ASX wind issue or autopilot problem?

[vgbaron 3,609]

Merry Christmas to all!Have a strange problem that I'm trying to resolve. Using the F/a-18 from Accceleration or the Eaglesoft Twin Comanche - when following a GPS flightplan using the A/P, the A/C flies with the right wing seriously low as if it were turning into a quartering wind. In this case the desired track was 50, the heading was 49 and the wind was 358 @37. To me, if anything, this would indicate that the left wing might be low to compensate for drift. The A/C is not turning.However, when I switched to the default Mooney - wings leveled and a/c followed track as expected.The wind data was obtained from the ctrl-z data.I've posted this at the Eaglesoft forum in case it is an A/P issue but wondered if anyone has seen this behavior before?I've attached two screenies - one from the Mooney and one from the Twinkie.Thanx,Vicedit: During another flight, got the same results - then I shut down ASX in mid flight and continued - same problem - right wing low.Q6600 G0 CPU 2.4 o/c 3.65Evga 680i A1 with P31 BIOS 2G XP2-8500 DDR2 1066FSB Mushkin 996535 RAM 5-5-4-12-2T320G 7200 HD partitioned for XP/Vista/Programs 2 - 74G Raptors in RAID0 500G 7200 HD for backup SATA DVD burner Evga 8800GTS 640 PCIx 169.13 betaKandalf LCS case w/ built in liquid cooling 850W Thermaltake power supplyVisit the Virtual Pilot's Centerwww.flightadventures.comhttp://www.hifisim.com/banners/hifi-supporter-sigbanner.jpgRadar Contact Supporter: http://www.jdtllc.com/

[Damian Clark 1,231]

Hi Vic,Hmmm.. I don't think we're looking at an ASX or wind problem here. Airplanes don't "bank" into the wind, they "crab" with a wind correction angle - unless you're doing a forward slip with opposite rudder applied. Once the correction angle is correct they fly wings level and the ground track should be appropriate.If the airplane is maintaining heading with such a bank angle I would assume it is one of the following:- One engine is developing low (or no) power- The rudder trim is set hard to one side- The rudder itself is being applied hard to one side- Severe fuel imbalance (one wing tank much more full than the other)If you fly these aircraft without ASX at all does the problem still occur?Best,

[vgbaron 3,609]

Hi Damian - I guess you didn't see my edit - tried it w/o ASX and had the same result.What puzzles me is that, so far, it only happens on two a/c. I was hoping someone had seen the problem before.It's a definite bank but the a/c isn't turning. Interesting side note, if I use CTL V (wing leveler) the wings will level and the a/c will start to drift left as if it was getting a strong wind from the right.Strange.VicQ6600 G0 CPU 2.4 o/c 3.65Evga 680i A1 with P31 BIOS 2G XP2-8500 DDR2 1066FSB Mushkin 996535 RAM 5-5-4-12-2T320G 7200 HD partitioned for XP/Vista/Programs 2 - 74G Raptors in RAID0 500G 7200 HD for backup SATA DVD burner Evga 8800GTS 640 PCIx 169.13 betaKandalf LCS case w/ built in liquid cooling 850W Thermaltake power supplyVisit the Virtual Pilot's Centerwww.flightadventures.comhttp://www.hifisim.com/banners/hifi-supporter-sigbanner.jpgRadar Contact Supporter: http://www.jdtllc.com/

[Damian Clark 1,231]

Hi again Vic,Yes strange indeed. However if the wind was "blowing" from one side your bank would not change, only your ground track would be affected. Your heading would not change either.The only thing that can change your heading with level wings is yaw (by rudder) or assymetric thrust (by multi engine aircraft not developing the same thrust level for each engine).Since your engines are obviously developing similar thrust via the manifold pressure gauge readout, it must be yaw. Wonder what your rudder trim/position is? Can you verify this? Maybe something is conflicting here causing a "hard over" rudder trim on these aircraft?Best,

[vgbaron 3,609]

I'll take a look again tonight. Since it only happens with the F/A 18 and the Eaglesoft Twin Comanche it has to be some user error. I've never flown either IRL and I'm sure if it were a defect, many others would have seen it.I have enough PIC time IRL to know how to set up an a/c so I'm wondering if some 'twitch' from my yoke would tweak the rudder trim. Flights have been too short for fuel imbalance to be an issue but I'll double check the loading anyway.It will probably be something simple and obvious to all but me!:)Thanx,VicQ6600 G0 CPU 2.4 o/c 3.65Evga 680i A1 with P31 BIOS 2G XP2-8500 DDR2 1066FSB Mushkin 996535 RAM 5-5-4-12-2T320G 7200 HD partitioned for XP/Vista/Programs 2 - 74G Raptors in RAID0 500G 7200 HD for backup SATA DVD burner Evga 8800GTS 640 PCIx 169.13 betaKandalf LCS case w/ built in liquid cooling 850W Thermaltake power supplyVisit the Virtual Pilot's Centerwww.flightadventures.comhttp://www.hifisim.com/banners/hifi-supporter-sigbanner.jpgRadar Contact Supporter: http://www.jdtllc.com/

[vgbaron 3,609]

Mystery solved! Started looking at the raw data being sent from my rudder pedals and realized they were out of calibration. When centered they were applying a tad left rudder. Looks like the A/P wanted to counteract that and dropped the right wing. Basically flying along in a slip. Realized when I applied right rudder and the right wing came up. Recalibrated and all is well!:)Thanx, Damian - your comments got me thinking along the right track!VicQ6600 G0 CPU 2.4 o/c 3.65Evga 680i A1 with P31 BIOS 2G XP2-8500 DDR2 1066FSB Mushkin 996535 RAM 5-5-4-12-2T320G 7200 HD partitioned for XP/Vista/Programs 2 - 74G Raptors in RAID0 500G 7200 HD for backup SATA DVD burner Evga 8800GTS 640 PCIx 169.13 betaKandalf LCS case w/ built in liquid cooling 850W Thermaltake power supplyVisit the Virtual Pilot's Centerwww.flightadventures.comhttp://www.hifisim.com/banners/hifi-supporter-sigbanner.jpgRadar Contact Supporter: http://www.jdtllc.com/