Diagnosing a throttle issue

[curbz]

Hi Pete,

Hoping you can perhaps give me some advice to diagnose a throttle issue I am experiencing with the PMDG 737 NGX in P3D v4.1 - note that this is not an FSUIPC issue so feel free to stop reading, I am using FSUIPC to read data from the sim so as to help me find where the problem lies.

I have a Saitek throttle quadrant that is has two of it's three axis levers mapped directly in P3D to throttles 1 and 2. Both axis are calibrated in P3D.

With the NGX on the ground I can move the hardware throttles back and forth through the full range and the NGX virtual cockpit throttles respond without issue, settling nicely back in the idle position whenever I move my hardware levers back to their minimum positions.

However, during flight and upon touchdown, the virtual cockpit throttles will never fully return to the idle position despite my hardware levers being in their minimum positions. They sit just a little bit shy of the idle position as can be seen here:

 

This means that I cannot deploy the reversers as the throttles must be in the idle position to do this.

I have tried multiple sets of hardware, calibrations and so on, to no avail. So what I am trying to do is to determine whether my controller is sending the correct information to P3D and whether it is a case of the NGX not responding to these values. I am hoping FSUIPC will be able to help me do this. What I have done is to register FSUIPC offsets within SIOC and use the SIOC console to display these values. This is what I am seeing (offset 0366 is the ground/air flag where ground = 1):

On the ground before take-off (offset 0366 = 1): With my hardware lever axis in it's minimum position, offset 3330 (description: Throttle 1 Axis input value, post calibration, just before being applied to the simulation) has a value of zero. Offset 088C (Engine 1 throttle lever) has a value of 1. This is what I would expect.

During flight (offset 0366 =0 ) and upon touchdown (offset 0366 = 1):  With my hardware lever axis in it's minimum position, offset 3330 (description: Throttle 1 Axis input value, post calibration, just before being applied to the simulation) has a value of zero. Offset 088C (Engine 1 throttle lever) has a value of 1311. This isn't what I'd expect and probably explains why the NGX virtual cockpit levers are not quite in the idle position.

Does my analysis seem correct to you or are there other offsets that I should be looking at, as there are quite a few that relate to throttle positioning? Many thanks.

[Pete Dowson]

7 minutes ago, curbz said:

Does my analysis seem correct to you or are there other offsets that I should be looking at, as there are quite a few that relate to throttle positioning?

Better to use the logging in FSUIPC Options instead. Don't fret about offsets so much in looking at the hardware side as the PMDG code may be doing something with the internal values.

When you get the problem happening, enable Axis logging, operate the throttle(s) again, briefly, bringing them right back, then dissable the axis logging (so the log doesn't get too big) and look at the Log file in the sim's modules folder. See what the actual axis value was at idle.

You could also check the actual joystick input more directly by going into FSUIPC's Axes tab and seeing the IN value changing.

From what you say it does seem like more of a PMDG question, so also try posting in their support forum. Maybe others have seen this and solved it.

Pete

 

[curbz]

Many thanks Pete - I'll give this a try. I posted a couple of weeks ago in the PMDG forum - had a couple of good suggestions but nothing that solved he issue for me. Seems like a few others do suffer with this and have needed to employ workarounds or resort to pressing F1 on the keyboard to cut the throttles.