Excessive friction in the aiteron circuit in SZD-55

Hi

I have recently acquired SZD-55. The glider was manufactured in 1996
and has some 450 hrs. As far as I can tell the glider was maintained
very well by German workshop. Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

I can not directly talk about the 55.
I have a 27 which had a sticky problem.
I simply isolated, (disconnect the links from the stick)
Fortunate, I did not have to go further, as I discovered that the
2 bearings, that control the pitch were kaput.
In any case the above procedure should apply for isolating any sort of
excessive friction or bad bearings.
You did not say if it was in pitch or lateral control.
If lateral control is an issue you should have friends lift the
wingtips
and operate the stick under bending load while on the ground.
Udo


Hi

I have recently acquired SZD-55. *The glider was manufactured in 1996
and has some 450 hrs. *As far as I can tell the glider was maintained
very well by German workshop. *Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. *The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. *I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. *Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

On Apr 20, 7:10 am, Paul B wrote:
Hi

I have recently acquired SZD-55. The glider was manufactured in 1996
and has some 450 hrs. As far as I can tell the glider was maintained
very well by German workshop. Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

Hi Paul, I am anew SZD-59 owner and it also has a lot of friction in
the aileron circuit, but this is a known quality in the 59 not a
defect. The 59's ailerons are very heavy due to control circuit
friction, with no load, and naturally get much MUCH stiffer with
increasing airspeed. It is an acro ship though, and it could have been
intentional to reduce over-stressing tendencies, but it seems rather
extreme when actually experienced. I have little 55 experience, but it
would not be the first Polish ship with heavy ailerons if it turns out
to be a normal condition, (as opposed to damaged bearings and such) so
I am curious as to the answers and solutions, short of redesigning
major components. If it's as simple as a combo of strategic felt/uhmw/
teflon/etc then I'm all for it.

About the aileron droop, most ships have some sort of dip like that
while the ailerons are unloaded, but as soon as they are
aerodynamically loaded they should (assuming this adjustment is
correct) be in perfect cord with the rest of the wing when held
neutral. many people have tried to "fix" their sagging ailerons, much
to the detriment of the ship's performance, and is most likely a
calculated/built in feature. That said however, always get somebody
smarter than you (definitely smarter than me ) to look at anything in
doubt. Polish repair/maintenance manuals are usually pretty specific
on such matters as well for that matter...

Paul Hanson

On Apr 20, 4:14*pm, sisu1a wrote:
On Apr 20, 7:10 am, Paul B wrote:





Hi

I have recently acquired SZD-55. *The glider was manufactured in 1996
and has some 450 hrs. *As far as I can tell the glider was maintained
very well by German workshop. *Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. *The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. *I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. *Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

Hi Paul, I am anew SZD-59 owner and it also has a lot of friction in
the aileron circuit, but this is a known quality in the 59 not a
defect. The 59's ailerons are very heavy due to control circuit
friction, with no load, and naturally get much MUCH stiffer with
increasing airspeed. It is an acro ship though, and it could have been
intentional to reduce over-stressing tendencies, but it seems rather
extreme when actually experienced. I have little 55 experience, but it
would not be the first Polish ship with heavy ailerons if it turns out
to be a normal condition, (as opposed to damaged bearings and such) so
I am curious as to the answers and solutions, short of redesigning
major components. If it's as simple as a combo of strategic felt/uhmw/
teflon/etc then I'm all for it.

About the aileron droop, most ships have some sort of dip like that
while the ailerons are unloaded, but as soon as they are
aerodynamically loaded they should (assuming this adjustment is
correct) be in perfect cord with the rest of the wing when held
neutral. many people have tried to "fix" their sagging ailerons, much
to the detriment of the ship's performance, and is most likely a
calculated/built in feature. That said however, always get somebody
smarter than you (definitely smarter than me ) to look at anything in
doubt. Polish repair/maintenance manuals are usually pretty specific
on such matters as well for that matter...

Paul Hanson- Hide quoted text -

- Show quoted text -

The sagging ailerons are explained it the rigging manual that is in
the maintenance section of your flight manual. The 55 has a builtin
-2.5dig. set in each side. See Fig 1 page 31.. As for them being
heavy? In the technical service manual para 2.2.7. Parmissible
friction in the control system. Aileron 0.2 +/- 1.0 daN ( 0.44 +/-
2.2 lbs.) I would look for a bad bearing in the linkages. I feel that
the ailerons on my ship are very light.

Thanks Udo, that's where I was heading with wing tips to simulate
flight loads, I was just trying to find out if this is normal for the
type. Not sure yet how to apply bending loads to a single wing in
order to check if the problem is specific to one side only, but
certainly worth a try.

Cheers

Paul

Udo wrote:
I can not directly talk about the 55.
I have a 27 which had a sticky problem.
I simply isolated, (disconnect the links from the stick)
Fortunate, I did not have to go further, as I discovered that the
2 bearings, that control the pitch were kaput.
In any case the above procedure should apply for isolating any sort of
excessive friction or bad bearings.
You did not say if it was in pitch or lateral control.
If lateral control is an issue you should have friends lift the
wingtips
and operate the stick under bending load while on the ground.
Udo


Hi

I have recently acquired SZD-55. �The glider was manufactured in 1996
and has some 450 hrs. �As far as I can tell the glider was maintained
very well by German workshop. �Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. �The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. �I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. �Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

On Apr 21, 9:14 am, sisu1a wrote:
On Apr 20, 7:10 am, Paul B wrote:



Hi

I have recently acquired SZD-55. The glider was manufactured in 1996
and has some 450 hrs. As far as I can tell the glider was maintained
very well by German workshop. Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

Hi Paul, I am anew SZD-59 owner and it also has a lot of friction in
the aileron circuit, but this is a known quality in the 59 not a
defect. The 59's ailerons are very heavy due to control circuit
friction, with no load, and naturally get much MUCH stiffer with
increasing airspeed. It is an acro ship though, and it could have been
intentional to reduce over-stressing tendencies, but it seems rather
extreme when actually experienced. I have little 55 experience, but it
would not be the first Polish ship with heavy ailerons if it turns out
to be a normal condition, (as opposed to damaged bearings and such) so
I am curious as to the answers and solutions, short of redesigning
major components. If it's as simple as a combo of strategic felt/uhmw/
teflon/etc then I'm all for it.

About the aileron droop, most ships have some sort of dip like that
while the ailerons are unloaded, but as soon as they are
aerodynamically loaded they should (assuming this adjustment is
correct) be in perfect cord with the rest of the wing when held
neutral. many people have tried to "fix" their sagging ailerons, much
to the detriment of the ship's performance, and is most likely a
calculated/built in feature. That said however, always get somebody
smarter than you (definitely smarter than me ) to look at anything in
doubt. Polish repair/maintenance manuals are usually pretty specific
on such matters as well for that matter...

Paul Hanson

Hi Paul

Yes I have found a number of references to 59 heavy ailerons, not so
much for the 55. The sagging ailerons is my fault, I have missed it
in the manual, a poster later in this thread has pointed me to it.

Cheers

Paul

- Show quoted text -

The sagging ailerons are explained it the rigging manual that is in
the maintenance section of your flight manual. The 55 has a builtin
-2.5dig. set in each side. See Fig 1 page 31.. As for them being
heavy? In the technical service manual para 2.2.7. Parmissible
friction in the control system. Aileron 0.2 +/- 1.0 daN ( 0.44 +/-
2.2 lbs.) I would look for a bad bearing in the linkages. I feel that
the ailerons on my ship are very light.

Hi

Thank you for pointing me to the correct page on the manual. The
2.5deg translate to a bit over 5mm which is pretty much what it is. I
am assuming that the permissible forces are quoted when stationary,
but that is not my problem. The aileron only load up in flight.
Essentially the stick never returns to the centre by itself, when
cruising with the the stick in the centre, I can tap it pretty hard
and it does not budge. I am encouraged to hear that ailerons are
light, so I should be able to get it fixed.

Cheers

paul

Did you check the clearance between ailerons and wing (spanwise) under load?

Bert

"pb2525" wrote in message
...


- Show quoted text -

The sagging ailerons are explained it the rigging manual that is in
the maintenance section of your flight manual. The 55 has a builtin
-2.5dig. set in each side. See Fig 1 page 31.. As for them being
heavy? In the technical service manual para 2.2.7. Parmissible
friction in the control system. Aileron 0.2 +/- 1.0 daN ( 0.44 +/-
2.2 lbs.) I would look for a bad bearing in the linkages. I feel that
the ailerons on my ship are very light.

Hi

Thank you for pointing me to the correct page on the manual. The
2.5deg translate to a bit over 5mm which is pretty much what it is. I
am assuming that the permissible forces are quoted when stationary,
but that is not my problem. The aileron only load up in flight.
Essentially the stick never returns to the centre by itself, when
cruising with the the stick in the centre, I can tap it pretty hard
and it does not budge. I am encouraged to hear that ailerons are
light, so I should be able to get it fixed.

Cheers

paul

Hi Bert

No I did not, but I will add it to the things to check. However, the
problem seems to be friction, rather then anything else. The reason I
say that is that it takes more force to start the stick moving, then
it is to keep it moving (static friction requires more force to
overcome then sliding friction).

Cheers

Paul

On Apr 21, 11:19 pm, "Bert Willing" bw_no_spam_ple...@tango-
whisky.com wrote:
Did you check the clearance between ailerons and wing (spanwise) under load?

Bert

"pb2525" wrote in message

...



- Show quoted text -

The sagging ailerons are explained it the rigging manual that is in
the maintenance section of your flight manual. The 55 has a builtin
-2.5dig. set in each side. See Fig 1 page 31.. As for them being
heavy? In the technical service manual para 2.2.7. Parmissible
friction in the control system. Aileron 0.2 +/- 1.0 daN ( 0.44 +/-
2.2 lbs.) I would look for a bad bearing in the linkages. I feel that
the ailerons on my ship are very light.

Hi

Thank you for pointing me to the correct page on the manual. The
2.5deg translate to a bit over 5mm which is pretty much what it is. I
am assuming that the permissible forces are quoted when stationary,
but that is not my problem. The aileron only load up in flight.
Essentially the stick never returns to the centre by itself, when
cruising with the the stick in the centre, I can tap it pretty hard
and it does not budge. I am encouraged to hear that ailerons are
light, so I should be able to get it fixed.

Cheers

paul

On 20 apr., 16:10, Paul B wrote:
Hi

I have recently acquired SZD-55. *The glider was manufactured in 1996
and has some 450 hrs. *As far as I can tell the glider was maintained
very well by German workshop. *Whilst I was aware that the 55 has quite
a heavy stick, I have only flown one other, this one seems to require
quite a force to move the stick whilst in flight. *The friction force on
the ground is negligible. Whilst I found the glider great to fly,
responsive etc., the force required to move the stick becomes tiring
after a while. *I also find that I tend to "overshoot" small
corrections, static friction requiring more force to overcome compared
to sliding friction. *Has anyone had similar experience and if so how
could it be overcome.

Also I have noticed that when the stick is at dead centre, both ailerons
are deflected down by about 3mm (1/8").

Any help appreciated.

cheers

Paul

Hello,

I own one SZD 55, Ser No 006.

The deflection of both ailerons downwards is normal and is also
described in tehnical instructions .

My control stick runs VERY smoothly.

Best Regards,

Marko Kovac, Slovenia