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Thread: Mixture Control Creep

  1. #11
    Senior Member Andy's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by Daveembry View Post
    Every 363i engine I've run does exceptionally well LOP without roughness to as lean as I want to go. The induction air (intake manifold) is no doubt flow tested and custom made out of the carbon fiber and really flows even and true (as do the injectors), making this a very good engine that runs extremely smooth with consistent temps.
    Sure, lots of people agree on the wisdom of running cruise LOP but CubCrafters specifically prohibits it. Why? Lycoming also does not approve it - again why?

    Perhaps some insight here - https://www.advancedpilot.com/articl...articleid=1838

  2. #12
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    Default Re: Mixture Control Creep

    Cubcrafters referred the manual I gave you for the XP-360 engine. It specifically says to run LOP for economy cruise in section 4.9.2. Thatís how I do it and will keep doing it. It seems like Lycoming has always been known for sticking their head in the sand. Superior 363i engines seem to tell it differently.

    Quote Originally Posted by Andy View Post
    Sure, lots of people agree on the wisdom of running cruise LOP but CubCrafters specifically prohibits it. Why? Lycoming also does not approve it - again why?

    Perhaps some insight here - https://www.advancedpilot.com/articl...articleid=1838
    Last edited by Daveembry; 02-16-2021 at 08:19 PM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  3. #13
    Administrator Pete D's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by kiwibob View Post
    The mixture control on my FX-3 has started to creep rich in the cruise (I lean LoP using Fuel Flow per the manual).

    Anyone know if there's a simple fix to this?
    The detent friction is from a spring on the housing that rides on the bumps you see on the center part when it is all the way out. The spring is located right on the back side of the instrument panel. It sounds like the spring may have been displaced out of the slot or it is possibly broken. If it is displaced you may be able to access it and push it back into the slot, if it is broken then you would need to change the cable out.

    An alternate method if the spring is broken would be to put a slight bend in the cable and housing by hand to add some friction. Do a little, try it, add more if needed. Sneak up on it, it is tough to un-do. This was the method used before the de-tented cables were spec'd out.


    20210216_142559.jpg
    Pete Dougherty
    R & D Shop Manager
    Cub Crafters Inc

  4. #14
    Senior Member kiwibob's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by Pete D View Post
    The detent friction is from a spring on the housing that rides on the bumps you see on the center part when it is all the way out. The spring is located right on the back side of the instrument panel. It sounds like the spring may have been displaced out of the slot or it is possibly broken. If it is displaced you may be able to access it and push it back into the slot, if it is broken then you would need to change the cable out.

    An alternate method if the spring is broken would be to put a slight bend in the cable and housing by hand to add some friction. Do a little, try it, add more if needed. Sneak up on it, it is tough to un-do. This was the method used before the de-tented cables were spec'd out.
    Thanks Pete, That's exactly what I needed. I'll take a look.
    Bob Gray, FX-3 #38, ZK-FXC

  5. #15
    Senior Member kiwibob's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by Andy View Post
    Sure, lots of people agree on the wisdom of running cruise LOP but CubCrafters specifically prohibits it. Why?
    They do? I've not seen that. Certainly they approve it for the CC340 and Superior clearly think it's ok for the XP-360.
    Bob Gray, FX-3 #38, ZK-FXC

  6. #16
    Senior Member Andy's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by kiwibob View Post
    They do? I've not seen that. Certainly they approve it for the CC340 and Superior clearly think it's ok for the XP-360.
    I was unable to find an AFM reference to LOP operation of the CC363i engine. I must have remembered that incorrectly.

    I noted in my AFM search that the conditions for the cruise performance tables had changed. Rev NC specifies mixture leaned for best power. Rev B specifies 50 degrees rich of peak.

    Since you refer to the XP-360 you may be interested in this AFM warning:

    "WARNING
    SUPERIOR XP360 OPERATORíS MANUAL INCLUDES
    INFORMATION THAT IS NOT APPLICABLE TO THE
    CC363i ENGINE. NOTE THAT PERFORMANCE
    CURVES AND RELATED INFORMATION REFERENCE
    THE SIMILAR XP-360 ENGINE."

    Just to be clear - I have never said that LOP operation is inappropriate for the CC363i engine regardless of who built it. A lot of my cruise is at 60% power with quite low fuel flow. The FX-3 won't go fast so may as well go slow and enjoy the view.

  7. #17
    Senior Member kiwibob's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by Andy View Post
    I noted in my AFM search that the conditions for the cruise performance tables had changed. Rev NC specifies mixture leaned for best power. Rev B specifies 50 degrees rich of peak.

    Just to be clear - I have never said that LOP operation is inappropriate for the CC363i engine regardless of who built it. A lot of my cruise is at 60% power with quite low fuel flow. The FX-3 won't go fast so may as well go slow and enjoy the view.
    There's a Rev B of the AFM? Amazing how much I don't know.

    You have my complete agreement.
    Bob Gray, FX-3 #38, ZK-FXC

  8. #18
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    Default Re: Mixture Control Creep/LOP Operation

    I know this is thread creep but since we started going there thought I'd post this here as well as in another thread.

    No one I've spoken with so far at CC has said they prohibit running LOP. In fact, most everyone I've gotten to respond says they do.....and the Lycoming runs even better LOP than the Superior.

    If you follow the most experienced "flyers".... as opposed to an engine builder/non-flyer.....they will all pretty much agree LOP operations are safer and keep your engine much better for wear and tear than ROP and ESPECIALLY 50 ROP which put you in the very highest CHT's when running over 65% power or more and much more susceptible to denotation (which is still not much of a risk but certainly moreso when running CHT's at their highest point.....50 ROP)

    Again I'll post this article (just one of MANY) from Mike Busch about mixture control that was published in EAA.

    https://resources.savvyaviation.com/...ox-red-fin.pdf

    I also want to repost the link that Andy posted, which was a very good article laying it out how Lycoming is behind the times with their head stuck in the sand regarding this issue. I had read many of the Pelican articles years ago and agree.

    https://www.advancedpilot.com/articl...articleid=1838

    As I understand it, CC originally supplied/installed Superior 363i CC engines assembled by Aerosport. The manual link for that was prescribed was the XP-360. As I stated before, they clearly RECOMMEND running LOP at economy cruise below 75% and say to NOT run from peak to 50 ROP.

    All I have run so far are these Superior engines but have installed and ground run the Lycoming version in a plane I will start flying in the coming days. Lycoming suggest running PEAK egt for economy cruise and no mention of LOP. You can see from the above article why they say that (they refuse to modernize their old wives tales and suggest what is commonly known now that LOP is the way to go even though they do state there is nothing wrong with running LOP, etc)

    I have attached LYCOMING SERVICE INSTRUCTION 1094D; "Fuel Mixture Leaning Procedures" that came with my latest Lycoming engine from CC.

    On page 3 it states that when using an EGT gauge, "...lean the mixture to 100F on the rich side of peak for best power". And ...."...for best economy cruise, operate at peak EGT." So they stay away from that PEAK to 50 RED BOX.....waaaay away from it.

    I assume they are essentially the same engine (I know they have different cylinders), so why does one "leading edge" engine builder recommend LOP and not the other one? Read that article above for the answer maybe.

    Someone suggested that running LOP using the dual Lightspeed electronic ignitions on these engine, might cause "exhaust valve failure". This made no sense whatsoever to me so I reached out to Klaus at Lightspeed to see his response. Here it is:

    Dave,

    Using the Plasma III, you CAN lean to levels you can never get to with magnetos or even other systems.

    The further you are past peak, the lower the Egts by definition! I can lean to 150 degrees LOP at which point you are air-cooling instead of ROP where you are fuel cooling. The best engine with magnetos canít run more than 50 degrees LOP which means their EGTs run 100 degrees hotter than necessary!

    The problem is that if you canít get ALL cylinders past peak, one might lag behind and run at peak.

    Keep your EGTs below 1450 ROP or LOP to minimize wear.
    Best Regards,
    Klaus Savier
    Light Speed Engineering, LLC


    So, in my humble and well research opinion......running LOP saves fuel; can run CHT's much cooler than ROP; keeps the engine out of the "red box" with much less chance of ever having detonation. Understanding LOP operations on an engine can save you money in fuel and engine maintenance. Not just my opinion but many others with extensive "on the job" research and testing (Like the Gami guys here in Ada, OK just down the road from me).
    Last edited by Daveembry; 02-19-2021 at 09:01 AM.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

  9. #19
    Senior Member kiwibob's Avatar
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    Default Re: Mixture Control Creep

    Quote Originally Posted by Pete D View Post
    The detent friction is from a spring on the housing that rides on the bumps you see on the center part when it is all the way out. The spring is located right on the back side of the instrument panel. It sounds like the spring may have been displaced out of the slot or it is possibly broken. If it is displaced you may be able to access it and push it back into the slot, if it is broken then you would need to change the cable out.

    An alternate method if the spring is broken would be to put a slight bend in the cable and housing by hand to add some friction. Do a little, try it, add more if needed. Sneak up on it, it is tough to un-do. This was the method used before the de-tented cables were spec'd out.
    Thanks Pete,

    This was the exact situation.

    It looked like the flat part of the spring was displaced but as soon as I tried to move it the spring broke at the bend. The slight bend technique has been effective (well for a 45 minute flight anyway) and I've ordered a replacement cable.
    Bob Gray, FX-3 #38, ZK-FXC

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