Cowl exit

[slscott715]

I'm finishing up the cowling on my LSA and was wondering what others are doing for the cowl exit, e.g. exit area? Lip or no lip? How large? Any data points from those with flying LSAs would be appreciated. I'd like to get this right out of the gate so I don't have to butcher my paint job modifying it later if possible. Thanks in advance.

 

[Bearhawk Aircraft]

Recommended is 30 degree angle 3in lip

 

[DBeaulieu]

Hey, any info for us Patrol builders on this subject?

 

[PropMan]

I'm finishing up the cowling on my LSA and was wondering what others are doing for the cowl exit, e.g. exit area? Lip or no lip? How large? Any data points from those with flying LSAs would be appreciated. I'd like to get this right out of the gate so I don't have to butcher my paint job modifying it later if possible. Thanks in advance.

Here's a picture of mine. Fabricated from aluminum and riveted on. I can get measurements Wednesday. 40 plus hours so far, temps are good, even with the 100 plus temps this summer. I'll add, I am not running an oil cooler or filter

 

[DBeaulieu]

Thank you...looks good. Will certainly challenge my fabrication/sheet metal abilities!

 

[jaredyates]

It can be made out of composites as well.

 

[slscott715]

Cool. Thanks for the info guys. I had heard the 30 degree/3" recommendation before but was curious if that has proven to be adequate for those with flying airplanes. I'll roll with that. Thanks again!

 

[Sierra Skydog]

Mine is 2”, 40 degrees, also works great. First flew without a lip, adding it lowered cht temps 30-40 degrees

 

[gregc]

Mine is only about 1.5" and roughly 30 degrees. It works fine. CHTs on an O-360 are 350 degrees or less. I think the cowl opening size is much more important.

 

[PropMan]

Here's a picture of mine. Fabricated from aluminum and riveted on. I can get measurements Wednesday. 40 plus hours so far, temps are good, even with the 100 plus temps this summer. I'll add, I am not running an oil cooler or filter

Measurements and photos, 2 1/8" and right at 30 degrees. Opening is a bit over 4" for the width of the tunnel.

 

[DBeaulieu]

It can be made out of composites as well.

Will certainly challenge my nonexistent (okay rudimentary) fiberglass skills...