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PC-12 NGX Throttle Beta Range Fix/Implementation

Anyone who tried the PC-12 NGX in MSFS 2024 almost immediately noticed that something is not right with the ground handling. The aircraft races forward even on idle throttle and you have to ride the brakes to keep it in check.

And if you ask “is this realistic?” The answer is yes, the real aircraft would do this too.

But then what to do?

Do it like in the real aircraft, move the throttle back below idle, into the beta range.

And this is where the real frustration starts. Even if you set up your controls properly and can move the throttle below idle either by using the reverse button or mapping an axis to throttle (0 to 100%) or any other way you quickly notice that the PC-12 NGX immediately goes into reverse thrust and starts to slow rapidly then starts to move backwards.

It is NOT your fault. 

The default Carenado/Microsoft PC-12 NGX simply does not have a beta range implemented.

Bummer… pretty big oversight if you ask me.

So here I come. I did it. 

With this mod you will have a beta between idle and reverse.

Just drop it into your community folder like any other mod.

Yes

No

In practice and principle Yes , in numbers? No, not even close but that is on MSFS. If I get some numbers from real life operations I might try to bring the numbers closer to reality, torque, rpm, itt are all over the place , it needs some real love from experts.

Just move your throttle behind idle (with your mouse , with the reverse button, with an axis , does not matter) As you move it more back the less thrust you will get and you will be able to taxi slowly. As you move it back even more you will notice a sudden jolt and sound change, this is the point where the reverser kicks in, but do not worry , it won’t start you racing backward, you are at minimum backwards thrust barely enough to start slowing you down from taxi speed. If you keep moving back with your throttle reverse thrust increases until you hit maximum reverse thrust when the throttle is full back.

Just like the real thing! 

Cool isn’t it ?

Practical tip::

Listen to the sound change as I mentioned. The RPM is the highest in the Beta range just around the point before the thrust become negative, you can use this clue to maintain your taxi speed and slow down without touching the brakes, speed up slowly just by the sound or watching the RPM, you will notice the RPM will start to decrease again as you keep moving the throttle back, this means your propeller is producing more and more negative thrust if you leave it there you might come to a full stop or even start to go backwards, so keep that throttle moving ;)

What I did is programmed a custom beta range behaviour that tries to mimic how it works in real life.

In the beta range you control the propeller pitch directly moving it from minimum ground pitch angle all the way back into reverse.

But there is a catch. Our beloved simulator has something against mathematics and aerodynamics when the propeller pitch is between +6 to about -6 degrees.

In this range all kinds of wacky things happen, most noticeably without custom code the RPM would run away, and I mean RUN into infinity (I didn’t wait more than 4000 RPM, but I guess it would have gone until the sim crash) and with great RPM comes great resp.. I mean thrust , so after a while you would become a rocketship. 

So I had to manually control the RPM and do a semi-simulation myself.

What happens in real life is that as the propeller approaches the 0 thrust propeller angle , when it is so flat that it effectively produces no thrust and the RPM increases a bit then as you keep moving towards revers the RPM goes back down a bit then it starts to increase again as the engine starts to produce more and more power.

This is what you will experience with mod as well.

If you are familiar with the PC-12 NGX, you might notice that the numbers are still all over the place, and yes this is ture. I did not mod anything else  just added the beta range and tuned it to the current numbers.

Torque is too high in idle, it does not go down during beta, RPM is too high in dile, RPM is to high during beta,  ITT is too low across the board, the transition from + to - thrust it very sudden and “jumpy” ect ect

These are all problems I can only acknowledge and not fix (yet) I’m not a pilot, nor a developper nor have I access to NGX POH or a pilot who knows the real numbers.

This mod is as is, just control part of the beta range and a sanity check on the RPM and thrust during it.

But I hope you appreciate the effort and enjoy your ability to finally taxi at proper speed without burning your career money on new brake pads 😀

PS.: If any PC-12 NGX pilot could tell me about the typical TRQ , RPM and ITT numbers during startup and taxi , I would very much like to try to fix all of those things (If I can) so contact me.

I'm just a frustrated sim pilot who asked the right question from Grok about JavaScript :D

Seriously I'm not a developper but have some aviation and development knowladge and I like the PC-12 and it frustrated me enought to do something about it.

Please enjoy your slow and controlled taxi speed.