Posible Bug with turbo props torque formulas

Questions & Community Discussions Aircraft
,
1

Dear Asobo, There is some strange behavior I am noticing with MSFS and the
ShaftThurst calculation. I tweaked my numbers as per POH, and all is good,
everything matching perfectly, for this I used loading the airplane ready for
taxi on the runway since the airplane was up and running… the calculated
torque, etc. was spot on ISA 0, and follows perfectly at different altitudes.
However today when I loaded the airplane from the Apron state, I noticed the
values are totally off, like the formulas are not calibrated anymore, this is
happening on the same airport, same ISA conditions, temperature, etc. To test,
I reloaded again on “taxi” and again the formulas are perfect… re-loaded from
Apron… all ruined… is like somehow loading from Apron (cold / dark) vs Taxi
causes a different set of calculations to take place? Here is a picture of the
engines debug, from apron the prop is running at 1332 and the ShaftThrust is
way too high at the same N1.

1365×555 496 KB

Then from Taxi flight load, perfect numbers as calibrated:
1353×559 588 KB
Surely the method of loading a
flight should not affect these figures? I am at lost here, unable to
understand the reason and what I need to do to correct the problem. Have you
guys noticed this before? what could be the reason? I triple checked
everything, the weather conditions are the same, even copied the taxi.flt
values to the apron.flt values, and made no difference,the behavior persist…
Can anyone from Asobo please help? And to everyone else, have other 3rd party
developers noticed this before? Best, Raul

2

Hello Simbol, Could be that the sim programming has a cold warmup period where
the engine is running in a cold start and changes as it gets to running
temperature? Just a theory. That would explain a different performance when
starting cold, but consistent on running hot. Bill of the gray eyebrow
people… LHC

3

Nope, even leaving the engine running for 1 hour, nothing performance is
higher loading on Apron… (Cold) makes no sense… R.

4

Further tests reveals the same results with the TBM and Cessna Caravan… this
is a problem guys, how can we tweak our engine performance having this issue?
Regards, Raul

5

Hi All, Found the cause, it is the engine anti ice system triggered by the
ASOBO_DEICE_Switch_InertSep_Template. This causes the engine to bleed more
power, it seems I tweaked my engine with the anti-ice enabled, so when loading
at the GATE and the anti-ice is OFF, the power is high than usual. One thing
is weird thought, the Asobo anti-ice template is defined like this:

SWITCH
INERT_SEP
1
DEICE_Switch_InertSep
DEICE_Switch_InertSep
DEICE_Switch_InertSep
deice_inertsep_switch_on
deice_inertsep_switch_off
40


1 #TIME_TO_DEPLOY_SEC# /
(A:GENERAL ENG ANTI ICE POSITION:#ID#, percent) 0 > if{ (>B:DEICE_Engine_1_On) }

The variable A:GENERAL ENG ANTI ICE POSITION is defined in the
documentation as a boolean, so this must be incorrect since all the templates
are clearly monitoring the position range in the code… Best, Raul