IO-550A "Auto Lean"

[74657]

Anyone have any idea what "auto lean" is on the IO-550A that is in my Missile?  I have searched around and haven't found out what it means.

Thanks.

[carusoam]

Is it a button or like the JPI Lean find mode?  (manually lean through the peak EGT, and the JPI will "auto"matically save/display the peak value)

Sounds cool....

-a-

[AustinChurch]

Auto lean is an automatic leaning feature on the 550-A.  It has an altitude compensating fuel pump that senses barometric pressure and above 3000 feet msl, it starts leaning by reducing fuel flow.  There is a bulletin on the Continental website that discusses the proper way to adjust it.  To check that it is properly adjusted, at sea level full throttle/2700RPM, you should burn between 24.2 and 25.6 gallons per hour.  Here is the link:

http://www.tcmlink.com/pdf2/SID97-3E.pdf

When I fly my Missile, I leave it full rich until I level off.  Once leveled, I use the mixture to fine tune the leaning.  I run 50 degrees ROP and I find it takes very little adjusting.

 

[testwest]

Auto-lean is a feature of the specific fuel injector servo and fuel pump combo on the IO-550-A as configured for the Missile. You basically take off with the mixture knob at full rich no matter what takeoff density altitude you are at. You can leave it at full rich throughout the climb as well.

Actually, what AustinChurch said!   ...except for the 50 ROP part. That's not a good place to run unless you are at pretty low power.

[carusoam]

For the IO-550G we have a blue range on the ship's EGT.   Instructed to keep the mixture in the blue during climb and descent.  It is a crude way of leaning during climb and keeping from running to lean as power increases during descent.

-a-

[KLRDMD]

Quote: AustinChurch

 I run 50 degrees ROP . . .