What are cowl flaps?

What are cowl flaps for, and how are they used? The name implies that
they are some sort of aerodynamic control surface, but they don't
appear to have any aerodynamic effects. In simulation, they are doors
on the bottom of the engine nacelles that open for some unclear
purpose (I see what looks like exhaust pipes or something inside).
What do they do, and why do I have a control for opening and closing
them? This is on a Baron 58, the aircraft I usually fly in
simulation.

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"Mxsmanic" wrote in message
...
What are cowl flaps for, and how are they used? The name implies that
they are some sort of aerodynamic control surface, but they don't
appear to have any aerodynamic effects. In simulation, they are doors
on the bottom of the engine nacelles that open for some unclear
purpose (I see what looks like exhaust pipes or something inside).
What do they do, and why do I have a control for opening and closing
them? This is on a Baron 58, the aircraft I usually fly in
simulation.

http://stoenworks.com/Tutorials/Cowl...ngine%20C.html

Mxsmanic wrote:
What are cowl flaps for, and how are they used? The name implies that
they are some sort of aerodynamic control surface, but they don't
appear to have any aerodynamic effects. In simulation, they are doors
on the bottom of the engine nacelles that open for some unclear
purpose (I see what looks like exhaust pipes or something inside).
What do they do, and why do I have a control for opening and closing
them? This is on a Baron 58, the aircraft I usually fly in
simulation.


They control cooling air through the engine cowls. They are flap
shaped "valves" if you want on the outflow of the cooling air.
When open, you get more cooling air but that also means more
drag. In my plane, I can get another five to ten knots when
I close them. I take-off and climb with them open and close
them at cruise.

"Mxsmanic" wrote in message
...
What are cowl flaps for, and how are they used? The name implies that
they are some sort of aerodynamic control surface, but they don't
appear to have any aerodynamic effects. In simulation, they are doors
on the bottom of the engine nacelles that open for some unclear
purpose (I see what looks like exhaust pipes or something inside).
What do they do, and why do I have a control for opening and closing
them? This is on a Baron 58, the aircraft I usually fly in
simulation.

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They are not aerodynamic control surfaces... They are for regulating engine
temperature under certain power/speed combinations...

From Wikipedia...

If the aircraft is equipped with adjustable Cowl Flaps:

Cowl Flap Position Control - Cowl Flaps are opened during high power/low
airspeed operations like takeoff to maximize the volume of cooling airflow
over the engine's cooling fins.
Cylinder Head Temperature Gauge - Indicates the tempertaure of all cylinder
heads or on a single CHT system, the hottest head. A Cylinder Head
Temperature Gauge has a much shorter response time than the oil temperature
gauge, so it can alert the pilot to a developing cooling issue more quickly.
Engine overheating may be caused by:
Running too long at a high power setting.
Poor leaning technique
Restricting the volume of cooling airflow too much.
Insufficient delivery of lubricating oil to the engine's moving parts.

I went to a restaurant and they had these things called "flapjacks".
I'm so confused, are they some sort of aerodynamic device as the name
implies, or something you use to hold up the airplane while you change
those little black round things (Sorry I can't remember the name of
those!)? And what are they doing on a menu? How could I possibly
answer this question without annoying a large number of people? I
tried typing "flapjacks" into my Google simulator because I'm too
scared of the actual Google. But my computer crashed, imagine what the
real Google might have done!

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Mxsmanic wrote:
What are cowl flaps for, and how are they used? The name implies that
they are some sort of aerodynamic control surface, but they don't
appear to have any aerodynamic effects. In simulation, they are doors
on the bottom of the engine nacelles that open for some unclear
purpose (I see what looks like exhaust pipes or something inside).
What do they do, and why do I have a control for opening and closing
them? This is on a Baron 58, the aircraft I usually fly in
simulation.

Plonk. Get a life.

Gary Drescher writes:

http://stoenworks.com/Tutorials/Cowl...ngine%20C.html

Thanks, that's quite a comprehensive description.

It amazes me how much engine junk one is expected to worry about on
small aircraft. I'm also amazed that the engines are still
air-cooled.

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Ron Natalie writes:

They control cooling air through the engine cowls. They are flap
shaped "valves" if you want on the outflow of the cooling air.
When open, you get more cooling air but that also means more
drag. In my plane, I can get another five to ten knots when
I close them. I take-off and climb with them open and close
them at cruise.

Do you do this more or less routinely, or do you actually look at the
engine temperatures to see when to open or close them? I get the
impression that it's not a super-critical item except in a few
circumstances.

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That was funny.
"tjd" wrote in message
oups.com...
I went to a restaurant and they had these things called "flapjacks".
I'm so confused, are they some sort of aerodynamic device as the name
implies, or something you use to hold up the airplane while you change
those little black round things (Sorry I can't remember the name of
those!)? And what are they doing on a menu? How could I possibly
answer this question without annoying a large number of people? I
tried typing "flapjacks" into my Google simulator because I'm too
scared of the actual Google. But my computer crashed, imagine what the
real Google might have done!

--
Transpose my head and my butt to reach me by email.

"Mxsmanic" wrote in message
...
Gary Drescher writes:

http://stoenworks.com/Tutorials/Cowl...ngine%20C.html

Thanks, that's quite a comprehensive description.

You're welcome. (It's the first page that comes up if you google "cowl
flaps".)