Fuel condition lever idle speeds
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A quick question on the fuel condition lever idle speeds:
At around 15°C OAT on the ground, bleed air off, stabilised:
Low Idle sits around 54% Ng, High Idle around 58% Ng. As far as I know the book values are 52% and 65% respectively, is that right?I understand idle speeds vary a little with temperature, so the slightly high Low Idle doesn't surprise me. What does surprise me is that the two deviate in opposite directions: Low Idle a touch high, but High Idle notably low. The value is stable and independent of power lever position within the idle/beta range, and the engine does reach 65% Ng once I advance the power lever into the power range, so it can get there, just not at high idle itself.
Is the high idle governing intended to sit this low, or should it be closer to 65%? Just want to make sure I'm reading it right. Thanks!
-
A quick question on the fuel condition lever idle speeds:
At around 15°C OAT on the ground, bleed air off, stabilised:
Low Idle sits around 54% Ng, High Idle around 58% Ng. As far as I know the book values are 52% and 65% respectively, is that right?I understand idle speeds vary a little with temperature, so the slightly high Low Idle doesn't surprise me. What does surprise me is that the two deviate in opposite directions: Low Idle a touch high, but High Idle notably low. The value is stable and independent of power lever position within the idle/beta range, and the engine does reach 65% Ng once I advance the power lever into the power range, so it can get there, just not at high idle itself.
Is the high idle governing intended to sit this low, or should it be closer to 65%? Just want to make sure I'm reading it right. Thanks!
@freemind This is one of the worst places where I run up against MSFS's terribly inadequate turbine engine simulation. I'll spare you a lot of the details, but the gas generator idle RPM puts me between a rock and a hard place like few other things in the simulation. It's virtually impossible to get a good spread and good acceleration from low to high idle without also generating too much static thrust, making the aircraft difficult to taxi, and difficult to slow down. I've spent a long time trying to coax anything better out of the simulation, but I'm afraid those couple of percent are here to stay for now. I can apply yet another layer of corrections on top of those numbers, but with every layer, the aircraft become exponentially harder to maintain. I hope you understand these tradeoffs that I make as a developer. I know some things must seem like they are easy, while others seem difficult, and it can be very hard to predict which is which from the outside.
