the beginning to always do well-banked
turns to base and final. The instructor explained, and demonstrated
how it is much more difficult to stall, or get close to the stall,
with a good bank on.

Then it may be a different matter if you are _just_ making it back
from a cross country and are so low that you might hit the ground
with the wingtip. Though I have never been there myself I have heard
about people making their final turn "with the rudder" in that
situation. I just wonder whether it would help at all, since there'd
be quite a penalty in height for the unclean flying involved.
(Apart from the fact that there will have been some fairly poor
airmanship involved to end up in that situation in the first place.)

CV

[Arnold Pieper]

Ok, Here is to Mike and CV. Apparently both of you aren't listening.

If you make a turn with just the rudder and the wings level or almost level,
in other words, an uncoordinated turn, close to the ground, THAT will be
your last turn.

If you don't have height abouve the ground enough to perform a coordinated
turn, you SHOULD NOT be turning.

Here's the bottom-line : THAT level turn with the rudder-only, performed at
10 or 15ft height, is what produces the first part of a Spin and results in
gliders hitting the ground with the nose and wingtip first, usually
crippling the pilot.
My gosh, you guys don't seem to get it, or read enough accident reports.


"CV" > wrote in message
...
>
> Arnold Pieper wrote:
> > 3) "Always fly flatter close to the ground" - Now here is one that
REALLY
> > bothers me.
> > This is probably the WORST misconception that insists in lingering
around
> > hangar talk, internet talk and in other media with many "experts".
> > It should be replaced with "Always fly coordinated !" or "Fly with the
right
> > amount of bank for the turn you want to make".
> > That's the simple, naked, honest truth.
> >
> > Instilling fear of banking close to the ground is one of the worst
things
> > you can do to your students.
> > I really hate people who insist on this one.
>
> I was actually taught from the beginning to always do well-banked
> turns to base and final. The instructor explained, and demonstrated
> how it is much more difficult to stall, or get close to the stall,
> with a good bank on.
>
> Then it may be a different matter if you are _just_ making it back
> from a cross country and are so low that you might hit the ground
> with the wingtip. Though I have never been there myself I have heard
> about people making their final turn "with the rudder" in that
> situation. I just wonder whether it would help at all, since there'd
> be quite a penalty in height for the unclean flying involved.
> (Apart from the fact that there will have been some fairly poor
> airmanship involved to end up in that situation in the first place.)
>
> CV
>

[Michel Talon]

Mike Lindsay > wrote:
>>
> OTOH if you do a well banked turn close to the ground and there is a
> steepish wind gradient, its liable to be the last one you ever do.
>>

Lack of speed?
I have flewn places with very steep wind gradient and i am still here.
Number one assurance against problems is keeping speed, and rather more
speed than not enough when there is strong wind.

>>
>

--

Michel TALON

[Geir Raudsandmoen]

I know at least one pilot who was saved from serious
injury or death by his ability to quickly recover from
an incipient spin at very low altitude (probably below
50 m). I watched it happen.

I am probably also in that category myself, having
once unintentionally started to spin a LS7 when flying
a very turbulent thermal close to a mountainside near
Orcierres in the Alps, and being saved by quick recovery
action.

As we are not perfect, we should try to have two (or
more) lines of defence whenever possible:
First line of defence: Have sufficient airspeed and
fly coordinated when you are low.
Second line of defence: Be able to quickly recognise
and recover from an incipient spin.

Regarding the value of training fully developed spins:
I think the main benefits are to (hopefully) eliminate
the panic effect in a spin, and also to learn how to
avoid overspeeding or overstressing the sailplane in
the pull-out phase. The pull-out is normally very different
after a fully developed spin vs. after the typical
quarter-turn incipient spin.

Geir

At 10:12 27 January 2004, Michel Talon wrote:
>Arnold Pieper wrote:
>>
>> Therefore, if you're maintaining the correct Speed
>>in the traffic pattern,
>> you can (and SHOULD) bank the glider as appropriate
>>for the turn. ALWAYS.
>> There is no exception.
>>
>> A glider will not Stall/Spin from a coordinated turn
>>with the proper speed.
>>
>> It will do so always from an uncoordinated turn, usually
>>with the Wings
>> close to level in a skidding turn and the stick aft.
>> Remember what I said about Wings level and the stick
>>full aft.
>
>How true! I have NEVER spun unintentionally in many
>years of practising
>gliding doing that. Learning how to recover from spin
>will not save a
>single life when 99% of accidents are close to the
>ground, either
>landing or ridge flying. Learning to fly perfectly
>coordinated in ALL
>circumstances will save lifes. Learning to keep speed
>and not stupidly
>thermalling at slower speed than necessary will both
>increase climb rate
>and save lifes. I can unfortunately say that i have
>seen instructors
>learning to fly both too slow and with the rudder inside
>the turn,
>on a ridge. This is criminal. The argument was that
>the aileron produces
>more drag, that inverse effects suffice to bank the
>glider and other
>bull****. I always wondered how the instructor didn't
>kill himself.
>When i became more proficient, i discovered i could
>exploit small lift
>exactly as efficiently flying a little faster and with
>correct banking
>of the glider than he was doing with these dangerous
>techniques.
>
>
>--
>
>Michel TALON
>
>

[Ian Johnston]

On Tue, 27 Jan 2004 01:44:43 UTC, "Arnold Pieper"
> wrote:

: 1) "The spin is caused primarily by the position of the controls" - True,
: but spins can also be cause by external factors.

: A glider will not Stall/Spin from a coordinated turn with the proper speed.

Unless the external factors bite you!

Ian

[Ian Johnston]

On Tue, 27 Jan 2004 19:06:15 UTC, "Arnold Pieper"
> wrote:

: Ok, Here is to Mike and CV. Apparently both of you aren't listening.
:
: If you make a turn with just the rudder and the wings level or almost level,
: in other words, an uncoordinated turn, close to the ground, THAT will be
: your last turn.

CV was reporting this as something that other people claim to do. And
we all know, from the accident statistics, just how safe competition
pilots are, don't we?

In

[Pete Zeugma]

At 18:24 27 January 2004, Mike Lindsay wrote:
>>
>>3) 'Always fly flatter close to the ground' - Now here
>>is one that REALLY
>>bothers me.
>>This is probably the WORST misconception that insists
>>in lingering around
>>hangar talk, internet talk and in other media with
>>many 'experts'.
>>It should be replaced with 'Always fly coordinated
>>!' or 'Fly with the right
>>amount of bank for the turn you want to make'.
>>That's the simple, naked, honest truth.
>>
>>Instilling fear of banking close to the ground is one
>>of the worst things
>>you can do to your students.
>>I really hate people who insist on this one.
>>Gliders will not Stall or Spin due to bank angles.
>>They will do so because
>>of angle of attack (pitch) not angle of bank.
>>Since most of us don't have an AOA indicator in our
>>gliders, we use Speed as
>>an easy way to determine it.
>>
>OTOH if you do a well banked turn close to the ground
>and there is a
>steepish wind gradient, its liable to be the last one
>you ever do.


If you are flying on a day that has a strong wind gradient,
surely you would actually have compensated for that
with a higher approach speed? I personally have never
had any problem with steeply banked, cordinated final
turns, even under conditions of severe turbulence or
rotor. Spin and stall avoidance is all about the speed
you have. I take it from your comment you have never
explored the stalling characteristics of any aircraft
you have flown under different angles of bank?

[Pete Zeugma]

>> Then it may be a different matter if you are _just_
>>making it back
>> from a cross country and are so low that you might
>>hit the ground
>> with the wingtip. Though I have never been there myself
>>I have heard
>> about people making their final turn 'with the rudder'
>>in that
>> situation. I just wonder whether it would help at
>>all, since there'd
>> be quite a penalty in height for the unclean flying
>>involved.
>> (Apart from the fact that there will have been some
>>fairly poor
>> airmanship involved to end up in that situation
>>in the first place.)
>>
>> CV
>>
>

Hmmm, did'nt realise you could 'make a turn' with the
rudder!

Who ever the instructor is that taught this wonderful
technique, and who ever their CFI is that alow them
to continue to practice this technique, they both should
be sacked and banned from ever instructing again.

While there maybe secondary roll effects when you yaw
your glider, the whole purpose of the rudder is to
align the glider with the airflow. It is the ailerons
which instigate a turn by rolling the wings. The rudder
is used to 1) correct the adverse yaw 2) control any
slide or skid 3) align the airframe with the airflow
as you roll. The elevator is used to maintain a constant
speed through out.

If you chose to fly at or near the stall, and your
glider has a strong incipient spin characteristic,
it makes no odds whether you are turning or flying
straight and level.

Assume that if you touch that rudder near the stall
you will spin, and you will die!

[Pete Zeugma]

>First line of defence: Have sufficient airspeed and
>fly coordinated when you are low.
>Second line of defence: Be able to quickly recognise
>and recover from an incipient spin.

Souldnt that be....
1) airspeed Airspeed AIRSPEED
2) ALWAYS fly coordinated
2) dont get low and try hard not to land out
3) dont fly so slow you have to worry about an incipient
spin

[Michel Talon]

Geir Raudsandmoen m> wrote:
> I know at least one pilot who was saved from serious
> injury or death by his ability to quickly recover from
> an incipient spin at very low altitude (probably below
> 50 m). I watched it happen.

Woow! He must have experienced the fear of his life.

>
> I am probably also in that category myself, having
> once unintentionally started to spin a LS7 when flying
> a very turbulent thermal close to a mountainside near
> Orcierres in the Alps, and being saved by quick recovery
> action.

Sure, ridge flying is one of the most spin prone activities
if one gets into the habit of flying too slow and too "flat".

>
> As we are not perfect, we should try to have two (or
> more) lines of defence whenever possible:
> First line of defence: Have sufficient airspeed and
> fly coordinated when you are low.
> Second line of defence: Be able to quickly recognise
> and recover from an incipient spin.

You are perfectly right.

>
> Regarding the value of training fully developed spins:
> I think the main benefits are to (hopefully) eliminate
> the panic effect in a spin, and also to learn how to
> avoid overspeeding or overstressing the sailplane in
> the pull-out phase.

This is the point of concern to me. A lot of modern single
seater glasses don't like very much the pull-out phase, and
tend to take horrendous speeds in the dive. Hence my own opinion
to avoid as much as possible entering spin and if incipient spin
either appears, get out immediately. Of course on a good old
Ask13 one can play the game as much as one likes it. I seem to
remember examples where people *have* indeed overstressed glasses
in the pull-out phase, unfortunately for them.


--

Michel TALON

[CV]

Arnold Pieper wrote:
> Ok, Here is to Mike and CV. Apparently both of you aren't listening.

Hmmm. Surprising reaction, considering my post mainly supported your
views.

> If you make a turn with just the rudder and the wings level or almost level,
> in other words, an uncoordinated turn, close to the ground, THAT will be
> your last turn.
>
> If you don't have height abouve the ground enough to perform a coordinated
> turn, you SHOULD NOT be turning.

> Here's the bottom-line : THAT level turn with the rudder-only, performed at
> 10 or 15ft height, is what produces the first part of a Spin and results in
> gliders hitting the ground with the nose and wingtip first, usually
> crippling the pilot.
> My gosh, you guys don't seem to get it, or read enough accident reports.

As Ian already pointed out I reported this as something that other
people claim to do, and I was in fact questioning it.

On the other hand your claim that any uncoordinated flying
automatically leads to a spin is just ridiculous. It rather
detracts from your credibility and otherwise sensible views.

And I must say, in all kindness, that you would benefit by trying
not to be so pompous. These discussions are much more interesting
and helpful if we can air our views and experiences on an equal
footing rather someone dishing out "bottom-lines" and "simple,
naked, honest truths" from their preacher's pulpit.

Cheers CV

[Owain Walters]

>we all know, from the accident statistics, just how
>safe competition
>pilots are, don't we?


Ian,

I am assuming you are being sarcastic? Where are you
getting your competition vs. normal flying accident
statistics from?

I am interested because the vast majority of accident
reports I read are nothing to do with competitions.

Owain

[Robert Ehrlich]

Geir Raudsandmoen wrote:
> ...
> Regarding the value of
> I think the main benefits are to (hopefully) eliminate
> the panic effect in a spin, and also to learn how to
> avoid overspeeding or overstressing the sailplane in
> the pull-out phase. The pull-out is normally very different
> after a fully developed spin vs. after the typical
> quarter-turn incipient spin.
>

Maybe there is another benefit of training fully developed spins.
A pilot told me how this training and the way it was done saved
his life. The instructor who trained him insisted on practising
fully developed spins, with exit after a precise number of turns
in a precise direction, this varying with each exercise. Later
he was once ridge flying in front of a cliff when he has a spin
departure. He was about to attempt the recovery when he realized
that this would bring the glider just facing the cliff at exit
with no way to avoid crashing onto it, so he delayed this recovery
for a half turn as he was taught and made the exit in the proper
direction.

[Ian Johnston]

On Wed, 28 Jan 2004 12:37:49 UTC, Owain Walters
> wrote:

: >we all know, from the accident statistics, just how
: >safe competition
: >pilots are, don't we?
:
: I am assuming you are being sarcastic?

Yup.

: Where are you
: getting your competition vs. normal flying accident
: statistics from?

Reading the blood-and-gore pages of S&G

: I am interested because the vast majority of accident
: reports I read are nothing to do with competitions.

Well of course not. When you stuff up landing a glider in a field
after pressing on, too late, too low and too tired, you don't have to
compound things by owning up ...

Incidentally, note that I said "competition pilots" and not "pilots
flying in competitions" ...

Ian

[Eric Greenwell]

Arnold Pieper wrote:
> Therefore, if you're maintaining the correct Speed in the traffic pattern,
> you can (and SHOULD) bank the glider as appropriate for the turn. ALWAYS.
> There is no exception.
>
> A glider will not Stall/Spin from a coordinated turn with the proper speed.

This begs the question: a glider will NOT stall/spin from an
UNcoordinated turn with the proper speed, either.
>
> It will do so always from an uncoordinated turn, usually with the Wings
> close to level in a skidding turn and the stick aft.
> Remember what I said about Wings level and the stick full aft.

I've routinely stalled our club's Blanik from coordinated turns, and
other gliders, too. Establish a shallow banked turn (10-15 degrees,
say), then simply slow down while maintaining a coordinated turn. At
some point, the inner wing falls and the spin begins.

Coordination is important, but not sufficient to protect you from a spin.

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

Eric Greenwell
Washington State
USA

[Mark James Boyd]

Geir Raudsandmoen m> wrote:
>
>I am probably also in that category myself, having
>once unintentionally started to spin a LS7 when flying
>a very turbulent thermal close to a mountainside near
>Orcierres in the Alps, and being saved by quick recovery
>action.

I read in one of his notes that Carl Herold doesn't ridge soar
any more, because he thinks it is too dangerous. After I read
that, I had a little talk with myself about how close
I came to ridges a few times...

>
>As we are not perfect, we should try to have two (or
>more) lines of defence whenever possible:
>First line of defence: Have sufficient airspeed
>and
>fly coordinated when you are low.

OK, I've got to agree with PART of this, but in detail.
The US FAA Glider Flying Handbook, although it's nice to have
one, is edited poorly, in my opinion. It has a lot of different
definitions of a skid vs. slip, in different chapters
(clearly written by different people). The editor should
have seen this and standardized it.

I think a slip is an uncoordinated manuever where both wings
are at the same airspeed. A skid is an uncoordinated
manuever where the wings are at different airspeeds.
Straight flight is a coordinated manuever where both
wings are at the same airspeed. Banked, turning flight is
a coordinated manuever where both wings are at
different airspeeds.

Beyond this, I do a lot of training where the glider is
uncoordinated. Boxing the wake, slips (on the takeoff roll
and on landing), slack line recovery. I don't worry at
all because neither wing ever stalls.

What is coordinated? Well, if the yaw string or ball were
at the CG, and centered, that would be coordinated. But
the string isn't. It is often in front of and higher than
the CG. When this is the case, at high roll rates,
and steep banks, keeping the yaw string
perfectly centered means I am in a skid.
Think about a string on the end of a pole 20 feet long
at 45 degrees up from the nose. Would you want to use
this? Now let's make the wingspan really long and
put your CG back 4 inches, and leave your top of the
canopy yawstring in the same place. Now what happens?
With that high aspect ratio where the difference between
min sink angle-of-attack and stall is just a few degrees?

Now I assume I actually have a yawstring right at the CG instead.
I fly my Lingus with the 300 foot wingspan, which
stalls at 38 knots. I decide to put it into a
coordinated 60 degree bank, and fly at 53 knots. The
"G" chart says this is the correct speed, and the radius of turn
is 144 feet. Does anyone see anything wrong with this idea?
I certainly do. Some of the wing is actually flying
backwards. A glider with a 20 foot wingspan vs. a
300 foot wingspan is going to get a different result.
Even in coordinated flight, the wings are at different airspeeds.
Then I can just imagine the amount of opposite
aileron one would need...
Using the same "G" loading chart for airspeeds for
aircraft with different wingspans seems puzzling to me.

Now I go up in my glider, and I get in straight flight,
and I pull the stick back to the stop, and hold it
perfectly centered for about a minute. If the CG or design
don't allow a continual stall, the glider bucks up and down
in pitch. I try my best to keep it straight, but eventually
a wing drops, and it goes into a bucking spin/spiral.
If the CG or design allow a continued
stall, I try my best to keep it straight, and a wing drops,
and it goes into a spin. If I keep the stick all the way
back and centered, I can change the direction of the
spin with rudder (including a momentary straightness)
but can't keep it straight consistently.

The only aircraft I've been able to do a true full stall
straight falling leaf is in Cezzna 150/152/172s.
Washout, dihedral, huge vertical stab, huge rudder, CG hanging low.
I've never been able to do a straight ahead stall, stick back and
centered for a full minute, in any glider.

So from my way of thinking, keeping the yaw string straight
and using the airspeed indicator are a poor man's way of
trying to keep either wing from stalling. Then
applying airspeed rules for bank with no consideration
for wingspan or aileron drag is another poor man's technique.


If I flew a nice schmancy L/D one billion glider with
long sexy wings, I'd invest in AOA indicators for each
wing (maybe halfway or more along).
I'd either rig them for worst case (worst flaps,
worst aileron deflection, worst spoilers) or I'd link
in the flap and aileron position info somehow.
The Beech Duchess has an stall horn/AOA indicator on
each wing (one side is for flaps up, the other for
flaps down), so this isn't entirely novel (although
it isn't specifically for spin avoidance).

An AOA indicator on each wing wouldn't be perfect
(bugs and ice and stuff still wouldn't get factored in),
but I'd sure like it :) Seriously, how much
drag would a couple of these cause?

Until then, I fly little short-wingspan things with
low aspect ratio and sacrifice performance. And I
use wide patterns, slow roll rates, excessive
airspeed, medium or less banks, and gentle control
inputs when close to the ground.

>Second line of defence: Be able to quickly recognise
>and recover from an incipient spin.

I'd say be able to quickly recognise and recover from
an incipient stall. Since I've not been able to
maintain a straight stall, I assume a stall = spin.
If I'm uncoordinated, it just happens faster.

[Arnold Pieper]

(...............)
> I've routinely stalled our club's Blanik from coordinated turns, and
> other gliders, too. Establish a shallow banked turn (10-15 degrees,
> say), then simply slow down while maintaining a coordinated turn. At
> some point, the inner wing falls and the spin begins.
>
> Coordination is important, but not sufficient to protect you from a spin.
>

Correct, coordination and speed will do.

If you banked a little more and kept flying coordinated you would at one
point reach the aft limit in the Stick travel and not be able to stall /
spin...

[Stewart Kissel]

SNIP
I read in one of his notes that Carl Herold doesn't
ridge soar
any more, because he thinks it is too dangerous. After
I read
that, I had a little talk with myself about how close
I came to ridges a few times...

SNIP

I cannot recall his exact words, but the interpretation
of it that I came away with is-'If you are flying the
mountains of the western USA in strong summer conditions
there is no reason to get down that low. And if you
are that low you are asking for trouble.' IMHO that
makes a lot of sense.

With 1,000'/minute sink not uncommon in this terrain,
working nooks and crannies can bite hard. I have flown
with Carl, but cannot recall if we discussed this then.
Perhaps someone can refresh my memory, was this thought
of his from a forum or post?

[Tony Verhulst]

> What is coordinated? Well, if the yaw string or ball were
> at the CG, and centered, that would be coordinated.

Center of pressure or aerodynamic center... but, yeah, right.

But
> the string isn't. It is often in front of and higher than
> the CG. When this is the case, at high roll rates,
> and steep banks, keeping the yaw string
> perfectly centered means I am in a skid.

I did some "back of the envelope" caculations, using nothing more than
high school trig and geometry and it's not as bad as you think.
Assumming a 45 degree banked turn at 55 kts, the turn radius is 240 feet
(source American Soaring Handbook). If the yaw string is 6 feet or so in
front of the center of pressure, the yaw string error, due to it's
position, is 1.4 degrees. Close enough, I think.

Tony V.

[Jim]

On Wed, 28 Jan 2004 19:25:52 GMT, "Arnold Pieper"
> wrote:

>(...............)
>> I've routinely stalled our club's Blanik from coordinated turns, and
>> other gliders, too. Establish a shallow banked turn (10-15 degrees,
>> say), then simply slow down while maintaining a coordinated turn. At
>> some point, the inner wing falls and the spin begins.
>>
>> Coordination is important, but not sufficient to protect you from a spin.
>>
>
>Correct, coordination and speed will do.
>
>If you banked a little more and kept flying coordinated you would at one
>point reach the aft limit in the Stick travel and not be able to stall /
>spin...
>

Please be very careful about this. Some gliders may not have enough
rudder authority under high load factors to achieve stall AOA but some
gliders are very happy to snap into a stall over the low wing in the
same circumstances.

[Jim]

On Wed, 28 Jan 2004 16:32:45 -0500, Todd Pattist
> wrote:

(Mark James Boyd) wrote:
>
>> I think a slip is an uncoordinated manuever where both wings
>>are at the same airspeed. A skid is an uncoordinated
>>manuever where the wings are at different airspeeds.
>
>A slip can occur while you are flying straight or while
>turning. By definition, a skid can *only* occur in a turn.
>

Well, maybe so, but my understanding of a skid is a little
different. In my notion of a skid it is a flight condition in which
the amount of rudder applied is too great for the amount of bank
applied. Thus, in my thinking, if you are flying at zero bank -
not in a banked turn - ANY application of rudder will result in a
skid, not a slip.

Please let me know if I have this mixed up!

>The wings are at different airspeeds in a turn regardless of
>whether you are slipping, skidding or coordinated. They are
>at the same airspeed in straight flight regardless of
>whether you are slipping or coordinated. If you are
>turning, and the airflow is coming across the fuselage from
>the outside of the turn, you're in a skid. If it's coming
>from the inside of the turn, you're in a slip.
>
>>Straight flight is a coordinated manuever where both
>>wings are at the same airspeed. Banked, turning flight is
>>a coordinated manuever where both wings are at
>>different airspeeds.
>
>
>
>Todd Pattist - "WH" Ventus C
>(Remove DONTSPAMME from address to email reply.)

[Tom Seim]

>
> What is coordinated? Well, if the yaw string or ball were
> at the CG, and centered, that would be coordinated. But
> the string isn't. It is often in front of and higher than
> the CG. When this is the case, at high roll rates,
> and steep banks, keeping the yaw string
> perfectly centered means I am in a skid.

Humm, so we are all flying uncoordinated in a turn?

I couldn't pass this up, so I calculated how much the yaw string is
off. Assume a 300' turn radius, the yaw string is 5' ahead of the CG
and is 4" long. With these numbers the yaw string is off by 0.033
inch, much smaller than the diameter of the string itself!

Tom

[Owain Walters]

Ian,

You have near enough admitted that you are extrapolating
information that clearly isnt there from the accident
reports. In my 15 years of reading S+G I have never
seen a 'Competition Pilots not in Competition accident
section'. Also accusing every comp pilot of not owning
up to incidents is just plain rubbish not to mention
insulting.

Please keep you amateur accident statistics thoughts
to yourself. You dont do anyone any favours including
yourself.

BTW. I have seen an early solo pilot 'Push on' which
resullted in a crash. Was he an aspiring comp pilot,
influenced by a comp pilot or did he just get it wrong?

Owain




At 17:36 28 January 2004, Ian Johnston wrote:
>On Wed, 28 Jan 2004 12:37:49 UTC, Owain Walters
> wrote:
>
>: >we all know, from the accident statistics, just how
>: >safe competition
>: >pilots are, don't we?
>:
>: I am assuming you are being sarcastic?
>
>Yup.
>
>: Where are you
>: getting your competition vs. normal flying accident
>: statistics from?
>
>Reading the blood-and-gore pages of S&G
>
>: I am interested because the vast majority of accident
>: reports I read are nothing to do with competitions.
>
>Well of course not. When you stuff up landing a glider
>in a field
>after pressing on, too late, too low and too tired,
>you don't have to
>compound things by owning up ...
>
>Incidentally, note that I said 'competition pilots'
>and not 'pilots
>flying in competitions' ...
>
>Ian
>

[Jim]

On Wed, 28 Jan 2004 19:25:52 GMT, "Arnold Pieper"
> wrote:

>(...............)
>> I've routinely stalled our club's Blanik from coordinated turns, and
>> other gliders, too. Establish a shallow banked turn (10-15 degrees,
>> say), then simply slow down while maintaining a coordinated turn. At
>> some point, the inner wing falls and the spin begins.
>>
>> Coordination is important, but not sufficient to protect you from a spin.
>>
>
>Correct, coordination and speed will do.
>
>If you banked a little more and kept flying coordinated you would at one
>point reach the aft limit in the Stick travel and not be able to stall /
>spin...
>

Please be very cautious about this. Some gliders may have
insufficient elevator authority to reach stall AOA under higher load
factors but this is not true of all gliders. Some do have the
elevator authority to very happily stall and fall off over the low
wing under higher load factors. The location of the Center of Gravity
in a particular flight influences this, but we still must be prepared
for stalls out of steep turns.

[Pete Zeugma]

>If you have zero bank, and apply rudder you will begin
>a
>flat turn.

Wrong! UTTERLY WRONG!!!! A rudder yaws the airframe,
it does not 'turn' or 'steer' the aircraft.

Your whole problem seems to be in compairing a glider
with a boat. They may both have rudders, but they both
do totally different things.

Next time you fly in your glider, line yourself up
with a straight feature. Apply some rudder to yaw the
glider, but keep the wings level. All you will do is
continue in a straight line, sideways on. (commonly
known as a side slip)

However, the rudder does has a secondary control effect,
which introduces a roll moment due to differences in
lift between the wings. (which is why the first thing
you do is apply full opposite rudder to counteract
the rotation in a spin)

It is the ailerons that instigate a turn, the rudder
is used in a coordinated manner to 1) check the adverse
yaw (secondary effect of ailerons), and 2) to align
the airframe correctly into the airflow.

Please stop using language which inforces a belief
that the rudder is used to turn a glider in flight.
Your very action in doing so may well end up enforcing
that belief into a low airtime pilot reading these
posts and KILLING THEM!

[Doug Taylor]

(Mark James Boyd) wrote in message news:<401810d2$1@darkstar>...

> Now I go up in my glider, and I get in straight flight,
> and I pull the stick back to the stop, and hold it
> perfectly centered for about a minute. If the CG or design
> don't allow a continual stall, the glider bucks up and down
> in pitch. I try my best to keep it straight, but eventually
> a wing drops, and it goes into a bucking spin/spiral.
> If the CG or design allow a continued
> stall, I try my best to keep it straight, and a wing drops,
> and it goes into a spin. If I keep the stick all the way
> back and centered, I can change the direction of the
> spin with rudder (including a momentary straightness)
> but can't keep it straight consistently.
>
> The only aircraft I've been able to do a true full stall
> straight falling leaf is in Cezzna 150/152/172s.
> Washout, dihedral, huge vertical stab, huge rudder, CG hanging low.
> I've never been able to do a straight ahead stall, stick back and
> centered for a full minute, in any glider.
>


You haven't flown a SparrowHawk yet! Couldn't resist a short remark
here. You can even hold the stick full aft AND be fully cross
controlled through a number of pitch breaks in the SparrowHawk.

Doug Taylor

[Mark James Boyd]

Todd Pattist > wrote:
(Mark James Boyd) wrote:
>
>> I think a slip is an uncoordinated manuever where both wings
>>are at the same airspeed. A skid is an uncoordinated
>>manuever where the wings are at different airspeeds.
>
>A slip can occur while you are flying straight or while
>turning. By definition, a skid can *only* occur in a turn.

Aha. Quite true. I suppose I didn't include the slipping turn
because it is not generally taught, and could be a little
hard to grasp for brand new pilots...

I've also seen new pilots do skids on base to final, and tell me
they were doing a slip from base to final, and this was OK
because their previous instructor said slips are perfectly
safe. A+ for theory, D- for application...so I only teach
the kind of slips where both wings have the same airspeed...

[Mark James Boyd]

In article >,
Jim > wrote:
>On Wed, 28 Jan 2004 16:32:45 -0500, Todd Pattist
> wrote:
>
(Mark James Boyd) wrote:
>>
>>> I think a slip is an uncoordinated manuever where both wings
>>>are at the same airspeed. A skid is an uncoordinated
>>>manuever where the wings are at different airspeeds.
>>
>>A slip can occur while you are flying straight or while
>>turning. By definition, a skid can *only* occur in a turn.
>>
>
>Well, maybe so, but my understanding of a skid is a little
>different. In my notion of a skid it is a flight condition in which
>the amount of rudder applied is too great for the amount of bank
>applied.

I think a lot of this thread is about what exactly "the right
amount of rudder" is. String centered? Does wingspan matter?
Does angle of bank matter? Does roll rate matter? But these
are real nuances, so what you write above is something I'd
believe is fine...

>Thus, in my thinking, if you are flying at zero bank -
>not in a banked turn - ANY application of rudder will result in a
>skid, not a slip.

Ahhh...mostly. I've flown some hella misrigged stuff (including my
own 172) and if you have more drag on the left aileron/flap/tip fairing/etc.
you may have to put in rudder even with the wings perfectly level
(0 bank). And I would call this a slip, in this case a straight slip
(even though the nose is cocked to the side) and the ground track
follows a straight line and both wings have the same airspeed. Jump planes
do this too when they have some yahoo hanging on the wing strut
hoping the pilot is holding the wheel brake for another few seconds...
(since the yahoo is standing on the wheel). As another poster mentioned,
this may not be the most aerodynamically clean slip, but I bet
the jumper prefers it to any bank angle...

>
>Please let me know if I have this mixed up!

It seems like you have it well in hand, except for the
squirrel cases bored winter pilots come up with...

[Mark James Boyd]

In article >,
Tom Seim > wrote:
>>
>> What is coordinated? Well, if the yaw string or ball were
>> at the CG, and centered, that would be coordinated. But
>> the string isn't. It is often in front of and higher than
>> the CG. When this is the case, at high roll rates,
>> and steep banks, keeping the yaw string
>> perfectly centered means I am in a skid.
>
>Humm, so we are all flying uncoordinated in a turn?
>
>I couldn't pass this up, so I calculated how much the yaw string is
>off. Assume a 300' turn radius, the yaw string is 5' ahead of the CG
>and is 4" long. With these numbers the yaw string is off by 0.033
>inch, much smaller than the diameter of the string itself!
>
>Tom

Several posters pointed this out. In my defense, I've seen
this sitting in the back seat of a glider with two yaw strings,
and I know it is real. However, as someone else pointed out,
the string is made even more sensitive by the canopy
splitting the airflow a little, so miniscule angles can
be detected.

I'm going to look a little more at how large of an impact
this really has. It may simply be dwarfed by the other effects,
and so small as to be insignificant, as Tom seems to suggest.

I'm still convinced of the second part though. I think there is
some significant error caused on the yaw string at slow airspeeds
with high roll rates when the string is above the
center of gravity...er...center of pressure (thanks for the
correction to this one too).

When I do high rate dutch rolls, the glider seems to
perfectly rotate around the axis, but the string is way
all over the place. Explain THAT whydontcha? :PPP

[Mark James Boyd]

In article >,
Doug Taylor > wrote:
(Mark James Boyd) wrote in message news:<401810d2$1@darkstar>...
>
>> Now I go up in my glider, and I get in straight flight,
>> and I pull the stick back to the stop, and hold it
>> perfectly centered for about a minute. If the CG or design
>> don't allow a continual stall, the glider bucks up and down
>> in pitch. I try my best to keep it straight, but eventually
>> a wing drops, and it goes into a bucking spin/spiral.
>> If the CG or design allow a continued
>> stall, I try my best to keep it straight, and a wing drops,
>> and it goes into a spin. If I keep the stick all the way
>> back and centered, I can change the direction of the
>> spin with rudder (including a momentary straightness)
>> but can't keep it straight consistently.
>>
>> The only aircraft I've been able to do a true full stall
>> straight falling leaf is in Cezzna 150/152/172s.
>> Washout, dihedral, huge vertical stab, huge rudder, CG hanging low.
>> I've never been able to do a straight ahead stall, stick back and
>> centered for a full minute, in any glider.
>>
>
>
>You haven't flown a SparrowHawk yet! Couldn't resist a short remark
>here. You can even hold the stick full aft AND be fully cross
>controlled through a number of pitch breaks in the SparrowHawk.
>
>Doug Taylor

I can imagine that with some dihedral, at some weight, and
with certain limits to the full travel of the controls,
one could design a glider to do this. If the sparrowhawk
also does this through the full range of pilot weights and
CG as well, that would be even more interesting.

I can't wait to try it! Sparrowhawk world tour?

[Mark James Boyd]

Todd Pattist > wrote:
(Mark James Boyd) wrote:
>
>> A+ for theory, D- for application...so I only teach
>>the kind of slips where both wings have the same airspeed...
>
>I find that very odd. The slipping turn is a highly useful
>maneuver.
>Todd Pattist - "WH" Ventus C
>(Remove DONTSPAMME from address to email reply.)

Perhaps this is something I will look more at.
I was never taught this, I was never asked to
demonstrate it during a dozen check rides, and
I haven't ever seen a written reference to a slipping
turn, so I perhaps haven't thought about it
much.

Hmmm...

[Eric Greenwell]

Todd Pattist wrote:
> A skidding turn, as you described is the opposite of a
> slipping turn. The student needs to be taught the
> difference. If he is doing a slipping turn, the yaw string
> will be out of the turn, if he's skidding it will be inside
> the turn.
>
>
>> A+ for theory, D- for application...so I only teach
>>the kind of slips where both wings have the same airspeed...
>
>
> I find that very odd. The slipping turn is a highly useful
> maneuver.

Refresh my memory, which doesn't seem to include this. Under what
circumstances and glider types would this be true? If I'm too high, I
adjust the pattern or open the airbrakes. I will slip on final for
crosswind compensation, but why would I want make slipping turns in the
pattern or elswhere?

--
-----
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Eric Greenwell
Washington State
USA

[Marc Ramsey]

Eric Greenwell wrote:
> Refresh my memory, which doesn't seem to include this. Under what
> circumstances and glider types would this be true? If I'm too high, I
> adjust the pattern or open the airbrakes. I will slip on final for
> crosswind compensation, but why would I want make slipping turns in the
> pattern or elswhere?

When I'm flying our Duo, a slipping turn from base to final is my
standard procedure. I like to carry extra energy in the pattern (too
much flying at Truckee), but the airbrakes aren't terribly effective, so
I use a slipping turn to dissipate the excess energy, and hold it
until I'm at an acceptable (shallow) approach angle. It also makes it a
lot easier to see what's happening on the runway from the back seat.

Marc

[Eric Greenwell]

Marc Ramsey wrote:

> Eric Greenwell wrote:
>
>> Refresh my memory, which doesn't seem to include this. Under what
>> circumstances and glider types would this be true? If I'm too high, I
>> adjust the pattern or open the airbrakes. I will slip on final for
>> crosswind compensation, but why would I want make slipping turns in
>> the pattern or elswhere?
>
> When I'm flying our Duo, a slipping turn from base to final is my
> standard procedure. I like to carry extra energy in the pattern (too
> much flying at Truckee), but the airbrakes aren't terribly effective, so
> I use a slipping turn to dissipate the excess energy, and hold it until
> I'm at an acceptable (shallow) approach angle. It also makes it a lot
> easier to see what's happening on the runway from the back seat.

Are you using the spoilers at the same time? Of course, they won't help
the view from the back seat.

--
-----
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Eric Greenwell
Washington State
USA

[Eric Greenwell]

Todd Pattist wrote:

> Eric Greenwell > wrote:
>
>
>>Refresh my memory, which doesn't seem to include this. Under what
>>circumstances and glider types would this be true? If I'm too high, I
>>adjust the pattern or open the airbrakes. I will slip on final for
>>crosswind compensation, but why would I want make slipping turns in the
>>pattern or elswhere?
>
>
> I suppose it's like asking why you would ever want spoilers
> in a turn. You can retract them if you want, but I like
> having some extra descent rate as an option. If your
> spoilers are frozen shut, you can fly a normal pattern and
> just substitute slip wherever you'd use spoilers.
>
> We've got a short runway perpendicular to the ridge that
> starts near the ridge base. It's nicely aligned with the
> wind on a ridge day, but you have to fight the ridge lift on
> base, hold your speed for safety in the turbulence, and you
> can't open up your pattern due to the proximity of the
> ridge. You need maximum descent rate if you want to land
> short. I often slip through the base-final turn there.

Is it practical to just do a lower pattern, knowing the ridge lift is
there? Or is it not there once in a while?

Would it be practical to use a full spoiler "dive" (say, 70 knots) on
final to increase your approach angle, rather than slipping plus some
spoilers at a slower speed?

> Plus, there are times when I can see the runway better in a
> slipping turn.

In a two seater, like Marc?
--
-----
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Eric Greenwell
Washington State
USA

[Mark James Boyd]

In article >,
Todd Pattist > wrote:
>
>As a matter of interest, how did you handle the request to
>demonstrate a "no airbrakes" landing where you needed a
>forward slip on both base and final? Did you bring the
>rudder fully through to the opposite side (inside of the
>turn) to intersperse a coordinated turn between your forward
>slips?

Yep. Exactly. I've used slips in taildraggers extensively,
during no-flap demonstrations, and on lots of checkrides.
Always interspersed a coordinated turn. Kinda funny
to write it here now that I think about it. Just something
I haven't done before, I can't really explain why...

And I've never been in a situation where this has been insufficient.
Combined with adjusting more by flying faster or slower than
best glide on final, this has worked ok.

A coupla aircraft (Katana, PW-5) have such little pipsqueak
popsicle stick rudders that slips seem to do VERY little,
and I've had to mostly use airspeed control for glideslope.
God forbid I hit positive shear or updrafts with no spoilers/flaps
in these ships: overshoot of even a long runway seems likely...

[Marc Ramsey]

Eric Greenwell wrote:

> Marc Ramsey wrote:
>> When I'm flying our Duo, a slipping turn from base to final is my
>> standard procedure. I like to carry extra energy in the pattern (too
>> much flying at Truckee), but the airbrakes aren't terribly effective,
>> so I use a slipping turn to dissipate the excess energy, and hold it
>> until I'm at an acceptable (shallow) approach angle. It also makes it
>> a lot easier to see what's happening on the runway from the back seat.
>
>
> Are you using the spoilers at the same time? Of course, they won't help
> the view from the back seat.

Yes, I use the spoilers at the same time. The spoilers work fine if you
are making a shallow approach at 60 knots or so. They are marginal,
at best, when making a high close-in approach at 70+ knots (typical
Truckee afternoon landing).

Marc

[Nyal Williams]

Getting down fast! I was getting ready to enter the
wave window at Mt. Mitchell, NC, and the cold suddenly
told me my bladder was about to let go. Full divebrakes
in a slipping turn got me on the runway in time, but
I had to jump out and run to a ditch beside the runway;
at 75 yards, the FBO toilet was just too far away.

At 20:48 29 January 2004, Eric Greenwell wrote:
>Todd Pattist wrote:
>> A skidding turn, as you described is the opposite
>>of a
>> slipping turn. The student needs to be taught the
>> difference. If he is doing a slipping turn, the yaw
>>string
>> will be out of the turn, if he's skidding it will
>>be inside
>> the turn.
>>
>>
>>> A+ for theory, D- for application...so I only teach
>>>the kind of slips where both wings have the same airspeed...
>>
>>
>> I find that very odd. The slipping turn is a highly
>>useful
>> maneuver.
>
>Refresh my memory, which doesn't seem to include this.
>Under what
>circumstances and glider types would this be true?
>If I'm too high, I
>adjust the pattern or open the airbrakes. I will slip
>on final for
>crosswind compensation, but why would I want make slipping
>turns in the
>pattern or elswhere?
>
>--
>-----
>change 'netto' to 'net' to email me directly
>
>Eric Greenwell
>Washington State
>USA
>
>

[Eric Greenwell]

Marc Ramsey wrote:
> Eric Greenwell wrote:
>
>> Marc Ramsey wrote:
>>
>>> When I'm flying our Duo, a slipping turn from base to final is my
>>> standard procedure. I like to carry extra energy in the pattern (too
>>> much flying at Truckee), but the airbrakes aren't terribly effective,
>>> so I use a slipping turn to dissipate the excess energy, and hold it
>>> until I'm at an acceptable (shallow) approach angle. It also makes
>>> it a lot easier to see what's happening on the runway from the back
>>> seat.
>>
>> Are you using the spoilers at the same time? Of course, they won't
>> help the view from the back seat.
>
>
> Yes, I use the spoilers at the same time. The spoilers work fine if you
> are making a shallow approach at 60 knots or so. They are marginal, at
> best, when making a high close-in approach at 70+ knots (typical Truckee
> afternoon landing).

If I understand this right:

1) you are coming down more steeply at 70 knots than you did at 60
knots, but it's still not steep enough;
2) and that's because at Truckee, you want to come in _very_ steeply
over/near the threshold to avoid the downwash off the end;
3) and at 80 knots, the descent would be steep enough, but you'd be
stopping wwaaayyy at the other end.

I've only made a couple of landings at Truckee, so I'm trying to picture
the situation.

--
-----
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Eric Greenwell
Washington State
USA

[Eric Greenwell]

Nyal Williams wrote:

> Getting down fast! I was getting ready to enter the
> wave window at Mt. Mitchell, NC, and the cold suddenly
> told me my bladder was about to let go. Full divebrakes
> in a slipping turn got me on the runway in time, but
> I had to jump out and run to a ditch beside the runway;
> at 75 yards, the FBO toilet was just too far away.

What speed did you use? Could you have just used full spoilers and
spiralled down at 90 knots or so (or faster, if air was smooth), and had
the same descent rate?
--
-----
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Eric Greenwell
Washington State
USA

[Marc Ramsey]

Eric Greenwell wrote:
> If I understand this right:
>
> 1) you are coming down more steeply at 70 knots than you did at 60
> knots, but it's still not steep enough;
> 2) and that's because at Truckee, you want to come in _very_ steeply
> over/near the threshold to avoid the downwash off the end;
> 3) and at 80 knots, the descent would be steep enough, but you'd be
> stopping wwaaayyy at the other end.

You've got it. The spoilers don't provide a lot of drag, so it takes a
bit of distance to burn off the extra 10 to 20 knots before making a
normal touchdown. You can fly it on and hit the fine hydraulic brake,
but then it will slam down on the nosewheel, making your partners nervous...

> I've only made a couple of landings at Truckee, so I'm trying to picture
> the situation.

For those who don't know, gliders at Truckee (near Lake Tahoe, elevation
5900 feet) normally use runway 19, which features a cliff-like drop off
at the threshold. In the afternoons, the winds are often between 15 and
30 knots right down the runway, which sets up an interesting rotor-like
condition just before the threshold, resulting in big sink and a
significant wind gradient. We normally try to arrange things on windy
days so the turn from base to final is over the numbers. But sometimes,
circumstances prevent that, like a Skyhawk put-putting along on final,
in which case you want lots of extra energy. Let me just say, if you
ever find yourself below the threshold of 19, *push*, then pull at the
last moment, and if you're lucky, you'll end up making a very low energy
landing right on the numbers...

Marc

[Tom Seim]

(Mark James Boyd) wrote in message news:<40194105$1@darkstar>...
> In article >,
> Tom Seim > wrote:
> >>
> >> What is coordinated? Well, if the yaw string or ball were
> >> at the CG, and centered, that would be coordinated. But
> >> the string isn't. It is often in front of and higher than
> >> the CG. When this is the case, at high roll rates,
> >> and steep banks, keeping the yaw string
> >> perfectly centered means I am in a skid.
> >
> >Humm, so we are all flying uncoordinated in a turn?
> >
> >I couldn't pass this up, so I calculated how much the yaw string is
> >off. Assume a 300' turn radius, the yaw string is 5' ahead of the CG
> >and is 4" long. With these numbers the yaw string is off by 0.033
> >inch, much smaller than the diameter of the string itself!
> >
> >Tom
>
> Several posters pointed this out. In my defense, I've seen
> this sitting in the back seat of a glider with two yaw strings,
> and I know it is real. However, as someone else pointed out,
> the string is made even more sensitive by the canopy
> splitting the airflow a little, so miniscule angles can
> be detected.
>
> I'm going to look a little more at how large of an impact
> this really has. It may simply be dwarfed by the other effects,
> and so small as to be insignificant, as Tom seems to suggest.
>
> I'm still convinced of the second part though. I think there is
> some significant error caused on the yaw string at slow airspeeds
> with high roll rates when the string is above the
> center of gravity...er...center of pressure (thanks for the
> correction to this one too).
>
> When I do high rate dutch rolls, the glider seems to
> perfectly rotate around the axis, but the string is way
> all over the place. Explain THAT whydontcha? :PPP


OK, I'll bite again.

Dutch rolls are, by definition, uncoordinated. So I would expect the
yaw string to be behaving as you said. It is your perception that is
wrong.

Tom

[Judy Ruprecht]

At 20:30 29 January 2004, Mark James Boyd wrote:

>Perhaps (slipping turns for descent are) something
>I will look >more at. I was never taught this, I was
>never asked to
>demonstrate it during a dozen check rides, and
>I haven't ever seen a written reference to a slipping
>turn, so I perhaps haven't thought about it much.


See the US Private & Commercial Glider Practical Test
Standards, Area of Operation IV on landings, Task R,
Slips to Landings. See also the Soaring Flight Manual
and its new FAA-published successor (whose name escapes
me).

Judy

[Pete Zeugma]

At 21:00 29 January 2004, Marc Ramsey wrote:
>Eric Greenwell wrote:
>When I'm flying our Duo, a slipping turn from base
>to final is my
>standard procedure. I like to carry extra energy in
>the pattern (too
>much flying at Truckee), but the airbrakes aren't terribly
>effective, so
> I use a slipping turn to dissipate the excess energy,
>and hold it
>until I'm at an acceptable (shallow) approach angle.
>

Our Club Duo had iniffective airbrakes when we bought
it, and it also was standard practice to side-slip
on final (ie: not turning, going in a straight line).
We discovered that there was some packaging that prevented
the full travel of the airbrake. You should have your
glider checked out, as once we had our problem identified,
the airbrakes were quite good.

[Marc Ramsey]

Pete Zeugma wrote:
> We discovered that there was some packaging that prevented
> the full travel of the airbrake.

What do you mean by "some packaging"?

Marc

[Pete Zeugma]

At 04:30 30 January 2004, Marc Ramsey wrote:

>For those who don't know, gliders at Truckee (near
>Lake Tahoe, elevation
>5900 feet) normally use runway 19, which features a
>cliff-like drop off
>at the threshold.

How long is your runway? Club I fly fairly often at
in Scotland, Deeside GC (Aboyne), has quite wonderful
rotor/curlover/wind shear right down to the deck in
strong southerlies. It has two thin (5m and 7m ish)
parallel runways about 500m long (all figs approx)
situated between two ridgelines. There are two windsocks
either side of the runways, and in these strong southerlies
the socks are generally pointing in opposite directions.
I've had many a fast landing there in these conditions,
80-90knots is quite typical. It is common practice
to run on all the way to the end of the runway, to
keep it clear at all times. Of course, what you forget
to mention is that these are airspeeds, not ground
speeds. Landing a glider at 90knots ground speed is
very exciting!

[Pete Zeugma]

At 01:42 30 January 2004, Mark James Boyd wrote:
>In article ,
>Todd Pattist wrote:
>>
>>As a matter of interest, how did you handle the request
>>to
>>demonstrate a 'no airbrakes' landing where you needed
>>a
>>forward slip on both base and final? Did you bring
>>the
>>rudder fully through to the opposite side (inside of
>>the
>>turn) to intersperse a coordinated turn between your
>>forward
>>slips?
>
>Yep. Exactly. I've used slips in taildraggers extensively,
>during no-flap demonstrations, and on lots of checkrides.
>Always interspersed a coordinated turn. Kinda funny
>to write it here now that I think about it. Just something
>I haven't done before, I can't really explain why...
>


Ah, power planes, not gliders! Do you not think perhaps
we should be differentiating between rudder usage in
power plane, and a glider? I started flying originally
in gliders, so I dont have any bad habits from power
flying, and when I fly powered aircraft, i cant help
but fly coordinated all the time. I know that power
pilots who make the transition to gliders quite often
make fundemental errors due to the power mindset when
sat in a glider. What do you think?

[Pete Zeugma]

At 07:00 30 January 2004, Marc Ramsey wrote:
>Pete Zeugma wrote:
>> We discovered that there was some packaging that prevented
>> the full travel of the airbrake.
>
>What do you mean by 'some packaging'?
>

cant remeber the exact details, but it was either packing
or a spacer in the control rods at the wing root or
in the rods for the airbrake handle. Give val at our
club an email (london gliding club) and ask her to
get the workshop to give you further detail. After
this was removed from our duo it was much better and
we no longer have to do side slipping finals. Before
this I always thought that the blades did not appear
to be fully clear of the wing slot.

[F.L. Whiteley]

"Marc Ramsey" > wrote in message
...
> Eric Greenwell wrote:
> > If I understand this right:
> >
> > 1) you are coming down more steeply at 70 knots than you did at 60
> > knots, but it's still not steep enough;
> > 2) and that's because at Truckee, you want to come in _very_ steeply
> > over/near the threshold to avoid the downwash off the end;
> > 3) and at 80 knots, the descent would be steep enough, but you'd be
> > stopping wwaaayyy at the other end.
>
> You've got it. The spoilers don't provide a lot of drag, so it takes a
> bit of distance to burn off the extra 10 to 20 knots before making a
> normal touchdown. You can fly it on and hit the fine hydraulic brake,
> but then it will slam down on the nosewheel, making your partners
nervous...
>
> > I've only made a couple of landings at Truckee, so I'm trying to picture
> > the situation.
>
> For those who don't know, gliders at Truckee (near Lake Tahoe, elevation
> 5900 feet) normally use runway 19, which features a cliff-like drop off
> at the threshold. In the afternoons, the winds are often between 15 and
> 30 knots right down the runway, which sets up an interesting rotor-like
> condition just before the threshold, resulting in big sink and a
> significant wind gradient. We normally try to arrange things on windy
> days so the turn from base to final is over the numbers. But sometimes,
> circumstances prevent that, like a Skyhawk put-putting along on final,
> in which case you want lots of extra energy. Let me just say, if you
> ever find yourself below the threshold of 19, *push*, then pull at the
> last moment, and if you're lucky, you'll end up making a very low energy
> landing right on the numbers...
>
> Marc
>
You might mention there are three turnouts (or at least there were). My
first landing there, I radioed I'd take the first, but ended up taking the
third due to high altitude energy and poor wheel brake;^)

Furthermore, there's been more than one incident there. It is better to be
high and hot than the alternative. Rocks is hard.

Still, a lovely place to fly.

Frank Whiteley
Colorado

[F.L. Whiteley]

"Pete Zeugma" > wrote in message
...
> At 04:30 30 January 2004, Marc Ramsey wrote:
>
> >For those who don't know, gliders at Truckee (near
> >Lake Tahoe, elevation
> >5900 feet) normally use runway 19, which features a
> >cliff-like drop off
> >at the threshold.
>
> How long is your runway? Club I fly fairly often at
> in Scotland, Deeside GC (Aboyne), has quite wonderful
> rotor/curlover/wind shear right down to the deck in
> strong southerlies. It has two thin (5m and 7m ish)
> parallel runways about 500m long (all figs approx)
> situated between two ridgelines. There are two windsocks
> either side of the runways, and in these strong southerlies
> the socks are generally pointing in opposite directions.
> I've had many a fast landing there in these conditions,
> 80-90knots is quite typical. It is common practice
> to run on all the way to the end of the runway, to
> keep it clear at all times. Of course, what you forget
> to mention is that these are airspeeds, not ground
> speeds. Landing a glider at 90knots ground speed is
> very exciting!
>
>
When I flew at Aboyne, there was only one runway, a gravel pit at one end,
and stone fence at the other. Landing with rotor over the airfield was
_really_ interesting as the ASI didn't settle until about 5 feet off the
deck, swinging 30-70kts all the way downwind, base, and final. Radios were
important. The one sod with the broken radio flew a right hand circuit when
all others were flying left. He ( Open Diamant ) landed behind RAF L-13
(land long!) and in front of K-8(land short!). All three touched down at
the same moment and only just behind me. However, four wave flights in a
week and Gold altitude (4000ft cloud climb included). What a treat,
including the low-levels by the Buccaneers and Jaguars!

Frank Whiteley
Colorado

[Marc Ramsey]

F.L. Whiteley wrote:
> You might mention there are three turnouts (or at least there were). My
> first landing there, I radioed I'd take the first, but ended up taking the
> third due to high altitude energy and poor wheel brake;^)

Use of the first turnout by gliders is now actively discouraged, due to
the potential for taking out a towplane or glider in the tie-down area.
The second one has been expanded, which is quite helpful. The third
one is there, and I use it when necessary, but it is not possible to
clear the runway without getting out and pushing.

> Furthermore, there's been more than one incident there. It is better to be
> high and hot than the alternative. Rocks is hard.

Indeed.

> Still, a lovely place to fly.

That it is.

Marc

[Pete Zeugma]

At 14:48 30 January 2004, Todd Pattist wrote:
>Pete Zeugma wrote:
>
>> Before
>>this I always thought that the blades did not appear
>>to be fully clear of the wing slot.
>
>When blades are fully clear of the wing slot, you have
>to be
>certain that air loads will not flex them sufficiently
>to
>prevent them from re-entering the wing slot.

Thats probably why there is a placarded max rough air
speed!

Personally I dont touch them above this, unless I am
flying in known icing conditions where i crack them
open every now and then to make sure they have not
frozen (at a speed less than max rough air)

>I presume the
>modification you made (if that's what it was) was in
>accordance with factory recommendations.

The problem here was that there was something left
in by the manufacturer that prevented full travel.
The offending item (which I cant remember exactly)
was removed in consultation with Schempp-Hirth by our
workshop.

>I know some Grobs
>had this problem, and the fix was to limit airbrake
>throw
>specifically to prevent the blades from clearing their
>slots, thereby ensuring they could not lock the brakes
>open.

The problem here was about inefectual power in the
brakes as they did not open sufficeintly enough (i
think ours only open half their designed throw) hence
Marc saying he has to side-slip to get a good decent
rate with full brake open.

[Robert Ehrlich]

Todd Pattist wrote:
> ...
> A skidding turn, as you described is the opposite of a
> slipping turn. The student needs to be taught the
> difference. If he is doing a slipping turn, the yaw string
> will be out of the turn, if he's skidding it will be inside
> the turn.
> ...

This terminology is or was source of a lot of discussions and
misconceptions also in France where 2 equivalent terms exists,
"glissade" for slip, "dérapage" for skid. So the team responsible
for deciding the method and terminology that should be used
by all glider instructors decided, after some discussion, that only
one term should be used, "dérapage" was the choosed one.
During a turn, a slip should be called "dérapage intérieur"
(inside skid), a skid "dérapage extérieur" (outside skid).
In straight line we speak of "dérapage à gauche" (skid toward
left side) or "dérapage à droite" (skid toward right side).
This has the advantage of uniformity, any case where the string
is not in the middle is called by the same name and the further
qualification (inside, outside, left, right) always indicate the
side from which the relative wind is coming and the string is going
away.

[Pete Zeugma]

At 14:48 30 January 2004, Todd Pattist wrote:
>Pete Zeugma wrote:
>
>> Before
>>this I always thought that the blades did not appear
>>to be fully clear of the wing slot.
>
>When blades are fully clear of the wing slot, you have
>to be
>certain that air loads will not flex them sufficiently
>to
>prevent them from re-entering the wing slot.

Dug out a photo i took on decent in the discus I fly
so you can see the extent of full travel of a schempp-hirth
airbrake. The blades are clear of the slot, as designed
to be.

http://uk.f2.pg.photos.yahoo.com/ph/a_zeugmata/detail?.dir=/glidin
g&.dnm=Save0018.jpg

link should work, hopefully!


I presume the
>modification you made (if that's what it was) was in
>accordance with factory recommendations. I know some
>Grobs
>had this problem, and the fix was to limit airbrake
>throw
>specifically to prevent the blades from clearing their
>slots, thereby ensuring they could not lock the brakes
>open.
>Todd Pattist - 'WH' Ventus C
>(Remove DONTSPAMME from address to email reply.)
>

[Mark James Boyd]

Judy Ruprecht > wrote:
>
>See the US Private & Commercial Glider Practical Test
>Standards, Area of Operation IV on landings, Task R,
>Slips to Landings. See also the Soaring Flight Manual
>and its new FAA-published successor (whose name escapes
>me).
>
>Judy

Can't you just reduce the throttle and then desc...

Hey WAIT A MINUTE!?!?

....there it is, big as can be, "TURNING SLIPS TO A LANDING"!

right there in the PTS. I coulda read it 200 times and never
actually seen it. This ain't in that darned airplane PTS.
And it wasn't in my training, and it wasn't on any of my
checkrides.

But now I'll practice and teach it. This is one more tool
in my toolbox.

Thanks!

[Mark James Boyd]

Pete Zeugma > wrote:
>
>Ah, power planes, not gliders! Do you not think perhaps
>we should be differentiating between rudder usage in
>power plane, and a glider? I started flying originally
>in gliders, so I dont have any bad habits from power
>flying, and when I fly powered aircraft, i cant help
>but fly coordinated all the time. I know that power
>pilots who make the transition to gliders quite often
>make fundemental errors due to the power mindset when
>sat in a glider. What do you think?
>
Absolutely there are subtle differences that get overlooked.
Primacy is a factor here. Use of spoilers, wheel brake
not at the feet, no stall horn, can't use throttle to
descend, actually seeing adverse yaw, etc. All these
were probably much harder to learn (unlearn) than if
one started as a glider pilot first.

And the whole idea of energy management for rollout and
taxi was completely new, and the one wheel thing
and possibility of groundloop, etc. etc. etc.

Absolutely there are bad habits from transition.
And catching all of them is unlikely without additional
study by the student or new pilot. Instruction and
experience only go so far...study and discussion for me
seem to take it that extra step...

Cheers!

Mark

[David]

I often slip our club gliders down (1-34 and Grob III).

The way I look at it, being right on the glide slope is
just "more intense" than arriving a little high and slipping.
Especially when that end of the runway is really rowdy.

When I fly the two place and I'm landing, my arrival height is
occassionally of concern to the copilot. Then when I slip it down
they ask why didn't I just set up lower?

Oh well. To each his own.

David

Marc Ramsey > wrote in message >...
> Eric Greenwell wrote:
> > Refresh my memory, which doesn't seem to include this. Under what
> > circumstances and glider types would this be true? If I'm too high, I
> > adjust the pattern or open the airbrakes. I will slip on final for
> > crosswind compensation, but why would I want make slipping turns in the
> > pattern or elswhere?
>
> When I'm flying our Duo, a slipping turn from base to final is my
> standard procedure. I like to carry extra energy in the pattern (too
> much flying at Truckee), but the airbrakes aren't terribly effective, so
> I use a slipping turn to dissipate the excess energy, and hold it
> until I'm at an acceptable (shallow) approach angle. It also makes it a
> lot easier to see what's happening on the runway from the back seat.
>
> Marc

[Mark James Boyd]

Tom Seim > wrote:
>>
>> When I do high rate dutch rolls, the glider seems to
>> perfectly rotate around the axis, but the string is way
>> all over the place. Explain THAT whydontcha? :PPP
>
>OK, I'll bite again.
>
>Dutch rolls are, by definition, uncoordinated. So I would expect the
>yaw string to be behaving as you said. It is your perception that is
>wrong.
>
>Tom

Assume you make a glider which is a big cylinder with a huge
hollow tube going through the middle. I lay it on its
side and put a clear plexiglass on the top part for the pilot to
see out of, and give him a seat inside. Then I put three yawstrings
on it: one on the plexiglass "canopy", one in the middle of the
center tube, and one on the bottom.

I drop this "glider bomb" and it heads straight down (maybe there's
a drogue chute). A gyro rotates the cylinder on the way down.
Assuming no surface friction and ignoring gyroscopic
precession for now, all three yaw strings, from the
pilot seat, show different things. If the cylinder is
rolling right, the "glider bomb pilot" sees the yawstring on
the canopy and instinctively wants to add right rudder.
The string in the center of pressure shows straight, and the
bottom string would make the pilot want to add left rudder.

None of this has anything to do with gravity, adverse yaw,
or the cylinder slipping or skidding.

I contest that there is an error caused on the yaw string
depending on the roll rate, airspeed, and the distance of the
yaw string above the center of pressure, and this will
always tell the pilot to add more rudder in the direction
of roll (assuming the yawstring is above the center of
pressure), i.e. skid.

The size and importance of this error is another
matter entirely :PPP

[Jack]

On 1/29/04 9:00 AM, in article ,
"Owain Walters" > wrote:

> ... accusing every comp pilot of not owning
> up to incidents is just plain rubbish not to mention
> insulting.

Is this a claim that the statistics based on reports of accidents/incidents
involving competition pilots are never skewed by the actions these pilots
may take to avoid being included in official reporting?

No one accused "every comp pilot", though the implication that some would
like to remain unidentified in certain reporting is inescapable and, I
suspect, quite true.

More evil tricks by the "dirty old men" of EU soaring is it, Owain?


-------
Jack
-------

[ADP]

This is one of the biggest nonsense myths in the soaring community. It
amounts to an irrational prejudice towards power pilots who transition to
gliders.
There is considerably greater difference between, say, flying a Bonanza and
flying a Boeing 757 than flying any glider.
Gliders are incredibly easy to fly. Simply be aware of the differences.
It really amounts to attitude. (In both senses of the word.)
When flying a Bonanza, think Bonanza. When flying a King Air, think King
Air. When flying a B-757, think 757. When flying a F18, think F18. When
flying a glider, think glider. When flying a motor glider, think glider.
It can't be much simpler.

Allan

"Mark James Boyd" > wrote in message
news:401acc7c$1@darkstar...
> Pete Zeugma > wrote:
> >
> >Ah, power planes, not gliders! Do you not think perhaps
> >we should be differentiating between rudder usage in
> >power plane, and a glider? I started flying originally
> >in gliders, so I dont have any bad habits from power
> >flying, and when I fly powered aircraft, i cant help
> >but fly coordinated all the time. I know that power
> >pilots who make the transition to gliders quite often
> >make fundemental errors due to the power mindset when
> >sat in a glider. What do you think?
> >
> Absolutely there are subtle differences that get overlooked.
> Primacy is a factor here. Use of spoilers, wheel brake
> not at the feet, no stall horn, can't use throttle to
> descend, actually seeing adverse yaw, etc. All these
> were probably much harder to learn (unlearn) than if
> one started as a glider pilot first.
>
>....Snip....

[Richard Brisbourne]

Jack wrote:

> On 1/29/04 9:00 AM, in article ,
> "Owain Walters" > wrote:
>
>> ... accusing every comp pilot of not owning
>> up to incidents is just plain rubbish not to mention
>> insulting.
>
> Is this a claim that the statistics based on reports of
> accidents/incidents involving competition pilots are never skewed by the
> actions these pilots may take to avoid being included in official
> reporting?

How do they do this??

> No one accused "every comp pilot", though the implication that some would
> like to remain unidentified in certain reporting is inescapable and, I
> suspect, quite true.

I'm sure that lot's of people involved in accidents (comps or otherwise)
would like to remain unidentified to save embarrassment.

You made the potentially libellous insinuation that "some" unnamed pilots
actually subvert the system to achieve this. Or it would be except there
is not one substantiated fact behind the innuendo.

And you are then disingenuous enough to express surprise that a competition
pilot takes offence?

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

[Nyal Williams]

At 03:30 30 January 2004, Eric Greenwell wrote:
>Nyal Williams wrote:
>
>> Getting down fast! I was getting ready to enter the
>> wave window at Mt. Mitchell, NC, and the cold suddenly
>> told me my bladder was about to let go. Full divebrakes
>> in a slipping turn got me on the runway in time, but
>> I had to jump out and run to a ditch beside the runway;
>> at 75 yards, the FBO toilet was just too far away.
>
>What speed did you use? Could you have just used full
>spoilers and
>spiralled down at 90 knots or so (or faster, if air
>was smooth), and had
>the same descent rate?
>--
>-----
>change 'netto' to 'net' to email me directly
>
>Eric Greenwell
>Washington State
>USA
>
80kts in an ASK-21, but who knows the accuracy of
an ASI in a slip? I was turning to the left with full
right rudder and the nose as far down as I dared; the
noise was tremendous.

[Vaughn]

"ADP" > wrote in message
...
> This is one of the biggest nonsense myths in the soaring community. It
> amounts to an irrational prejudice towards power pilots who transition to
> gliders.

Gosh, don't I know it! After 2+ years of CFIGing, often teaching very
accomplished power pilots transitioning to gliders, I have turned the
tables. I am learning to fly the old fashioned way, bouncing around the
pattern and the practice area in a tired but trusty Cessna. My instructors,
who know nothing of gliders and have never before dealt with any transition
student, see many of my glider "skills" as a series of curious "bad habits"
to be corrected. (They were particularly horrified by my brisk, power-off,
stall recoveries) As they have no frame of reference with which to deal
with me, I just tell them to think of me as a primary student and start from
the beginning.

Vaughn

[Bill Daniels]

"Vaughn" > wrote in message
...
>
> "ADP" > wrote in message
> ...
> > This is one of the biggest nonsense myths in the soaring community. It
> > amounts to an irrational prejudice towards power pilots who transition
to
> > gliders.
>
> Gosh, don't I know it! After 2+ years of CFIGing, often teaching
very
> accomplished power pilots transitioning to gliders, I have turned the
> tables. I am learning to fly the old fashioned way, bouncing around the
> pattern and the practice area in a tired but trusty Cessna. My
instructors,
> who know nothing of gliders and have never before dealt with any
transition
> student, see many of my glider "skills" as a series of curious "bad
habits"
> to be corrected. (They were particularly horrified by my brisk,
power-off,
> stall recoveries) As they have no frame of reference with which to deal
> with me, I just tell them to think of me as a primary student and start
from
> the beginning.
>
> Vaughn
>

You'll be so good at landings they'll probably never get around to teaching
go-arounds.

One day, an airplane will taxi on to your runway while you are on short
final. You'll probably revert to glider mode and land the Cessna on the
grass parallel to the runway. Then, you'll have to think up a really good
story to explain that.

Bill Daniels

[Vaughn]

"Bill Daniels" > wrote in message
...
>
> >
>
> You'll be so good at landings they'll probably never get around to
teaching
> go-arounds.

Yep, landings are not much of an issue.
>
> One day, an airplane will taxi on to your runway while you are on short
> final. You'll probably revert to glider mode and land the Cessna on the
> grass parallel to the runway. Then, you'll have to think up a really good
> story to explain that.

I had a talk with the chief instructor about just that the other day.
I explained to her that "go arounds" are not part of the glider experience.
We decided to make that a priority.

Vaughn


>
> Bill Daniels
>

[Bill Daniels]

"Vaughn" > wrote in message
...
>
> "Bill Daniels" > wrote in message
> ...
> >
> > >
> >
> > You'll be so good at landings they'll probably never get around to
> teaching go-arounds.
>
> Yep, landings are not much of an issue.
> >
> > One day, an airplane will taxi on to your runway while you are on short
> > final. You'll probably revert to glider mode and land the Cessna on the
> > grass parallel to the runway. Then you'll have to think up a really
good
> > story to explain that.
>
> I had a talk with the chief instructor about just that the other day.
> I explained to her that "go arounds" are not part of the glider
experience.
> We decided to make that a priority.
>
> Vaughn
>
>
Power pilots think:
Altitude must be exact. Speed is good and more speed is better.

Glider pilots think:
Speed must be exact. Altitude is good and more altitude is better.

Bill Daniels

[Tom Seim]

> Assume you make a glider which is a big cylinder with a huge
> hollow tube going through the middle. I lay it on its
> side and put a clear plexiglass on the top part for the pilot to
> see out of, and give him a seat inside. Then I put three yawstrings
> on it: one on the plexiglass "canopy", one in the middle of the
> center tube, and one on the bottom.
>
> I drop this "glider bomb" and it heads straight down (maybe there's
> a drogue chute). A gyro rotates the cylinder on the way down.
> Assuming no surface friction and ignoring gyroscopic
> precession for now, all three yaw strings, from the
> pilot seat, show different things. If the cylinder is
> rolling right, the "glider bomb pilot" sees the yawstring on
> the canopy and instinctively wants to add right rudder.
> The string in the center of pressure shows straight, and the
> bottom string would make the pilot want to add left rudder.
>
> None of this has anything to do with gravity, adverse yaw,
> or the cylinder slipping or skidding.
>
> I contest that there is an error caused on the yaw string
> depending on the roll rate, airspeed, and the distance of the
> yaw string above the center of pressure, and this will
> always tell the pilot to add more rudder in the direction
> of roll (assuming the yawstring is above the center of
> pressure), i.e. skid.
>
> The size and importance of this error is another
> matter entirely :PPP

Well, the size and importance DOES matter because you are making such
a point of it. I think that I adequately proved that your last point
was, shall we say, pointless. The offset of the yaw string to the
center of the roll axis is much less than its displacement from the
CG, making your "errors" proportionally less. I think you ought to
pursue a more reasonable hypothesis; like TWA 800 was downed by a
stray Navy missle.

Tom

[Caracole]

Aerodynamics 101.
Parasitic drag as a topic.
If you truly want down fast, a slip is not the most effective tool.
AS-K 21, full spoilers deployed and 90 knots airspeed will descend at
4000 fpm.
You are below both maneuvering and rough air speed.

Slipping turns are a useful tool. They should be understood.
So should parasitic drag. Try it at altitude. Carry a GNSS recorder
(GPS logger for us unruly Americans). Analyze the data later about
how much sink rate you manufacture.

Don't believe it? Come fly with us. Or watch from the ground if you
wish. It works for everything from 1-26s up to Nimbus 3s and all the
standard class stuff inbetween. There are no too-little or
ineffective spoilers, just mild differences in sink rates.
Now, the AS-W 12, that's a different story.....until they fitted a
fitful drogue chute. Or the Carbon Dragon.

Slipping on approach to landing (or anytime), pitch attitude is your
friend for airspeed control.

Cindy B
www.caracolesoaring.com


> >
> >What speed did you use? Could you have just used full
> >spoilers and
> >spiralled down at 90 knots or so (or faster, if air
> >was smooth), and had
> >the same descent rate?
> >--
> >-----
> >change 'netto' to 'net' to email me directly
> >
> >Eric Greenwell
> >Washington State
> >USA
> >
> 80kts in an ASK-21, but who knows the accuracy of
> an ASI in a slip? I was turning to the left with full
> right rudder and the nose as far down as I dared; the
> noise was tremendous.

[Mark Grubb]

> Parasitic drag as a topic.
> If you truly want down fast, a slip is not the most effective tool.
> AS-K 21, full spoilers deployed and 90 knots airspeed will descend at
> 4000 fpm. You are below both maneuvering and rough air speed.
>
It works for everything from 1-26s up to Nimbus 3s and all the
> standard class stuff inbetween. Now, the AS-W 12, that's a different story.....until they fitted a fitful drogue chute. Or the Carbon Dragon.
>
> Slipping on approach to landing (or anytime), pitch attitude is your
> friend for airspeed control.


A second enthusiastic for parasitic drag - and slipping turns.
Downwind abeam the touchdown spot at 7000 ft agl, full brakes, 90 kts
and you have to be careful to keep the pattern snug to avoid
undershooot (or changing configurations). Yields about a 3:1 L/D or a
glide similar to the space shuttle. The angles look pretty strange in
the steep turns but one adapts.

Slipping turns are the ticket in non-spoilered beasts (AS-W12 or
Pawnee). Both can be flown in near-90 degree banks with full top
rudder, pulling lots of G and plummeting like a stone. The "look'
from inside and outside the cockpit is a bit strange but one adapts.
One can blow the side windows out of Super Cubs and probably Pawnees
doing this in sub-zero Colorado WX at 14,000 ft in dawn wave sorties
(we will not discuss howe I know this). Hard on airframe of aircraft
and pilot alike. Parasitic drag descents are much better.

High-G, high bank angle slipping turns are very useful for burning
airspeed (energy) in the pattern as well but are very tiring if done
repeatedly. The turn allows one to load up the wing with high G's
making the slip markedly more effective. Similar to military overhead
break approaches with the slip thrown in for good measure.

Practice at altitude and be very careful in the "know-it-all" phase of
the learning curve. The "pitch" angles in these maneuvers will bear
no resemblence to a conventional approach and if they do (when you
revert to the known and familiar angles and habits), you have a big
problem. :-)

[Pete Zeugma]

At 02:54 31 January 2004, Adp wrote:

Except it isnt is it! Gliders require you to understand
fully things like adverse yaw, energy management, not
being able to power-on and go around. When you land
a glider, you only get one shot at it, what ever the
conditions happen to be thrown at you. How much time
do you spend thinking of where you are going to land
out when you are at 1500 feet above the ground in
your power plane? It has nothing what ever to do with
irrational prejudice.

>This is one of the biggest nonsense myths in the soaring
>community. It
>amounts to an irrational prejudice towards power pilots
>who transition to
>gliders.
>There is considerably greater difference between, say,
>flying a Bonanza and
>flying a Boeing 757 than flying any glider.
>Gliders are incredibly easy to fly. Simply be aware
>of the differences.
>It really amounts to attitude. (In both senses of
>the word.)
>When flying a Bonanza, think Bonanza. When flying
>a King Air, think King
>Air. When flying a B-757, think 757. When flying
>a F18, think F18. When
>flying a glider, think glider. When flying a motor
>glider, think glider.
>It can't be much simpler.
>
>Allan
>
>'Mark James Boyd' wrote in message
>news:401acc7c$1@darkstar...
>> Pete Zeugma wrote:
>> >
>> >Ah, power planes, not gliders! Do you not think perhaps
>> >we should be differentiating between rudder usage
>>>in
>> >power plane, and a glider? I started flying originally
>> >in gliders, so I dont have any bad habits from power
>> >flying, and when I fly powered aircraft, i cant help
>> >but fly coordinated all the time. I know that power
>> >pilots who make the transition to gliders quite often
>> >make fundemental errors due to the power mindset when
>> >sat in a glider. What do you think?
>> >
>> Absolutely there are subtle differences that get overlooked.
>> Primacy is a factor here. Use of spoilers, wheel
>>brake
>> not at the feet, no stall horn, can't use throttle
>>to
>> descend, actually seeing adverse yaw, etc. All these
>> were probably much harder to learn (unlearn) than
>>if
>> one started as a glider pilot first.
>>
>>....Snip....
>
>
>

[Robert Ehrlich]

Todd Pattist wrote:
>
> Robert Ehrlich > wrote:
>
> >This terminology is or was source of a lot of discussions and
> >misconceptions also in France where 2 equivalent terms exists,
> >"glissade" for slip, "dérapage" for skid. So the team responsible
> >for deciding the method and terminology that should be used
> >by all glider instructors decided, after some discussion, that only
> >one term should be used, "dérapage" was the choosed one.
> >During a turn, a slip should be called "dérapage intérieur"
> >(inside skid), a skid "dérapage extérieur" (outside skid).
> >In straight line we speak of "dérapage à gauche" (skid toward
> >left side) or "dérapage à droite" (skid toward right side).
> >This has the advantage of uniformity, any case where the string
> >is not in the middle is called by the same name and the further
> >qualification (inside, outside, left, right) always indicate the
> >side from which the relative wind is coming and the string is going
> >away.
>
> Thanks for posting this. It is fascinating to see something
> familiar from a totally different perspective.
>
> I admit to not really understanding the advantage of using
> your integrated terminology. A "skid" is almost never
> (ever?) an appropriate maneuver, so giving it a completely
> different name from a "slip" allows immediate recognition
> that we're talking about something that's inappropriate to
> do. I would be more concerned that a student would be
> confused between when it's OK to "dérapage" and when it's
> not

One of the ideas behind this integrated terminology is that
neither skid nor slip is an appropriate maneuver in today's
gliders having powerful airbrakes, morever on some of them
the POH prohibits skids and/or slips.

[Chris OCallaghan]

Pete,

Unfortunately, you are wrong on this one. You can, in fact, use rudder
to change direction, much to the aerodynamicist's chagrin. It is very
inefficient, but by holding wings level and ruddering (a skid) you
create an inward pointing force caused by the fuselage (along with a
rearward componenet -- drag). It is this force that allows you to slip
by counteracting the turning force of the wing with an opposite force
from the fuselage. (Again, much to the chagrin of the aerodynamicist.)

You need rethink your model. Remember, things only go straight if in
equilibrium. An aircraft flying sideways through the air wings level
won't be in equilibrium, therefore either speed or direction must
change.

Pete Zeugma > wrote in message >...
> >If you have zero bank, and apply rudder you will begin
> >a
> >flat turn.
>
> Wrong! UTTERLY WRONG!!!! A rudder yaws the airframe,
> it does not 'turn' or 'steer' the aircraft.
>
> Your whole problem seems to be in compairing a glider
> with a boat. They may both have rudders, but they both
> do totally different things.
>
> Next time you fly in your glider, line yourself up
> with a straight feature. Apply some rudder to yaw the
> glider, but keep the wings level. All you will do is
> continue in a straight line, sideways on. (commonly
> known as a side slip)
>
> However, the rudder does has a secondary control effect,
> which introduces a roll moment due to differences in
> lift between the wings. (which is why the first thing
> you do is apply full opposite rudder to counteract
> the rotation in a spin)
>
> It is the ailerons that instigate a turn, the rudder
> is used in a coordinated manner to 1) check the adverse
> yaw (secondary effect of ailerons), and 2) to align
> the airframe correctly into the airflow.
>
> Please stop using language which inforces a belief
> that the rudder is used to turn a glider in flight.
> Your very action in doing so may well end up enforcing
> that belief into a low airtime pilot reading these
> posts and KILLING THEM!

[Pete Zeugma]

At 14:24 02 February 2004, Chris Ocallaghan wrote:
>Pete,
>

Every now and then, I like to keep my hand in with
sidesliping on finals. One airfield I fly at has a
real narrow tarmac strip, like 5 meters. When I am
in a nice balanced, wings level sideslip, how come
I maintain a striaght path all the way down to my reference
point where I kick it off to round out?



>Unfortunately, you are wrong on this one. You can,
>in fact, use >rudder to change direction, much to the
>aerodynamicist's
>chagrin.

especially if you have and engine up front.

>It is very
>inefficient, but by holding wings level and ruddering
>(a skid)

side slip actually

> you
>create an inward pointing force caused by the fuselage
>(along with a
>rearward componenet -- drag). It is this force that
>allows you to slip
>by counteracting the turning force of the wing with
>an opposite force
>from the fuselage. (Again, much to the chagrin of the
>aerodynamicist.)

Please, expand on this 'force', from an aerodynamics
point of veiw. I'd love to know what law of physics
you have created this thrust vector from.

>
>You need rethink your model. Remember, things only
>go straight if in
>equilibrium.

actually, all objects in motion exhibit a natual tendancy
to go in a straight line, unless an external force
is applied to upset that equilibrium. One of Mr Newtons
laws I think!

>An aircraft flying sideways through the air wings level
>won't be in equilibrium, therefore either speed or
>direction
>must change.

I did loads of sideways flying this weekend soaring
on our hill!
Wings level, straight line constant 60knots, crabbing
along at 40 odd degrees.

in order to keep the wings level while applying yaw,
you have to apply a roll moment to counter the secondary
roll moment caused by the yaw. This puts the aircraft
back into equilibrium by force. If you release the
aileron, the secondary roll moment caused by the yaw
will eventually bank the aircraft into a turn. Stick
an engine into the equation, and it all changes.

[Fredrik Thörnell]

Pete Zeugma > skrev den 2 Feb 2004
15:16:31 GMT:
>> you
>> create an inward pointing force caused by the fuselage
>> (along with a
>> rearward componenet -- drag). It is this force that
>> allows you to slip
>> by counteracting the turning force of the wing with
>> an opposite force
>> from the fuselage. (Again, much to the chagrin of the
>> aerodynamicist.)
>
> Please, expand on this 'force', from an aerodynamics
> point of veiw. I'd love to know what law of physics
> you have created this thrust vector from.

The same laws which keep you in the air, in fact. When the fuselage is
going through the air at a beta angle (sideslip), it generates lateral
lift. That's what makes knife edge flight possible.

Chances are this effect is not very noticeable in a glass bird with the
streamlined fuselage, meaning that the bank angle required to keep the
glider travelling in a straight path might be marginal and not really
noticeable.

Cheers,
Fred

[Ian Johnston]

On Mon, 2 Feb 2004 15:16:31 UTC, Pete Zeugma
> wrote:


: > you
: >create an inward pointing force caused by the fuselage
: >(along with a
: >rearward componenet -- drag).

: Please, expand on this 'force', from an aerodynamics
: point of veiw. I'd love to know what law of physics
: you have created this thrust vector from.

May I jump in? He's right, and it's dead easy, really. If the fuselage
is yawed to the right, the airflow comes from the left. Which tends to
push the big front big - the cockpit - to the right. And I'm an
aerodynamicist, amongst other things.

: in order to keep the wings level while applying yaw,
: you have to apply a roll moment to counter the secondary
: roll moment caused by the yaw. This puts the aircraft
: back into equilibrium by force. If you release the
: aileron, the secondary roll moment caused by the yaw
: will eventually bank the aircraft into a turn.

Whoops. I think you are confusing the effects of yawing and the
effects of being yawed. As you yaw, one wing moves faster than the
other and produces more lift, tending to roll the glider unless
prevented. But once you are yawed, this effect ends. There may be
other effects requiring use of aileron while yawed - sweep forward in
the wings, for example.

: Stick
: an engine into the equation, and it all changes.

Not very much changes, actually.

Ian

[George William Peter Reinhart]

Todd,
Ever try to slip an Ercoupe?
No slip needed for crosswinds either.
And.. There's nothing quite like flying one over the city on a fine spring
evening with the window down.
Cheers!

Todd Pattist > wrote in article
>...
> Robert Ehrlich > wrote:
>
> snip
> I don't see how a POH could entirely prohibit slips - as you
> could never land in a crosswind. :-)
>
> Todd Pattist - "WH" Ventus C
> (Remove DONTSPAMME from address to email reply.)
>

[ADP]

It appears that you have missed my point - but managed to illustrate it very
nicely!
I rest my case.

Allan

"Pete Zeugma" > wrote in message
...
> At 02:54 31 January 2004, Adp wrote:
>
> Except it isnt is it! Gliders require you to understand
> fully things like adverse yaw, energy management, not
> being able to power-on and go around. When you land
> a glider, you only get one shot at it, what ever the
> conditions happen to be thrown at you. How much time
> do you spend thinking of where you are going to land
> out when you are at 1500 feet above the ground in
> your power plane? It has nothing what ever to do with
> irrational prejudice.
>
> >This is one of the biggest nonsense myths in the soaring
> >community. It
> >amounts to an irrational prejudice towards power pilots
> >who transition to
> >gliders.
> >There is considerably greater difference between, say,
> >flying a Bonanza and
> >flying a Boeing 757 than flying any glider.
> >Gliders are incredibly easy to fly. Simply be aware
> >of the differences.
> >It really amounts to attitude. (In both senses of
> >the word.)
> >When flying a Bonanza, think Bonanza. When flying
> >a King Air, think King
> >Air. When flying a B-757, think 757. When flying
> >a F18, think F18. When
> >flying a glider, think glider. When flying a motor
> >glider, think glider.
> >It can't be much simpler.
> >
> >Allan
> >
> >'Mark James Boyd' wrote in message
> >news:401acc7c$1@darkstar...
> >> Pete Zeugma wrote:
> >> >
> >> >Ah, power planes, not gliders! Do you not think perhaps
> >> >we should be differentiating between rudder usage
> >>>in
> >> >power plane, and a glider? I started flying originally
> >> >in gliders, so I dont have any bad habits from power
> >> >flying, and when I fly powered aircraft, i cant help
> >> >but fly coordinated all the time. I know that power
> >> >pilots who make the transition to gliders quite often
> >> >make fundemental errors due to the power mindset when
> >> >sat in a glider. What do you think?
> >> >
> >> Absolutely there are subtle differences that get overlooked.
> >> Primacy is a factor here. Use of spoilers, wheel
> >>brake
> >> not at the feet, no stall horn, can't use throttle
> >>to
> >> descend, actually seeing adverse yaw, etc. All these
> >> were probably much harder to learn (unlearn) than
> >>if
> >> one started as a glider pilot first.
> >>
> >>....Snip....
> >
> >
> >
>
>

[Robert Ehrlich]

Todd Pattist wrote:
>
> Robert Ehrlich > wrote:
>
> >One of the ideas behind this integrated terminology is that
> >neither skid nor slip is an appropriate maneuver in today's
> >gliders having powerful airbrakes, morever on some of them
> >the POH prohibits skids and/or slips.
>
> I don't see how a POH could entirely prohibit slips - as you
> could never land in a crosswind. :-)
>

Well, the method taught at present time for crosswind landing
in France is to correct for the crosswind by having the nose
pointed into the wind by just the amount necessary to compensate
for this crosswind so that the flight path remain aligned with
the runway, while the wings are kept level and the string in the
middle, up to just before touchdown, where rudder is used to
re-align the axis of the glider with the axis of the runway.
At this time, stricly speaking, you are effectiveley slipping,
even if the POH prohibits it. For such a short time it does not
really matter.

[Stefan]

Todd Pattist wrote:

> I don't see how a POH could entirely prohibit slips - as you
> could never land in a crosswind. :-)

I don't see how slipping and crosswind correction could be related, as
the only correct way cope with crosswind is crabbing. Oh wait, I just
started another famous winter thread...

Stefan

[Mark James Boyd]

In article >,
Tom Seim > wrote:
>>
>> The size and importance of this error is another
>> matter entirely :PPP
>
>Well, the size and importance DOES matter because you are making such
>a point of it. I think that I adequately proved that your last point
>was, shall we say, pointless. The offset of the yaw string to the
>center of the roll axis is much less than its displacement from the
>CG, making your "errors" proportionally less.

First of all, I believe the size and importance is worthy of
discussion, I just usually separate noticing an error and
figuring out how important it is into two parts.

I was ALSO hoping someone else would do the
math so I didn't have to :PPPP

In another vein, the forward of CG vs. above CG is totally different,
because the "above CG" is about roll rate (which can be
significant) while the "forward of CG" isn't about yaw rate (which
would be hard to sustain at a high rate for several seconds
without running out of rudder.) So I'm talking about
two completely different possible sources of error.

In the end, however, after SWAG calculations, it looks like at
very high roll rates (90 deg in 4 sec), and yaw string
displaced 2 feet+ from the CG/center of pressure, at very
low speeds (30 knots), the trig indicates 1-2 degrees
of error. Bigger than the forward yaw string error, but
still dwarfed by the asymmetric AOA's caused by
long wings, high bank angles, and aileron AOA.

>I think you ought to
>pursue a more reasonable hypothesis; like TWA 800 was downed by a
>stray Navy missle.
>
>Tom

Well, a negative result is sometimes useful for someone.
And besides, it's not like I'm writing about
gliding on MARS or something, for goodness sake :PPP

[George William Peter Reinhart]

I know there were a few with rudders, but I don't think I've ever seen one.
I did see the Mooney re-hash a few years back. Ugly.
I loved flying it but my wife wouldn't even consider buying one because it
_didn't_ have rudder pedals.
Cheers!

Todd Pattist > wrote in article
>...
> "George William Peter Reinhart" > wrote:
>
> >Todd,
> >Ever try to slip an Ercoupe?
>
> With or without the uncoupled rudders mod :-)
>
> (It has its wheels behind the CG - my glider doesn't)
>
> Todd Pattist - "WH" Ventus C
> (Remove DONTSPAMME from address to email reply.)
>

[Robert Ehrlich]

Stefan wrote:
>
> Todd Pattist wrote:
>
> > I don't see how a POH could entirely prohibit slips - as you
> > could never land in a crosswind. :-)
>
> I don't see how slipping and crosswind correction could be related, as
> the only correct way cope with crosswind is Oh wait, I just
> started another famous winter thread...
>
> Stefan

But crabbing ends by uncrabbing, and this is slipping.

[Andy Durbin]

Robert Ehrlich > wrote in message >...
>
> One of the ideas behind this integrated terminology is that
> neither skid nor slip is an appropriate maneuver in today's
> gliders having powerful airbrakes, morever on some of them
> the POH prohibits skids and/or slips.

Can you give some examples of glider POH that probibit slips or skids.
I don't think anything I have flown has such a probibition.

I make a point of practicing at least one full airbrake, full rudder,
slipping approach at the start of every season. I get plenty of
opportunity to practice shallow approach angles from contest finishes.

And yes, I have needed to use the technique for a field landing in the
past. I was very glad I was familiar with flying a stable approach
with zero indicated airspeed (ASW 19 with pot pitot).


Andy

[Chris OCallaghan]

I don't have the time right now, but anyone care to hazard a few lines
of discussion on the increase in induced drag during a slip and
compare it with the high speed, high drag descent Cindy described?

It might start something like this:

During a slip, the effective span and aspect ratio of the wing and
elevator decrease substantially. Additionally, total lift required to
maintain a constant airspeed is much increased (without any increase
in g loading) due to the tilting of the lift vector. Therefore, a much
higher angle of attack is required to maintain a given (low) airspeed,
one which might be employed to accomplish a steep approach into a very
short field.

Different circumstances, of course. But it would be interesting to see
someone develop this. Frankly, I don't think I've ever seen an
analysis of a slip that properly weighs the effects of induced drag.

Just out of interest, Cindy, according your data, which creates the
steepest approach (min L/D) (as opposed to greatest sink rate)? Yes,
we're likely to get some discussion on TV airbrakes, but we'll just
have to suffer through that.

[Bill Daniels]

Cindy, perhaps you would address that bit of nonsense in the Private Pilot
Practical Test Standards about no-spoiler accuracy landings. (I've always
thought it was there in order to make the PTS 2-33 specific.)

Bill Daniels

"Caracole" > wrote in message
om...
> Aerodynamics 101.
> Parasitic drag as a topic.
> If you truly want down fast, a slip is not the most effective tool.
> AS-K 21, full spoilers deployed and 90 knots airspeed will descend at
> 4000 fpm.
> You are below both maneuvering and rough air speed.
>
> Slipping turns are a useful tool. They should be understood.
> So should parasitic drag. Try it at altitude. Carry a GNSS recorder
> (GPS logger for us unruly Americans). Analyze the data later about
> how much sink rate you manufacture.
>
> Don't believe it? Come fly with us. Or watch from the ground if you
> wish. It works for everything from 1-26s up to Nimbus 3s and all the
> standard class stuff inbetween. There are no too-little or
> ineffective spoilers, just mild differences in sink rates.
> Now, the AS-W 12, that's a different story.....until they fitted a
> fitful drogue chute. Or the Carbon Dragon.
>
> Slipping on approach to landing (or anytime), pitch attitude is your
> friend for airspeed control.
>
> Cindy B
> www.caracolesoaring.com
>
>
> > >
> > >What speed did you use? Could you have just used full
> > >spoilers and
> > >spiralled down at 90 knots or so (or faster, if air
> > >was smooth), and had
> > >the same descent rate?
> > >--
> > >-----
> > >change 'netto' to 'net' to email me directly
> > >
> > >Eric Greenwell
> > >Washington State
> > >USA
> > >
> > 80kts in an ASK-21, but who knows the accuracy of
> > an ASI in a slip? I was turning to the left with full
> > right rudder and the nose as far down as I dared; the
> > noise was tremendous.

[Pete Zeugma]

At 10:00 04 February 2004, Adp wrote:
>It appears that you have missed my point - but managed
>to illustrate it very
>nicely!
>I rest my case.
>
>Allan
>

Hardly, been busy and away from the office. Plus pilotnet
has been down the last couple days. This just fills
in my time between while waiting for software builds
to complie. Mind you, your theories on flight dynamics
have caused intence amusement here. several posts are
currently on our main notice board collecting comments
from within the flight dynamics group!

[Mark James Boyd]

In article >,
Chris OCallaghan > wrote:
>I don't have the time right now, but anyone care to hazard a few lines
>of discussion on the increase in induced drag during a slip and
>compare it with the high speed, high drag descent Cindy described?
>
>It might start something like this:
>
>During a slip, the effective span and aspect ratio of the wing and
>elevator decrease substantially. Additionally, total lift required to
>maintain a constant airspeed is much increased (without any increase
>in g loading) due to the tilting of the lift vector. Therefore, a much
>higher angle of attack is required to maintain a given (low) airspeed,
>one which might be employed to accomplish a steep approach into a very
>short field.
>
>Different circumstances, of course. But it would be interesting to see
>someone develop this. Frankly, I don't think I've ever seen an
>analysis of a slip that properly weighs the effects of induced drag.
>
>Just out of interest, Cindy, according your data, which creates the
>steepest approach (min L/D) (as opposed to greatest sink rate)? Yes,
>we're likely to get some discussion on TV airbrakes, but we'll just
>have to suffer through that.

Well, the 2-33 manual says in a full slip that something like
45 to 50mph gives the most efficient slip.

I wonder if this means most amount of altitude loss
for distance travelled, or highest sink rate per
minute. I'd believe the first, but have trouble
believing the second.

And if it really is just best altitude loss for
distance of glide, then wind effects could change
the correct speed significantly...

[ADP]

Well, not only have you missed my point but you have confused me with
someone else.
To what theories of flight dynamics are you referring?
I don't have any theories on flight dynamics.
It also seems that your "group" is starved for items of amusement.
My theory on spinning is simple - don't get into one and you won't have to
recover!
My point, to which you took exception, had to do with the thought that power
pilots
are deemed to be inferior to ab initio glider pilots when learning to fly
gliders and that
power training is of little use when transitioning to gliders.
Having run into this perception multiple times, I pointed out that it is
nonsense.
The few differences that define glider flying are small when compared to the
differences
between powered aircraft.
Aerodynamics are aerodynamics. They apply to gliders, powered aircraft,
buzz bombs and flat plates.
You just have to be aware of the differences.

Allan


"Pete Zeugma" > wrote in message
...
> At 10:00 04 February 2004, Adp wrote:
> >It appears that you have missed my point - but managed
> >to illustrate it very
> >nicely!
> >I rest my case.
> >
> >Allan
> >
>
> Hardly, been busy and away from the office. Plus pilotnet
> has been down the last couple days. This just fills
> in my time between while waiting for software builds
> to complie. Mind you, your theories on flight dynamics
> have caused intence amusement here. several posts are
> currently on our main notice board collecting comments
> from within the flight dynamics group!
>
>

[Chris OCallaghan]

Pete,

It sounds like you have the axioms down pat, but are having a little
trouble with recognizing that the controls allow pilots to do all
sorts of things that the designer didn't intend. Of course you can
(not should) rudder a glider wings level around a turn. Just like the
rudder on a boat. This is commonly called a skid.

Frankly, I can't tell whether you are trolling or exhibiting genuine
ignorance. Let's hope it is the latter -- there's a cure for what you
don't know. At any rate, I'd stop arguing on this point until you've
had a discussion with a CFI, power or sailplane. Your heart appears to
be in the right place. (It's the wings that turn an aiplane. The
rudder is to counteract adverse yaw.) But you're failing to recognize
how a pilot can abuse the controls to a variety of ends. Slips are
one. Skidding turns another. Stalls still another. Some are useful.
Some less so. Skidding turns fall into the second category.

[Andy Durbin]

"Bill Daniels" > wrote in message >...
> Cindy, perhaps you would address that bit of nonsense in the Private Pilot
> Practical Test Standards about no-spoiler accuracy landings. (I've always
> thought it was there in order to make the PTS 2-33 specific.)
>
> Bill Daniels
>

When I was more active instructing I used to give students simulated
airbrakes jammed full open and jammed closed (separate flights). I
expected them to demonstrate that they could complete the circuit and
landing. I released the malfunction on short final, or sooner if they
couldn't cope.

Isn't the PTS requirement to demonstate simulated jammed closed?


Andy

[Eric Coleson]

"Bill Daniels" > wrote in message >...
> Cindy, perhaps you would address that bit of nonsense in the Private Pilot
> Practical Test Standards about no-spoiler accuracy landings. (I've always
> thought it was there in order to make the PTS 2-33 specific.)
>
> Bill Daniels

That would have to be "Schweizer specific" at the very least wouldn't
it, Bill? I was once forced by reason of a 2-32's spoilers being
frozen solidly closed to slip from 28,000 ft MSL near Pikes Peak to
land without them at old BFGP. (Not much of an accuracy landing
challenge there, of course, but my feet were pretty cold and I was
grateful for the rate of descent). FAA's aircraft registry lists at
least 1335 Schweizers having spoilers or divebrakes of similar
configuration, of which 2-33's of all varieties number only 375.

I'm embarassed to admit that I've also inadvertently jettisoned the
drag chute on a Salto on the base leg to a much smaller landing site
where I really could have used it, and an agressive slipping turn to
final made the difference between an otherwise certain overshoot and a
merely memorable pattern. Modern sailplanes don't ordinarily present
as much flat plate to the airstream and plummet from altitude quite as
dramatically as the Schweizers, but they all descend a bit more
steeply flying sideways and there are any number of reasons that extra
little increment of drag may be useful.

As training exercise, I'd argue that no-spoiler slipping patterns to
an accuracy landing can be uses to develop advanced levels of both
judgement and command of the aircraft in maneuvering with attention
focused largely outside the cockpit. In that sense, is demonstrating
proficiency in it any less "practical" a test item than some of the
ground reference maneuvers found in the airplane PTS?

[Bill Daniels]

"Eric Coleson" > wrote in message
om...
> "Bill Daniels" > wrote in message
>...
> > Cindy, perhaps you would address that bit of nonsense in the Private
Pilot
> > Practical Test Standards about no-spoiler accuracy landings. (I've
always
> > thought it was there in order to make the PTS 2-33 specific.)
> >
> > Bill Daniels
>
> That would have to be "Schweizer specific" at the very least wouldn't
> it, Bill? I was once forced by reason of a 2-32's spoilers being
> frozen solidly closed to slip from 28,000 ft MSL near Pikes Peak to
> land without them at old BFGP. (Not much of an accuracy landing
> challenge there, of course, but my feet were pretty cold and I was
> grateful for the rate of descent). FAA's aircraft registry lists at
> least 1335 Schweizers having spoilers or divebrakes of similar
> configuration, of which 2-33's of all varieties number only 375.
>
> I'm embarassed to admit that I've also inadvertently jettisoned the
> drag chute on a Salto on the base leg to a much smaller landing site
> where I really could have used it, and an agressive slipping turn to
> final made the difference between an otherwise certain overshoot and a
> merely memorable pattern. Modern sailplanes don't ordinarily present
> as much flat plate to the airstream and plummet from altitude quite as
> dramatically as the Schweizers, but they all descend a bit more
> steeply flying sideways and there are any number of reasons that extra
> little increment of drag may be useful.
>
> As training exercise, I'd argue that no-spoiler slipping patterns to
> an accuracy landing can be uses to develop advanced levels of both
> judgement and command of the aircraft in maneuvering with attention
> focused largely outside the cockpit. In that sense, is demonstrating
> proficiency in it any less "practical" a test item than some of the
> ground reference maneuvers found in the airplane PTS?

I've watched pilot attempt a no-spoiler approach in a Grob 103 and the only
way that a reasonably accurate landing could be done was to fly way too slow
for comfort because the 103 floats so far in ground effect. My Nimbus 2C
(No tail 'chute) floats so far that if the air brakes don't work, I'll need
several kilometers of runway to get stopped.

If you have a glider that exhibits a pronounced float in ground effect, I'd
advise against a no-spoiler approaches. I think this may be where accidents
due to training will be greater than those due to a real spoiler failure.

Bill Daniels

[Pete Zeugma]

At 18:30 04 February 2004, Adp wrote:
>My theory on spinning is simple - don't get into one
>and you
>won't have to recover!

strangly, thats basically what ive been saying all
along, and objecting to the 'experts' who insist its
ok to turn a glider using rudder alone!

>My point, to which you took exception, had to do with
>the
>thought that power pilots are deemed to be inferior
>to ab initio
>glider pilots when learning to fly gliders

didnt mention ab initio at all, neither did i say they
were inferior.

>and that power training is of little use when transitioning
>to
>gliders.

actually i said that there was a degree of unlearning
and bad habits that typically show up, in this particularly
instance the general theme was in the misuse of the
rudder pedals and the misguided belief that because
you can do something in a powered aircraft the same
must apply to gliders.

>Having run into this perception multiple times, I pointed
>out
>that it is nonsense.

you may well think so in your own experiences, however
it still remains true. old habits are hard to break,
especially when they become instinctive.

>The few differences that define glider flying are small
>when
>compared to the differences between powered aircraft.

and it is those small differences which when wrongly
applied to glider flight can rapidly end life!

>Aerodynamics are aerodynamics. They apply to gliders,
>
> powered aircraft, buzz bombs and flat plates.
>You just have to be aware of the differences.

no argument there.

[Andy Durbin]

"Bill Daniels" > wrote in message
>
> If you have a glider that exhibits a pronounced float in ground effect, I'd
> advise against a no-spoiler approaches. I think this may be where accidents
> due to training will be greater than those due to a real spoiler failure.
>
> Bill Daniels


I think the distinction should be made between no spoiler
patterns/circuit/approaches and no spoiler landings.

I think a simulated jammed closed, or jammed open, situation is useful
training but, as I said earlier, I always released the malfunction on
short final. The landing float was not an issue as spoiler/airbrake
could be used for the landing.

When doing simulated engine fails with airplane pilots I always make
it clear that the engine is available on short final. No point in
busting the airplane with a hard landing.


Andy

[Chris OCallaghan]

Pete Zeugma > wrote in message >...
> strangly, thats basically what ive been saying all
> along, and objecting to the 'experts' who insist its
> ok to turn a glider using rudder alone!


Pete,

No one in this group has suggested it is "OK to turn a glider using
rudder alone." In an earlier post you stated in no uncertain terms
that turning a glider with rudder only was an aerodynamic
impossiblity. You then "proved" your point by stating that unbalanced
movement of the rudder produces a forward slip. Is it surprising that
several of the group's readers, ones who lay hands on the controls
occasionally, took exception?

Your absolutism isn't uncommon. It is a tool used by good students to
learn and apply their lessons. It is especially common in flight
training, where instuctors must daily grapple with the fact that they
are giving their students access to an environment that capitalizes on
any lack of experience and exacts a brutal cost when it finds pilots
wanting. An axiomatic approach is warranted -- a short cut, proven to
be a fair trade between rapid progress to certification and safety in
the air. A pilot can even afford to arrest his development at this
point, but if you are going to engage in discussions on the philosophy
of flight, you'll need to start looking behind the short cuts your
flight instructor proffered to keep you safe in the air.

I assume your need for a strawman is a first step in overcoming
denial. That's a good thing. Get past this.

[Pete Zeugma]

At 13:42 05 February 2004, Chris Ocallaghan wrote:
>Your absolutism isn't uncommon. It is a tool used by
>good >students to learn and apply their lessons.

its also an approach used as an instructor, for good
reasons.

>It is especially
>common in flight training, where instuctors must daily
>grapple
>with the fact that they are giving their students access
>to an
>environment that capitalizes on any lack of experience
>and
>exacts a brutal cost when it finds pilots wanting.
>

quite right. so does it not make you rather disturbed
when you read posts the suggest that its you can turn
a glider with rudder alone? what brutal cost will that
exact on the poor sod who reads some of todds posts
and puts it into practice when flying low and slow,
'oh, todd said i can make a flat turn using my rudder'

>An axiomatic approach is warranted -- a short cut,
>proven to
>be a fair trade between rapid progress to certification
>and
>safety in the air.

actually, there is no warrented approach or short cut
between progress and safety in the air. basic understanding
of the correct use of controls and why it is so important
to engrain into a student the necessity to fly coordinated
in turns at all times.

>A pilot can even afford to arrest his development at
>this
>point, but if you are going to engage in discussions
>on the
>philosophy of flight, you'll need to start looking
>behind the
>short cuts your flight instructor proffered to keep
>you safe
>in the air.

my instructor, some 28 years ago now, taught me well.
he drilled into me why you fly turns correctly, why
you dont over rudder in turns. the gliders flown way
back then had a habit of killing those who did not.
i dont know of any instructor who looks for short cuts.


go read the BGA instructors manual. it explains quite
nicely why right from the first moment it should be
drummed into a trainees head 'that the rudder does
not turn a glider like a boat' and if you disagree,
email the BGA and give them your little gems of wisdom.

>I assume your need for a strawman is a first step in
>
>overcoming denial. That's a good thing. Get past this.

if being in denial is to confront and challenge techniques
used by power pilots being encouraged or suggested
to be used with gliders then so be it. If challenging
claims that a glider will turn wings level just with
the rudder alone, due to the fuselage generating lift,
then so be it.

or do you not think you have a duty of responsibility
to prevent accidents and death..... if you have not
noticed, there is already one low-time pilot who has
picked up on some of the ideas stated here, and is
thinking of trying them out..........

[Bill Daniels]

"Andy Durbin" > wrote in message
om...
> "Bill Daniels" > wrote in message
> >
> > If you have a glider that exhibits a pronounced float in ground effect,
I'd
> > advise against a no-spoiler approaches. I think this may be where
accidents
> > due to training will be greater than those due to a real spoiler
failure.
> >
> > Bill Daniels
>
>
> I think the distinction should be made between no spoiler
> patterns/circuit/approaches and no spoiler landings.
>
> I think a simulated jammed closed, or jammed open, situation is useful
> training but, as I said earlier, I always released the malfunction on
> short final. The landing float was not an issue as spoiler/airbrake
> could be used for the landing.
>
> When doing simulated engine fails with airplane pilots I always make
> it clear that the engine is available on short final. No point in
> busting the airplane with a hard landing.
>
>
> Andy

I'll eagerly accept that any exercise that improves a students judgement in
pattern work is worthwhile and I agree that no spoiler patterns would do
that. The problem is that some have interpreted the "no-spoiler" exercise
as a landing to a stop without the use of any spoilers at all to simulate a
spoiler system failure. That's scary.

Bill Daniels

[Andreas Maurer]

On 5 Feb 2004 05:15:35 -0800, (Andy Durbin)
wrote:


>I think the distinction should be made between no spoiler
>patterns/circuit/approaches and no spoiler landings.
>
>I think a simulated jammed closed, or jammed open, situation is useful
>training but, as I said earlier, I always released the malfunction on
>short final. The landing float was not an issue as spoiler/airbrake
>could be used for the landing.

Does this mean that the student pilot makes the approach by using
sideslip only?
Bye
Andreas

[Andy Durbin]

Andreas Maurer > wrote in message
>
> Does this mean that the student pilot makes the approach by using
> sideslip only?
> Bye
> Andreas

Depending on the simulated malfuction the student will make the
approach with full spoilers or with no spoilers. A slipping approach
can be used in either case to vary the glide path.

For the case where a full open jam is simulated at the spoiler check
on downwind, it gets obvious fairly quickly whether the pilot can
adapt to the condition.

I thought this was a standard training/evaluation exercise in UK. Any
comments from the UK group?


Andy

[Chris OCallaghan]

Sigh...

Ah well, I gave it a try. Some valley's just can't be crossed.

[Mark James Boyd]

>> In that sense, is demonstrating
>> proficiency in it any less "practical" a test item than some of the
>> ground reference maneuvers found in the airplane PTS?

I did a full slip and got really low at one point, and
my CFI at the time remarked he wasn't comfortable that
low with a wing down.

I took a look out the side and said to myself
"Self, where did those hella long wings come from?"
and then pulled out the slip.

Heck yeah, slips in a glider are a lot different than
in a 152 :PPP

[Mark James Boyd]

>I'll eagerly accept that any exercise that improves a students judgement in
>pattern work is worthwhile and I agree that no spoiler patterns would do
>that. The problem is that some have interpreted the "no-spoiler" exercise
>as a landing to a stop without the use of any spoilers at all to simulate a
>spoiler system failure. That's scary.
>
>Bill Daniels

In many situations I could see it being scary, but in at least one
case I liked it.

I flew a Katana DA-20-C1, and the instructor simulated a
no-electrics landing. With no flaps, the thing floated all the
way down the runway, and we went around (but we could have landed,
long runway).

His point was to show that if the flaps (like spoilers) fail,
find a looong runway. If the runway is long enough, no problem...

[Martin Gregorie]

On 6 Feb 2004 05:36:23 -0800, (Andy Durbin)
wrote:

>Andreas Maurer > wrote in message
>>
>> Does this mean that the student pilot makes the approach by using
>> sideslip only?
>> Bye
>> Andreas
>
>Depending on the simulated malfuction the student will make the
>approach with full spoilers or with no spoilers. A slipping approach
>can be used in either case to vary the glide path.
>
>For the case where a full open jam is simulated at the spoiler check
>on downwind, it gets obvious fairly quickly whether the pilot can
>adapt to the condition.
>
>I thought this was a standard training/evaluation exercise in UK. Any
>comments from the UK group?
>
I've never been handed either situation by an instructor, though I
have known them to open the airbrakes during a cable launch.


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :