Why does one need to LEAN OUT a CARB when climbing?

Bertie the Bunyip wrote:
ah wrote in news:4977e445$0$35423
:

Bertie the Bunyip wrote:
"Maxwell" #$$9#@%%%.^^^ wrote in :


"Bertie the Bunyip" wrote in message
...
Tman wrote in news:-
:

wrote:
On Jan 19, 7:05 pm, "Todd W. Deckard"
wrote: It diverts low pressure air from the back of the venturi
into the
fuel float bowl.
Never taken a close look at an airplane carb, but I understand
that
the standard config (not this stromberg, but rather something like
in a basic 172N) has a fuel-bowl vent upstream of the venturi,
making the air pressure in the fuel bowl pretty much equal to the
air intake pressure.... Kind of like a standard auto carb from a
few
years ago when they still had them. Let me know if that's not
right.


They're basically a float bowl and a tube. not a lot to complicate
them, really. Probably the simplest carbs in operation today.

Bertie

You're an idiot.




Nope.

But please don't let that stop you maxie.

What's new on teh gasket-front, Cap'N?

Not much. Need a gearbox though..

Do you need synchromesh?
--
ah

Bertie the Bunyip wrote:
ah wrote in news:4977e445$0$35423
:

Bertie the Bunyip wrote:
"Maxwell" #$$9#@%%%.^^^ wrote in :


"Bertie the Bunyip" wrote in message
...
Tman wrote in news:-
:

wrote:
On Jan 19, 7:05 pm, "Todd W. Deckard"
wrote: It diverts low pressure air from the back of the venturi
into the
fuel float bowl.
Never taken a close look at an airplane carb, but I understand
that
the standard config (not this stromberg, but rather something like
in a basic 172N) has a fuel-bowl vent upstream of the venturi,
making the air pressure in the fuel bowl pretty much equal to the
air intake pressure.... Kind of like a standard auto carb from a
few
years ago when they still had them. Let me know if that's not
right.


They're basically a float bowl and a tube. not a lot to complicate
them, really. Probably the simplest carbs in operation today.

Bertie

You're an idiot.




Nope.

But please don't let that stop you maxie.

What's new on teh gasket-front, Cap'N?

Not much. Need a gearbox though..

Can you do synchromesh?
--
ah

"ah" wrote in message
anews.com...
Bertie the Bunyip wrote:
ah wrote in news:4977e445$0$35423
:

Bertie the Bunyip wrote:
"Maxwell" #$$9#@%%%.^^^ wrote in :


"Bertie the Bunyip" wrote in message
...
Tman wrote in news:-
:

wrote:
On Jan 19, 7:05 pm, "Todd W. Deckard"

wrote: It diverts low pressure air from the back of the
venturi
into the
fuel float bowl.
Never taken a close look at an airplane carb, but I understand
that
the standard config (not this stromberg, but rather something
like
in a basic 172N) has a fuel-bowl vent upstream of the venturi,
making the air pressure in the fuel bowl pretty much equal to
the
air intake pressure.... Kind of like a standard auto carb from
a
few
years ago when they still had them. Let me know if that's not
right.


They're basically a float bowl and a tube. not a lot to
complicate
them, really. Probably the simplest carbs in operation today.

Bertie

You're an idiot.




Nope.

But please don't let that stop you maxie.

What's new on teh gasket-front, Cap'N?

Not much. Need a gearbox though..

Can you do synchromesh?
--
ah

Can you quit Slurping "Some Gay Guy", a.k.a. Art Deco ??
--
HJ

ah wrote in news:49791d81$0$57669
:

Bertie the Bunyip wrote:
ah wrote in news:4977e445$0$35423
:

Bertie the Bunyip wrote:
"Maxwell" #$$9#@%%%.^^^ wrote in :


"Bertie the Bunyip" wrote in message
...
Tman wrote in news:-
:

wrote:
On Jan 19, 7:05 pm, "Todd W. Deckard"
wrote: It diverts low pressure air from the back of the venturi
into the
fuel float bowl.
Never taken a close look at an airplane carb, but I understand
that
the standard config (not this stromberg, but rather something
like
in a basic 172N) has a fuel-bowl vent upstream of the venturi,
making the air pressure in the fuel bowl pretty much equal to
the
air intake pressure.... Kind of like a standard auto carb from a
few
years ago when they still had them. Let me know if that's not
right.


They're basically a float bowl and a tube. not a lot to
complicate
them, really. Probably the simplest carbs in operation today.

Bertie

You're an idiot.




Nope.

But please don't let that stop you maxie.

What's new on teh gasket-front, Cap'N?

Not much. Need a gearbox though..

Can you do synchromesh?

They're OK, just need to do the spigot bearings.


Bertie

On Wed, 21 Jan 2009 19:25:39 -0500, Tman
wrote:

wrote:
In
the carb, one-half the density should then cut the pressure
differential and therefore fuel flow by one quarter, which will give
us a mixture twice a rich as when we took off.
At the risk of dragging on the subject ... Wouldn't that actually lean
it out, requiring one to compensate by richening the mixture at higher
altitudes? One-half the density i.e. one half the mass airflow at
constant velocity, fuel flow by quarter... sounds like that mixture is
leaner!

totally correct. you richen the air in the mixture by reducing the
fuel.

"Bertie the Bunyip" wrote in message
...
ah wrote in news:497d9da3$0$57661

He actually had sum?

Well, presumably enough to navigate his way out of the womb.
OTH being an ass baby would explain a lot..

Bertie


Heckle and Jeckle, identical twin retards.

On Jan 19, 1:23*pm, Tman wrote:
Somebody posed that seemingly simple question to me, but kept coming
back to the point that they stumped me.... And I am stumped. *What do
you see wrong with the logic in this dialog?

Q: Why do I need to lean out my carb when I climb?

A: *Ahem, seems you forgot your PPL ground school. *The air is less
dense. *Fewer air molecules per unit volume. *Therefore, you need less
gas, so you lean it out!
lots of really interesting stoichimetric ratio stuffage snipp-ed)....

Anyone see what is amiss?

T

Yes, the obvious answer to any Texas Aggie: "because it's easier than
leaning out the window".

"Maxwell" #$$9#@%%%.^^^ wrote in :


"Bertie the Bunyip" wrote in message
...
ah wrote in news:497d9da3$0$57661

He actually had sum?

Well, presumably enough to navigate his way out of the womb.
OTH being an ass baby would explain a lot..

Bertie


Heckle and Jeckle, identical twin retards.

Oh good one maxie.



I love heckle and jeckle, BTw Old chum!


Bertie

Q: Why do I need to lean out my carb when I climb?

Stealth Pilot is rude but he is also correct.
I think your confusing volume with density. As the aircraft climbs into less dense air the amount of oxygen for a given volume decreases. That IO 360 engine (ie) is still breathing in 360 cubic inches of air every 2 revolutions, but that air is less dense and carries less Ox at altitude than it does down low. A rule of thumb is that 50% of the Ox in the atmosphere is below 18k'.