aircraft brakes were never designed for stopping aircraft.

some interesting points came out of one guy's query re servicing some
old brake master cylinders.

gringomasloco commented regarding broken brake lines spraying brake
fluid over hot calipers and setting the wheels on fire. hmmmmm.

I am talking about light private aircraft here...

as I put it in the subject line aircraft brakes were never designed
for stopping aircraft. they were designed to hold aircraft.
now that may sound like semantic nonsense but it is true.

aircraft brakes were designed for use in holding the aircraft still
while the engine was started. after the taxy out and the engine has
warmed you do a run up check to make sure that the magneto circuits
are up to the bit of work that lies ahead for them. the brakes are
applied to hold the aircraft while the revs are bought up and each
maggy checked in turn.

from a design aspect that is the end of the use of a light aircraft's
brakes until after landing and we wish to hold the aircraft still for
shutdown and disembarkation.

of course brakes are brakes and people will use them like they were
driving cars. light aircraft brakes were never designed for slowing an
aircraft when landing.
I know that they get used for that by students of bad piloting
technique but the design intent is a fact borne out by their
diminutive size.

I'll give one concrete example. The Stinson 108 is a huge aircraft, 4
seats in 1940's luxury, yet it only has brake pucks the same size as a
5.00x5 cleveland. in fact on the one Chris M-F ownes the brakes *are*
cleveland 5.00x5 calipers.

it is quite ok to be masters of the world and fly however you like.
you'll just wear out your aeroplanes faster.

just remember though that aircraft brakes are for holding the aircraft
not stopping it.

now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

Stealth Pilot

"Stealth Pilot" wrote in message
...
just remember though that aircraft brakes are for holding the aircraft
not stopping it.

now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

Apparently Cessna has also yet to realize that.

From Cessna 152 POH: (Step 6 of short field landing procedure) "6. Brakes--
APPLY HEAVILY."


Good Morning! ;-)
Vaughn

On Jul 19, 7:27�am, "Vaughn Simon"
wrote:
"Stealth Pilot" wrote in message

...

just remember though that aircraft brakes are for holding the aircraft
not stopping it.

now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

� �Apparently Cessna has also yet to realize that.

From Cessna 152 POH: (Step 6 of short field landing procedure) "6. Brakes-- �
APPLY HEAVILY."

Good Morning! �;-)
Vaughn

Where do light and heavy begin? I have a 2,000 pound gross
weight airplane. We picked the brakes based on a start braking speed
of about 70 knots. I can do multiple stops from slower speeds during
high speed taxi testing. Braking capacity is mostly a funtion of how
much mass the disk has whcih in turn determines how much heat it can
absorb. Keep the brakes small to keep the airplane light and limit
your runway options. Add some mass and stop with brakes on shorter
runways. You're experimental. Take your pick. BTW, I changed my
brake pads after about 1,200 hours because they were getting thin, but
not worn out. For me, it's cheaper and easier to change brake pads
than tires worn out by long rollouts and long taxi distances.

Denny

On Jul 19, 3:54*am, Stealth Pilot
wrote:


as I put it in the subject line aircraft brakes were never designed
for stopping aircraft. they were designed to hold aircraft.
now that may sound like semantic nonsense but it is true.

--------------------------------------------------------------------------------------------

That is what I was taught. The distinction was based on breaking
surface area.

Military and commercial aircraft, meaning those having a need to bring
the loaded airplane to a full stop AND TO HOLD IT THERE during run-up
or whatever, were often fitted with brake drums rather than pucks &
rotors, since you could get more breaking surface for less weight when
using a drum & shoe arrangement.

However, modern puck & rotor systems commonly use calipers that
present a puck to each side of the rotor, allowing you to double the
breaking surface for only a modest increase in weight.

The down-side here is the need to get rid of the heat such systems can
produce when going for a full-stop.

Some modern-day systems offer a dual system, with single-pucks
intended to do the slowing/steering and dual pucks coming on-line to
provide the stoping & holding.

-R.S.Hoover

In article ,
Stealth Pilot wrote:

some interesting points came out of one guy's query re servicing some
old brake master cylinders.

gringomasloco commented regarding broken brake lines spraying brake
fluid over hot calipers and setting the wheels on fire. hmmmmm.

I am talking about light private aircraft here...

as I put it in the subject line aircraft brakes were never designed
for stopping aircraft. they were designed to hold aircraft.
now that may sound like semantic nonsense but it is true.

aircraft brakes were designed for use in holding the aircraft still
while the engine was started. after the taxy out and the engine has
warmed you do a run up check to make sure that the magneto circuits
are up to the bit of work that lies ahead for them. the brakes are
applied to hold the aircraft while the revs are bought up and each
maggy checked in turn.

from a design aspect that is the end of the use of a light aircraft's
brakes until after landing and we wish to hold the aircraft still for
shutdown and disembarkation.

of course brakes are brakes and people will use them like they were
driving cars. light aircraft brakes were never designed for slowing an
aircraft when landing.
I know that they get used for that by students of bad piloting
technique but the design intent is a fact borne out by their
diminutive size.

I'll give one concrete example. The Stinson 108 is a huge aircraft, 4
seats in 1940's luxury, yet it only has brake pucks the same size as a
5.00x5 cleveland. in fact on the one Chris M-F ownes the brakes *are*
cleveland 5.00x5 calipers.

it is quite ok to be masters of the world and fly however you like.
you'll just wear out your aeroplanes faster.

just remember though that aircraft brakes are for holding the aircraft
not stopping it.

now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

Stealth Pilot

Nonsense: complete and utter.

What aircraft brakes aren't designed for is stopping aircraft
*repeatedly*.

The chief advantage of putting larger brakes on any vehicle is that it
providess a greater heat sink to allow for more braking before the
brakes overheat.

Aircraft brakes need to be able to stop an aircraft *once* and then have
an essentially infinite amount of time to cool down again.

--
Alan Baker
Vancouver, British Columbia
http://gallery.me.com/alangbaker/100008/DSCF0162/web.jpg

Stealth Pilot wrote:

as I put it in the subject line aircraft brakes were never designed
for stopping aircraft. they were designed to hold aircraft.
now that may sound like semantic nonsense but it is true.

How does one steer a C152 while taxiing?

I was headed bopping down the downhill section of KTTA's single taxiway, when one of the LSA trainees decided that his
fuel was more important than mine. He pulled out heading straight to me. There was only one turn off, and I had about
20 feet to come to a complete stop or we'd have a mess. The old hacker that I am, I decided that using the brakes were
the best way to accomplish the task. I know that it wasn't the right thing to do. I should have cut the engine, jumped
out, and grabbed the tail to drag it to a halt like everyone is taught in groundschool. But I guess I'm just lazy.

On Sat, 19 Jul 2008 18:54:27 +0800, Stealth Pilot
wrote:


some interesting points came out of one guy's query re servicing some
old brake master cylinders.

gringomasloco commented regarding broken brake lines spraying brake
fluid over hot calipers and setting the wheels on fire. hmmmmm.

I am talking about light private aircraft here...

as I put it in the subject line aircraft brakes were never designed
for stopping aircraft. they were designed to hold aircraft.
now that may sound like semantic nonsense but it is true.

aircraft brakes were designed for use in holding the aircraft still
while the engine was started. after the taxy out and the engine has
warmed you do a run up check to make sure that the magneto circuits
are up to the bit of work that lies ahead for them. the brakes are
applied to hold the aircraft while the revs are bought up and each
maggy checked in turn.

Ahhh...I beg to differ here. First time I got someone qualified to
ride with me so I could get back in the air, they were astounded that
I could lock the brakes and acellerate.

(No, I didn't let it go very far as that's kinda hard on the tires,
but I assure you that with some planes you can take off with the
brakes locked *IF* the tires hold out. OTOH the landing and taxi are
going to be a bit bumpy:-))

BTW the brakes will hold it to do a runup IF you don't go past the RPM
listed for the runup of 2100 RPM at cycling the prop. Even the taxiway
*must* be clean and dry. It's already moving at 2400 and acellerting
when firewalled.

Those tires have a linear tread for squeezing water out and
maintaining direction. They aren't worth much for traction when it
comes to braking. Actually if you lock them up they start to
hydroplane on their own vaporized rubber.

It ain't the brakes, it's the tires and a lack of traction by those
tires. The brakes on the Deb will lock up the tires and that's as
much as you can get out of any brakes.


now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

Stealth Pilot
Roger (K8RI) ARRL Life Member
N833R (World's oldest Debonair)
www.rogerhalstead.com

now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

Stealth Pilot


What an utterly absurd statement! You may not need to use the brakes
to stop but that's what they're there for. On a long enough runway I
may not use the brakes at all but on a short runway, you better
believe the brakes will be needed to stop whether you're flying a 747
or a C-150. Everything is a compromise concerning weight and
capability on an aircraft; aircraft brakes on light aircraft may not
have the stopping power of power disc brakes on a dump truck but both
are designed for "stopping."

On Wed, 30 Jul 2008 16:14:26 -0700 (PDT), 150flivver
wrote:

now brakes for commercial aircraft are different and they *are* used
for stopping, but the brakes on little lighties arent.
some people have yet to realise that.

Stealth Pilot


What an utterly absurd statement! You may not need to use the brakes
to stop but that's what they're there for. On a long enough runway I
may not use the brakes at all but on a short runway, you better
believe the brakes will be needed to stop whether you're flying a 747
or a C-150. Everything is a compromise concerning weight and
capability on an aircraft; aircraft brakes on light aircraft may not
have the stopping power of power disc brakes on a dump truck but both
are designed for "stopping."

one day it is hoped that you will learn something of aircraft design
and good piloting skills.
untill then I suppose you'll just keep plugging away doing the best
you can as a poor pilot.

the brake pads on your aircraft are about 3/4" x 2" in size.
the aircraft weighs 1500lb.

....but why am I surprised. the average american doesnt even know how
to change a tyre.

Stealth Pilot

"Stealth Pilot" wrote in message
...
one day it is hoped that you will learn something of aircraft design
and good piloting skills.

And perhaps one day you will learn to read the responses to your posts,
several of which have proven you to be wrong about the purpose of aircraft
brakes. Did you ever bother to read any Cessna POH? (From Cessna 152 POH: (Step
6 of short field landing procedure) "6. Brakes-- APPLY HEAVILY.")

What are the FAA certification requirements regarding aircraft brakes? Do the
required certification tests involve actually stopping the aircraft?

Further, if light aircraft brakes are only there for holding the aircraft
against the engine (and perhaps for taxiing), why does every glider I have ever
flown have a brake installed on the main wheel?

Vaughn