Cirrus Killer? Cessna just doesn't get it...

"john smith" wrote in message
...
In article ,
"Morgans" wrote:

"john smith" wrote in message
...
I just got a mailing from Cessna yesterday. Look here...
www.cessnareasons.com

What did you find interesting in this mailing, relevant (or even close)
to
this thread?

According to the brouchure, it lists 43 reasons to buy a Cessna.

Right!
--
Jim in NC

"Matt Whiting" wrote in message
...
[...]
That is because you aren't correct. Tire pressure only has a significant
impact on very soft surfaces such as sand, where the extra surface area
helps with flotation. In most snow, it makes little difference.

Actually, we're both incorrect.

My statement was based on a theoretical understanding of friction in which
the friction depends on the force over an area. Since tire pressure
directly determines this, I assumed it had a direct effect on friction.

I found at least one reference that says that physicists ignore the area
over which the force is distributed, for the purpose of determining
friction. It did say that's actually an incorrect assumption, but that it's
"close enough" for most purposes.

I didn't bother to look further to see just how far off this "close enough"
assumption is. The reference didn't go into much detail on that regard.

Beyond that, the same reference also had a discussion of tires on snow,
oddly enough (I wasn't even looking for that specifically). They claim that
increased tire pressure actually *reduces* friction, because packed snow has
lower friction than unpacked snow, and higher tire pressures result in
greater packing of the snow.

So, tire pressure has a very significant effect on tire friction when
driving on snow. But it's opposite what would be the case on a solid
surface. So, chalk that point up for the anti-SUV crowd.

I still think it's a silly argument.

Pete

"Matt Whiting" wrote in message \

That is because you aren't correct. Tire pressure only has a significant
impact on very soft surfaces such as sand, where the extra surface area
helps with flotation. In most snow, it makes little difference.

Makes a big difference on packed snow and ice. Ice racers use inner tubes
and run the tire pressures very low. Pump them up and they don't stick.

moo

On 2005-10-01, Paul Tomblin wrote:
In a previous article, "Morgans" said:
and their stuff, kids friends, and other general stuff. Four wheel drive,
so you can still go when it snows, or you park in the wet grass, and get
^^^^^^^^^^^^^^^^
Too bad they don't give you the ability to stop when it snows.

Justice was served a couple of years ago in the Cottonwood Canyons (I
don't remember which one, I think it was the one going to Brighton).
Friends and I were carefully going up the canyon in a Volkswagon Jetta
TDi with snow chains. The guy in the 4x4 behind us was obviously getting
impatient, and went roaring by us.

Half a mile later, we passed him - as he was trying to extract his truck
from a ditch.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

On 2005-10-01, Matt Whiting wrote:
Yes, most folks don't tow their trailer to work every day with them.
However, they may tow it every weekend.

Most folks with SUVs never tow anything at all. SUVs were popular where
I used to live in Houston. I'd estimate from suburban driveways that
about 1 in 10 SUVs ever towed anything at all, and about the same
proportion ever used more than 4 seats - ever. Out of the 1 in 10 that
had a trailer to pull, about half of those trailers could easily be
towed safely by a normal midsize car. Most SUVs are bought not to
offroad, tow, haul 7 passengers - but to look cool.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

TaxSrv wrote:
"Matt Whiting" wrote:

Why? Most companies at least ostensibly exist to make a profit.

Matt


Sure, and Textron is profitable, but the impact of piston singles
on their financials is insignificant, perhaps less than 1% of their
$12 billion business. What I was trying to say is if they lose
money on singles, as you theorize and so might I, they can still
have a business reason to tolerate it and not uncommon in industry
at all. In their latest annual report, they mention the singles
only in passing, but as opposed to lengthy discussion of jets and
other product lines, they don't state the amount of "segment
profit" on the piston products. Maybe there ain't any?

OK, I see what you were saying. I suspect it is mainly based on the
personal desires of some Cessna executives as well as a
marketing/strategic purpose to build brand loyalty in pilots early. I
don't think it was purely the airplanes themselves that catapulted
Cessna to the top of the bizjet market relatively quickly. I suspect it
was also at least partly due to all of the pilots trained in Cessna's
who now fly for, or own, many of the companies that fly Cessna jets.


Matt

Peter Duniho wrote:

"Matt Whiting" wrote in message
...

[...]
That is because you aren't correct. Tire pressure only has a significant
impact on very soft surfaces such as sand, where the extra surface area
helps with flotation. In most snow, it makes little difference.


Actually, we're both incorrect.

My statement was based on a theoretical understanding of friction in which
the friction depends on the force over an area. Since tire pressure
directly determines this, I assumed it had a direct effect on friction.

I don't recall area being a part of the thoeretical equation. My
Physics book says that F=uN, where F is the total force due to friction,
u (mu) is the coefficient of static or dynamic friction as the case may
be, and N is the normal force holding the two surfaces together. Area
isn't part of the equation. Now there are materials reasons that area
does have an impact, that that isn't in the basic theory.


I found at least one reference that says that physicists ignore the area
over which the force is distributed, for the purpose of determining
friction. It did say that's actually an incorrect assumption, but that it's
"close enough" for most purposes.

Actually, every reference I've ever seen ignores area, because it is
only a factor in special circumstances and then it is related to the
materials failing, not to the underlying theory of friction.


I didn't bother to look further to see just how far off this "close enough"
assumption is. The reference didn't go into much detail on that regard.

That is because you are wrong and didn't want to further show that.


Beyond that, the same reference also had a discussion of tires on snow,
oddly enough (I wasn't even looking for that specifically). They claim that
increased tire pressure actually *reduces* friction, because packed snow has
lower friction than unpacked snow, and higher tire pressures result in
greater packing of the snow.

That is a somewhat specious description, but in any event tire pressure
is at best a second or third order effect, it isn't a first order affect.


So, tire pressure has a very significant effect on tire friction when
driving on snow. But it's opposite what would be the case on a solid
surface. So, chalk that point up for the anti-SUV crowd.

Still wrong. Tire pressure is little affect.


I still think it's a silly argument.

Yes, when I'm shown to be wrong, I usually think it was a silly argument
at that point as well. :-)

Matt

Happy Dog wrote:

"Matt Whiting" wrote in message \


That is because you aren't correct. Tire pressure only has a significant
impact on very soft surfaces such as sand, where the extra surface area
helps with flotation. In most snow, it makes little difference.


Makes a big difference on packed snow and ice. Ice racers use inner tubes
and run the tire pressures very low. Pump them up and they don't stick.

Most also use studs or spikes. :-)


Matt

Dylan Smith wrote:

On 2005-10-01, Matt Whiting wrote:

Yes, most folks don't tow their trailer to work every day with them.
However, they may tow it every weekend.


Most folks with SUVs never tow anything at all. SUVs were popular where
I used to live in Houston. I'd estimate from suburban driveways that
about 1 in 10 SUVs ever towed anything at all, and about the same
proportion ever used more than 4 seats - ever. Out of the 1 in 10 that
had a trailer to pull, about half of those trailers could easily be
towed safely by a normal midsize car. Most SUVs are bought not to
offroad, tow, haul 7 passengers - but to look cool.

I can't speak for TX as I don't live there, but I don't think your stats
hold true in PA.


Matt

Not to mention:

C130
C141
C5
C17