Should I be scared -- C172 over Gross

terry wrote in news:303fdf2b-7e83-4b08-aaf8-
:

On Apr 22, 10:16*am, tman inv@lid wrote:
tman wrote:

, and also the day turned out to be +20F hotter than I thought
it would. *I've experienced that heat not only hurts the planes
performance, but the pilots too. *Oh yeah, a slightly gusty xwind
too.
Pretty happy I planned on leaving one pax behind.

If you look very closely at the take off performance data of a 172
( which I have) you will find that higher temperature actually
improves performance, for the same air density. Now I know that
contradicts what we get taught in flight school, and while it is
generally true that when temperature is lower the air will be more
dense , the atmosphere is a dyanmic system and pressure and
temperature can vary independantly. So it is possible to have the
same air density , or density altitude at 2 different temperature and
the day with the higher temperature wil give you better performance.
It is related to engine performance and the best explanation I have
got is that at the same density on a higher temperature day, the
pressure will also be higher ( since density = PM/RT where M is
molecular wt, R is gas constant, P and T press and temp), and the
higher pressure provides a greater driving force to suck air into the
engine. If you do the same analysis on the landing distance you see
no such temperature effect because landing distance is not power
related , only lift related.
In the next few days I will get around to providing a link to this
data, but you can easily prove it yourself if you have the Cessna
takeoff distance tables..
Terry

Yeah, you'll get about 1% per 5 deg C on a typical normally aspirated
lightplane engine under those circumstances.

Bertie

gregvk wrote in news:Xns9A89A923F1A08E817AC3D8380227
@127.0.0.1:

Bertie the Bunyip wrote in news:fuo8tf$6rt$1
@blackhelicopter.databasix.com:

"Maxwell" luv2^fly99@cox.^net wrote in
:


"gregvk" wrote in message
...
Bertie the Bunyip wrote in news:fuo1ls$iga$1
@blackhelicopter.databasix.com:

"Maxwell" luv2^fly99@cox.^net wrote in
:


"Mxsmanic" wrote in message
...
writes:

Funny that where ever you post there seems to be a "treehouse
club" that thinks you are a twit.

I consider it more sad than funny. There are a lot of mean
people
in the world, and for some reason cyberspace encourages them to
show their true colors.

It's always someone else's fault, isn't it?





1


Bertie

"Results 1 - 10 of about 1,280 for group:rec.aviation.piloting
author:Maxwell"

Erm, better start the counter at 1,281.

Ahh, give it a rest Bertie. Your sockpuppet routine isn't fooling
anyone, just showing how lame you really are.

Besides, your statistics are waaaay off.



Uh, yeh, sure k00kie boi.


I thought you were running away? Forget something?



Bertie

/rolls eyes

Am I your sock or are you my sock? Just wondering.

I'm not fussy. In Maxie's mind anything is possible, so maybe we're like
that Escher drawing of the two hands drawing each other..

And I like how Maxie-poo thinks his post count is more accurate than
Google's post count. It's... cute.


He's adorable.


Bertie

On Apr 24, 9:31 am, terry wrote:
On Apr 22, 10:16 am, tman inv@lid wrote: tman wrote:

, and also the day turned out to be +20F hotter than I thought it would. I've experienced that heat not only hurts the planes
performance, but the pilots too. Oh yeah, a slightly gusty xwind too.
Pretty happy I planned on leaving one pax behind.

If you look very closely at the take off performance data of a 172
( which I have) you will find that higher temperature actually
improves performance, for the same air density. Now I know that
contradicts what we get taught in flight school, and while it is
generally true that when temperature is lower the air will be more
dense , the atmosphere is a dyanmic system and pressure and
temperature can vary independantly. So it is possible to have the
same air density , or density altitude at 2 different temperature and
the day with the higher temperature wil give you better performance.
It is related to engine performance and the best explanation I have
got is that at the same density on a higher temperature day, the
pressure will also be higher ( since density = PM/RT where M is
molecular wt, R is gas constant, P and T press and temp), and the
higher pressure provides a greater driving force to suck air into the
engine. If you do the same analysis on the landing distance you see
no such temperature effect because landing distance is not power
related , only lift related.
In the next few days I will get around to providing a link to this
data, but you can easily prove it yourself if you have the Cessna
takeoff distance tables..
Terry
PPL Downunder

You can play with your C172 N weight and balance here
http://home.new.rr.com/trumpetb/alph/wb172N.html

Mxsmanic wrote:
Dudley Henriques writes:

You are to be Congratulated!

With this absolutely astounding statement of astronomically historic and
infallible intellect, you have succeeded in completely negating the
entire concept of learning.

You're confusing acquired knowledge with intelligence. Intelligence is
relatively static throughout life, but acquired knowledge tends to steadily
increase.

Learning is the process of acquiring knowledge; it has no effect on
intelligence. However, aptitude--the capacity to learn--is largely a function
of intelligence. Smart people learn faster and more easily, all else being
equal. This is why smart people tend to know more than stupid people.

You are truly amazing :-)

--
Dudley Henriques

WingFlaps writes:

Well, you'd have a hard time understaning how a 172 can fly to Haiwaii
then. Try simulating a 172 300# over MTOW?

I don't exceed weight limits.

george writes:

You are demonstrating as to why you are the group clown.
If an aircraft impacts the ground after takeoff it will be engine
failure or loss of control (spin off departing turn) nothing to do
with load..

I've already pointed this out:

http://www.alexisparkinn.com/photoga...loaded-172.wmv

Doesn't look like an engine failure or spin to me. The aircraft was
overweight, though.

Dudley Henriques wrote in
:

Mxsmanic wrote:
Dudley Henriques writes:

You are to be Congratulated!

With this absolutely astounding statement of astronomically historic
and infallible intellect, you have succeeded in completely negating
the entire concept of learning.

You're confusing acquired knowledge with intelligence. Intelligence
is relatively static throughout life, but acquired knowledge tends to
steadily increase.

Learning is the process of acquiring knowledge; it has no effect on
intelligence. However, aptitude--the capacity to learn--is largely a
function of intelligence. Smart people learn faster and more easily,
all else being equal. This is why smart people tend to know more
than stupid people.

You are truly amazing :-)

He is, isn't he? He's like one of those battery powered Japanese robots
from the early sixties. you know, the kind that runs around the floor
moaking a lot of noise and get stuck every time he hits the edge of the
carpet.

Bertie

Dudley Henriques writes:

You are truly amazing :-)

Thank you. Maybe I should write an article in Wikipedia promotiong myself.

writes:

Have you ever wondered why you always seem to have this problem?

No. I've seen others treated in exactly the same way, as soon as they
disagree with the alpha dog(s). I've seen it right here in this newsgroup,
and, in fact, at any given time there are usually at least one or two bullies
insulting a few targets in the group.

Have you ever wondered why few people other than you have this problem?

No, because a lot of people are equally harassed by the kiddies. Anyone who
fails to submit to bullies becomes a target of them. There are more bullies
in cyberspace because they are better protected, which encourages even the
more cowardly among them to misbehave.

Mxsmanic wrote in
:

Dudley Henriques writes:

You are truly amazing :-)

Thank you. Maybe I should write an article in Wikipedia promotiong
myself.


Oh! Let me!


bertie