Thanks for your definition. This is my definition:
What is propeller drag? If you set full thrust, you have first a mismatch between how fast the air around the airplane moves and how fast the propeller wants to move this air. You get acceleration until this mismatch is resolved. If you set thrust to idle, you have another mismatch. The air moves faster then the propeller wants to move the air. This results in a deceleration that we call “propeller drag”.
Seb Wloch spoke about engine friction. I found the parameters max_rpm_friction_scalar, idle_rpm_friction_scalar, engine_friction_table, recip_stop_arc_friction_factor, power_absorbed_cf, prop_power_cf. For me, the last two parameters looks most interesting (C172 values):
power_absorbed_cf = 0.0 ; Coefficient of friction for power absorbed by propeller
prop_power_cf = 0.0:0.000:0.200:0.400:0.600:0.800:1.000:1.200:1.400:1.600:1.800:2.000:2.200:2.400, 15.0:0.032:0.029:0.025:0.022:0.009:-0.057:-0.188:-0.338:-0.522:-0.705:-0.915:-1.092:-1.220, 20.0:0.084:0.075:0.066:0.058:0.045:0.010:-0.074:-0.188:-0.338:-0.525:-0.726:-0.942:-1.120, 25.0:0.098:0.094:0.088:0.080:0.070:0.050:0.020:-0.040:-0.134:-0.272:-0.468:-0.717:-0.933, 30.0:0.138:0.132:0.128:0.120:0.110:0.099:0.078:0.040:-0.017:-0.110:-0.248:-0.468:-0.741, 35.0:0.206:0.198:0.188:0.178:0.163:0.150:0.130:0.105:0.070:0.023:-0.074:-0.254:-0.510, 40.0:0.250:0.242:0.233:0.223:0.214:0.204:0.190:0.175:0.150:0.118:0.072:0.019:-0.059
It is in the [PROPELLER] section. But at the moment I am happy with my “missing propeller drag workaround” and I work in other areas of flight model - right now on improving FSX conversion flight model.
But BusPeeGee wrote in Flight Model mod for the DA40NG - #19 by BusPeeGee
“it turns out that several parameters are not having any impact on the engine performance. Especially prop_efficiency_table and prop_power_cf”
Again we are at the Asobo “dumbed down” topic. Seb talks about we have it already in MSFS 2020. I say this is marketing speech. They may have the parameters, but the flight dynamics engine is not using them (at the moment).