Vintage Brake upgrade-JJ or anyone else who knows

Good answers guys-

JJ's response got me thinking. Because I have greater
elevator authority at higher speeds, I apply much harder
brake when moving fast knowing I can keep the tail
down with back stick. But it sounds like that may
be tough on the drum.

At 18:42 03 March 2004, Ken Ward wrote:
In article ,
Stewart Kissel wrote:

What is it that these guys do to improve braking?

Assuming all ships could use help, are some (say a
Ventus) more improved then others? How much $. Thank
you.




To start with, Michael at Vintage Brake has a primary
business of doing
drum brakes for vintage motorcycle racers. This means
he has a lot of
experience separating inferior mechanical brake assemblies
from quality
ones, he has a large assortment of pad materials on
hand, he gets a lot
of feedback from the racers about what works and what
didn't, so
ultimately he's got a good grasp of all the variables
involved in
picking a compound to match the mechanism and the application.

So, I sent him my LAK-12 main wheel assembly, as the
brakes just weren't
up to the task of adequately slowing down a 1000# glider.
Although my
glider is Experimental, he won't reject other types;
it's up to you and
your mechanic to know what you can/can't do to your
glider.

He looked it over, and says the brake components are
strong, well made,
good materials used, etc; I think it comes straight
out of a Blanki. We
then discussed the typical operating conditions such
as runway surface,
temperature, wet/dry, weight. He also wanted cable
length and
dimensions of the brake lever pivot assembly.

After all that, he recommended a pad material suited
to stopping
something heavy, low duty cycle, no glazing. He installed
the new pad
material on the existing shoes, cleaned and examined
all pivoting parts,
made sure the drum itself was smooth, then arced the
pads to exactly fit
the drums. Total cost was about $150.

What I found was vastly improved braking. It worked
great time after
time, with no fading. Only drawback was that it worked
a little *too*
well, as vigorous braking at low speeds would lift
the tail off the
ground. I spoke with him and he recommended removing
material from the
leading edge of the pads, 0.5' at a time, just enough
to keep the pad
off the drum.

This improved the situation, but I feel it's really
more of an issue
about where the brake is located with reference to
the CG. Above
10-15kts full back stick keeps the tail planted, even
with full brakes.
Below that speed the tail starts coming up. Some say
SZDs exhibit the
same behavior. I'm going to take another 0.5' off
this winter and put
on a new tire.

Ken
San Jose, CA

Stewart Kissel wrote:

What is it that these guys do to improve braking?
Assuming all ships could use help, are some (say a
Ventus) more improved then others? How much $. Thank
you.


This is one of those periodic topics. Here's what I did to greatly improve
the braking of my old Tost drum brake. This is an old post.

-Doug




The article is by Tillman Steckner. I performed the modification exactly as
he outlines, not difficult if you are somewhat handy with tools. It
worked/works great. I can lift the tail off the ground if I want. The feel
is progressive and has no tendency to 'grab'. If you botch the job, not
likely in my opinion, then you simply have to replace one brake shoe because
that is all that is modified.

This has all been discussed here before. Do a google search on the newsgroup
for "brake".

Regards,

-Doug

From: "John Shelton"
Organization: EarthLink Inc. -- http://www.EarthLink.net
Newsgroups: rec.aviation.soaring
Date: Thu, 27 Feb 2003 20:16:41 GMT
Subject: TOST brake mod?

Years ago, a modification appeared in Soaring for TOST drum brakes. The idea
was to get the braking shoe (the one engaged to stop when rolling forward)
to push the non-braking shoe (used to stop when rolling backwards) against
the drum thereby actually being able to stop.

One friend did it to his DG300 and it worked great and is still working
great. I have also heard that if done wrong, you end up on your nose.

Does anyone know where I can get accurate sketches and description of this
mod? Apparently, the sketch in Soaring was wrong. And, do I really want to
do this?

I had Michael "Mercury" Morris overhaul my Tost P.O.S. err I mean drum
brake. The new pads and blueprinting (as described by Bob and others
in this thread) significantly improved braking and fade resistance.
In addition, Mr Morris found and corrected a worn/ovalized actuator
arm and hole on my Tost.

I would recommend Mr. Morris and his modifications highly.

That said, there is NO comparison between a (modified) Tost drum and
a Cleveland disc brake. Putting anything less than a 500X5 Cleveland
on a modern glider is ignorant.

The old air-cooled volksie bugs were never known to have great brakes.
They weighed in at about 1600 lbs and had 80 sq in of brake area. A
15-meter might go 700 lbs and I doubt the common Tost brake has more
than 15 sq in.

There's just not that much braking surface to work our improvements on.

BJ

Stewart Kissel wrote:

What is it that these guys do to improve braking?
Assuming all ships could use help, are some (say a
Ventus) more improved then others? How much $. Thank
you.