Comment

Comment by Danal Estes on October 3, 2012 at 10:36am

Hey Bob, since you know this airplane quite well... you should know that it has 2 degrees more prop pitch since Rick/Mark were flying it, and baffling around the oil cooler.  Still working on getting CHT 5 down.  EGTs have helped, but more airflow is needed around 5.  Talking to Jabiru USA about that as well. 

Comment by Bob McDonald on October 2, 2012 at 7:51pm

That is pretty cool technology at work. Helping to solve the engine tuning mystery.

Comment by Danal Estes on October 2, 2012 at 4:31pm

This is a test flight after adding an "Airflow Straightener" to the carb intake on a Jabiru 3300.  The intake is radiator hose (smooth inside).  I added a vertical piece of aluminum that extends from the carb heat box, around the curve, down the straight, and stops about 1/2 or 3/4 inch before the carb (to avoid interfering with the bottom atomizer port). 

Prior to this change, the EGTs during climb were spread over 400+ deg F.  As you can see, they are now within 150F.  I'm thinking of going to a "cross" shaped airflow straightener made of glass and west system epoxy. 

Also, I believe that my needle jet is WAY too rich... target EGT in the 2850 cruise portion of the flight should be 1325, and the temps are clustered around 1125, nearly 200 too low.  I've emailed this graph to Jabiru USA and am waiting to hear back. 

Danal