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Emi

Lear 35 not following the routeline

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Hey guys,

 

does anyone else have an issue with the Lear not following the route from the GTN750?

Mine keeps overshooting in turns, then it screws up the correction and overshoots again. This way it takes 2 or 3 turns until it gets aligned with the new course.

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Hi Emi,

 

Haven't really had an issue with that - are these turns greater than 90 degrees ? I believe the GTN calculates your turn curve based on speed... Is your yaw damper on - I believe that it should help maintain coordinated turns - which should allow for sharper turns than uncoordinated ones... I'm sure you know - but just to be sure - you have to steer your autopilot onto you NAV track interception - before the NAV hold will capture it... I typically slow down to 160 to 180 KIAS before starting any part of an approach procedure - seems to fly them pretty well...

 

Regards,

Scott

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Hey guys,

 

does anyone else have an issue with the Lear not following the route from the GTN750?

Mine keeps overshooting in turns, then it screws up the correction and overshoots again. This way it takes 2 or 3 turns until it gets aligned with the new course.

If you are talking about when the GTN is in VLOC, you might find the AP does a better job of intercepting a course by changing these AP PID values in the aircraft.cfg under the AP section:

(The values after the // are the commented out original values.)

 

[autopilot]

.............

nav_proportional_control = 12.0 // 25.0 orig

nav_integrator_control = 0.00  // 0.10 orig

 

And as Scott mentions above, speed is definitely an issue. If you want the GPS to fly a procedure turn or a holding pattern, for example, you want to keep the speed down.

 

Al

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Is your yaw damper on - I believe that it should help maintain coordinated turns

Yaw damper is used to prevent a roll-yaw coupling phenomenon called Dutch roll, I will not go into detailed mechanics of it, you can find more info online, but you can try quickly moving the rudder full left-neutral-full right-neutral in the simulator while flying trimmed straight and level with the autopilot and yaw damper off and observe the behavior of the aircraft (hands off the controls after the rudder input). Yaw damper doesn't help coordinate your turn, nor does it affect the turn rate.

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Hi Emi,

 

Haven't really had an issue with that - are these turns greater than 90 degrees ? I believe the GTN calculates your turn curve based on speed... Is your yaw damper on - I believe that it should help maintain coordinated turns - which should allow for sharper turns than uncoordinated ones... I'm sure you know - but just to be sure - you have to steer your autopilot onto you NAV track interception - before the NAV hold will capture it... I typically slow down to 160 to 180 KIAS before starting any part of an approach procedure - seems to fly them pretty well...

 

Regards,

Scott

 

Hi Scott,

 

I actually meant the "normal" flight, so special manouvers, etc.

For example when there is a 30-40° turn on my route the autopilot will take too long to initiate the turn and then maintain not enough bank.

The 1/2 BNK button is turned off in such situations, but it almost feels as if it was on, even though the airplane still banks to about 19-20°. But not enough to follow the route.

 

If I program a HOLD in the GTN it even just stops the turn completly after having flown some 50°. It then just very slowly lowers the bank until adchieving a wings level situation (I did not press the Wings Level button!) and then just continues on the present heading.

 

I'll try to capture a video of this behaviour this evening if I can.

 

As Vladimir explained earlier the Yaw Damper is not designed to coordinate a turn, it is a pure feature to counteract the Dutch Roll, so I don't believe this to be related.

However, yes, the yaw damper is on :)

 

If you are talking about when the GTN is in VLOC, you might find the AP does a better job of intercepting a course by changing these AP PID values in the aircraft.cfg under the AP section:

(The values after the // are the commented out original values.)

 

[autopilot]

.............

nav_proportional_control = 12.0 // 25.0 orig

nav_integrator_control = 0.00  // 0.10 orig

 

And as Scott mentions above, speed is definitely an issue. If you want the GPS to fly a procedure turn or a holding pattern, for example, you want to keep the speed down.

 

Al

 

Hi Al.

 

thanks for these values, I'll give it a try this evening.

I'm flying the holdings at the typical holding speeds.

230 below FL140 and up to 265 above FL140.

It surely should be able to cope with a holding at these speeds?

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I'm flying the holdings at the typical holding speeds.

230 below FL140 and up to 265 above FL140.

It surely should be able to cope with a holding at these speeds?

It doesn't, at least not in my experience with the L35. One possible explanation is the AP models old technology from the steam gauge era. Another possible explanation is the AP might be based heavily on the FSX default AP which is not very good.

Al

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It doesn't, at least not in my experience with the L35. One possible explanation is the AP models old technology from the steam gauge era. Another possible explanation is the AP might be based heavily on the FSX default AP which is not very good.

Al

 

The old tech should not be the reason, even back in the day the APs were good enough to be able to fly whatever you put into them.

Sure there were exceptions, but these were rare.

 

I did just now do a flight with the changes to the aircraft.cfg you recommended earlier and everything went fine. Probably these fixed it already!

Two more flights on my schedule for today, so I'll have an eye out on my next two trips.

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Hi Folks,

 

Thanks for the yaw damper info - I could swear back in FS9 the yaw damper = coordinated flight on planes - I seem to recall being unable to use the rudder and needed to turn the yaw damper off to regain control - but - it could just be something I picked up incorrectly - live an learn...

 

Al - you are definitely a treasure trove on this plane - thanks for ALL you contribute... Another mod I need to make...

 

So where ya head'n Emi ? Always curious how others fly...

 

Regards,

Scott

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I flew MUC-MXP-MUC this evening (VATSIM event), originally I planned to fly another leg back to MXP, but cancelled that when they closed the LIMM FIR due to high traffic - didn't want to spend 25 minutes in the holding waiting for clearence to enter that FIR.

On my next flights I really want to go to Nishnij Novgorod if time permits, that is a promising airport and got to be fun in russian winter!

Genoa and Sumburgh (Shetlands) are also among my favorits for the Lear though!

 

On the second flight again everything was fine with the changes recommended by AI. Thanks for them, now I just got to try holdings to see if these also work now.

That's something for tomorrow though, definately time to go to bed now. I got a full day of learning GNAV coming up tomorrow.

 

 

Another mod I need to make...

 

May I ask which other mods you did?

So far I got the replacement VC textures and the VAS savings. Anything I miss that I should have?

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Hi Emi,

 

Sounds like a full day - one of these days I've got to try flying around Europe myself - and with this Lear I finally may have the legs to get there - via a hop or two of course...

 

Two other things you might want - need to see that wizard Al again - he has LUA scripts that give you button control over all the autopilot functions and many of the other essential controls not normally available in FS or FSUIPC (thrust reversers, engage steering, etc etc etc)  - invaluable in my book....

 

Al also has a MDL file for the VC that fixes the erroneous indication for windshield heat on the indicator panel...

 

LOL - he might have more in his bag of tricks since he continues to surprise us...

:wink:

 

Regards,
Scott

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So far I got the replacement VC textures ....................................

 

Could you, and/or others,  please explain what changes you see with the replacement VC textures, and where the file is available.

Thx,

Al

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Could you, and/or others,  please explain what changes you see with the replacement VC textures, and where the file is available.

Thx,

Al

 

It's mainly some dirt added around the switches and some reflections to the glass of the gauges.

You can get it on FSW's repaints page here: http://www.flysimware.com/website/repaints.html

Scroll down a little to find it.

Don't get disappointed by the preview pictures, in my opinion the actual repainted looked quite a tad nicer in the sim than it did on the pics.

 

Hi Emi,

 

Sounds like a full day - one of these days I've got to try flying around Europe myself - and with this Lear I finally may have the legs to get there - via a hop or two of course...

 

Two other things you might want - need to see that wizard Al again - he has LUA scripts that give you button control over all the autopilot functions and many of the other essential controls not normally available in FS or FSUIPC (thrust reversers, engage steering, etc etc etc)  - invaluable in my book....

 

Al also has a MDL file for the VC that fixes the erroneous indication for windshield heat on the indicator panel...

 

LOL - he might have more in his bag of tricks since he continues to surprise us...

:wink:

 

Regards,

Scott

 

I've had a look at the LUA's, but I can somewhat not get in line with that program. I don't know, it's just not mine. That's not the LAU's fault though, but purely me not liking the interface - lol.

I'll give that VC model a look, thanks!

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Hi Al,

 

LOL - like Emi - I looked at the pix on the FSW site - and I could see no difference - the pix don't do it justice - I think it's a big improvement and gives the pit a lived in look...

 

Hi Emi,

 

Are we talking about the same thing with LUA ??? There is no program or interface to load - Al made a series of small scripts that you dump in your modules directory - these scripts are simply called after you set them up in FSUIPC via a button press after assigning a keystroke to it... Takes all of 10 minutes to setup - the hardest part is just finding "unused" keystrokes to assign... They work flawlessly...

 

Just send Al a PM request with your email address and he would probably send you all his files... For me they're essential...

 

Here is some help if you need to find unused keys in the sim:

http://www.fsdeveloper.com/wiki/index.php?title=Keys_-_Listing_-_Default_Types_(FSXA)

 

Here's the list - I think he's added a few more since this was published:

 

Lear35A Autopilot Scripts (Note: The FSX standard Z key control toggles the autopilot on and off, so no script is needed for that.)

 

L35AP_ALTHLD_Btn – Altitude Hold button toggle

 

L35AP_ALTSEL_Btn - Altitude Select button toggle

 

L35AP_VS_Btn – Vertical Speed button toggle

 

L35AP_SPD_Btn – Speed button toggle

 

L35AP_GS_Btn – Glide Slope button toggle

 

L35AP_HDG_Btn – Heading Hold button toggle

 

L35AP_NAV_Btn – Nav button toggle

 

L35AP_LVL_Btn -Level button toggle

 

L35AP_BC_Btn – Backcourse button toggle

 

L35AP_H_BNK_Btn – Half Bank button toggle

 

L35AP_TST_Btn –AP Lights Test button toggle

 

L35AP_SFT_Btn – AP Soft button toggle (this function is difficult to test and the script has not been tested in flight. The SFT button does light up and move as expected, however, and should work as expected.)

 

 

 

Lear35A General Scripts

 

Lear35Land_Lts - Taxi and Landing lights 3-way switch toggle

 

Lear35Rec_Lts -- Recognition lights switch toggle

 

Lear35GearHorn – Gear warning horn off switch

 

Lear35Reversers – Arm Reversers switch toggle

 

Lear35SteerLock –Steering modes Toggle

 

Lear35YawDamper – Primary Yaw damper powered and on toggle

 

Lear35StopWatch – Panel Stopwatch 3-way toggle

 

Lear35SpoilerSw - Toggles Spoilers on and off

 

Lear35Go_Around – Pushes (activates) Ground Around button on left throttle

 

Lear35Radio_Alt – Toggles radio Altimeters on and off

 

L35CabinAltHorn – Silences cabin altitude warning horn

 

L35HdgBugSync - Syncs (aligns) HSI heading bug with current a/c heading

 

Regards,

Scott

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Hi Folks,

 

On a side note - - - what does the "Go Around" button do on this plane ???

 

Regards,

Scott

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Scott,

 

It sets the flight director command bars to wings level, 10 degree pitch attitude for a go around or for take off to establish rotation attitude.On a missed approach press the control wheel master button to disengage the autopilot and then depress the go around button on the power lever. Once established you would reselect whatever AFCS mode desired. For a takeoff just press the GA button on line up and then select heading mode on the AFCS if desired.

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