Hello everyone! 

 After years waiting for MSFS2020 and then saving up for my build... I am FINALLY back in the sim  and on VATSIM with MSFS2020. After getting all my settings figured out I have come across one massive issue... I can't taxi or make accurate turns. I have tried stock aircraft, PMDG 737 series, and LatinVFR Airbus. Not a single aircraft is accurately making turns within an acceptable or realistic radius while taxiing. Every airplane nose wheel just "skids" if trying to make tight turns above literally 2kts or a "creep." With full nose wheel deflection even at 3-5kts the aircraft all "skid" and even on less drastic turns, the turning accuracy while taxiing is completely unrealistic. I have tried to see if it was my joystick set up (X56) but even with keyboard inputs I have the same issue. I have attempted to look in Control, General, and Assistance settings and have not found anything that has fixed this..... Has anyone encountered this? I purchased MSFS2020 from the webstore this Monday, so I am unsure if the current update has anything to do with this, but the turning while taxiing will not gain accurate "tire traction" for tighter turns unless I am below 2kts or at a creep... something is completely off... and before anyone asks.... ATP with multiple type ratings, I promise I am not overthinking or overcriticizing the sim.. Any tips, tricks, or adjustments will be HIGHLY appreciated! 

Thanks in advance! 

1 hour ago, gear_d0wn1256 said:

Hello everyone! 

 After years waiting for MSFS2020 and then saving up for my build... I am FINALLY back in the sim  and on VATSIM with MSFS2020. After getting all my settings figured out I have come across one massive issue... I can't taxi or make accurate turns. I have tried stock aircraft, PMDG 737 series, and LatinVFR Airbus. Not a single aircraft is accurately making turns within an acceptable or realistic radius while taxiing. Every airplane nose wheel just "skids" if trying to make tight turns above literally 2kts or a "creep." With full nose wheel deflection even at 3-5kts the aircraft all "skid" and even on less drastic turns, the turning accuracy while taxiing is completely unrealistic. I have tried to see if it was my joystick set up (X56) but even with keyboard inputs I have the same issue. I have attempted to look in Control, General, and Assistance settings and have not found anything that has fixed this..... Has anyone encountered this? I purchased MSFS2020 from the webstore this Monday, so I am unsure if the current update has anything to do with this, but the turning while taxiing will not gain accurate "tire traction" for tighter turns unless I am below 2kts or at a creep... something is completely off... and before anyone asks.... ATP with multiple type ratings, I promise I am not overthinking or overcriticizing the sim.. Any tips, tricks, or adjustments will be HIGHLY appreciated! 

Thanks in advance! 

I have no idea what your problem is. 

21 minutes ago, Bobsk8 said:

I have no idea what your problem is. 

If not control quadrant, and not control assignment related... what in the sim would be the "parameters" for a tight radius turn vs a high speed turn and if it's across the board...... I'm just as baffled. None of my friends are reporting the issue I am encountering....

1 hour ago, gear_d0wn1256 said:

.....so I am unsure if the current update has anything to do with this, but the turning while taxiing will not gain accurate "tire traction" for tighter turns unless I am below 2kts or at a creep... something is completely off... and before anyone asks.... ATP with multiple type ratings, I promise I am not overthinking or overcriticizing the sim.. Any tips, tricks, or adjustments will be HIGHLY appreciated! 

Thanks in advance! 

The problem is that the sim turn radius, especially in larger aircraft, is tied to the yaw inertia unless you taxi at a crawl:

empty_weight_yaw_MOI = 89315555

The above is the yaw inertia setting for the B747 in its flight_model.cfg file. Unfortunately the required Yaw inertia for flight also affects the turn radius on the ground if you taxi at higher than very low speeds while turning. If you drastically reduce the Yaw Inertia value (and I mean REALLY drastic) then you'll get tighter turning on the ground but in the air the Yaw will tend to be way too twitchy. Also, too low Yaw inertia can lead to shaking of the whole aircraft as its weight/mass requires a much, much higher yaw inertia than, say, a C172. There are a couple of workarounds related to tire grip discussed in the latest SDK after SU11.

Turn radius is also a function of the nosewheel steering angle set in the flight_model.cfg file. Most MSFS airliners have a high steering angle set (at least 60 degrees and up to 75 degrees which is extremely tight but as you know as a pilot is correct) in contrast to smaller aircraft which have typically 20-30 degrees steering angle. Without tweaking the only way to manage this in larger MSFS aircraft is to slow down to VERY slow when making tight turns - for example when entering a runway.

I recommend you have a good read of the SDK documents related to the flight model file. It is not an easy fix but it is possible.

Edited January 15, 20233 yr by robert young

34 minutes ago, Bobsk8 said:

I have no idea what your problem is. 

Thanks Bob

41 minutes ago, robert young said:

The problem is that the sim turn radius, especially in larger aircraft, is tied to the yaw inertia unless you taxi at a crawl:

empty_weight_yaw_MOI = 89315555

The above is the yaw inertia setting for the B747 in its flight_model.cfg file. Unfortunately the required Yaw inertia for flight also affects the turn radius on the ground if you taxi at higher than very low speeds while turning. If you drastically reduce the Yaw Inertia value (and I mean REALLY drastic) then you'll get tighter turning on the ground but in the air the Yaw will tend to be way too twitchy. Also, too low Yaw inertia can lead to shaking of the whole aircraft as its weight/mass requires a much, much higher yaw inertia than, say, a C172. There are a couple of workarounds related to tire grip discussed in the latest SDK after SU11.

Turn radius is also a function of the nosewheel steering angle set in the flight_model.cfg file. Most MSFS airliners have a high steering angle set (at least 60 degrees and up to 75 degrees which is extremely tight but as you know as a pilot is correct) in contrast to smaller aircraft which have typically 20-30 degrees steering angle. Without tweaking the only way to manage this in larger MSFS aircraft is to slow down to VERY slow when making tight turns - for example when entering a runway.

I recommend you have a good read of the SDK documents related to the flight model file. It is not an easy fix but it is possible.

 

 Thanks, I'll read up on SDK Docs for SU11, but the question begs is this due to a sim update? My friends who have been running FS2020 without update are not reporting this issue I am having after just purchasing this week...

You could also check:

ground_crosswind_effect_zero_speed, ground_crosswind_effect_max_speed, ground_high_speed_steeringwheel_static_friction_scalar, ground_high_speed_otherwheel_static_friction_scalar.

and this post: Setting Tire Pressure to affect "Ground_....._static_Friction_scalar" - MSFS DevSupport (flightsimulator.com)

6 hours ago, gear_d0wn1256 said:

 

 Thanks, I'll read up on SDK Docs for SU11, but the question begs is this due to a sim update? My friends who have been running FS2020 without update are not reporting this issue I am having after just purchasing this week...

It’s not due to a sim update and none of your friends are running FS2020 “without update” as that’s not possible.

We’re all on the same version.

Ground handling and the whole interface around leaving the ground needs some work. This has been acknowledged by the devs in the past.

We await developments.

11 hours ago, robert young said:

The problem is that the sim turn radius, especially in larger aircraft, is tied to the yaw inertia unless you taxi at a crawl:

empty_weight_yaw_MOI = 89315555

I recommend you have a good read of the SDK documents related to the flight model file. It is not an easy fix but it is possible.

You are 100% correct.

Unfortunately, ASOBO, for some unknown reason they refuse to understand (even though actual information and data were provided) that steering the airplane via rudder, tiller, or combination of both works more differently than they think. It's there but poorly implemented.

As an example, regardless of weight (inertia) on a dry surface and tire conditions in real-world operations turn radius and nosewheel tire scrubbing will be a factor above 10 KTS GS. We can exercise the tiller up to a full 75 degrees left/right all day long without any issues, when above that speed, usually, the first sign is tire vibration, the second is tire scrubbing where turn radius starts to be a factor, and eventually, the tire will come off the wheel assembly.

 

Talking about the 747 and others of that category 10 KTS GS is common even during tight turns.

 

Now, my observation is that there is a magical number where above exactly 7 KTS GS or so this turn widening starts to show the issue. This should not happen under normal taxi conditions.

Also, it can be observed if we watch the tiller movement above that speed that is returning slowly to the center by itself even if the tiller device is held to the max deflection on the left/right extremity.

 

I would be very interested (even via PM) in what kind of fixes are you thinking about and what can be achieved without ASOBO fixing their faulty coding. I tried the "tire grip" values after the SDK SU11 without any success. My knowledge is limited and their explanations are not so great.

*UPDATE* 

 After attempting one last thing, I was able to improve my turning capabilities by what I would consider another 20-30% but still not accurate. I assigned my nose wheel steering to the same key bindings and axis assignments as my rudder on my joystick. So while I no longer have a "tiller" on my quadrant, I can make a more accurate turn at brisk walk to high speed exit from landing roll out. The infamous 75 degree low speed turn still has a lot to beg for... Seems like the remaining issues are on ASOBO and MSFS2020..... Hopefully they come to their senses and make the necessary adjustments. 

Do most users of MSFS just accept stuff like this? It would drive me nuts if I could not taxi my plane smoothly on the ground.

Hi Christopher.

I have had the sim from day one. I fly GA aircraft like the Baron and it works just fine for me. I am not a real world pilot, although my son was an Airbus Captain. If one wishes to be a bit picky then there is some stuff in the sim that can be picked up on. However, if like me, you just want to fly around and see new places then this sim is simply brilliant. The Baron flies just fine for a non real world pilot like me. I just enjoy what I have.

Regards...Kenny.

13 minutes ago, Christopher Low said:

Do most users of MSFS just accept stuff like this? It would drive me nuts if I could not taxi my plane smoothly on the ground.

There is definitely a need for improvement.... But overall I am massively impressed so far. 

6 hours ago, cagarini said:

You could also check:

ground_crosswind_effect_zero_speed, ground_crosswind_effect_max_speed, ground_high_speed_steeringwheel_static_friction_scalar, ground_high_speed_otherwheel_static_friction_scalar.

and this post: Setting Tire Pressure to affect "Ground_....._static_Friction_scalar" - MSFS DevSupport (flightsimulator.com)

I'm not going to even try to say I know what to do when it comes to adjustments and development, read this article... will changing the value to "0" change the tire "friction" to "grip" at a better speed for tight turns? Since the defaults are "1" and they are inaccurate...

IRL, planes don't take short turns at 20 KTS. Taxi to the jetways is done at 5/10 KTS