SZD 51-1 Junior break

[Gary Boggs]

Our club has a Jantar Junior and if we adjust the break so that it doesn't
drag, we have almost no breaking power. If we adjust it so that we have a
little breaking power, it is dragging too much. The break is activated by a
squeeze grip on the spoiler handle like a bicycle break. As far as I know,
it's the original set up. Does anyone that has any experience with the
break on the Junior give us any clues as to how to make our break work and
not drag?

Thanks,

Gary Boggs

[Bob Kuykendall]

At 00:30 14 January 2003, Gary Boggs wrote:

> Our club has a Jantar Junior and if we adjust
> the break so that it doesn't drag, we have
> almost no breaking power. If we adjust it so
> that we have a little breaking power, it is

> dragging too much...

In my limited experience with glider drum brakes, spongy
brake feel like that usually indicates that the brake
shoes are contacting the brake drums over too small
an area. That contact patch tends to overheat and glaze
over, which reduces its coeffecient of friction.

The best fix for that problem is to have the arc of
the shoes recut on a lathe so that they contact the
drum over the largest possible area. It also might
be a good thing to have the friction material on the
shoes changed to a more modern compound.

The place that I've heard of doing that is Vintage
Brake in Sonora, CA, right across the river from me.
There's a group of Rolladen-Schneider operators who
are having their Tost wheels re-shod and arc-cut there
right now. I delivered their brake units to the guy,
and he seems knowledgeable and responsible.

In my opinion, having that work done is a much better
idea than trying the self-energizing mods that are
occasionally proposed. But then, the glider brakes
I've used most lately are band-over-tire (HP-11) and
Matco disk (HP-18), so that is not a well-supported
opinion on my part.

Thanks, and best regards

Bob K.
http://www.hpaircraft.com

[Gary Boggs]

The break on the Junior isn't a drum break, the hub rotates and screws into
the pads on the wheel. The pads are making good, even contact so that's not
the problem, thanks for the reply, anyone familiar with the SZD break?

Boggs

"Bob Kuykendall" <REMOVE_TO...@hpaircraft.com> wrote in message
news:avvt0s$k1jb4$1...@ID-49798.news.dfncis.de...

[B Lacovara]

<<anyone familiar with the SZD break?>>

It's the same brake used on the Jantar Standards and it is difficult to adjust
properly. The four pointed star adjuster really needs to have eight points for
finer adjustment.

There are a couple of things you can do to help. When you disassemble the brake
you find a large course threaded hub that rotates forcing the brake pad against
the disk on the hub. The casting for the threaded hub is fairly rough which
affects the drag on the hub assembly.

Get some valve lapping compound and spend an evening working the threads
together to smooth out the roughness. When you think you are done, give it
another couple hundred twists. Lube the threads well upon re-assembly (but not
so much that the grease gets on the brake disk.

The other thing is to make sure the brake return spring is up to full tension
(replace if necessary), so the level arm fully rotates to the release position.
These two things may allow you to take that extra turn on the star adjuster and
not have the brake cinch up too tight.

Beyond that, it's an infernal SZD wheel brake....

Bob
Jantar Std 3
2BT

[Stefan]

No way, the Junior brake just doesn't work by design.

Stefan

[JJ Sinclair]

I agree with Bob. Apply equal amounts of patience and cursing. It dosen't work
by design.
JJ Sinclair

[Basil Fairston]

I'd agree with that. It is poorly engineered. With no proper thrust
bearing it tends to stick on if adjusted so it can be applied hard. Best to
adjust it so it only works a bit.

Basil

"Stefan" <ste...@mus.BOUNCE.ch> wrote in message
news:3E23D264...@mus.BOUNCE.ch...

[Martin Gregorie]

On Mon, 13 Jan 2003 16:19:43 -0800, "Gary Boggs"
<gary....@charter.net> wrote:

>Our club has a Jantar Junior and if we adjust the break so that it doesn't
>drag, we have almost no breaking power. If we adjust it so that we have a
>little breaking power, it is dragging too much.
>

Our two club Juniors are exactly like that. After annual inspection
the brake works, but ground handling is hell. After a couple of months
the brake goes back to normal - doesn't work but doesn't drag either.

The only Junior I've seen with a nice brake was the one at Williams
Soaring. They replaced it with a hydraulic brake operated off full
airbrake. Both the new brake and the new actuation worked well.

Does anybody know if that mod has been published or if it's a Williams
special? We'd be interested in converting our Juniors.

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

[Janusz Kesik]

It might be one of the prototypes, which had many in common with Jantars.
In Poland we have one Junior with wings in the wingroot - aileron section
using the Jantar Standard's NN-8 airfoil.

Regards,

--
Janusz Kesik
janusz...@gazeta.pl
------------------------
Take a look at interesting websites:
www.kssse.pl
www.ksse.com.pl

[--=JJay=--]

Użytkownik "Janusz Kesik" <janusz...@gazeta.pl> napisał w wiadomości
news:b01nmv$mda$1...@news.tpi.pl...

| In Poland we have one Junior with wings in the wingroot - aileron section
| using the Jantar Standard's NN-8 airfoil.

Hi

Where exactly is that Junior, does it performs better than "normal" Junior ?

Regards

--
--=JJay=--
www.aeroklub.deblin.pl

[Janusz Kesik]

This one flies at Warsaw club, it's the first ever Junior which has been
built.
There are pics of this particular glider at my website - it wears "PJ"
contest marks if I remember correctly.
I've heard the difference is not significant, maybe in strong conditions...
My site:
www.soaring.enter.net.pl
Look for "2002 Regionals" in the gallery section.

Regards,

--
Janusz Kesik
janusz...@gazeta.pl
------------------------
Take a look at interesting websites:
www.kssse.pl
www.ksse.com.pl

> Where exactly is that Junior, does it performs better than "normal" Junior

[denbighglidingclub]

I own a Std Jantar the brake is operated by the airbrake lever i.e full
airbrake,
I looked at modding it to go from a hand lever (bike type) but decided that
there was not enough throw, to operate the brake mechanism enough, If the
Junior brake is the same (and it sounds like it is) then this may be the
problem , that is the movement given by the lever is so small that the brake
has to be set almost on in its off state. Hope that this helps in some way

Tony
"Gary Boggs" <gary....@charter.net> wrote in message
news:v26lt0i...@corp.supernews.com...

[Janusz Kesik]

Sotty, it's the "TE".
The one with a yellow strip on the fin.

JK

[Roger Druce]

Tost have a variety of disc braked main wheel retro fit kits for gliders
including Jantar, Bocian, Puchacz, SZD55 and a range of German 1970's and
1908's fibreglass gliders. The catalog I have in front of me doesn't list
the Junior however. Not withstanding it may be possible to adapt one of the
kits and they may be able to advise. I do not operate a Junior so I am
unclear as to the mainwheel hub size and whether it is a common hub size to
the Jantar/Puchacz/Bocian/SZD55.

I have last year fitted a Tost disc brake kit to our SZD Puchacz to get away
from the hassles with the main wheel brake servicability (rather lack of
servicability) similar to the hassles expressed by others posting to this
thread on the Junior. We are very pleased with the result. Whilst it was
not cheap to buy the kit and a few more days went by installing it than I
anticipated, we think it is a worthwhile safety improvement. It also makes
it easy to inflate the mainwheel.

The kit consisted of a replacement Tost mainwheel hub (which has simple
valve access, not the difficult access of the original Polish mainwheel),
disc, disc brake, hydraulic hose and master cylinder plus drawings photos
and instructions. However this kit did not extend to hardware for mounting
the master cylinder or hardware for wheel brake actuation.

Tost were very helpful in replying to my email queries in...@tost.de .

Best regards
Roger Druce (DownUnder)

"Martin Gregorie" <mar...@see.sig.for.address> wrote in message
news:0u982vko670d13r91...@4ax.com...

[iPilot]

Typos are fun :-))

[Martin Gregorie]

On Wed, 15 Jan 2003 00:20:12 +1100, "Roger Druce"
<rogd...@melbpc.org.au> wrote:

>Tost have a variety of disc braked main wheel retro fit kits for gliders
>including Jantar, Bocian, Puchacz, SZD55 and a range of German 1970's and
>1908's fibreglass gliders. The catalog I have in front of me doesn't list
>the Junior however. Not withstanding it may be possible to adapt one of the
>kits and they may be able to advise. I do not operate a Junior so I am
>unclear as to the mainwheel hub size and whether it is a common hub size to
>the Jantar/Puchacz/Bocian/SZD55.
>
>I have last year fitted a Tost disc brake kit to our SZD Puchacz to get away
>from the hassles with the main wheel brake servicability (rather lack of
>servicability) similar to the hassles expressed by others posting to this
>thread on the Junior. We are very pleased with the result. Whilst it was
>not cheap to buy the kit and a few more days went by installing it than I
>anticipated, we think it is a worthwhile safety improvement. It also makes
>it easy to inflate the mainwheel.
>
>The kit consisted of a replacement Tost mainwheel hub (which has simple
>valve access, not the difficult access of the original Polish mainwheel),
>disc, disc brake, hydraulic hose and master cylinder plus drawings photos
>and instructions. However this kit did not extend to hardware for mounting
>the master cylinder or hardware for wheel brake actuation.
>
>Tost were very helpful in replying to my email queries in...@tost.de .
>
>Best regards
>Roger Druce (DownUnder)
>

Thanks - I'll pass the information on in the appropriate direction.