Leaning Mixture?
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When do I lean the mixture in this aircraft? I keep reading that turbocharged engines should not be leaned until over the critical altitude?
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You do not have to lean turbocharged aircraft for maximum power before passing the critical altitude, but you still can lean them once you've arrived in cruise for better fuel economy.
For example, if you're only cruising at 12,000ft, once you've leveled off, you will still see a fuel flow greatly above the POH values. Press the right button on the EDM-760, and then press between both buttons (to press both at the same time) to activate lean-of-peak lean assist mode. Leaning as shown on the EDM will reduce your fuel flow by as much as 30% without having a significant impact on cruise performance.
Otherwise, if you're climbing through the critical altitude, you will have to progressively lean the engine as you would with a normally aspirated aircraft to maintain maximum possible climb power.
Hope that helps! There is much more on the theory and pitfalls of turbocharged operation in the manual, by the way.
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Looks to be "critical" around 17,000 feet. Just as with any other aircraft, you are expected to monitor airspeed and engine performance during all phases. Early in the climb you don't have to adjust mixture. Likely above 10,000 or even closer to 17,000 you will need to lean her out. I haven't taken the piston version up yet. But in the Bonanza TC for example, I pay attention to engine manifold pressure and other factors. You will see a drop in horsepower and speed, some of which you can hear. That 19,000 foot area in the Bonanza requires me to lean the mixture as I climb, and I just pay most attention to peak MP and HP until I hit cruise. Then I use the engine performance monitor to find LOP (lean of peak), then add about 50 back into rich. My engines always stay healthy and no failures. I tend to run a bit low on the power in all my prop aircraft to keep them healthy.
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If anybody is interested: On this video I lean the mixture to ROP and gain almost 30 Kts of speed. (I not intend to save fuel, always make short flights).
https://youtu.be/rf_5B7bFh4E -
Learned my lesson many times in the turbocharged Baron... Above 20k ft if you're not leaning aggressively than you're bout to go through your emergency checklist...
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Hello,
As in manual:
"Mixture & Fuel Flow
Unfortunately, the MSFS internal combustion simulation is lacking as it concerns mixture and
fuel flow. Under all but extremely high density altitude conditions, reducing the mixture setting
should always result in decreased fuel flow at the same throttle setting. In MSFS, fuel flow will
fall off as horsepower decreases with an overly rich mixture setting. This is not detrimental to
the operation of this aircraft, but is nevertheless unrealistic. A potential solution is being
researched for future Black Square aircraft, and updates for the Piston Duke."So @Black-Square did you find maybe some solution for this case and can we expect any changes in next update?
