On Mon, 18 Oct 2010 13:34:38 -0700 (PDT), Robatoy
wrote:

On Oct 18, 1:23Â*pm, wrote:
On Sun, 17 Oct 2010 22:59:03 -0400, wrote:
On Sun, 17 Oct 2010 20:43:53 -0400, "Josepi"
wrote:

Rust on the back disks from lack of heavy usage.

I doubt it would be oak rust, though.

"Robatoy" wrote in message
...
All you need to do is look at the history of the disc brake.
Lightweight, high-speed stopping power, reliable, operable in wet
conditions... IOW...aircraft.

Â*And you are WRONG again, Robotoy.
Disc brakes were invented before flight.

The drum brake, as it is now known, became all-dominant in the United
States. In Europe, particularly in Great Britain, it had to share the
stage with disc brakes. Disc brakes became more or less standard on
European cars during the '50s, about 20 years before they were adopted
by American manufacturers in 1973.

This is ironic, because the spot-type disc brake is an American
invention. In 1898, Elmer Ambrose Sperry of Cleveland designed an
electric car having front-wheel disc brakes.

He made a large disc integral with the hub on each wheel.
Electromagnets were used to press smaller discs, lined with a friction
material, against spots on the rotating disc to bring the wheel to a
stop. Springs retracted the spot discs when current was interrupted.

Meanwhile in Great Britain, a patent was issued in 1902 to F. W.
Lanchester for a nonelectric spot disc braking system that's similar
in principle to what we have today. The biggest problem that
Lanchester encountered was noise. Metal-to-metal contact between his
copper linings and the metal disc caused an intense screech that sent
chills through anyone within earshot.

The problem was solved in 1907 when Herbert Frood, another Englishman,
came up with the idea of lining pads with asbestos. The new material
was quickly adopted by car manufacturers on both drum and disc brakes.
Asbestos linings also outlasted other friction materials by a wide
margin. The 10,000-mile brake job had arrived.

As roads improved and cars began to be driven at high speeds,
manufacturers recognized the need for even greater braking power. One
solution to the problem became apparent during the Elgin road Race of
1915. A Duesenberg took the flats at 80 mph, then screeched to a
virtual crawl to negotiate the hairpin curves. Duesenberg's secret for
such magnificent braking power was to simply use an internal brake on
each front wheel as well as each rear wheel.

In 1918, a young inventor named Malcolm Lougheed (who later changed
the spelling of his name to Lockheed) applied hydraulics to braking.
He used cylinders and tubes to transmit fluid pressure against brake
shoes, pushing the shoes against the drums. In 1921, the first
passenger car to be equipped with four-wheel hydraulic brakes appeared
-- the Model A Duesenberg.

Carmakers as a group were not quick to adopt hydraulics. Ten years
after the Model A Duesie, in 1931, only Chrysler, Dodge, Desoto,
Plymouth, Auburn, Franklin, Reo, and Graham had hydraulic brakes. All
the others still had cable-operated mechanical brakes. In fact, it was
not until 1939 that Ford finally gave in, becoming the last major
manufacturer to switch to hydraulic brakes.

The basic braking system we have today was pretty much in place by
1921, including a refinement some regard as contemporary -- power
assist.

Power assist, technically, dates back to 1903 when a car called the
Tincher used air brakes. But the first car to be equipped with a
vacuum-operated power booster similar to those we have today was the
1928 Pierce-Arrow. It used vacuum from the inlet manifold to reduce
the physical effort needed to apply brakes. Vacuum boosters from then
to now have similar designs.

The first widespread deviation from vacuum power assist came about in
1985. Some '85 GM cars use an electrically driven brake booster, which
is smaller and lighter than the conventional vacuum booster, giving an
all-hydraulic system. Some cars with antilock brakes also use
all-hydraulic systems.

The first car to have self-adjusting brakes was the 1925 Cole. The
prototype for today's systems appeared on the 1946 Studebaker. The
mechanism by Wagner Electric Co., consisted of an adjusting wedge
under the influence of a tension spring. As linings wore, a plug
receded to move a pin and lever against the spring. This forced the
adjusting wedge against brake shoes, which expanded to keep linings at
a preset distance from the drums.

As for the antilock (antiskid) units now available in the U.S., they
are hardly new. The first practical antiskid braking system, named
Maxaret, was developed in 1958 by the Road Research Laboratories in
Great Britain and was first applied to the Jensen FF sports sedan in
1966.

Three years later, in 1969, the Lincoln Continental Mark III was
equipped with an Auto-Linear antilock unit developed by Kelsey-Hayes.
Sensors on the rear wheels transmitted signals to a transistorized
"computer" behind the glove box. The computer controlled a
vacuum-operated valve on the rear brake line to modulate pressure to
the rear brakes when the sensors told the computer that the brakes
were locking.

Cost and some technical problems caused the shelving of this unit. But
now, updated versions that give four-wheel skid control are offered on
almost every car model, although initially they were available only on
high-end cars like Lincoln and Mercedes, and a few European cars.

Computerized brakes notwithstanding, there is a piece of advice about
using brakes that's as relevant today as it was in 1909 when it was
first published in The American Cyclopedia of the Automobile:

"Good driving in traffic is shown by making the minimum use of brakes.
The strain on passengers amounts to intense nervousness when the car
is constantly driven so that the least alteration of direction or of
pace on the part of any vehicle ahead results in the violent
application of the brake."

And so it will always be.



On the back-end of a competition car, inboard disc brakes are often
used to reduce the unsprung weight. In high-end 4-wheel (Quattro)
competition drive systems, the discs are sometimes even found inboard,
at the front-end.

There simply isn't one single reason NOT to have disc brakes.

There were even a few inboard DRUM brake vehicles built. Front drive
too. IIRC one of the NSU or DKW models, and perhaps the SAAB Sonnett??

How does that make me wrong? Are you telling me that disc brakes are
not the preferred system for aircraft for all those reasons I laid
out? That it wasn't the aircraft people who developed many facets of
those systems?

You stated, or appeared to state, that disc brakes were developed for
aircraft use and they were lighter because of that.

In that, you are wrong. If that's not what you MEANT, it IS what you
SAID.
Tell you what..... there was a guy in my home-town in Holland who tied
his 1930-sh Somethingmobile to a tree with a rope so it wouldn't roll
down his laneway. Now I suppose you will give me a dissertation on
rope-brake systems through the frikkin' ages as well? What about
parachute brakes? There are all kinds of people using those. The
Veyron uses a big paddle that rises out of the back of the car to
assist slowing the thing down.
Anywhooo.. disc brakes are the preferred systems regardless whether or
not the Queen's carriage has a leather pad rubbing on the tyres.

And I never said disc brakes were not better, overall than drums.
All I said, which you have not been able to, and never will be able to
prove me wrong, is that a drum brake, properly set up and adjusted,
will stop a car more effectively on the first stop than a disc of the
same size on the same car. It is a proven fact.

It is also a proven fact that a properly designed and implemented disc
brake will outbrake any drum brake under extreme use and in repeated
applications. I have never disputed that.