ASW20 or LS6

On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:

I've owned a 20B, plus had several flights each in a couple of different
20s and a 20C. The 20B and 20C both had beautiful handling, no tendency
to spin unless forced, and were well mannered in all configurations.
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect Schleicher
was still learning how to build glass gliders in a repeatable fashion
during the 20 production run, the 20B/C show the benefits of experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Feb 5, 8:16*am, Martin Gregorie
wrote:
On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:
I've owned a 20B, plus had several flights each in a couple of different
20s and a 20C. *The 20B and 20C both had beautiful handling, no tendency
to spin unless forced, and were well mannered in all configurations.
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect Schleicher
was still learning how to build glass gliders in a repeatable fashion
during the 20 production run, the 20B/C show the benefits of experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...

Other significant sources of variability are rigging of flaps &
ailerons, type & condition of seals... and of course now more than
half the 20 fleet flies with winglets of one sort or another, these
make a difference too (especially the odd installation with more toe
on one side than the other).

You really do need to treat these ships as individuals. My 20B is a
pussycat in #4 and L, it's a little sharp in #3. I fly it at 90% aft,
with winglets. It flies straight, the spin behavior is symmetric...
but it does have a eccentric lift pin that someone installed to get it
that way.

Question for Dan: when you swapped ships with the 20B pilot, how much
different were you two in weight? Your story could be explained
rather neatly if you were a bigger guy than your friend. I haven't
flown a 6. Tried to buy one, but the owner wasn't ready to sell. I
ended up with the 20B a few weeks later, have not regretted this.
Cockpit, controls, landing flaps, landing gear and wheel brake are all
better or a lot better on the 20B. However it's certainly true that
the 20 flies best if you keep the roll rates about 1/2 of maximum. At
high aileron deflections, she gets a little draggy. Not sure if I
want to fly a 6... I'm pretty happy with my ship, want to stay that
way!

-Evan Ludeman / T8

On Feb 5, 9:29*am, T8 wrote:
On Feb 5, 8:16*am, Martin Gregorie
wrote:

On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:
I've owned a 20B, plus had several flights each in a couple of different
20s and a 20C. *The 20B and 20C both had beautiful handling, no tendency
to spin unless forced, and were well mannered in all configurations.
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect Schleicher
was still learning how to build glass gliders in a repeatable fashion
during the 20 production run, the 20B/C show the benefits of experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...

Other significant sources of variability are rigging of flaps &
ailerons, type & condition of seals... and of course now more than
half the 20 fleet flies with winglets of one sort or another, these
make a difference too (especially the odd installation with more toe
on one side than the other).

You really do need to treat these ships as individuals. *My 20B is a
pussycat in #4 and L, it's a little sharp in #3. *I fly it at 90% aft,
with winglets. *It flies straight, the spin behavior is symmetric...
but it does have a eccentric lift pin that someone installed to get it
that way.

Question for Dan: when you swapped ships with the 20B pilot, how much
different were you two in weight? *Your story could be explained
rather neatly if you were a bigger guy than your friend. *I haven't
flown a 6. *Tried to buy one, but the owner wasn't ready to sell. *I
ended up with the 20B a few weeks later, have not regretted this.
Cockpit, controls, landing flaps, landing gear and wheel brake are all
better or a lot better on the 20B. *However it's certainly true that
the 20 flies best if you keep the roll rates about 1/2 of maximum. *At
high aileron deflections, she gets a little draggy. *Not sure if I
want to fly a 6... I'm pretty happy with my ship, want to stay that
way!

-Evan Ludeman / T8

I'm curious to know how the eccentric lift pin works. How much
offset can introduced (expressed as an angle or linearly). How is it
possible to get any significant offset unless there is excessive play
in the main spar pins?

Surely the only way that an eccentric lift pin can be used to adjust
wing incidence is if it it done before the spars are bored for the
main pin bushings.

Andy

On Feb 5, 11:59*am, Andy wrote:
On Feb 5, 9:29*am, T8 wrote:



On Feb 5, 8:16*am, Martin Gregorie
wrote:

On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:
I've owned a 20B, plus had several flights each in a couple of different
20s and a 20C. *The 20B and 20C both had beautiful handling, no tendency
to spin unless forced, and were well mannered in all configurations..
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect Schleicher
was still learning how to build glass gliders in a repeatable fashion
during the 20 production run, the 20B/C show the benefits of experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...

Other significant sources of variability are rigging of flaps &
ailerons, type & condition of seals... and of course now more than
half the 20 fleet flies with winglets of one sort or another, these
make a difference too (especially the odd installation with more toe
on one side than the other).

You really do need to treat these ships as individuals. *My 20B is a
pussycat in #4 and L, it's a little sharp in #3. *I fly it at 90% aft,
with winglets. *It flies straight, the spin behavior is symmetric...
but it does have a eccentric lift pin that someone installed to get it
that way.

Question for Dan: when you swapped ships with the 20B pilot, how much
different were you two in weight? *Your story could be explained
rather neatly if you were a bigger guy than your friend. *I haven't
flown a 6. *Tried to buy one, but the owner wasn't ready to sell. *I
ended up with the 20B a few weeks later, have not regretted this.
Cockpit, controls, landing flaps, landing gear and wheel brake are all
better or a lot better on the 20B. *However it's certainly true that
the 20 flies best if you keep the roll rates about 1/2 of maximum. *At
high aileron deflections, she gets a little draggy. *Not sure if I
want to fly a 6... I'm pretty happy with my ship, want to stay that
way!

-Evan Ludeman / T8

I'm curious to know how the eccentric lift pin works. * How much
offset can introduced (expressed as an angle or linearly). *How is it
possible to get any significant offset unless there is excessive play
in the main spar pins?

Surely the only way that an eccentric lift pin can be used to adjust
wing incidence is if it it done before the spars are bored for the
main pin bushings.

Andy

There are two standard offsets available from Schleicher, 0.5 and
1.0mm. These can be installed in "up" or "down" positions in place of
any of the standard pins. The standard clearance on the pins is
(iirc) 0.006", but practically speaking I think (I'm not a Schleicher
mechanic) these are intended to be either up or down. The distance
between the pins fore to aft is on the order of 30", so the incidence
change is truly tiny. 1mm gives less than 0.08 deg incidence change.
Nothing with as much hand labor involved as an ASW-20 comes out
identical in every copy, so having a way to get every example to fly
straight despite manufacturing variance is a good thing.

-Evan Ludeman / T8

On Feb 5, 11:59*am, Andy wrote:
excessive play
in the main spar pins?

Sorry, reading comprehension challenged today...

I don't know what the standard clearance is on the main pins, but it
isn't particularly tight. 0.08 deg over a 2" span (the center spar
stub, center to edge) is about 25 _ten_thousandths, so no problem at
all.

-Evan Ludeman / T8

On Feb 5, 11:59*am, Andy wrote:

Surely the only way that an eccentric lift pin can be used to adjust
wing incidence is if it it done before the spars are bored for the
main pin bushings.

Sorry, I am both reading comprehension *and* math challenged today it
seems (I have a medical excuse, it's temporary, fortunately!).
Previous answer to this deleted.

The clearance on the main pins I don't know. I'd guess it's around
0.003" judging by feel, but that's a guess, I've never paid too much
attention. The change in clearance due to an incidence offset is easy
to calculate though, and it's about 0.0005" total on the depth of the
center spar stub for a 1mm offset pin. Those are all armchair
numbers, but the conclusion (supported by experience) is "No Problem".

-Evan Ludeman / T8

On Feb 5, 9:29*am, T8 wrote:
On Feb 5, 8:16*am, Martin Gregorie
wrote:

On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:
I've owned a 20B, plus had several flights each in a couple of different
20s and a 20C. *The 20B and 20C both had beautiful handling, no tendency
to spin unless forced, and were well mannered in all configurations.
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect Schleicher
was still learning how to build glass gliders in a repeatable fashion
during the 20 production run, the 20B/C show the benefits of experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...

Other significant sources of variability are rigging of flaps &
ailerons, type & condition of seals... and of course now more than
half the 20 fleet flies with winglets of one sort or another, these
make a difference too (especially the odd installation with more toe
on one side than the other).

You really do need to treat these ships as individuals. *My 20B is a
pussycat in #4 and L, it's a little sharp in #3. *I fly it at 90% aft,
with winglets. *It flies straight, the spin behavior is symmetric...
but it does have a eccentric lift pin that someone installed to get it
that way.

Question for Dan: when you swapped ships with the 20B pilot, how much
different were you two in weight? *Your story could be explained
rather neatly if you were a bigger guy than your friend. *I haven't
flown a 6. *Tried to buy one, but the owner wasn't ready to sell. *I
ended up with the 20B a few weeks later, have not regretted this.
Cockpit, controls, landing flaps, landing gear and wheel brake are all
better or a lot better on the 20B. *However it's certainly true that
the 20 flies best if you keep the roll rates about 1/2 of maximum. *At
high aileron deflections, she gets a little draggy. *Not sure if I
want to fly a 6... I'm pretty happy with my ship, want to stay that
way!

-Evan Ludeman / T8

Evan, I swapped with Tom Serkowski (5Z) and I think it was a 20B
(stiff wings rather than floppy). I'm a bit taller than Tom but I
think we're about the same weight and we both flew dry. After
landing, I asked him what he thought and he held up the index finger
of one hand and placed the palm of the other hand down on it
indicating balancing on the point of a needle. My reply to his
question was that I thought the 20 was on rails, meaning it was
difficult to roll. I'm sure that's because of the difference in
handling qualities of the two - the LS-6a being extremely light on the
controls.

Hope that answers your question.

On Feb 5, 5:16*am, Martin Gregorie
wrote:
On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:
I've owned a 20B, plus had several flights each in a couple of different
20s and a 20C. *The 20B and 20C both had beautiful handling, no tendency
to spin unless forced, and were well mannered in all configurations.
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect Schleicher
was still learning how to build glass gliders in a repeatable fashion
during the 20 production run, the 20B/C show the benefits of experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...

The worst of the two was in the single digits, it was destroyed
several years later in a fatal stall/spin accident with a low time
pilot at the controls. The other one I have no idea about. I'll also
mention that the most important reason I had at the time for buying a
used 20B instead of a 20 was the automatic elevator hookup, I've had
two soaring friends die as a result of disconnected elevators, and
both were far more diligent pilots than I...

Marc

The ASW20 in its day was/is a racing thoroughbred, set up properly and
flown by a experienced pilot was the best glider in its era. But it is not
tolerant of mishandling, in particular use the flaps wrongly and it will
bite you and in common with other designs of the time the wing is biased
to a climb profile.
Later designs used by the LS6, ASW27 and Ventus had much more cruise
biased wings and outclassed the 20. The earlier LS6 A and B were OK but
the 18m LS6C is the gem, as is the 18m LS8 and command premium price. As a
15m ship the ASW27 is still at the top of the tree and should be included
in this discussion.
In short if you are a switched on pilot with not many bucks you will love
the ASW 20 and accept its vices. If you value the extra refinement and can
pay double the bucks the LS6C is a damn good choice. Enjoy either for your
own pleasure and goals, neither will make you world champion,

Dave

At 17:44 05 February 2011, Marc wrote:
On Feb 5, 5:16=A0am, Martin Gregorie
wrote:
On Fri, 04 Feb 2011 18:31:23 -0800, Marc wrote:
I've owned a 20B, plus had several flights each in a couple of
differen=
t
20s and a 20C. =A0The 20B and 20C both had beautiful handling, no
tende=
ncy
to spin unless forced, and were well mannered in all configurations.
One 20 (low serial number, IIRC) would spin without much warning in
thermal or landing flap and always in the same direction (over the
top
if I was turning the opposite way), the other would do so only in
landing flap, both seemed a bit twitchy at times. I suspect
Schleicher
was still learning how to build glass gliders in a repeatable
fashion
during the 20 production run, the 20B/C show the benefits of
experience
(plus reduced landing flap travel)...

Curiosity: have you any idea what the serials were for those 20s?
Mine was 20034, so fairly early...

The worst of the two was in the single digits, it was destroyed
several years later in a fatal stall/spin accident with a low time
pilot at the controls. The other one I have no idea about. I'll also
mention that the most important reason I had at the time for buying a
used 20B instead of a 20 was the automatic elevator hookup, I've had
two soaring friends die as a result of disconnected elevators, and
both were far more diligent pilots than I...

Marc

On Feb 5, 2:10*pm, David Smith wrote:
In short if you are a switched on pilot with not many bucks you will love
the ASW 20 and accept its vices. If you value the extra refinement and can
pay double the bucks the LS6C is a damn good choice. Enjoy either for your
own pleasure and goals, neither will make you world champion,

I'm going to faintly disagree with you here, and say that the vices
had been pretty much worked out by the time the 20B and C went into
production, I've never heard of anyone having problems with either.
The 20 is a mixed bag, some (perhaps most) are apparently fine if set
up with non-aggressive CG, others seem to have issues with stall/spin
characteristics no matter how they are set up. The higher prices
commanded by the B and C models likewise reflect that extra
refinement...

Marc