Unrealistic engine behavior at high altitudes
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Can confirm. Use 55% power settings, FL280, OAT -40 C getting much higher manifold pressure than expected and subsequently higher KTAS.
Could this possible have something to do with the fact that cabin pressurization doesn't seem to have an effect on aircraft power? Bleed air for cabin pressurization is pulled off of the turbo charger. Closing the pressurization valves and shutting off bleed air the cabin seems to have a negligible effect on manifold pressure as one would think that you should see an increase in manifold pressure by shutting off the cabin pressurization bleeds. Commonly aircraft would do unpressurized (bleeds off) take offs when maximum performance is needed from the engines.
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@Black-Square Thank you for an amazing aircraft. A day one purchase for me. I really enjoy flying it.
Are you aware of this issue? Are we doing something wrong or is this somehow related to MSFS limitations?
B.rgd.
Christian -
@DxMarovitch Yes, talking about the Piston version. I am currently at FL240, manually set the RPM and MAP to 2750 and 34.1 leaned to 50 degrees ROP. and I'm also showing much higher airspeed and fuel burn than the charts.
https://gyazo.com/18d4cf5695613da7622c409347473ce9
But when I flew yesterday at FL200, the numbers were much closer to the chart figures.
Kat
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maybe this higher speed explain the extra FF, and once at table airspeed FF may match table values, just a matter of torque not 100% matching.
I guess the overpower torque are due to other spec involved in the Flight Model to match better the aircraft spec (such has take off rolls, whole flight phases, approach speed) ... there is so many factor to take in account (aircraft load & weight, 0 wind, 15°C at sea level, sim does have some inconsistency to apply air density variation over altitude, gauge arn't 100% accurate I used to check a HUD bar to get specific variable values and compare them to table)
I also keep in mind it s first version, flight model require lot of time to tweak, aircraft was designed for SU15 initially ... -
@Nicotine70 I think its more of a case of the turbocharger overperforming. If you set your throttle to the manifold pressure settings in the tables, the KTAS is a lot closer.
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@lilycrose Remember, the tables are at max gross weight at ISA. Here's my flight at 55% power at near max gross weight in cruise as a test flight. OAT is bit below ISA for FL280 at -40C. My indicated TAS is about 220 knots so within 10 knots of the chart.
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Is this the DUKE 60 &A60??
Looking for the POH -
@Hawkeye That's interesting, are you at full throttle or setting the MAP? And I have a full fuel load but only 50 lbs of cargo and 120 lbs in the Pilot seat, so I can see the speed faster, but the fuel burn is much higher as well. And -40C is only 1 degree off standard day.
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@lilycrose I’m using my throttle to set the power to the proper setting within the power charts. I’m demonstrating that the turbocharger is overperforming at high altitudes because when the proper power settings are achieved, the aircraft behaves as expected per the manual. TLDR: Turbocharger issue, not Flight Model Issue.
