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Old Jan 13, 2015, 10:25 PM
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Yep I have that cowl in wood and glass

Ken
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Old Jan 14, 2015, 03:39 AM
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Wow! I can see how a 'round' cowl wouldn't be an easy match.

That looks like the Chevy powered airplane Don Olsen built last year.
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Old Jan 14, 2015, 08:42 AM
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I always saw baffling as a must on round cowlings to improve the engine cooling and to shrink the airflow exit space. I know how a picture clears things up so here is a SC-W 3 drawing that illustrates what I am talking about. The firewall is the inner line of station 3 and the second/outer line is the cowling.
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Old Jan 14, 2015, 09:03 AM
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Quote:
Originally Posted by flyerinokc View Post
I always saw baffling as a must on round cowlings to improve the engine cooling and to shrink the airflow exit space. I know how a picture clears things up so here is a SC-W 3 drawing that illustrates what I am talking about. The firewall is the inner line of station 3 and the second/outer line is the cowling.
Mike,. I've always thought it was the opposite.

Baffles limit air intake, and direct it to a desired location. Too much intake can trap hot air inside the cowl.

This is why the exit area is usually 2-3 times that of the intake.
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Old Jan 14, 2015, 10:39 AM
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Mike, looks like you are starting round radial like up front and transitioning to a rounded off squarish at the back. Still looks bigger at back (slightly) than in front.
Hey have fun with that
Actually I like that, but I am glad it's you and not me. Looks beyond my pay grade.

I sure want to watch you build that cowl.

Another 2 or 3 hours on my trainer wing and it will be ready for what ever pieces of film I have. Then I have to move my build desk and bench tool stand. And add plane storage above the desk.

The hello GL!! So yeah next month, early I think.
I am finding that with the projects for my mother and her running around, I just have to allot her so much and me so much. And stick to the me part. Otherwise there would be no me time.

Ken
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Old Jan 14, 2015, 10:46 AM
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I wish my Mom were here to ask me to do something- anything.

Enjoy, it Ken.
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Old Jan 14, 2015, 10:53 AM
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good point earl
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Old Jan 14, 2015, 02:35 PM
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Quote:
Originally Posted by TomCrump View Post
Mike,. I've always thought it was the opposite.

Baffles limit air intake, and direct it to a desired location. Too much intake can trap hot air inside the cowl.

This is why the exit area is usually 2-3 times that of the intake.
That was what I was trying to say the smaller the intake the smaller exit for the hot air. If you baffle you get less flow but over the area you want so less air that must exit.
Clear as mud?
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Old Jan 14, 2015, 03:18 PM
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Originally Posted by greyflight390 View Post
Mike, looks like you are starting round radial like up front and transitioning to a rounded off squarish at the back. Still looks bigger at back (slightly) than in front.
Hey have fun with that
Actually I like that, but I am glad it's you and not me. Looks beyond my pay grade.

I sure want to watch you build that cowl.
Ken
Ken you are correct! I sure want to see me build this cowling too! I just hope I can get it built. Who knows maybe I'll surprise myself? The first time you do something it always seems harder and takes three times as long as the second one. The airbrake worries me too but I could get away with leaving it off I can't do that with a cowling.
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Old Jan 14, 2015, 03:23 PM
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yep you bet Mike
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Old Jan 14, 2015, 04:33 PM
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Baffled about baffles...

I know- more from the crazy guy who mounts fuel tanks cross-ways.....but ! this is enough intake area for cooling air for an OS .91 four cycle engine in the 'Coupe.

Plywood baffles direct the air past the cylinder closely, and through an exit in the bottom of the cowl and fuselage...It's just a duct, from cowl to exit....

I'll post pics in the Monocoupe thread, when I get that far.

The intake only has to be as large as the cylinder profile, and directed around it.

Tom's pics of the C195 show it perfectly- the air can only go THROUGH the cylinder fins.
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Old Jan 14, 2015, 07:36 PM
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I bet it is enough
Have you seen the cowling on control line speed planes? That is very high nitro. Just a tiny slit in front of the cylinder. Tightly cowled engines. Looks like they should turn into molten pools of metal. But it is enough. They go over 200mph. I think a bunch of us would have a heart attack try to spin around that fast. Holy smokes.
You got tons more than that Mike.
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