Jump to content

Sign in to follow this  
scubadan

Tracking Issues with RXP GTN 750 and 4x time accel.

Recommended Posts

I recently purchased the RXP GTN 750 and have installed it into Prepar3D v2.5 and v4.2.  This is an amazing product and I am so glad that I purchased this unit.  So far, I have installed it into 2D Windows for the Lear 45, Baron 58 and Mooney Bravo.  Of all the things that I love about this unit, there is one problem that I am experiencing with each aircraft.  During flights that require course changes of 30 degrees or more, the aircraft starts preforming S-Turns and has difficulty tracking and locking on course.  The P3D standard G1000 that I used before I purchased the GTN 750 did not have this problem.  It seems to me that the GTN 750 over responds to course changes greater than 30 degrees.

Is anyone else having this tracking issue?  Is there a way to correct this problem?

Thanks for your help.

Share this post


Link to post
Share on other sites

Hi,

If you use time acceleration at 4 or more, it is more than possible it causes this. At 2x is should be fine enough.

The only limiting factor to the A/P coupling performance is the A/P settings in the aircraft.cfg. These are usually the ones about how fast the autopilot reacts to F/D changes and what is the maximum bank angle. The default B58 should be ok, the default Mooney more or less ok as well.

Otherwise, you might want to fine-tune and see if you can enhance these aircraft?

http://www.prepar3d.com/SDKv4/sdk/simulation_objects/aircraft_configuration_files.html#autopilot

notably:

  • max_pitch_acceleration
  • max_pitch_velocity
  • max_bank_acceleration
  • max_bank_velocity
  • max_bank

And for the PIDs:

  • nav_proportional_control
  • nav_integrator_control
  • nav_derivative_control
  • nav_derivative_control
  • nav_derivative_boundary

About PID:
https://en.wikipedia.org/wiki/PID_controller
http://www.pidlab.com/en/


Jean-Luc | reality-xp.com
This message from Reality XP is protected by a disclaimer: reality-xp.com/aboutrealityxp/email.html

Share this post


Link to post
Share on other sites

Thanks for your good advice.  I kept the Autopilot settings standard in the Aircraft.cfg file with one exception - for the Lear 45, I adjusted the nav_proportional_control from 11.0 to 9.0.  It didn't seem to help.  I'll adjust the time acceleration from x4 to x2.

Thanks for your help.

 

Share this post


Link to post
Share on other sites

Hi, just to let you know, the latest GTN v2.5 (and GNS V2 v2.4) are now compatible with host simulator time acceleration, up to 128x. 

I can tell you I was even skeptical at first during beta tests, but it is amazingly tracking the flight plan including turns!

Thank you for your feedback, it has been in our list since day 1 but we've never had the chance to further this capability before.

Edited by RXP

Jean-Luc | reality-xp.com
This message from Reality XP is protected by a disclaimer: reality-xp.com/aboutrealityxp/email.html

Share this post


Link to post
Share on other sites

GTN 750 v2.5 has completely resolved my tracking issues.  With the Lear 45 set at 300 kts [GS@380 kts], I can make enroute turns at x16 and x32 without any issues.  Significant improvement in tracking,  good job RXP.

Thanks for your assistance with this issue.

  • Upvote 1

Share this post


Link to post
Share on other sites

Yes it makes a whole lot different indeed, and like I said above, I was even skeptical this would track this good at these time acceleration factors. It is nearly amusing to see the GTN (and the GNS V2 has the same capability in v2.4 too) make the aircraft turn so fast and align so promptly to the track!


Jean-Luc | reality-xp.com
This message from Reality XP is protected by a disclaimer: reality-xp.com/aboutrealityxp/email.html

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
  • Donation Goals

    AVSIM's 2020 Fundraising Goal

    Donate to our annual general fundraising goal. This donation keeps our doors open and providing you service 24 x 7 x 365. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. We reset this goal every new year for the following year's goal.


    5%
    $1,415.00 of $25,000.00 Donate Now
×
×
  • Create New...