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I’m flying an RV-12 that now has ten hours on the Hobbs meter and I have been using 100LL so far. 

Van’s has defined the caution band for EGTs as 1,470 - 1,620 F (799 - 882 C).  The RV-12 POH defines a Cruise limit of 1560 F (849 C) and a Take-off limit of 1616 F (880 C).  

I have observed that my EGTs don’t reduce when going from Take-off to Cruise (~ 5,000 rpm) and may increase slightly.  Both EGTs are similar and one or the other may be the larger of the two. 

The highest EGT that I have recorded is 1501 F (861 C).  

Is this typical?  What are typical EGTs and trends?

 

 Thanks. 

Brett in Columbus, IN

 

9562_1_B52355A6-A4B7-431B-A24A-51DF192655FC.jpeg (You do not have access to download this file.)
  • Re: EGTs for a 912 ULS, What is typical?

    by » 3 months ago


    I typically see 1300-1350 with my early SN RV-12.  A friend's RV-12 runs about 100F higher.

    Photo attached is typical cruise...

    34570_2_Screenshot 2022-12-03 at 1.41.19 PM.png (You do not have access to download this file.)

  • Re: EGTs for a 912 ULS, What is typical?

    by » 3 months ago


    This has always confused me as well. The  manual says 1470 is normal . Neither of my engines ever run at 1470. normal is average cruise is around 1200. SOme mechanics say cooler is better others say hotter is better. Rotax manual says 1470.

    what is the correct answer and why does rotax recommend 1470 if mechanics disagree? Shouldnt we lean these engines to 1470 average?

     No one mentions there are warmer cylinders and cooler ones. I go by the hottest one?

     


  • Re: EGTs for a 912 ULS, What is typical?

    by » 3 months ago


    Fred:

    Thanks for response. 

    Two questions:

    1.) Which document does Rotax specify the 1470 F value for EGT? I see where Van’s calls it out. But, not Rotax. 
    2.) I don’t understand your comment about adjusting mixture. The 912 ULS doesn’t have a mixture control.  So, how would one do this?

    Thanks. 

    Brett

     


  • Re: EGTs for a 912 ULS, What is typical?

    by » one month ago


    In reviewing the Rotax  documentation for the 912 ULS EGT limits, the only specification that I can find is a maximum limit of 1616 F (880 C).  Nothing that specifies a different limit for take-off and cruise and nothing that specifies a maximum difference between the two readings.

     

    Is this the understanding that others have?

     

    Thanks

     

    Brett


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