The Cessna 120-140 Association Forum

Hello all,

I’m currently in the process of installing Randy’s O-200 STC in N120CM, and wanted to see if anyone knows what the lower cowl doubler looks like (does anyone have pictures of current installations?), and does anyone know where I can find one? Is this something I can make myself? What’s the actual purpose of the doubler?

Ive been trying to find information on this doubler, and it seems kinda hard to find….


I would appreciate any input

Thanks!
Matt

Have one I made for my 46 using a shrinker and stretcher.
In my opinion the 46 cowering already has too much airflow so I made a second one which blocks off more airflow.
The 47 cowel has less flow and generally runs hotter. (IMO)
See private message to text me for pictures.
Joe

The purpose is to draw more air thru the cowling. There are three different cowling shapes, and it’s best to fabricate one. Basically it’s a lip facing down at a 45 degree angle. 11/2 to 2 inches wide. There is one shown in the parts catalog as part of the summarization kit.

Thanks for the information, I didn’t realize there were 3 different cowl shapes. What’s the difference between the cowl designs?

My lower cowl currently has a silicon/rubber type “chin” or doubler lip. Is that part of the old design cowl, or a newer type?

This might help, I just bent two pieces of straight .032 to about 45 degree's and riveted them on.

matthewhinmann120cm wrote: ↑Wed Feb 23, 2022 7:55 pmMy lower cowl currently has a silicon/rubber type “chin” or doubler lip. Is that part of the old design cowl, or a newer type?

That would be a modification. There were no cowls from the factory with other than an aluminum lip.