more confusion on cessna performance chart

On Jan 16, 4:44*am, "RST Engineering" wrote:
It is a steeped-in-tradition engineering convention used to describe
something that is very, very close to the correct answer. *It derives from
the very fine hair found on the lower-midsection of the adult female, of
which the red has been experimentally found to be the smallest in diameter..

It took centuries of trial and measurement to prove this experiment correct
{;-)

Well thanks for that Jim. Downunder we have a similar but slightly less technical saying for something that is very close. It is called "within a bees dick"

Terry

On Jan 16, 7:05*am, "Ken S. Tucker" wrote:
Humidity feeds into "density altitude" because water
vapour molecule H2O has density ~ 10 compared to
Nitrogen N2 ~ 14 *at equal pressures*

Not quite. The density is proportional to molecular weight, which
would be in the ratio of 18 for water to 28 for nitrogen ( g /mol )
But of course we are really interested in the density ratio between
water and air which would be 18 to 28.9

Ths simply comes from rearranging the Gas Equation we all learn in
high school
PV =nRT
substiute n =m/M where m is mass and M molecular weight , you
rearrange to get
m/V = PM / RT
m/V of course = density
( assuming ideal behaviour exists which is a pretty good assumption at
the pressures and temperatures involved in flying light aircraft ).

I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
* In Quantum Theory that makes sense.
To start, warm air is more chaotic than cold air at the
molecular level, and the chaos *seeds* the turbulence.
You know, hot fluids are less viscous than cold and so
less sticky. That's likely a secondary correction.
Regards
Ken- Hide quoted text -

So if warm air is more turbulent ( I think I can accept that ) wouldnt
that mean that at higher temperatures for the same density altitude
you would get less lift and require longer take off distance?
As previously stated the results are the other way around.

Cheers
Terry

"RST Engineering" wrote in
:


"Jim Macklin" wrote in message
...
roflol, what kinds of experiments are/were needed to prove
the axiom?

Don't get me started. You know how I am...



Two guys walking down the sidewalk and pass a good looking brunette.

"Ever sleep with a brunette?" "Yeah, I've slept with a few brunettes."

They pass a beautiful blonde.

"Ever sleep with a blonde?" "Yeah, I've slept with a few blondes."

They pass a KNOCKOUT redhead.

"Ever sleep with a redhead?" "Not a wink."




"Redheads buck like goats"

~Jimmy Joyce


Bertie

"Ken S. Tucker" wrote:
I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.

Your sudden invocation of quantum theory doesn't make any sense to me. At
no point does one need to utilize the Schrodinger, Dirac, or Klein-Gordon
equations or any of their related equations in order to model or understand
the onset of turbulence.

Jim Logajan wrote in
:

"Ken S. Tucker" wrote:
I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.

Your sudden invocation of quantum theory doesn't make any sense to me.
At no point does one need to utilize the Schrodinger, Dirac, or
Klein-Gordon equations or any of their related equations in order to
model or understand the onset of turbulence.



When the molecules in your coke can start sonoluminescing from the
turbulence, prolly.

Bertie

Bertie the Bunyip wrote:
Jim Logajan wrote in
:

"Ken S. Tucker" wrote:
I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.

Your sudden invocation of quantum theory doesn't make any sense to me.
At no point does one need to utilize the Schrodinger, Dirac, or
Klein-Gordon equations or any of their related equations in order to
model or understand the onset of turbulence.



When the molecules in your coke can start sonoluminescing from the
turbulence, prolly.

Ah - I see - I think. How stupid of me. So would that result in cold fusion
or coke fusion?

Jim Logajan wrote in
:

Bertie the Bunyip wrote:
Jim Logajan wrote in
:

"Ken S. Tucker" wrote:
I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.

Your sudden invocation of quantum theory doesn't make any sense to
me. At no point does one need to utilize the Schrodinger, Dirac, or
Klein-Gordon equations or any of their related equations in order to
model or understand the onset of turbulence.



When the molecules in your coke can start sonoluminescing from the
turbulence, prolly.

Ah - I see - I think. How stupid of me. So would that result in cold
fusion or coke fusion?


I think the latter may explain Ken...


Bertie

On Jan 15, 5:59 pm, terry wrote:
On Jan 16, 7:05 am, "Ken S. Tucker" wrote:

Humidity feeds into "density altitude" because water
vapour molecule H2O has density ~ 10 compared to
Nitrogen N2 ~ 14 *at equal pressures*

Not quite. The density is proportional to molecular weight, which
would be in the ratio of 18 for water to 28 for nitrogen ( g /mol )
But of course we are really interested in the density ratio between
water and air which would be 18 to 28.9

Ths simply comes from rearranging the Gas Equation we all learn in
high school
PV =nRT
substiute n =m/M where m is mass and M molecular weight , you
rearrange to get
m/V = PM / RT
m/V of course = density
( assuming ideal behaviour exists which is a pretty good assumption at
the pressures and temperatures involved in flying light aircraft ).

I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.
To start, warm air is more chaotic than cold air at the
molecular level, and the chaos *seeds* the turbulence.
You know, hot fluids are less viscous than cold and so
less sticky. That's likely a secondary correction.
Regards
Ken- Hide quoted text -

So if warm air is more turbulent ( I think I can accept that ) wouldnt
that mean that at higher temperatures for the same density altitude
you would get less lift and require longer take off distance?

" As previously stated the results are the other way around."
Cheers
Terry

I checked what you "previously stated", and the words
"correction" and "difference" didn't have the usual "+/-"
in them.
Is the Cessna handbook online, that will save time,
I'm interested.
Regards
Ken

On Jan 15, 10:05 pm, Jim Logajan wrote:
"Ken S. Tucker" wrote:

I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.

Your sudden invocation of quantum theory doesn't make any sense to me. At
no point does one need to utilize the Schrodinger, Dirac, or Klein-Gordon
equations or any of their related equations in order to model or understand
the onset of turbulence.

Warmer atmospheric gas has a greater photon
exchange rate and that creates repulsion, that of course
is why a heated closed volume increases in pressure.
We may term that as "anti-viscosity", where viscosity
is similiar to "stickiness".

In brief, *warm things repel warm things* better than
*cold things repel colds things*, all other things being
equal.
Regards
Ken

On Jan 15, 10:27 pm, Jim Logajan wrote:
Bertie the Bunyip wrote:



Jim Logajan wrote in
0:

"Ken S. Tucker" wrote:
I'm guessing: but I get the impression that the onset
of turbulence over wings was also dependant on temp-
erature, even when the density altitude is the same.
In Quantum Theory that makes sense.

Your sudden invocation of quantum theory doesn't make any sense to me.
At no point does one need to utilize the Schrodinger, Dirac, or
Klein-Gordon equations or any of their related equations in order to
model or understand the onset of turbulence.

When the molecules in your coke can start sonoluminescing from the
turbulence, prolly.

Ah - I see - I think. How stupid of me. So would that result in cold fusion
or coke fusion?

Hey, be quiet, I've nearly got the wife, aka "money bags"
talked into taking flying lessons. Once that happens I
might be able to squeak some funds for our own A/C.
I needs encouragement!
Ken