Virtual throttle position after A/T disconnect

[Jeroen Hoppenbrouwers]

So, just to make sure I understand: immediately after A/T disconnect, the hardware throttle levers are in relative mode, where any motion from where they were at A/T disconnect leads to the same amount of motion of the software throttle levers. This is to assure a smooth pickup of manual control. The difference in position between H/W and S/W is kept constant.

However since the H/W and S/W do not necessarily share the same absolute position, there is a compensation mechanism in place which is usually called "squeeze out": if one of the two throttles (H/W versus S/W) hits the end stop, and the other one pushes further, the difference between the throttles is squeezed out. If you stop squeezing and revert your throttle motion, the difference will remain constant again. So in order to totally eliminate the difference, you have to move your H/W against the forward end stop if the H/W was lower than the S/W, and against the aft end stop if the H/W was higher than the S/W. Or, commonly, simply against both the forward and the aft end stop to squeeze out all difference.

The proposal is to introduce a way to reduce this difference to zero also in another way, which is less intrusive than the full forward/aft motion to set the H/W and S/W throttles to the same end stops.

Motorized throttle H/W does not have this problem as it starts out with zero difference from the S/W when you disconnect the A/T. If you would manually set your H/W exactly where it should be before A/T disconnect, you would have the same situation. One proposal therefore is to show a special simulator mark on the N1 or other indicator if the H/W is being moved while S/W (A/T) has control, so you can align before disconnect. The disadvantage of this is that in the real 744, you can override the A/T exactly like this, by moving the H/W against the  motor. This is a crucial difference between Airbus and Boeing, in fact.

Alternatively a permanent indicator of the actual difference in S/W versus H/W throttle, which otherwise would drive the motorized throttle, would be suitable. If this would be part of the permanent flight control input position indicators in the top-left, it would become second nature to once in a while adjust the throttles to match up with the A/T. I believe this can be implemented in a very unobtrusive way.

Another proposal is to have an explicit pilot command to squeeze out the difference between H/W and S/W in one (smooth but quick) go. The third push on the A/T disconnect button has been suggested and seems operationally suitable. If the pilot clicks the disco button three times and then smoothly moves the H/W to where (s)he thinks it should be, the S/W throttle may not even noticeably change.

A combination of both may be valuable: one permanent small indicator of the difference between H/W and S/W as part of the flight controls indicator, and the third push to smoothly align.

Lastly, if and only if the pilot disconnects the A/T via two pushes on the disconnect buttons, it could be an option to always immediately but smoothly squeeze out the throttle difference. This is not Boeing philosophy: disconnecting any automation should not lead to immediate and potentially large control input changes. But since pushing these buttons in practice is only done with your hand on the throttle levers, it may be the best compromise (as a selection option). If the squeeze removal is done over a predictable three seconds, it can be anticipated.

So the choice seems to be:

1. Permanent indicator near the control inputs of the actual difference between H/W and S/W throttles, i.e., "move forward/aft to align".

2. Two pushes on A/T disconnect smoothly aligns H/W and S/W over a few seconds.

3. Three pushes on A/T disconnect smoothly aligns H/W and S/W over a few seconds.


Hoppie

[Hardy Heinlin]

I just implemented #3. On the 3rd push, the software jumps to the hardware, provided any USB throttles are enabled on the Instructor.

It looks good!


|-|ardy


This does not affect TCP/IP throttles: they always inject absolute TLAs.

[JP59]

Thank you very much Hardy and Jeroen for your contribution with my reflexion. I'm very impatient to test the Alpha 31 and feedback.

[Jeroen Hoppenbrouwers]

JP, thank you for making me feel like I actually do something here    :-D

I will get back into PSX development but currently all my time and most of my attention goes to real-world stuff for Boeing that isn't exactly open to suggestions of the kind we thrive on at this Forum.


Hoppie

[JP59]

JP, thank you for making me feel like I actually do something here    :-D

I will get back into PSX development but currently all my time and most of my attention goes to real-world stuff for Boeing that isn't exactly open to suggestions of the kind we thrive on at this Forum.


Hoppie

No doubt. This forum contributors are more open-minded  

[cagarini]

Whow!

Faster than I thought!  Tks guys for your suggestions and HH for your support !

[tango4]

Indeed !
Much appreciated here.

Charles

[cagarini]

It works beautifully!!!!

Thank you HH!!!

[kiek]

I just implemented #3. On the 3rd push, the software jumps to the hardware, provided any USB throttles are enabled on the Instructor.

If you (like me) are using  an AT/DISC button connected to an Opencockpits Master card input + PSXseecon, you can use the SIOC code below.

It will generate the third push automatically, so the pilot only has to push the AT/DISC button twice (!).

Code Select Expand


// AT/DISC button, for cockpits with non-motorized throttles (!):

// Automatic generation of the third AT/DISC to sync the throttles.
// For the Captain two pushes will do, one for AT Disconnect and one for
// preventing/clearing (if later then 1 second) the alarms
// and syncing of the Throttles.
// The second push has to be within 3 seconds of the first.

Var 3704 Static name ThrustDiscLeft Value 0  // Toggle value for PSX

Var 9000 name FirstPush Value 1
Var 9001 name TimeWindow Value 0
{
  IF &TimeWindow = 0
  {
    &FirstPush = 1
  }
}

Var 9002 name ATDiscValue Value 0

Var 9003 name ATDiscLeftBut Link IOCARD_SW Device 1 Input 117 Type P
{
  IF &FirstPush = 1
  {
    IF &TimeWindow = 0
    {
      // first push: AT/DISC
      &ATDiscValue = CHANGEBITN 0 &ATDiscValue
      &ThrustDiscLeft = &ATDiscValue
      &FirstPush = 0
      &TimeWindow = 1
      &TimeWindow = DELAY 0 300  // 3 seconds
    }
//    ELSE
//    neglect more than the first two pushes within the Time Window (3 seconds)
  }
  ELSE
  {
    // second push within 3 seconds:
    &FirstPush = 1   // prevent coming here again
 
    // 1. prevent/clear AT/DISC aural and visual Warning
    &ATDiscValue = CHANGEBITN 0 &ATDiscValue
    &ThrustDiscLeft = &ATDiscValue

    // 2. generate the 3d push to sync the throttles, after a delay of 0,5 second
    &ATDiscValue = CHANGEBITN 0 &ATDiscValue
    &ThrustDiscLeft = DELAY &ATDiscValue 50  
  }
}

The code is rather long, but that's to let it  behave correctly in all (other) circumstances

[JP59]

A usefull addition Nico, thanks for that.

Regards,

[emerydc8]

At the start of a three-engine approach, I clicked off the autothrottles and I noticed that to maintain approximately 65% N1, it required my physical throttles to be unusually far forward. Then I discovered that wihen I pushed my physical throttles full-forward, the most N1 I could get was about 84%. (I disconnected the autothrottles with the switches on the throttles (three clicks)).

I also noticed that when I moved the throttles all the way back to idle, then forward, full thrust authority was restored and I could get 100%.

Aside from cycling the throttles to idle and back, is there an option or work-around for this issue? If I could see the position of the physical throttles on the N1 indicator, I could match them to the virtual throttles before I disconect. I remember reading a more recent discussion about this in another post but can't seem to find it now.

Thanks,

Jon D.

[ADDENDUM]:

After experimenting a bit, I found that after the third click of the a/t disconnect, the position of the physical throttles appears on the N1 tape and I can quickly match that of the actual N1. Maybe this is the solution.

[Will]

emerydc8, that solution should work quite well. Hardy implemented it about a year ago for exactly the purpose you describe. Click the A/T disconnect three times, and the PSX software reads your hardware, and brings the software value to match your physical throttle positions.

[emerydc8]

Thanks, Will. It works well after trying it a few times. As you can tell, I'm still learning how to use PSX, but I'm really impressed with it. I had initially planned to be able to switch back and forth between my PMDG 777 and PSX. The more I fly PSX, the more I am convinced that I really don't want to go back to PMDG. I might even put my 777 MCP up for sale.

[Will]

You've been bitten by the bug! There's nothing quite like PSX. The sim is amazing and the community is responsive, helpful, and friendly. Glad you're having fun.

[cagarini]

emerydc8,

welcome to the exclamation of PSX users

I would like to point out also as important it is to carefully set your controllers in the USB menu to get the best out of PSX. It really makes a difference when your deadzones are carefully set to match the precision of your joystick / yoke...

Very recently I decided to buy an inexpensive T16000 thrustmaster joystick, with HAL sensors. My old x52 Pro has most of it's buttons broken, and I didn't like, and returned, the x55... The T16000 is great, and I am using it with the x52 throttle/hotas unit, but, it has it's limitations, as referred at another thread.

I think that if one decides to concentrate seriously in PSX, then getting proper harware, as well as a multi-monitor / multi-pc config is probably the best option.

VisualPSX, and XView, are also excellent freeware add-ons that allow you to use all of the investment in scenery you made for FSX or X-Plane 10, but IMO, you really need to run those "visual generators" in a separate PC, unless you own a really powerful machine. In my setup, and although I still find VisualPSX the best solution for my single PC setup, I have reverted back to use PSX standalone. Under some circumstances, the fluidity of the visuals you get running both sims on the same (old, i5 in my case ...) PC is simply not adequate, and indeed the smoothness of PSX visuals is a must.

I still hope that some day a dedicated visuals generator product, a totally naked Earth Simulator for aviation, with no burden from flight dynamics and systems modeling other than those pertaining to airport lighting and other systems, can become available.  In FSX we have a flatland at the airports ( rw and tw ), in X-Plane 10 other irritating limitations...

I only regret not having more detailed runway lighting systems starting with the visual approach lighting systems, which are all based on an imaginary 1/2 PAPI setup..

Regarding the limitations in side views that we face when using only PSX visuals, I believe it can be overcome by switching between PF and PNF views, investing a bit in setting up a good 9-pack. The ND will also provide you with the additional visual queues.

[emerydc8]

Thanks for the welcome and good information, Jose. I am using a Precision Flight Controls yoke and rudder setup and I set them both at 10 for the neutral zones. The yoke has a Hall sensor, but I think the rudder neutral zone may need to be increased a bit because I always rest my feet on the rudders while flying and even just a little bit of pressure on the pedal may be causing Sarah to say "Check your rudder" (I think that's what I'm hearing occasionally).  

As for the visuals, I have three 39" screens dedicated to visuals and that was nice to have with FSX. This may sound counter-intuitive, but having come to PSX from that, I like the stock PSX visuals more because it forces you to stay inside longer. It makes the approach that much harder and is more like the real Level-D simulator than anything I've seen on an FSX setup. In fact, the only time I can remember seeing nice visuals in the Level-D sim is when they make me do a two-engine approach. Outside of that, it's usually down at minimums anyway.

[Hardy Heinlin]

Regarding the limitations in side views that we face when using only PSX visuals, I believe it can be overcome by switching between PF and PNF views, investing a bit in setting up a good 9-pack. The ND will also provide you with the additional visual queues.

The PF and PNF views are identical if their windshield portions have the same width. Just the position of the center post may be different, and thus may hide different scenery sections when in crosswind conditions.

The windshield view angle depends on the width of the visible windshield area within a layout subframe. Disregard the center post in this formula. If you see the whole windshield frame from left to right then you have the maximum available view angle onto the scenery. When you halve the width, you halve the view angle, no matter where this half is placed, be it over the left seat or the right seat, or over the MCP, it doesn't matter. And the aircraft heading is always in the middle of the windshield section, no matter where this windshield section is placed.


Cheers,

|-|ardy

[martin]

A pride of lions, an exaltation of larks, a richesse of martens, a mischief of mice, and now we have an...

...exclamation of PSX users.

Would make a very fitting addition to the list indeed!

 

[cagarini]

Thx HH for your coments regarding the widespread cockpit view giving the widest possible field of view. I just don't use it because it tends to "eclipse" my rw unless there is really a strong x-wind component, but I am still playing with my 9pack :-)

@martin: Let's offcialize it!!!  An Exclamation of PSX users :-) hehehe!