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.

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

"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

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.

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

"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".)

Gary,

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


Yeah, but that would make it impossible to start a long-winded discussion
with real pilots about how backwards and dangerous the engines on their
planes are.

--
Thomas Borchert (EDDH)

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

Yeah, but that would make it impossible to start a long-winded discussion
with real pilots about how backwards and dangerous the engines on their
planes are.

It would also make it impossible to torture us with responses like that
one. Perhaps you could try adding to a discussion instead of dissing
it. Even "real" pilots argue over the safety of GA engines.

Some people are good at Googling. It could be argued that there's no
reason to ever again see questions and answers in any group, since
somewhere out there is a reply. But that wouldn't be any fun, as
everyone must have their say :-)

There's also a lot of people who can't spend much time Googling, since
they're still on dialup. They do things the old way, posting multiple
pre-made responses at once. I think that actually made for more
thought out discussions, since people couldn't just make knee-jerk
responses like you see around here.

Kev

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.

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.

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

Mxsmanic wrote:
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.

I always open them before takeoff. With my old engine/cooling
setup it was really sensitive, so yes, I had to watch the the
temperature when closing them. On my new engine/cooling design
it runs pretty cool so I just shut them as a matter of routine
when I get to altitude. I do check the CHT and Oil Temp
periodically to make sure it's in the green.

5 or 10 knots? What are they freakn' barn doors or something? :-)
Sure your not fibbing?



Ron Natalie wrote:

In my plane, I can get another five to ten knots when
I close them.