Mixture control

[bigsky10 3]

Hi all,

Not sure this is a problem or just normal.  During normal flight I setup the prop and power levers, but when I put back on the mixture levers to lean it out a bit there is no change in the gauges to indicate the change.  I think all other Carenado aircraft show change when mixture is changes.  C337 has a noticeable change in engine sound and run.

 

Thanks

 

Dick

[RamonB 449]

Hello The Shrike does change engine sound and run when leaning.

 

First gauge you notice reacting is the fuel flow (very sensitive). However, the modeled EGT gauge reacts slowly to leaning,

RPM does not react and the Cyl. Head Temp gauge hardly moves. (I guess it could be done better).

 

The digital readouts on the EDM760 are more sensitive.

I Lean it a bit richer than needed to simulate keeping cylinders cooler and overheating the exhaust valves.

 

This link might Help JPI EDM 760.

 

Cheers.

[bigsky10 3]

Kabronicus,

 

Thanks for the info.  I will start watching the EDM760 and other gauges to see how that works.

Dick

[racklefratz 4]

 

 

During normal flight I setup the prop and power levers, but when I put back on the mixture levers to lean it out a bit there is no change in the gauges to indicate the change.

 

 

In which aircraft?

[RamonB 449]

In which aircraft?

 

In this case Dick the OP is referring to the Aero Commander 500S.

[racklefratz 4]

In this case Dick the OP is referring to the Aero Commander 500S.

 

Yeah, I see that now.  Missed that this is a product-specific section.  Disregard.

 

Aside from leaning indications on cockpit instruments, in real recip airplanes, pilots often just pull the mixture control back till rpms start dropping, then enrich till the engine smooths out, then a little more to be safely below peak egt. 

 

Doing it by egt gauges is much more precise, however, if the aircraft is so-equipped - not all are.  50-75 degrees below peak egt is the rule of thumb, set on the leanest cylinder - they won't all be equally lean, which is unavoidable.  Another technique which has become popular for some engines is leaning on the lean side of peak egt, a separate subject for discussion.

[udidwht 133]

Ahhhh....piston engine management. My specialty. The following graph illustrates piston engine management (Rich vs Lean). To many people believe lean is a death sentence for the engine. That depends greatly on where one is running AFR wise. Rule of thumb avoid 14.5 - 15.0 AKA (Death zone). See what happens to EGT as you progress lean-ward AFR wise? As well as your CHT? max horsepower will fall roughly 12.5 -12.8 AFR. I usually like to run in the low-mid 13's