Hello RXP, 

I recently switched from the F1 750/650 GTN to the RXP 750/650 GTN because the F1 system doesn't support the latest Garmin 750 trainer.  I happy with the RXP, as I was with the F1.  However, I am having a problem displaying the enroute GTN 750 VNAV path on HSI with the Flysimware Lear 35.  I have not tried the other two airplanes I use the 750 with, the Caranado Excel and the Xtreme Prototypes Lear 25.  

With the F1 GTN, I could display enroute VNAV path on the HSI.  I could not couple it to the autopilot, but that's to be expected with the FC 530 limits, but at least I could display the VNAV path using the ILS glideslope needle in the HSI.  This should be a normal option for this installation.  I have not been able to do the same with the RXP GTN.  Is there a way to display enroute VNAV on the HSI through software setting or config file edit? 

Thanks for your help!

Rich Boll

Wichita KS

On 1/26/2021 at 10:42 AM, richjb2 said:

This should be a normal option for this installation. 

I have no problem with an optional setting that would have the VNAV signal drive the glideslope indicator in the HSI... But PLEASE, do not make this the default as "the other vendor" has been doing..

For most airplanes, this is confusing at best....

..and yes, the standard flightsim autopilot would react to this signal in APR mode, which then screws up a standard LPV approach (as it does with "the other vendor"...)

 

Edited January 29, 20215 yr by Bert Pieke

23 hours ago, Bert Pieke said:

I have no problem with an optional setting that would have the VNAV signal drive the glideslope indicator in the HSI... But PLEASE, do not make this the default as "the other vendor" has been doing..

For most airplanes, this is confusing at best....

..and yes, the standard flightsim autopilot would react to this signal in APR mode, which then screws up a standard LPV approach (as it does with "the other vendor"...)

 

How does F1 implementation screw up the LPV approach in approach mode?  I've flown several LPV approaches in the FSW Lear 35 with the F1  with the FD in NAV and GS mode with no issues.  

Rich

4 hours ago, richjb2 said:

How does F1 implementation screw up the LPV approach in approach mode?  I've flown several LPV approaches in the FSW Lear 35 with the F1  with the FD in NAV and GS mode with no issues.  

Rich

Rich, it may depend on what aircraft and which approach..

With the F1 unit, I turned off the VNAV feature because I was getting active glideslope indicators well before the LPV glidepath was available  (caused by the VNAV feature).  In the real smaller GA airplanes which I am familiar with, that would not occur.

In your business jets... different story, I am sure.. 😉

1 hour ago, Bert Pieke said:

Rich, it may depend on what aircraft and which approach..

With the F1 unit, I turned off the VNAV feature because I was getting active glideslope indicators well before the LPV glidepath was available  (caused by the VNAV feature).  In the real smaller GA airplanes which I am familiar with, that would not occur.

In your business jets... different story, I am sure.. 😉

That is how the Garmin would work in a business jet.  The reason is to use vertical guidance down to the final approach fix.  We're engaged in FMS (NAV) and VNAV, or following the VNAV track all the way down along the STAR and the approach.  We don't like to drive and drive. 🙂 

Rich 

4 hours ago, richjb2 said:

That is how the Garmin would work in a business jet.  The reason is to use vertical guidance down to the final approach fix.  We're engaged in FMS (NAV) and VNAV, or following the VNAV track all the way down along the STAR and the approach.  We don't like to drive and drive. 🙂 

Rich 

Understand... ideally, the GTN would set a separate VNAV variable that can be used in a business jet panel, separate from the glideslope indicator variable..

That's the way likely is in real unit.  A pin setting. 

Once you get into STCs, almost any configuration and function is possible. 

Rich 

In the real unit, this is most likely the A429 output carrying the data and this would be up to the EFIS vendor to also read and use the label. In the ideal world, it would have been so easy an universal to implementing A429 emulation at the gauge SDK level so that it makes interfacing any 3rd party vendor gauge with any other 3rd party vendor gauge. Unfortunately it is not the case and any such feature quickly becomes a (O^2) problem.

The RXP GTN is at least exporting all essential simvars necessary for direct interfacing if needed, although it also includes a technology to overriding the default simvars so that the GTN output data is transparently feed into the simvars other gauges are reading.

The VDI is a recent addition in the Garmin GTN and we're not exposing it in any form for now. We're refactoring a piece of our code base related to interfacing with the Garmin trainer internals and only when this will be done, exposing VDI might become possible in a future update.