Lasar Cowl Closure

[EricJ]

1 hour ago, Buckeyechuck said:

If this is done as a DIY, how is it logged?  337?

Changes to the cowling are often considered major alterations since they can affect engine performance (cooling) as well as aerodynamics.   Most such things have an STC to provide the data for a 337 to be filed.

[Skates97]

On 12/24/2024 at 7:51 PM, Buckeyechuck said:

First in response to the above quote, I installed a JPI analyzer (not primary) shortly after the overhauled engine was installed. Due to the high numbers, one of the first thing I did was check the TC readings in a cup of boiling water. They checked ok.  
 

I’ve had one flight to check for improvements after the annual. I did a lot of work to close up the doghouse in the back and across the front of the #2 cylinder. After takeoff, climbing out at WOT, #3 was hottest at about 430 with #4 about 10 degrees cooler. This is opposite of how they ran before and much cooler. I’m not sure how much is due to climb at WOT, how much is due to doghouse improvements, and how much was due to the 30 degree outside temperature. I’m back in Florida now for the holidays and will update again once I get a few more flights. Here is a photo in cruise from the first post annual flight. 

 

My O-360-A1D was a narrow deck and replaced with a wide deck at overhaul. Previously my CHT's did well, but they had to make some modifications to the doghouse for the wide deck and I've been dealing with higher CHT's than before while tweaking things on the doghouse to get back to where I was with the old engine. Consequently during the process I have been trying different things (power/prop settings, airspeed) to reduce CHT's on initial climb out. I have found the most effective way to keep the CHT's from running away is to stay prop full forward but reduce throttle to about 22-23" after taking off until the CHT's stabilize and stop climbing, then as I climb I am able to add back in MP slowly.

[Buckeyechuck]

7 hours ago, N201MKTurbo said:

If it has an STC, you will need to file a 337 and an IA will need to approve it for return to service. 
 

You need to make friends with an IA.

My IA has a fiberglass version of the cowl closure but no STC.  I could probably get if for little to nothing but shy’d away due to lack of paperwork. 

[N201MKTurbo]

2 hours ago, Buckeyechuck said:

My IA has a fiberglass version of the cowl closure but no STC.  I could probably get if for little to nothing but shy’d away due to lack of paperwork. 

I would sign it off with a logbook entry….