Glider Wheel Brakes

[j***@saic.com]

I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

[5Z]

All the Schleichers built in the last 20+ years have excellent
Cleveland disc brakes.

[CLewis95]

I know, I know.  BTDT.  Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake?  The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.  I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers.  I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

The Blanik L33 Solo drum wheel brake works extremely well.

Curt - 95

[Philip Plane]

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.

The DG1000 has a good wheel brake. The Duo Discus has a good brake.

Post by j***@saic.com
I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

Considering a modern two seat glider will be hitting the ground
at 600+ kg and 100 kph with one little near slick tyre and most
likely a grass surface you got no show of getting serious braking.

The DG1000 is tall enough to go _over_ the barbed wire fence. Got to
love a tall undercarriage.

If you hit the spot you should be able to get down in 200 meters over
a normal fence in no wind. If you don't hit the spot a wheel brake won't
save you.

[Bruce]

That's if the DG1000s undercarriage is still in place. The only one I get to see
regularly is developing a bad habit of sliding on it's belly. The braking
effect is poor on grass, but great on tar ;-)

Twin Astir wheel brake works OK.

Like the DG1000 the DuoDiscus wheel brake is good enough to make the nose wheel
work - (well, the Duo has a nose wheel). Presumably all the recent disk braked
aircraft have this ability. Of course, as pointed out elsewhere hitting the
right spot at the right speed is far more important than a strong brake. From
personal experience - too fast, down hill and a 30+ year old 4" drum are a
recipe for trouble. Under these circumstances the best advice I can give is "try
not to point it at anything you want to keep"...

Post by Philip Plane

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.

The DG1000 has a good wheel brake. The Duo Discus has a good brake.

Post by j***@saic.com
I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

Considering a modern two seat glider will be hitting the ground
at 600+ kg and 100 kph with one little near slick tyre and most
likely a grass surface you got no show of getting serious braking.
The DG1000 is tall enough to go _over_ the barbed wire fence. Got to
love a tall undercarriage.
If you hit the spot you should be able to get down in 200 meters over
a normal fence in no wind. If you don't hit the spot a wheel brake won't
save you.

[j***@saic.com]

Post by Bruce
That's if the DG1000s undercarriage is still in place. The only one I get to see
  regularly is developing a bad habit of sliding on it's belly. The braking
effect is poor on grass, but great on tar ;-)
Twin Astir wheel brake works OK.
Like the DG1000 the DuoDiscus wheel brake is good enough to make the nose wheel
work - (well, the Duo has a nose wheel). Presumably all the recent disk braked
aircraft have this ability. Of course, as pointed out elsewhere hitting the
right spot at the right speed is far more important than a strong brake. From
personal experience - too fast, down hill and a 30+ year old 4" drum are a
recipe for trouble. Under these circumstances the best advice I can give is "try
not to point it at anything you want to keep"...

I know, I know.  BTDT.  Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake?  The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.

The DG1000 has a good wheel  brake. The Duo Discus has a good brake.

I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers.  I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

Considering a modern two seat glider will be hitting the ground
at 600+ kg and 100 kph with one little near slick tyre and most
likely a grass surface you got no show of getting serious braking.
The DG1000 is tall enough to go _over_ the barbed wire fence. Got to
love a tall undercarriage.
If you hit the spot you should be able to get down in 200 meters over
a normal fence in no wind. If you don't hit the spot a wheel brake won't
save you.- Hide quoted text -

- Show quoted text -

My question has been anwered. There seem to be several gliders being
produced today that have good brakes. Hooray! Maybe in 10 or 15
years I'll get to fly one! ;-D
Ah, to land on grass...... So far I've not had that experience.

[Cats]

On May 10, 3:12 pm, ***@saic.com wrote:
<snip>

   Ah, to land on grass...... So far I've not had that experience.

I fly in the air, but my ground runs are on grass... :)

[Bruce]

Depending on what kind of grass it is, the experience is well - variable.

The stuff we call grass at my home field is just cut veldt grass. First time I
landed my Cirrus on it I thought I had a flat and landed on the rim.
Subsequently learned to lower the pressure a little in the tyre...

The bowling green that Lasham call a runway, by comparison, is like landing on
slightly damp velvet. If the grass is wet your directional control will be
limited, and braking is unpredictable. If the ground is hard there is very
little retardation, if the ground is soft enough that the wheel digs in the
chance of a ground loop starts to increase proportional to how short the ground
run is.

Post by j***@saic.com

Post by Bruce
That's if the DG1000s undercarriage is still in place. The only one I get to see
regularly is developing a bad habit of sliding on it's belly. The braking
effect is poor on grass, but great on tar ;-)
Twin Astir wheel brake works OK.
Like the DG1000 the DuoDiscus wheel brake is good enough to make the nose wheel
work - (well, the Duo has a nose wheel). Presumably all the recent disk braked
aircraft have this ability. Of course, as pointed out elsewhere hitting the
right spot at the right speed is far more important than a strong brake. From
personal experience - too fast, down hill and a 30+ year old 4" drum are a
recipe for trouble. Under these circumstances the best advice I can give is "try
not to point it at anything you want to keep"...

Post by Philip Plane

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.

The DG1000 has a good wheel brake. The Duo Discus has a good brake.

Post by j***@saic.com
I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

Considering a modern two seat glider will be hitting the ground
at 600+ kg and 100 kph with one little near slick tyre and most
likely a grass surface you got no show of getting serious braking.
The DG1000 is tall enough to go _over_ the barbed wire fence. Got to
love a tall undercarriage.
If you hit the spot you should be able to get down in 200 meters over
a normal fence in no wind. If you don't hit the spot a wheel brake won't
save you.- Hide quoted text -

- Show quoted text -

My question has been anwered. There seem to be several gliders being
produced today that have good brakes. Hooray! Maybe in 10 or 15
years I'll get to fly one! ;-D
Ah, to land on grass...... So far I've not had that experience.

[Cats]

I know, I know.  BTDT.  Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake?  The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.  I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers.  I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

Our club Discus has a brake that's well capable of standing it on it's
nose. I'm guessing the new Discuses (Discii?) are the same.

[JJ Sinclair]

You are comparing a hydraulic disk brake (G-103) to mechanical drum
brakes (most older ships). I can shut down my Genesis in about 100
feet because it has a nose wheel, so I don't have to worry about
scraping the nose or banging the tail down, because it doesn't have a
tail.
I love old stubby,
JJ

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

[Ralph Jones]

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

My partners and I used to have an Astir-CS. A careful brake adjustment
would buy you one, maybe two, firm stops, and the next stop would get
more help from the tailskid than from the brake.

We tried grooving the brake shoes which our mechanic recommended, but
that had no effect. The real problem was in the linkage. It was
actuated by a motorcycle squeeze grip on the stick, and there just
wasn't enough travel available. If the handle moved more than an inch
before the shoe made contact, the rest of its travel would be used up
in stretching the cable, and the handle would hit the stick grip
before any real force got to the shoes.

So we decided to try replacing the cable with something stiffer. An
extensive parts search disclosed that the existing cable was precisely
identical to a Bultaco clutch cable...we were trying to stop a
600-pound sailplane with a cable meant to work the CLUTCH on a
200-pound motorcycle. We eventually found something that worked a bit
better, but still had to adjust pretty frequently.

rj

[j***@saic.com]

Post by Ralph Jones

I know, I know.  BTDT.  Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake?  The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.  I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers.  I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

My partners and I used to have an Astir-CS. A careful brake adjustment
would buy you one, maybe two, firm stops, and the next stop would get
more help from the tailskid than from the brake.
We tried grooving the brake shoes which our mechanic recommended, but
that had no effect. The real problem was in the linkage. It was
actuated by a motorcycle squeeze grip on the stick, and there just
wasn't enough travel available. If the handle moved more than an inch
before the shoe made contact, the rest of its travel would be used up
in stretching the cable, and the handle would hit the stick grip
before any real force got to the shoes.
So we decided to try replacing the cable with something stiffer. An
extensive parts search disclosed that the existing cable was precisely
identical to a Bultaco clutch cable...we were trying to stop a
600-pound sailplane with a cable meant to work the CLUTCH on a
200-pound motorcycle. We eventually found something that worked a bit
better, but still had to adjust pretty frequently.
rj

Yes, I've replaced the original cable on my Speed Astir with more
substantial cable, running in a Teflon sleeved outer. Some
improvement, but lets face it, the mass of the glider and the size of
that single leading shoe brake make it stop, quite predictiably, just
as well as an early 60's Harley.

[Doug Hoffman]

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

I agree completely with that last sentence!

I had an RS-15 in which the builder had installed a standard 4" Tost
drum brake (better than the kit's band-on-tire brake I suppose). The
brake was essentially useless. I've posted this before. I applied the
Tillmann Steckner brake modification (March 1998 Soaring) with superb
results. The new owner of the RS commented on how great the wheel brake
function is. But then this isn't a new glider. Sorry.

Regards,

-Doug

[j***@saic.com]

Post by Doug Hoffman

I know, I know.  BTDT.  Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake?  The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose.  I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers.  I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

I agree completely with that last sentence!
I had an RS-15 in which the builder had installed a standard 4" Tost
drum brake (better than the kit's band-on-tire brake I suppose).  The
brake was essentially useless.  I've posted this before.  I applied the
Tillmann Steckner brake modification (March 1998 Soaring) with superb
results.  The new owner of the RS commented on how great the wheel brake
function is.  But then this isn't a new glider.  Sorry.
Regards,
-Doug

Thanks for the reference Doug. I'm sure someone in our club has that
issue. I'll look into it. Your 4" tost wasn't the 'Lilliput" as used
on the Libelle, was it? Those are fairly hopeless. The brake on my
Speed Astir is the same as the LS-4. Both are marginal. At least the
Speed Astir doesn't have the undercarriage issues the LS-4 does!

[JJ Sinclair]

James,
If your brake is properly adjusted and still doesn't work, I would
check the drum for cracks which can occur from attempted hard
breaking. I tried to stop my LS-6 with a load of water and cracked the
drum in 3 places. Google Vintage Brake, they will install a soft shoe
and true up the system (turn the drum, spike the shoe) and give you
the best shot of reasonable breaking. Make sure your hard points are
secure, I once saw an ASW-15 where the bulkhead that mounted the wheel
hard-point, was moving just a tad, but enough to prevent the force
from being transmitted to the brake.
Hope this helps,
JJ

Post by j***@saic.com

Post by Doug Hoffman

I know, I know. �BTDT. �Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? �The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. �I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. �I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

I agree completely with that last sentence!
I had an RS-15 in which the builder had installed a standard 4" Tost
drum brake (better than the kit's band-on-tire brake I suppose). �The
brake was essentially useless. �I've posted this before. �I applied the
Tillmann Steckner brake modification (March 1998 Soaring) with superb
results. �The new owner of the RS commented on how great the wheel brake
function is. �But then this isn't a new glider. �Sorry.
Regards,
-Doug

Thanks for the reference Doug. I'm sure someone in our club has that
issue. I'll look into it. Your 4" tost wasn't the 'Lilliput" as used
on the Libelle, was it? Those are fairly hopeless. The brake on my
Speed Astir is the same as the LS-4. Both are marginal. At least the
Speed Astir doesn't have the undercarriage issues the LS-4 does!

[Bob Thompson]

Post by j***@saic.com
Thanks for the reference Doug. I'm sure someone in our club has that
issue. I'll look into it. Your 4" tost wasn't the 'Lilliput" as used
on the Libelle, was it? Those are fairly hopeless. The brake on my
Speed Astir is the same as the LS-4. Both are marginal. At least the
Speed Astir doesn't have the undercarriage issues the LS-4 does!

I would like to hear about the "undercarriage issues" with the LS-4.

Bob

[Darryl Ramm]

Post by Bob Thompson

Post by j***@saic.com
Thanks for the reference Doug. I'm sure someone in our club has that
issue. I'll look into it. Your 4" tost wasn't the 'Lilliput" as used
on the Libelle, was it? Those are fairly hopeless. The brake on my
Speed Astir is the same as the LS-4. Both are marginal. At least the
Speed Astir doesn't have the undercarriage issues the LS-4 does!

I would like to hear about the "undercarriage issues" with the LS-4.
Bob

??? Collapsing if the gas strut is weak??? But not an exclusive issue
to the LS4.

Darryl

[d***@nadler.com]

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

The Antares gliders use a Beringer brake and master cylinder.
These are very light, and stop this glider easily (I'm 550kg dry,
660kg at max gross). Only negative: remember not to touch
down with spoilers out full or you may end up replacing a tire !
I'm extremely happy with this system.

A good brake system is comprised of a lot of bits that need
to all be done properly. Here are some of the screw-ups
provided with existing offerings:
- bicycle cables that stretch (even actuating hydraulics)
- cable routing that shreds cables (sharp turns)
- travel limited by badly designed mixing with spoiler mechanism
- hydraulic reservoir below slave cylinder when gear retracted
(siphon action pulls slave cylinders away from disc)
- excess tension blocks open system from venting
- fluid type change leading to corrosion
- single leading shoe drums
- inadequate support for actuating cam in side casting
(wear and slop prevent proper actuation)
- bearings sized inadequately for static load of glider
at max gross (flats bearings which will burn out
on Minden take-offs)

I could go on...

See ya, Dave "YO electric"

[RW]

Post by d***@nadler.com

Post by j***@saic.com
I know, I know. BTDT. Has anyone purchased a NEW sailplane lately,
and been happy with the wheel brake? The ONLY glider I've ever flown
with a decent (not great, but decent) wheel brake is the LVVSA's G103
Twin Astir. For me, a GREAT brake will REQUIRE moderation on my part
to keep from grinding the nose. I'm used to relatively modern
motorcycles, that will lock the front wheel with 2 or 3 fingers. I
would vastly rather scrape my nose, than hit the barbed wire at the
far end of a landout.

The Antares gliders use a Beringer brake and master cylinder.
These are very light, and stop this glider easily (I'm 550kg dry,
660kg at max gross). Only negative: remember not to touch
down with spoilers out full or you may end up replacing a tire !
I'm extremely happy with this system.
A good brake system is comprised of a lot of bits that need
to all be done properly. Here are some of the screw-ups
- bicycle cables that stretch (even actuating hydraulics)
- cable routing that shreds cables (sharp turns)
- travel limited by badly designed mixing with spoiler mechanism
- hydraulic reservoir below slave cylinder when gear retracted
(siphon action pulls slave cylinders away from disc)
- excess tension blocks open system from venting
- fluid type change leading to corrosion
- single leading shoe drums
- inadequate support for actuating cam in side casting
(wear and slop prevent proper actuation)
- bearings sized inadequately for static load of glider
at max gross (flats bearings which will burn out
on Minden take-offs)
I could go on...
See ya, Dave "YO electric"

This topic was in vogue back in 2002. There was mention of a cycle
brake shop in California called VINTAGE BRAKE. I contacted Mike Morse
the owner, and eventually sent him my 5" Tost wheel. What he did was
to install a set of 'advanced composition' brake shoes designed to
minimize fading and to improve the overall performance of vintage
motorcycle drum brakes. He needed my actual wheel so he could first
true it and then 'arc in' the brake shoes to an exacting tolerance.
My DG200's braking went from virtually non-existent to nose-scrapingly
effective :) Make sure you keep full aft elevator if you lean on
these... I found the braking very very effective, yet progressive. I
also changed out the stock 'bicycle brake" quality handbrake lever
and cable, and installed a Harley clutch cable and a higher quality
bicycle handbrake lever on the control stick. It's a must to minimize
stretch in these cables if you want to deliver full force to your
brake shoes. The brake is now overdue for a new set of shoes. It has
been over 6 years since this overhaul was done, and I can tell that
the effectiveness is slipping a bit. Even though I'm overdue, the
braking is still much superior to the original 5" Tost. It was also
very inexpensive as I recall.
www.vintagebrake.com Mike Morse was very pleasant to work with.
I've tried some of the other exotic drum brake fixes out there without
success. One of these 'fixes" is downright dangerous, as it can
induce a lockup of the brake....hopefully one would not accidentally
touch the lever during a takeoff roll... Hope this will help
someone. It has served me well. RW

[Doug Hoffman]

Post by RW
This topic was in vogue back in 2002. There was mention of a
cycle
brake shop in California called VINTAGE BRAKE. I contacted
Mike Morse
the owner, and eventually sent him my 5" Tost wheel. What he
did was
to install a set of 'advanced composition' brake shoes
designed to
minimize fading and to improve the overall performance of
vintage
motorcycle drum brakes. He needed my actual wheel so he could
first
true it and then 'arc in' the brake shoes to an exacting
tolerance.
My DG200's braking went from virtually non-existent to
nose-scrapingly
effective :) Make sure you keep full aft elevator if you lean
on
these... I found the braking very very effective, yet
progressive. I
also changed out the stock 'bicycle brake" quality handbrake
lever
and cable, and installed a Harley clutch cable and a higher
quality
bicycle handbrake lever on the control stick. It's a must to
minimize
stretch in these cables if you want to deliver full force to
your
brake shoes. The brake is now overdue for a new set of shoes.
It has
been over 6 years since this overhaul was done, and I can tell
that
the effectiveness is slipping a bit. Even though I'm overdue,
the
braking is still much superior to the original 5" Tost. It
was also
very inexpensive as I recall.
www.vintagebrake.com Mike Morse was very pleasant to work
with.
I've tried some of the other exotic drum brake fixes out there
without
success. One of these 'fixes" is downright dangerous, as it
can
induce a lockup of the brake....hopefully one would not
accidentally
touch the lever during a takeoff roll... Hope this will
help
someone. It has served me well.

Makes one wonder how/why Tost built such poor brakes for so many
years.

[Andy]

Post by Doug Hoffman
Makes one wonder how/why Tost built such poor brakes for so many
years.

Maybe because glider manufacturers kept buying them? Maybe because a
good brake is not much use on wet grass?

Anyway they were not a bad as some people make out. I serviced mine
(ASW-19b) at every annual inspection and it was good for a season
unless called upon to do a max energy stop. Each year I dismantled
the brake, cleaned the drum and gave it a light wipe with 600 grit,
cleaned the shoes and busted any glaze with 600 grit, cleaned and
greased the cam faces and shaft and the pivot point. Its important
that the brake is applied as the wheel spindle nut is tightened to
ensure the brake plate is properly aligned. It's also important that
the cable and cam arm make an angle of about 85 deg to each other when
the brake is full on to get maximum mechanical advantage.

None of this was strange to me as I had years of experience dealing
with British motorcycle drum brakes before I got into gliding.

Andy