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TrevorS

Pitch stability

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I've raised this one before, but was told there is no problem with the pitch.I have calibrated the joystick using FSUIPC - there is no problem there.Null zones and sensitivity settings are default.While climbing, the nose keeps coming up. I trim down and the nose comes up - I trim down again and the nose comes up .....I have at one stage just let the nose keep coming up - it just continues until the plane stalls.One should not have to trim down every 5 seconds in a climb - definitely not in this 737 - it is NOT realistic.I tried to correct this in the air file - section 1101 primary aerodynamics. The section on pitch moment coeff at AoA (trim os). The value is negative 296. Any negative value will cause the nose to come up forcing one to trim down.I change this value to a positive number and that seemed to solve this problem. However, it created a new one - now the plane requires a ridiculous amount of trim at takeoff which sets off the alarm when thrust is applied.This pitch problem also makes it difficult to make turns while hand-flying. The nose keeps bobbing up and down in a turn - this is totally unrealistic - you should be able to execute a smooth turn.Does anyone have a solution or ideas ?If you think your flight dynamics are spot on, please e-mail them to me to try out.ThanksTrevor

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I would suspect a noisy joystick pot that is spiking intermittently outside the null zone with the A/P pitch axis engaged. CWS inputs are cumulative, so a pot spiking nose-up continues to increase the commanded pitch angle as each momentary nonzero excursion occurs. Another possibility is another controller assigned to the elevator axis somewhere in the FS controls making uncommanded inputs.


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None of the above.I have not engaged the AP and don't use the CWS. I am talking about hand-flying.I see there is another thread where folk have been having a problem controlling the pitch with an over sensitive trim.Also- I only have this problem with the TM. All other add-on planes work just fine. If it were the controller, the problem should still be there with other planes.Has anyone who has experienced this sensitivity problem found a solution ?Trevor

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I find the TM can be very sensitive and i have experiencedthe high pitch angles you describe. I think the problem is the pitch trim which needs to be moved forward well beyond the green zone soon after take off. Getting the aircraft clean and reducing to climb thrust nice and early also helps.


Peter Schluter

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I find the TM can be very sensitive and i have experiencedthe high pitch angles you describe. I think the problem is the pitch trim which needs to be moved forward well beyond the green zone soon after take off. Getting the aircraft clean and reducing to climb thrust nice and early also helps.
Takeoff trim is set to produce a trimmed condition at ~V2+10...it is normal to need to run in a lot of fwd trim as the aircraft accelerates during climbout.@TrevorS--if the pitch-up you're describing is occurring while the jet is accelerating, it's normal. The excessive trim sensitivity is something else--generally a problem associated with FS control acceleration...there's a fix for that in FSUIPC.

Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

System: i9-10900K @ 5.2GHz on custom water loop, ASUS Maximus XII Hero, 32GB GSkill 3600MHz CAS15, EVGA RTX3090 XC3 Ultra
Samsung 55" JS8500 4K TV@30Hz,
3x NVME 2x SATA Samsung SSD, EVGA 1KW PSU, 1Gbps internet
SoundBlaster XFi Titanium, TOSLINK to Yamaha RX-V467 HT Rcvr, Polk/Klipsch 6" bookshelf spkrs, Polk 12" subwoofer, 12.9" iPad Pro
PFC yoke/throttle quad/pedals with custom Hall sensors, Coolermaster HAF932 case, Stream Deck XL button box

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BobCould you please e-mail me the fd that you are using.ThanksTrevor
I'm using the same distribution .air file and aircraft.cfg that are included in the AVSIM downloads.What kind of flight controls are you using?

Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

System: i9-10900K @ 5.2GHz on custom water loop, ASUS Maximus XII Hero, 32GB GSkill 3600MHz CAS15, EVGA RTX3090 XC3 Ultra
Samsung 55" JS8500 4K TV@30Hz,
3x NVME 2x SATA Samsung SSD, EVGA 1KW PSU, 1Gbps internet
SoundBlaster XFi Titanium, TOSLINK to Yamaha RX-V467 HT Rcvr, Polk/Klipsch 6" bookshelf spkrs, Polk 12" subwoofer, 12.9" iPad Pro
PFC yoke/throttle quad/pedals with custom Hall sensors, Coolermaster HAF932 case, Stream Deck XL button box

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lower the trim effectiveness is 1101, to lets say 1.0 or 1.2 You have finer trim settings then.In the cfg file, make the pitch stability 2.0 or higher.Quick and dirty but helps a lot.

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Thanks Johan. You have pointed me in the right direction - it does make a difference. I'm busy fine-tuning the fd now. Hope I get it rightTrevor

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Finally - problem is solved. Plane flies more like the real thing now.Thanks Johan - I also corrected some power settings. Back to flying the -200 again.

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Finally - problem is solved. Plane flies more like the real thing now.Thanks Johan - I also corrected some power settings. Back to flying the -200 again.
So what exactly did you do?

Pat Callaghan
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BTW, your haircut fits nicely with the tinmouse when it came into service.. :(

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