I did a lovely night flight from YMAY to YMEN, GPS Direct at 9000ft and was messing around with settings - but noticed really strange behaviour.
The cruise was at 9000ft, which was above full throttle height.
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The mixture only seemed to change fuel flow. When reducing from 100%, the fuel flow initially increased (???), but there was no change in CHT or EGT readings.
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A gradual reduction of mixture to ~50% caused the fuel flow to rise, then fall again.
In theory, what should happen is that the fuel flow can only decrease as you reduce mixture. I can’t think of any reason why moving from 100 → 80% mixture would cause an increase in fuel flow.
The CHT / EGT should reduce as the aircraft climbs, but as mixture is reduced, should rise to a peak at the Chemically Correct Mixture (CCM) (which I believe should be a 14.7:1 air to fuel ratio), then fall off until rough running starts. Procedure would normally to be adjust mixture to (I think) ~25 degrees lower than CCM on the rich side.
It’s been a number of years since I’ve done this in a real baron, so someone might be able to elaborate further or correct any mistakes above from a bit more recency…