Theory Q: Cold Air, Lower Fuel Consumption?

Here is a question to challenge your understanding of engine operation...

During Winter in the colder climes, do you use less fuel when you fly
because the air is more dense?

more if you produce more power, the same at same power.



"john smith" wrote in message
...
| Here is a question to challenge your understanding of
engine operation...
|
| During Winter in the colder climes, do you use less fuel
when you fly
| because the air is more dense?

I would say more fuel for a given power output. Cold fuel in cold air does
not vaporize and burn as well. Therefore it takes more fuel to produce the
same power output. I suspect this effect is more than offset by the
aerodynamic improvements of wing and propellor in the thick air.
"john smith" wrote in message
...
Here is a question to challenge your understanding of engine operation...

During Winter in the colder climes, do you use less fuel when you fly
because the air is more dense?

Cold cool air means more O2 the engine runs better. Better mileage.
"pgbnh" wrote in message
...
I would say more fuel for a given power output. Cold fuel in cold air does
not vaporize and burn as well. Therefore it takes more fuel to produce the
same power output. I suspect this effect is more than offset by the
aerodynamic improvements of wing and propellor in the thick air.
"john smith" wrote in message
...
Here is a question to challenge your understanding of engine operation...

During Winter in the colder climes, do you use less fuel when you fly
because the air is more dense?

All engines have an optimal operating temperature. If you are above or
below it, the efficiency is likely to be lower. It's probably not a
big effect.

On Feb 3, 10:32 pm, "Jim Macklin"
wrote:
more if you produce more power, the same at same power.

"john smith" wrote in message

...
| Here is a question to challenge your understanding of
engine operation...
|
| During Winter in the colder climes, do you use less fuel
when you fly
| because the air is more dense?

"john smith" wrote in message
...
Here is a question to challenge your understanding of engine operation...

During Winter in the colder climes, do you use less fuel when you fly
because the air is more dense?

The engine produces more power and uses more fuel.

Danny Deger

john smith wrote:

During Winter in the colder climes, do you use less fuel when you fly
because the air is more dense?

First, lift is proportional to mass-air flow over a curved surface.
Cold air is denser so at a give speed, you'll get more lift from cold
air. Now, if you choose to, you can throttle back a bit to get better
fuel economy.

Then, the engine power is controlled by the fuel/air mixture. To burn
X fuel molecules you need Y air molecules. Cold air will supply the X
molecules of air easily.
--Bill

Stubby writes:

First, lift is proportional to mass-air flow over a curved surface.

A curved surface has nothing to do with lift.

--
Transpose mxsmanic and gmail to reach me by e-mail.

On Feb 4, 12:00 pm, Mxsmanic wrote:
Stubby writes:
First, lift is proportional to mass-air flow over a curved surface.

A curved surface has nothing to do with lift.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Of course it does, the propeller produces more thrust when the air is
colder ( A propeller is a curved surface )

Now, back to the orginal question, if the engine is maintained at a
constant rpm at a some cold and hot temperatures, it will burn more
fuel at the colder temperature, but it will also produce more thrust.
So to get the same thrust, you would throttle back and almost the same
fuel burn with less rpm.

On Feb 5, 7:00 am, Mxsmanic wrote:
Stubby writes:
First, lift is proportional to mass-air flow over a curved surface.

A curved surface has nothing to do with lift.


Riiiight.
NACA sections are just to make the wing look pretty