Tost Hooks, Rings and Airworthiness
Adams Folks
Some thoughts after reading some recent threads....
On Your Tost Tow Hook
-----------------------------------------
The Tost tow hook needs to be serviced regularly as required in the Tost
Manual which comes with every hook. I believe older hooks need to be
done every 3 years and newer ones every 4 years (older ones may get
the new limit once serviced). The main reason for the servicing is that
the internal springs need replacing. The springs age over time and stop
being able to do the job they were designed for. This aging is not a
function of the number of releases or the type of tow. It is a function
of time, as determined with testing by Tost. Also, other items can
deteriorate
from gear up landings and dirt from soft fields, etc. But the primary
reason is the aging of the springs.
Servicing of the Tost hook needs to be done by Tost, or someone they
have trained and who has the correct parts and tools to do the job.
Otherwise the Tost hook is not servicable per the documented Tost
requirements.
Most of us have have sailplanes with Standard Airworthiness certificates.
Or, Experimental Airworthiness certificates issued based on the fact that
the manufcturer has a Type Certificate in a foreign country, but not in the
USA. In BOTH cases these airworthiness certificates require that we
operate and maintain the sailplanes per the manuals published by the
manufacturer. (In the case of the Standard Airworthiness this is via the
US Type Certificate and in the case of the Experimental Airworthiness
this is via the Operating Limitations which accompany the Experimental
Airworthiness Certificate.) In all cases I have seen, these manuals
require that the Tost hook be used and maintained in compliance with
the Tost manual.
The two line summary of the above is that if your Tost hook is out of
service,
your sailplane is not airworthy. Now go read your insurance policy. It
probably
clearly requires your sailplane to be airworthy for the insurace to be
effective.
They don't care that some IA or A&P has signed it off with an out of
service
hook. If an IA or A&P signs it off in this condition, that just means they
goofed
and your sailplane is really not airworthy. Folks who really understand
sailplanes,
carefully review the Tost hook status as they don't want to face the
liability
consequences of such a goof-up. I continue to be supprised at how many
older
sailplanes I run across where the Tost hook has _never_ been serviced. (Of
course most Tost hook manuals are in German, as mine is, and folks don't
notice the 4 year or 2000 flight limit as I see in my spanky new German
manual.)
On Tost Rings
-------------------------------------
To start. Your Tost manual requires you to use Tost rings (probably in
German
of course). So the above analysis about airworthiness applies.
But these little rings are awfull expensive. So why? First they have to be
sized
correctly to "back release" under all kinds of adverse loading conditions.
(The
main reason the springs need to work properly as well.) Also, to do this
the
rings have to be defect free. Have you noticed that there are no seems? The
ring pairs are cast together. As I understand it, they are then
individually
inspected using processes to ensure there are no cracks. My presumtion is
that
the casting and test process are not cheap and result in a lot of scrap
ring sets.
You might think this is overkill, but the consequences of not doing some
of these steps in the past appear to have driven Tost to do this.
Personally,
I am thankful they will go to the effort, and expose themselves to the
liability in
continuing to make ring sets, and so gladly pay the bill for the rings.
Conclusion
-------------------------------------
BE SAFE! Be legal! Get your Tost hook serviced as required. Use Tost rings.
It's not worth a few bucks to deal with the potential consequences of not
doing so.
Marc Ramsey
Adams Folks <al...@info2000.net> wrote in article
<01bc44b4$193c1020$30e4...@hpalan.fc.hp.com>...
> On Your Tost Tow Hook
> -----------------------------------------
> The Tost tow hook needs to be serviced regularly as required in the Tost
> Manual which comes with every hook. I believe older hooks need to be
> done every 3 years and newer ones every 4 years (older ones may get
> the new limit once serviced). The main reason for the servicing is that
> the internal springs need replacing. The springs age over time and stop
> being able to do the job they were designed for. This aging is not a
> function of the number of releases or the type of tow. It is a function
> of time, as determined with testing by Tost. Also, other items can
> deteriorate from gear up landings and dirt from soft fields, etc. But
> the primary reason is the aging of the springs.
The Tost hook in my (experimental racing certificate) glider had not
been rebuilt in its 12 year life (I've owned it for 5). I finally had a
rebuilt unit put in during the gliders last annual. The existing one
appeared to be working fine, with one premature release in the last ~150
tows (most likely due to incorrect insertion of the ring). I figured my
insurance company wasn't likely to be as understanding as the A&Ps who
have done the inspections. BTW, if you have a pilot comfort system which
vents in front of a CG hook, you have a corrosion problem to consider.
I'm switching to a bag...
> On Tost Rings
> -------------------------------------
> To start. Your Tost manual requires you to use Tost rings (probably in
> German
> of course). So the above analysis about airworthiness applies.
>
> But these little rings are awfull expensive. So why? First they have to
be
> sized
> correctly to "back release" under all kinds of adverse loading
conditions.
> (The
> main reason the springs need to work properly as well.) Also, to do this
> the
> rings have to be defect free. Have you noticed that there are no seems?
The
> ring pairs are cast together. As I understand it, they are then
> individually
> inspected using processes to ensure there are no cracks. My presumtion is
> that
> the casting and test process are not cheap and result in a lot of scrap
> ring sets.
I've seen two examples of fractured Tost rings. I suspect they'll
crack if they hit the right sort of thing when the towplane is landing,
then fracture completely in a subsequent tow. Inspect them very carefully
before each flight...
Daniel M. Ladd
Newsgroups: rec.aviation.soaring
Subject: Re: Tost Hooks, Rings and Airworthiness
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In article <01bc44b4$193c1020$30e4...@hpalan.fc.hp.com>,
Adams Folks <al...@info2000.net> wrote:
>Some thoughts after reading some recent threads....
>
>On Your Tost Tow Hook
>-----------------------------------------
>The Tost tow hook needs to be serviced regularly as required in the Tost
>Manual which comes with every hook. I believe older hooks need to be
>done every 3 years and newer ones every 4 years (older ones may get
>the new limit once serviced). The main reason for the servicing is that
>the internal springs need replacing. The springs age over time and stop
>being able to do the job they were designed for. This aging is not a
>function of the number of releases or the type of tow. It is a function
>of time, as determined with testing by Tost. Also, other items can
It has always been a wonder to me why the German (glider) manufacturers
put up with
this almost criminal extortion of "make work" by Tost. Imagine if the it was
required that the valve springs on your car engine were required to be
replaced every three years whether you used your car or not! There would be
widespread outrage by consumers, multiple lawsuits and probable criminal
indictments against the owners of the company (which would soon be out of
business). As a practicing mechanical engineer, all I can say is a design
where a statically loaded spring needs to be replaced every three years is
an example of extremely poor engineering. The fact that Tost can not come
up with a better design does not bode well for the state of German engineering.
Dan Ladd PIK 20B 8N
Bert Willing
Daniel M. Ladd wrote:
>
> It has always been a wonder to me why the German (glider) manufacturers
> put up with
> this almost criminal extortion of "make work" by Tost. Imagine if the it was
> required that the valve springs on your car engine were required to be
> replaced every three years whether you used your car or not! There would be
> widespread outrage by consumers, multiple lawsuits and probable criminal
> indictments against the owners of the company (which would soon be out of
> business). As a practicing mechanical engineer, all I can say is a design
> where a statically loaded spring needs to be replaced every three years is
> an example of extremely poor engineering. The fact that Tost can not come
> up with a better design does not bode well for the state of German engineering.
>
> Dan Ladd PIK 20B 8N
Somewhat fuzzy to make a generalization from Tost (who indeed found a
nice business trick) to German engineering. It would be the same as if
Iwould conclude from the design of Schweizer sailplanes on the
performance of the US semiconductor industry, no?
The idea was just that Tost wanted to have their hooks checked on a
regular basis as they are somewhat sensitive to dirt. You can have your
glider during 3 years on a clean concrete operation, and you can have
the hook stuffed with dirt after a single muddy day. You are also
supposed to give your car to an annual/biannual vehicle test regardless
of the milage, it's the same idea.
And every service engineer, having opened the hook, will spend 50 cts to
replace a spring , two bolts and two nuts.
Ciao
Bert
Jeffry Stetson
In article <5iheti$p...@froude.nosc.mil>, la...@froude.nosc.mil says...
[snip]
>indictments against the owners of the company (which would soon be out of
>business). As a practicing mechanical engineer, all I can say is a design
>where a statically loaded spring needs to be replaced every three years is
>an example of extremely poor engineering. The fact that Tost can not come
>up with a better design does not bode well for the state of German engineering.
>
>Dan Ladd PIK 20B 8N
>
If you think the Tost hitches are bad, you haven't had a Tost wheel brake!
(Deflector shields UP!)
--
Jeffry Stetson ... Comm ASEL, Pvt SES & Glider, Instrument Airplane
EAA, SSA, AOPA, IAC, MAPA
Mooney M20E "Superduper 21"
Salto H-101 "Shiva - The Cosmic Dancer"
Nick Leaton
Bert Willing wrote:
> The idea was just that Tost wanted to have their hooks checked on a
> regular basis as they are somewhat sensitive to dirt. You can have your
> glider during 3 years on a clean concrete operation, and you can have
> the hook stuffed with dirt after a single muddy day. You are also
> supposed to give your car to an annual/biannual vehicle test regardless
> of the milage, it's the same idea.
>
> And every service engineer, having opened the hook, will spend 50 cts to
> replace a spring , two bolts and two nuts.
If you do have a dusty field, then it pays to tow out with the canopy
cover on, as this will protect the nose hook.
--
Nick
Hans Trautenberg t2466
: where a statically loaded spring needs to be replaced every three years is
: an example of extremely poor engineering. The fact that Tost can not come
: up with a better design does not bode well for the state of German engineering.
As does the poor performance of german made gliders :-))
--
--
=============================================================================
Dipl. Phys. Hans L. Trautenberg Universitaet Regensburg
Institut fuer Experimentelle und Angewandte Physik D-93040 Regensburg
phone (49) 941 943 2466 fax (49) 941 943 3196
e-mail hans.tra...@physik.uni-regensburg.de Germany
privat
phone (49) 941 949211 fax (49) 941 930792
10161...@compuserve.com http://ourworld.compuserve.com/homepages/HLT
Flurstr. 14 D-92348 Berg Germany
=============================================================================
David H. Noyes
In article <01bc453f$e2570060$4379bccc@technoir> "Marc Ramsey" <ma...@ranlog.com>
writes:
> BTW, if you have a pilot comfort system which vents in front of a CG hook,
> you have a corrosion problem to consider. I'm switching to a bag...
And not just the tow hook. Also the undercarriage structure and the rudder
mounting hardware. I have long since switched to an on-board fiber
glass container after seeing what was happening to my rudder hinge.
"NL"
David H. Noyes
>If you think the Tost hitches are bad, you haven't had a Tost wheel brake!
I've heard Tost wheel brakes "bad-mouthed" for 20 years. What problems do
people have with them? I've had 2 gliders with Tost brakes over the past 12
years with no problems. By "what problems do people have," I mean
specifically what fails? Just saying "They don't work," doesn't help much.
"NL"
Daniel M. Ladd
In article <334CE4...@lc.dmx.epfl.ch>,
Bert Willing <Bert.W...@lc.dmx.epfl.ch> wrote:
>
>The idea was just that Tost wanted to have their hooks checked on a
>regular basis as they are somewhat sensitive to dirt. You can have your
>glider during 3 years on a clean concrete operation, and you can have
>the hook stuffed with dirt after a single muddy day. You are also
>supposed to give your car to an annual/biannual vehicle test regardless
>of the milage, it's the same idea.
>
>And every service engineer, having opened the hook, will spend 50 cts to
>replace a spring , two bolts and two nuts.
>
>Ciao
>
>Bert
My main point was that the main rationalization for the 3 (or 4) year
service requirement was that the springs age (this is nonsense). This
presumably means that a hook sitting on the shelf for 3 years is out of
date and needs to be refurbished by the factory. The crack about
the state of German engineering, was an effort to get Tost to take some
pride in their product, and improve their product so it has some kind
of reasonable service life. If the real problem is dirt, then why does
Tost hide behind the "aging spring" argument. Or is it all just a
marketing ploy?
Dan Ladd PIK 20B (8N)
Jeffry Stetson
In article <dnoyes.38...@pop.service.ohio-state.edu>, dno...@pop.service.ohio-state.edu
says...
Ok, when you pull on the handle, nothing happens except a slight increase
in noise. There never seems to be anything broken, but the things just
flat don't stop the glider. This seems to be a common experience among
many (most?) of my friends with Tost drum brakes. This in spite of
trying: new shoes, heavier cable, different hand levers, Honda ATV shoes,
modifications to make it a 'full-floating'
configuration, dragging the glider across a field brakes on with a
car to "seat" the shoes, different pivot points, etc. etc., ad. nauseum.
Someone told me that a "properly maintained" Tost drum brake was great, but
was unable to tell me what properly maintained meant. I have a manual for
the Tost tow hitch at least. I've never seen or heard of one for the brake.
Someone else told me that they would "put you up on your nose". The only
time that happens is when I run over something I shouldn't, because the
damn thing won't STOP!
Actually, I take that back... I did end up on my
nose one other time. The signed-off-by-a-"respected & experienced"-FAA-
certified-mechanic who put in a new Tost wheel assembly (before I owned the
ship), in a vain attempt
to fix the old one that also didn't work, left out some spacers. This caused
the bearings to come out of the wheel. Upon landing, the wheel
attempted to rotate 30 degrees sideways. It was prevented from doing so
by the wheel well. The resulting friction wore through the fiberglass, but
did result in my first genuine "on the nose" stop ever generated for me
by Tost.
I really like the *concept* of being able to stop (having never actually
experienced it), and am willing to pursue
the matter, but have been unable to find something that works for anyone
other than the proponent of that particular 'fix'.
Additionally, on my particular unit, the wheel assembly is wildly out of
balance, even without a tire. Yes, it's in round, but out of balance;
go figure.
Given the choice, I wouldn't use a Tost
brake and wheel assembly on a golf cart, much less on something that can
kill me when the brakes fail.
SPAM.pi.net
On Thu, 10 Apr 1997 15:09:31 +0100, Nick Leaton <nic...@calfp.co.uk>
wrote:
>
>If you do have a dusty field, then it pays to tow out with the canopy
>cover on, as this will protect the nose hook.
>
>--
>
>Nick
I would love to see a cartoon picturing this ;-))
Marc Ramsey
David H. Noyes <dno...@pop.service.ohio-state.edu> wrote in article
do
> people have with them? I've had 2 gliders with Tost brakes over the past
12
> years with no problems. By "what problems do people have," I mean
> specifically what fails? Just saying "They don't work," doesn't help
much.
I just had to replace the half of the Tost wheel which contains the brake
drum. The brake lining had a number of stress cracks in it, apparently due
to heat build-up on hard braking (must have been that time I landed on a
model airplane field...). Tost does not sell the lining separately, their
only option is to sell you an entire wheel at $800 or so. Luckily I was
able
to get half a used wheel for $125...
__________________________
Marc Ramsey, ma...@ranlog.com
http://www.ranlog.com/ramsey/
Lars Peder Hansen
Jeffry Stetson wrote:
> >ste...@nscl.msu.edu (Jeffry Stetso
> >n) writes:
> >
> >>If you think the Tost hitches are bad, you haven't had a Tost wheel brake!
> >
> >I've heard Tost wheel brakes "bad-mouthed" for 20 years. What problems do
> >people have with them?
>
<snip>
>
> Ok, when you pull on the handle, nothing happens except a slight increase
> in noise. There never seems to be anything broken, but the things just
> flat don't stop the glider. This seems to be a common experience among
> many (most?) of my friends with Tost drum brakes. This in spite of
> trying: new shoes, heavier cable, different hand levers, Honda ATV shoes,
> modifications to make it a 'full-floating'
> configuration, dragging the glider across a field brakes on with a
> car to "seat" the shoes, different pivot points, etc. etc., ad. nauseum.
> Someone told me that a "properly maintained" Tost drum brake was great, but
> was unable to tell me what properly maintained meant. I have a manual for
> the Tost tow hitch at least. I've never seen or heard of one for the brake.
> Someone else told me that they would "put you up on your nose". The only
> time that happens is when I run over something I shouldn't, because the
> damn thing won't STOP!
>
<snip>
> I really like the *concept* of being able to stop (having never actually
> experienced it), and am willing to pursue
> the matter, but have been unable to find something that works for anyone
> other than the proponent of that particular 'fix'.
>
<snip>
> Given the choice, I wouldn't use a Tost
> brake and wheel assembly on a golf cart, much less on something that can
> kill me when the brakes fail.
> --
> Jeffry Stetson ... Comm ASEL, Pvt SES & Glider, Instrument Airplane
> EAA, SSA, AOPA, IAC, MAPA
> Mooney M20E "Superduper 21"
> Salto H-101 "Shiva - The Cosmic Dancer"
I will second that anytime. -Where do I sign..?
Regards,
Lars Peder
--
*********************************************************************
* *
* Lars Peder Hansen *
* Consultant, CAD/CAM & DtP *
* LEGO A/S, DK7190 Billund, Denmark. *
* e-mail: l...@post1.tele.dk or lars....@ims.legoas.lego.dk *
* Opinions are my own, I do not speak for LEGO A/S. *
* *
*************************************** I'd rather be soaring... ***
Jeffry Stetson
In article <01bc45eb$607bf9e0$4379bccc@technoir>, ma...@ranlog.com says...
>
>I just had to replace the half of the Tost wheel which contains the brake
>drum. The brake lining had a number of stress cracks in it, apparently due
>to heat build-up on hard braking (must have been that time I landed on a
>model airplane field...).
(Not to pick on you, but rather Tost...) If this is true, it confirms my
suspicion that this is the worse brake since leather bands on the outside
of drums back in horse & buggy days! *One* stop of a ~700 lb object from
50 mph is enough to crack the drum linings?! Mechanical drum brakes on old
motorcycles were no bigger and would last for years of street riding, or
hours of roadracing.
>Tost does not sell the lining separately, their
>only option is to sell you an entire wheel at $800 or so.
Why am I not surprised?
David H. Noyes
In article <5im5qb$a...@news.asu.edu> hi...@aztec.asu.edu (CLIFF HILTY) writes:
>Maybe its better in the ventus? I had a ASW 19B that had no brake to speak of
>and now I have a Ventus B that WILL put you on your nose. And both were Tost!
>Maybe I should write to Tost and Thank them, thats how I got my Ventus!
"Funny how experiences differ", my current glider is a Ventus C and the
previous one was an AS-W19. The Tost brakes on *both* of them was excellent!
"NL"
Thomas Knauff
Tost brakes have one fault only. They need annual maintenance.
Lubricate the cam that goes through the backing plate (The part that
holds the brake lining) with white lithium grease. (You can get it at
Wal Mart) This seems to be the only grease that works on the two
disimilar metals of the backing plate and cam. While you are at it, use
the same grease on the other obvious moving parts.
Assuming you have never done this, the hole in the backing plate is
probably worn oval shape. The brake actuating cam then cocks in the
hole and the force applied to the cam via the brake cable is used up in
a binding action rather than turning the cam.
It may be possible to fix the hole, but a new backing plate is probably
needed.
The brake lining needs to be de-glazed each year. Fine sandpaper and
alchohol can be used, but it is important to maintain the curvature of
the drum.
This can be done by laying the sandpaper on a flat surface and wiping
the brake lining in a curved motion against the sandpaper.
The brake cable also needs lubricated and this may require removal to
allow oil to flow the full length of the cable. Products like WD 40
are not good for lubricating anything.
Modifications such as the free floating idea do not work. If it did,
Tost would have done it.
Our company stocks many Tost parts including individual brake parts such
as lining, wheels and halves.
--
Tom Knauff
Schempp Hirth Sailplanes
Knauff & Grove Soaring Supplies
Keystone Gliderport
3523 South Eagle Valley Road
Julian, Pa USA 16844
Phone (814) 355 2483
Fax (814) 355 2633
http://www.glider.com/knauff/
CLIFF HILTY
In a previous article, pat...@NOSPAMworldnet.att.net (Todd Pattist) says:
>>Given the choice, I wouldn't use a Tost
>>brake and wheel assembly on a golf cart, much less on something that can
>>kill me when the brakes fail.
>
>It's amazing how experiences differ. When I purchased my
>ship two years ago, with the Tost brake, I was told to be
>careful with the brake because it could "put you on the
>nose". Having heard the bad-mouthing of Tost brakes for
>years, I was skeptical, but indeed, it will put me on my
>nose without trouble, despite being 10 years old and having
>had no significant work on the brake.
>
>In fact, when landing on asphalt (as compared to my usual
>turf field), the improved wheel to runway adhesion makes the
>ship much more sensitive to remaining aligned under hard
>braking. I regularly have to remind myself to keep
>alignment firmly in mind if I want to brake hard on asphalt,
>particularly near the end of the roll when rudder
>effectiveness is decreasing, and to back off the brake if
>necessary to keep things under control.
>
>
>---
>
>Todd Pattist Ventus C - WH
>Fly safely, fly often.
>(remove "NOSPAM" from my e-mail address to contact me)
>
Maybe its better in the ventus? I had a ASW 19B that had no brake to speak of
and now I have a Ventus B that WILL put you on your nose. And both were Tost!
Maybe I should write to Tost and Thank them, thats how I got my Ventus!
--
Cliff Hilty (CH) Ventus B
"Flying is alot like sex, even a bad flight is still pretty damn good!"
David H. Noyes
In article <334EB4...@mail.earthlink.net> Thomas Knauff <tkn...@mail.earthlink.net> writes:
>Tost brakes........ need annual maintenance.
>Lubricate the cam that goes through the backing plate (The part that
>holds the brake lining) with white lithium grease.
>use the same grease on the other obvious moving parts.
>...... the hole in the backing plate (may be) worn (to an) oval shape.
>It may be possible to fix the hole, but a new backing plate is probably
>needed.
>The brake lining needs to be de-glazed each year. Fine sandpaper and
>alchohol can be used,....
>The brake cable also needs to be lubricated and this may require removal to
>allow oil to flow the full length of the cable.
>(Knauff & Grove) stocks many Tost parts including individual brake parts such
>as lining, wheels and halves.
Tom: Thanks for posting this. I shall add this to my Annual Maintenance
protocol immediately.
Dave, "NL"
Wings
--
Wings and Wheels
Jeffry Stetson <ste...@nscl.msu.edu> wrote in article
<5ild70$240$1...@msunews.cl.msu.edu>...
> In article <01bc45eb$607bf9e0$4379bccc@technoir>, ma...@ranlog.com says...
> >
> >I just had to replace the half of the Tost wheel which contains the
brake
> >drum. The brake lining had a number of stress cracks in it, apparently
due
> >to heat build-up on hard braking (must have been that time I landed on a
> >model airplane field...).
>
> (Not to pick on you, but rather Tost...) If this is true, it confirms my
> suspicion that this is the worse brake since leather bands on the outside
> of drums back in horse & buggy days! *One* stop of a ~700 lb object from
> 50 mph is enough to crack the drum linings?! Mechanical drum brakes on
old
> motorcycles were no bigger and would last for years of street riding, or
> hours of roadracing.
>
> >Tost does not sell the lining separately, their
> >only option is to sell you an entire wheel at $800 or so.
>
> Why am I not surprised?
Not to try to defend TOST but the $800.00 or so wheel is stretching things
a bit...Plus you can but wheel parts from TOST or I can also get them for
you if I don't already have them here. You MIGHT have to buy a wheel 1/2
but this is considerably less than what you're saying. A complete wheel
price is still quite high depending on the model wheel ect but probably
more likely $400.-$500. for the complete wheel and about 1/2 this for the
brake drum half.
BTW: you can find the brake shoes for many of the TOST wheels at your local
Yamaha shop for about $12.00! Just take your old shoes with you and compare
them to what they have and you'll likely find an exact match!
tim
Wings & Wheels
USA(716)664-6894
SPAM.pi.net
>I've heard Tost wheel brakes "bad-mouthed" for 20 years. What problems do
>people have with them? I've had 2 gliders with Tost brakes over the past 12
>years with no problems. By "what problems do people have," I mean
>specifically what fails? Just saying "They don't work," doesn't help much.
>
This winter the Tost brake of my Discus was overhauled by a
specialized brake and friction materials service shop.
They were already familiar with this type of brake, as the repairman
immediately identified the brake as a glider or ultra light type.
They removed the old brake pads from the brake shoes and installed an
other kind with better friction qualities. They milled it to a tight
fit in the wheeldrum.
You also have to clean and slightly grease the bellcrank to prevent a
locked brake.
Now the braking is perfect and easy to modulate, so you don't have to
nose over.
I guess this work can be done all over the world by this kind of
repair shops
Ken Ward
The Tost brake on our club's Pegasus has always been miserable. The
only thing that happens when you pull the lever, is that a bad smell
occurs. Last summer at Truckee, a glider cut into the pattern ahead of
me and stopped on the runway, unable to exit. Due to the known poor
performance of the brakes, I elected to land (safely & successfully) on
the adjacent taxiway. I hate to think about what I would have had to do
had the taxiway been occupied by a light twin!
It seems that if I break the glaze on the pads, and tighten the cable,
the brake is better for one or two applications. I've heard of an STC
to substitute a disk brake kit; has anyone heard of this?
The real sad part about these brakes, is that they're apparently fitted
to ships much larger than Standard Class 15m, when they're only marginal
to start with. I heard a story from a mechanic, about one having been
fitted to a DG-500M. As you all know, the brake cable is connected to
the brake arm via a pinch nut. This particular DG landed and elected to
coast on into the tiedown area, not wanting to block the one-way
runway. Too late he applied the brake, whereupon the cable exited the
pinch nut. His stopping choices were the line of gliders, the line of
tow planes, the crowd of spectators, or the operations hut. When the
nose penetrated the wall of the hut, it knocked a clothes dryer over,
breaking the natural gas line. Fortunately the line got shut off before
a spark ignited the whole building.
Ken Ward
1000K Diplome wannabe
Bert Willing
Ken Ward wrote:
>
> The real sad part about these brakes, is that they're apparently fitted
> to ships much larger than Standard Class 15m, when they're only marginal
> to start with. I heard a story from a mechanic, about one having been
> fitted to a DG-500M. As you all know, the brake cable is connected to
> the brake arm via a pinch nut. This particular DG landed and elected to
> coast on into the tiedown area, not wanting to block the one-way
> runway. Too late he applied the brake, whereupon the cable exited the
> pinch nut. His stopping choices were the line of gliders, the line of
> tow planes, the crowd of spectators, or the operations hut. When the
> nose penetrated the wall of the hut, it knocked a clothes dryer over,
> breaking the natural gas line. Fortunately the line got shut off before
> a spark ignited the whole building.
What's the point with Tost in your posting?
If the guy istn't able to fix a cable properly to the pinch nut, he
shouldn't service brakes.
If the guy isn't able to plan and perform a landing without the use of
brakes, he shouldn't fly gliders single handed (or not without an idling
engine on his 500M ...).
Bert
David H. Noyes
>The Tost brake on our club's Pegasus has always been miserable.
> I heard a story about one fitted to a DG-500M...........
>The sad part about these brakes, is............
^^^^^^^^^^^^^^^^^
"These brakes" implies that *all* Tost brakes are badly designed and
function badly. But that is not true. *Some* of them work just fine.
Therefore, the design cannot be inherently bad. This leaves two
possibilities: (1) the manufacturing is erratic and exit quality control
is poor, or (2) use and/or care is improper.
I would be curious to hear from owners of *new* gliders to find out if
some Tost brakes are *delivered* in poorly working condition. This might give
us some idea about manufacturing quality control.
"NL" (was new, now 6 yrs old, 950 lb A.U.W. glider + pilot with original,
perfectly functioning Tost brake)
Martin Hoehle
Daniel M. Ladd (la...@froude.nosc.mil) wrote:
: >
: >And every service engineer, having opened the hook, will spend 50 cts to
: >replace a spring , two bolts and two nuts.
: >
: Tost hide behind the "aging spring" argument. Or is it all just a
: marketing ploy?
I bet it is !!! Why would they charge you around 80US$ (without shipping)
for replacing a 50cts spring etc. That's what i call 'organized crime' with
the help of the LBA, FAA & the like. Let's hope for someone to produce tow
hooks without this ridiculous TBO...
Cheers, Martin
_ _______________________________________________________ _
/ ) | | ( \
/ / | MARTIN HOEHLE University of Karlsruhe/Germany | \ \
_( (_ | _ irc: Flyby _ | _) )_
(((\ \> |/ ) ub...@rz.uni-karlsruhe.de ( \| </ /)))
(\\\\ \_/ / Martin...@stud.uni-karlsruhe.de \ \_/ ////)
\ / WWW: http://www.uni-karlsruhe.de/~Martin.Hoehle \ /
\ _/ \_ /
/ / |________ " Powered airplanes are for kids. " __________| \ \
/ / \ \
Doug Haluza
Bert Willing <bert.w...@lc.dmx.epfl.ch> wrote in article
<3351E4...@lc.dmx.epfl.ch>...
I agree. From the way you tell it, it sounds like poor planning on the part
of the pilot. If the pilot put himself in the situation where there were no
good options if the brake failed, that was poor pilot technique. You always
have to assume the brake won't work and have a plan for where to go.
NEVER aim to stop short of another glider. It may look very sharp if it
works, but it isn't worth the risk. I always teach my students to align
themselves so they will pass off to one side of the parked gliders. It's
easy to move the glider sideways one wingspan or so if you stop exactly in
the right spot. If not, no big deal.
If you come zooming in behind my glider and jump on the brakes to stop
short, expect an earful from me!
Doug Haluza
Janus C, N468G
Mike/Dana/Brian/Glenn Schuster
David H. Noyes wrote:
>
> I would be curious to hear from owners of *new* gliders to
> find out if some Tost brakes are *delivered* in poorly working
> condition. This might give us some idea about manufacturing
> quality control.
>
I can supply one more data point. I took delivery of a new
glider with a Tost brake last spring. After 39 starts to date,
the brake has always worked perfectly for me and remains capable
of stopping the glider quickly.
Concerning maintanence, here is the text from English side
of my orange the wheel tab card:
Wheel Tab for serial No. 4015
Instruction for adjustable brake lever: By the first and later
adjustment, torque the M 8x1 DIN 936 nut with the prescribed
momentum of minimum 18 Nm to maximum 22 Nm. If this is not
observed, the notch-cog connection could slip and be destroyed.
After mounting the tire tighten wheel screws with 9 to 10 Nm.
Advice: Also check wheels already in operation.
Important advice: Check regulary the correct rated inflation
pressure of tire acc. to aircraft manual.
Operating information: the braked wheel is constructed for
normal case. Do not use your braked wheel to perform precise
landings near the ground. Retain the safety of your brake for
its true purpose. Check at each control if the brake torque
with engaged brake is large enough. Adequate brake power only
is guaranteed if controls are accurately dimensioned, installed
in a large radius, correctly adjusted and regularly readjusted
during operation. If the brake linings are smeared after being
overloaded, the brake effect lessens considerably. Clean the
burnt lining surface with abrasive paper and alcohol. Replace
brake shoes if lining thickness is less than 1.5mm at one point.
Otherwise wheel could be damaged.
Mike Schuster
Discus CS N208CS "AJO"
Larry Goddard
Daniel M. Ladd wrote:
>
> In article <334CE4...@lc.dmx.epfl.ch>,
> Bert Willing <Bert.W...@lc.dmx.epfl.ch> wrote:
> >
> >The idea was just that Tost wanted to have their hooks checked on a
> >regular basis as they are somewhat sensitive to dirt. You can have your
> >glider during 3 years on a clean concrete operation, and you can have
> >the hook stuffed with dirt after a single muddy day. You are also
> >supposed to give your car to an annual/biannual vehicle test regardless
> >of the milage, it's the same idea.
> >
> >replace a spring , two bolts and two nuts.
> >
> >
> >Bert
>
> My main point was that the main rationalization for the 3 (or 4) year
> service requirement was that the springs age (this is nonsense). This
> presumably means that a hook sitting on the shelf for 3 years is out of
> date and needs to be refurbished by the factory. The crack about
> the state of German engineering, was an effort to get Tost to take some
> pride in their product, and improve their product so it has some kind
> of reasonable service life. If the real problem is dirt, then why does
> marketing ploy?
>
I agree with you. I don't think the emperor is wearing any clothes!
Larry Goddard
"01" LS-3a USA
Donald Ingraham
Larry Goddard wrote:
> > My main point was that the main rationalization for the 3 (or 4) year
> > service requirement was that the springs age (this is nonsense). This
> > presumably means that a hook sitting on the shelf for 3 years is out of
> > date and needs to be refurbished by the factory. The crack about
> > the state of German engineering, was an effort to get Tost to take some
> > pride in their product, and improve their product so it has some kind
> > of reasonable service life. If the real problem is dirt, then why does
> > Tost hide behind the "aging spring" argument. Or is it all just a
> > marketing ploy?
> >
> > Dan Ladd PIK 20B (8N)
>
> I agree with you. I don't think the emperor is wearing any clothes!
>
> Larry Goddard
> "01" LS-3a USA
But you must admit, a clothing-optional gig that pulls in
a day's wages for 30 minutes tinkering (2 hooks) with the same
mechanism day after day ain't bad work if you can get it ;-))))
One would think that a company with essentially a monopoly (at least
on the service end) would get good marks (no pun intended :-) on
either the PRICE of service (too high), the FREQUENCY of service (too
often)
or EFFICIENCY of service (takes too long). To be fair, I guess I haven't
heard of complaints about QUALITY.
Don
Ian Johnston
Donald Ingraham (d...@cray.com) wrote:
: To be fair, I guess I haven't
: heard of complaints about QUALITY.
I know of two UK clubs which have had serious problems with recently
purchased Tost hooks: one hook which I was looking at yesterday had
deformed to the point of unusability after fewer than 200 launches.
A cursory examination suggested that the metal of the hook was very
soft - perhaps a faulty batch of heat treatment?
Ian
JuanM
I just replaced my Tost hook and the enclosed manual says it can sit on
the shelf up to 12 months and still be legal to install and start counting
towards the 4 years TBO. After that it has to be checked again.
Juan Mandelbaum
ASW-20C
Sakari Havbrandt
Tost Hooks
In Sweden we have never cared about the 4-year rebuilding of the TOST
hooks. We do a careful annual inspection and a daily function test.
We do around 70 000 launches yearly and our statistics don't show any
problem in this aera. Some hooks are more than 20 years old.
Swedish Soaring Federation
Sakari Havbrandt
Chief engineer