Lateral instability in IXEG 733

[martinlest]

Anyone any idea why, as soon as I lift off, the 733 wants to bank to the right? All the flight controls are centred... as is my joystick (Saitek X52), according to both the XP joystick menu and the joy.cpl app. No wind is set in weather and I have no scripts or other that would add any crosswind.

The same on landing... as I get close to flare (AP on), the a/c becomes harder and harder to control - it wants to roll one way or the other. I am at VREF+5 at least, flaps correctly set (usually full). On touchdown, it seems to want to tip onto its side: it will roll and 'skate' around on the runway until I can get its speed down to under around 60kts. On approach, if I elect to turn off the AP and hand-fly, the moment the AP is disengaged ( have my one of my Saitek buttons set up for this, as in the instructions), the a/c starts to bank to the right. It's controllable, but the landing is always a mess.. I haven't crashed yet, but the plane is all over the place, as I described. Just about manage to keep it on the runway.

Does any of this ring any bells? I didn't use to have this issue when I first bought the 733 and it is certainly spoiling the pleasure I used to have flying this plane: the problem seems to have come on with XP11.50 (EFM is on, BTW), though that is just an impression I have.. Is there something I have missed in setup for 11.50?

Oddly, I have a similar issue (though a bit less pronounced) in the Zibo 738. But all my other a/c, such as the SSG b748, Toliss a319, JD a320, X-Crafts Embraers etc. etc. are perfectly fine, they do not show this problem at all. 

Thanks for any ideas.

[Litjan]

Hi,

I have no idea and this is the first time I heard about a problem like that with our plane - but this is what I would do to troubleshoot this:

1.) Output "weather" data to screen (little green numbers). A lot of people DO have wind influencing the aircraft but don´t know about it (even a wind set up at 30.000 feet will blow with the same strength on the ground).

2.) Output "flight control deflection" to screen. Really make sure that there is no aileron or rudder deflection when you see the roll happening.

3.) Make sure that both engines spin with the same N1 and that one reverser isn´t open inadvertantly (check orange reverser unlocked light).

4.) Make sure that there is no lateral inbalance due to fuel being inbalanced - both wing tanks (1 and 3) should show the same fuel level.

Cheers, Jan

 

[martinlest]

OK, thanks. I have discovered today that if I start a flight with the a/c on the runway and set 'ready for takeoff', then after setting flaps etc., on lift-off the plane behaves perfectly normally. If I have a flightplan loaded however (AP is not on, nor LNAV or VNAV!), then the plane banks.  This is very odd... maybe I should simply try reinstalling.

Anyway I will carry on experimenting, with your suggestions, and post back if I get anywhere. Thanks again.

[martinlest]

I loaded up a number of dataref outputs - I couldn't find one called "flight control deflection" - I selected those in the first screenshot.

Seems the rudder is the issue? That defelction starts at zero but increases quite quickly as soon as I take off. In the XP onscreen menu joystick window and in the Windows joy.cpl panel, all the axes on the Saitek are perfectly centred. Plus, if it were a hardware problem per se, I'd expect to see this in all my aircraft. I only see it in the IXEG 733 (and in the Zibo 738... very strange!).

This is also very odd:

Quote

I have discovered today that if I start a flight with the a/c on the runway and set 'ready for takeoff', then after setting flaps etc., on lift-off the plane behaves perfectly normally.

Hope someone may have some ideas.. if I just leave the joystick and do not put some quite forceful input to the left, the a/c rolls over to the right and will crash pretty quickly.

Thanks.

Edited November 14, 2020 by martinlest

[martinlest]

OK, I may possibly have found out the cause of this....

There is a problem with the Saitek X52 joystick, in that the trigger which most conveniently toggles the landing gear will not function in the X-Plane setup... plenty of posts about the issue out there. One way around this is to have the joy.cpl window open for the X52.. for some reason  this enables the 'pinkie' switch (as they call it) and you can toggle the landing gear up/down using that switch. 

https://forums.frontier.co.uk/threads/saitek-x52-pinkie-issue-finally-solved.521829/

For some reason (someone might say why), the IXEG 733 does not like this window being active. If I start a test flight ready to fly with the cpl window open, the plane banks as soon as it takes off. If I restart the flight (and reload the plane), without bringing up the cpl window, it does not deviate off course.

Need to go and try this in a 'real flight' (i.e one which starts cold and dark at a gate and in which I run all the usual setups), but seems from the tests at least that this is the problem. I'll have to use a different X52 button to toggle the gear!

Edited November 14, 2020 by martinlest

[Litjan]

Huh, this is really strange!

I checked the output of the datarefs in the pic you posted - and the rudder was the only one deflected, but it was deflected to the left (negative) while the plane was banking to the right...so I believe it is the yaw damper working against the turn, as it should.

Wind is not a factor (it is zero)

The discovery about your X52 window being open is interesting - and confusing! I do not know how this could make our plane turn.

I would try to not use any buttons on your joystick just to test - use the keyboard key "G" to control your landing gear?

Also did you check the fuel balance?

Cheers, Jan

[martinlest]

Hi again... thanks for the reply.

Oh, yes, fuel is balanced just fine.  I have still to test in a full flight (set up from cold and dark): testing with engines ready at the runway does not always call into play all the factors involved in troubleshooting an issue, I have found (in general). But after three or four test runs from 'takeoff ready', it did seem that the X52 joy.cpl being open was the trigger. I started a new flight, take-off ready with the window open.. the a/c banked. New flight, no cpl window.. no such problem, as I say. 

I do have a second button (not quite so conveniently placed) for toggling the gear, so for the IXEG/Zibo 737s, I will use that instead. Pretty sure that should be fine.

None of my other payware a/c - or Zibo 738 (hardly ever seem to fly the Laminar ones these days!) has the same issue: their not being affected by the open cpl window (for whatever reason) would certainly explain the difference.

Once I have flown a 'full flight' later, I'll post back to say whether the cpl window was the culprit, or I am back to square one!

Edited November 14, 2020 by martinlest

[martinlest]

Started a new flight from cold & dark...

To confirm: with no joy.cpl window active, the a/c flew exactly as it should, straight as a die. If you ever find out why the 733 does not work with that window active Jan, it'd be good to know the reason, because the X52 could then perhaps be made to work as it does with all my other payware aircraft, opening up the use of all the button options - but if not, no problem: the relief at having found the cause of this issue in one of my very favourite XP planes far outweighs any minor hardware inconvenience! X52 users can just use a different button on their joystick! 

Edited November 14, 2020 by martinlest

[martinlest]

Quote

To confirm: with no joy.cpl window active, the a/c flew exactly as it should, straight as a die

That was true for a few days. This morning the problem is back, even with no cpl window open. I even dug out an old MS Sidewinder joystick and tried that instead, just to determine that it isn't being caused by the Saitek hardware, but immediately after takeoff the 733 starts banking to the right with that joystick as well, and within 10 seconds, if I don't intervene, I am getting 'bank angle' warnings.. and the a/c will soon tip over and crash.

Not expecting any revelations by way of a reply, but I really don't know what else to try... I did make one change in the interim: I removed the Saitek X52 drivers (as recommended on X-Plane forums), which finally enabled me to map IXEG functions to the X52 on all buttons, not just some. Can also use the 'pinkie' trigger to toggle the landing gear. Now that those are working, the (big) downside seems to be this very marked banking to the right. I can make no sense of it. If, as the 733 tips over, I load the c172 (say), or the MD80, or one of my other payware aircraft instead, the problem is gone. If I reload the 733, the problem is still there.

There surely must be something in the 733 programming that is causing this, because (as I remarked in my first post), I have no issues like this if I test with other aircraft in XP11. I think I had in fact better go fly something else for a while (though I surely must get to the bottom of what is causing this at some stage!): this is getting pretty frustrating (not just for me, I suppose Jan!): third day now (is it?) of testing a troubleshooting.

Edited November 16, 2020 by martinlest

[Litjan]

Ok - Try to output field 8 (joystick deflections) and field 11 (flightcontrol deflections) in the DATA OUTPUT tab.

I just did a test-takeoff with those fields activated and there is almost no roll after takeoff.

Here is a screenshot:

I am at the end of my wits as to what is going on on your end

Cheers, Jan

 

[martinlest]

As I say, I too had no roll yesterday... I don't know if removing the Saitek drivers has done this, but clearly most people will not have Saitek drivers installed and do not have this issue. I am also at my wits end. I certainly appreciate your patience with it... 

Here are four screenshots. First is just before I start the takeoff roll, then three taken at about 5 second intervals after the a/c leaves the ground. The roll to the right is not triggered by anything I press on the joystick - it happens whether I bring the gear up or not. All I did whilst taking these screenshots was pull back a little to keep some degree of climb. But the a/c rolls with no joystick input at all (or if I unplug it - or, as I mentioned above, if disconnect the X52 and use a different joystick altogether).

Also tested several more a/c in my 'hangar', some Laminar, some other payware - and they all seem to be fine, no rolling or banking...  "Curiouser and curiouser!" 

 

Edited November 16, 2020 by martinlest

[Litjan]

Yes, everything is looking exactly like it should in your pictures - symmetric thrust, no fuel imbalance, no flightcontrol deflections...

One last thing to try - maybe a wing section got corrupted in your installation...output field 92 (wing lift) and see if all wings are creating lift equally?

[martinlest]

Quote

maybe a wing section got corrupted in your installation

Nice call!! This doesn't look right (did wing lift and wing drag), does it?

Edited November 16, 2020 by martinlest

[Litjan]

No, this looks very wrong! I would suggest re-installing the aircraft to see if that fixes it?

[martinlest]

I really thought this would do it - as I have a backup, I uninstalled (via the uninstall.exe and then installed again, via the installer. Fresh setup). Then back to the runway.

Same thing.  Here's the screenshot. However....

Given this result (I perhaps should have done this before), I tried the 733 in my 'vanilla' test installation of XP11.50: I simply used symlinks from the relevant IXEG folders (and Gizmo) in my full XP11.50 setup across to the clean installation. In that test, the a/c flies straight as a die. So no doubt there is something in my XP setup that is interfering with the IXEG a/c... all I have to do now is locate it! Haha.

I'll let you know of course when (not 'if'!!) I find the culprit, (and we can ritually burn it, as it were)!

Edited November 16, 2020 by martinlest

[martinlest]

Jan, you will be almost as relieved as I am to know that this seems to be fixed. I found at first that replacing the miscellaneous.prf file with the default one stopped the banking. But then if I re-engaged my IXEG joystick profile (from the XP onscreen joystick menu), the roll returned. So I deleted the IXEG profile and used the default one instead. I was able to map both the toggle gear and the TOGA function to the joystick in that default joystick profile.. and the past several test flights have been just fine, nice and straight after TO.

I don't want to tempt fate though: 'tomorrow is another day' of course, and I wouldn't put it past my PC to spite me and reinstate the problem after I boot up in the morning: but otherwise....

Just FYI I attach the IXEG prf files (you may, in an idle moment, should you ever have one, want to see if you can find the problem: if I reinstate these files and go back to using them for the 733 in XP, the roll issue returns, so I think these files must be the cause).

Also, a screenshot of my wing lift now, which looks a lot healthier.

Thanks so much for your input... customer service here is clearly as impressive as the IXEG 733 itself!

Martin

 

IXEG B733 - Joysticks.prf.zip

Edited November 16, 2020 by martinlest

[Litjan]

Ha, I am indeed very relieved that you found the problem! I know nothing about joystick preferance files, but I am really happy that you got it to work. Now holding my fingers crossed for your success to hold steady for the next days, weeks, months and years!

Cheers, Jan

 

[Morten]

An ancient X-Plane advice: Are you seeing odd behavior of any sort that you cannot explain - delete the XP prefs files