Mailing List lml@lancaironline.net Message #55685
From: Ron Raby <ronr@advanceddesign.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Fuel Control problem
Date: Tue, 13 Jul 2010 20:35:01 -0400
To: <lml@lancaironline.net>
Steve
 
I thought 27-28 was the right fuel flow for the IO550N?
 
Ron Raby
 
ES
----- Original Message -----
Sent: Tuesday, July 13, 2010 5:51 AM
Subject: [LML] Fuel Control problem

On another point – you say you lean to 1300 degrees on climb out.  I am surprised by 1300 degrees.  (Although I know that EGTs can differ according to installation, and since I have a 10:1 compression engine my EGTs should be lower.)

I arrived at 1300 degrees as recommended at the Advanced Pilot Seminar after Sun n Fun last year.  Assuming you have a fuel flow of at least 29 gallons per hour (they say 30 is better) on a stock IO550-N, look for the hottest EGT on the hottest cylinder (mine is #6) during takeoff to about 150’ agl on a near sea level runway.  They say this is a safe number to continue to lean to during the climb. 

 

How much ROP are you when you climb?

I’ll have to check.

 

Steve Colwell   Legacy  almost stock IO550-N  with stock pistons

 

 

 

 

From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Douglas Brunner
Sent: Monday, July 12, 2010 2:53 PM
To: lml@lancaironline.net
Subject: [LML] Re: Fuel Control problem

 

Steve,

 

I always put on low boost above 10,000 for “vapor suppression”.  On several occasions, I have experienced fluctuating decreases in RPM that I attributed to “vapor in the lines”.  Putting on the low boost seemed to solve the problem.

 

From what I remember of the Advanced Pilots Course (I took it in Jan of ’06), they suggested that the problem occurs with hot fuel at high altitudes – and your story seems to be just that.  Suggest you try using low boost over 10,000.

 

On another point – you say you lean to 1300 degrees on climb out.  I am surprised by 1300 degrees.  (Although I know that EGTs can differ according to installation, and since I have a 10:1 compression engine my EGTs should be lower.)   I lean to 1100 in the climb until I reach 70% power at which time I lean to 1200.  Since my peak EGTs are around 1325 (when I lean at 70% - probably higher at higher power settings), I figure I am at least 250 ROP when above 70% in the climb.

 

If you lean to 1300 in the climb, what do you think your peak EGTs are?

How much ROP are you when you climb?

 

If there are any “lurkers” from APS, what do you think of 1300?

 

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