A380 ILS instability

[wmeimes]

I'm using the whole Overland jets fleet, tested them one by one under the same conditions and I'm quite happy with them. Seem simple,have good VCs, many different and good textures are beautyful and reliable, but A380, is a sad exception. I had already seen something regarding its ILS instability in some forum, I can't remember where. Actualy it's unstable in auto pilot in general, and ILS in particular. I've tryed to change flight tunning in config as seen under (elevator effectiveness, pitch stability and alavator trim effectiveness), to no avail. Do anybody know of a patch or affective tweak for it?

[flight_tuning]
cruise_lift_scalar = 1.0850
parasite_drag_scalar = 1.000
induced_drag_scalar = 1.000
elevator_effectiveness = 0.8
aileron_effectiveness = 1.0
rudder_effectiveness = 1.0
pitch_stability = 1.2
roll_stability = 1.0
yaw_stability = 1.0
elevator_trim_effectiveness = 0.8
aileron_trim_effectiveness = 1.0
rudder_trim_effectiveness = 1.0

[wdscobie]

to adjust how the autopilot works play with the autopilot section {autopilot} in the aircraft.cfg file. the nav_ and gs_ are most important for ILS.

max_pitch =
max_pitch_acceleration =
max_pitch_velocity_lo_alt =
max_pitch_velocity_hi_alt =
max_pitch_velocity_lo_alt_breakpoint =
max_pitch_velocity_hi_alt_breakpoint =
max_bank =
max_bank_acceleration =
max_bank_velocity =
max_throttle_rate =
nav_proportional_control =
nav_integrator_control =
nav_integrator_boundary =
nav_derivative_control =
nav_derivative_boundary =
gs_proportional_control =
gs_integrator_control =
gs_derivative_control =
gs_integrator_boundary =
gs_derivative_boundary =


--

[wmeimes]

Thanks scobie, but which are the critical items for pitch instability and which are the values. Do you know where can I find this stuff? Do anybody know?
BTW it seems this is a game fault, because the heavier the airctaft the most unstable in the pitch axis it becomes, even the Overland birds. A320 an 737 never present this desease, but A300 sometimes, 777 very often, and of couse A380 monster is almost unlandable in ILS. I don't know, I'm just raising an hypotesis, to the debate of the forum...

[wdscobie]

...which are the critical items for pitch instability and which are the values. Do you know where can I find this stuff? Do anybody know?

i'm not a designer. i know from experience and beta testing the cfg area i posted is what designers change. there is no 'set way' to improve and FDE. one change the flight model to change throughout the flight envelope.

you can search/post in avsim's and flightsim's aircraft design forums from details.

BTW it seems this is a game fault, because the heavier the airctaft the most unstable in the pitch axis it becomes.

i've never noticed this w/the 'heavy' aircraft i fly (PSS A330/A340 w/bob scott FDEs, FT A330/340 and SGAs DC10s). it may be an issue of FDE design ... some are better than others - most are overpowered and react to fast.

20+ years ago i knew a 747-100/200 pilot (this is a guy that did 90% of his piloting pre-FMC). when we talked about flying the 747 he stated his piloting was 25-50nm ahead of the aircraft's current location. as a result of those discussions i pilot FS 'heavy' planes the same and don't (usually) have a challenge. you don't change your mind 'last minute' in a heavy.

what comments are you finding on overland's support forum?


--

[NikeHerk67]

I'm using the whole Overland jets fleet, tested them one by one under the same conditions and I'm quite happy with them. Seem simple,have good VCs, many different and good textures are beautyful and reliable, but A380, is a sad exception. I had already seen something regarding its ILS instability in some forum, I can't remember where. Actualy it's unstable in auto pilot in general, and ILS in particular. I've tryed to change flight tunning in config as seen under (elevator effectiveness, pitch stability and alavator trim effectiveness), to no avail. Do anybody know of a patch or affective tweak for it?

[flight_tuning]
cruise_lift_scalar = 1.0850
parasite_drag_scalar = 1.000
induced_drag_scalar = 1.000
elevator_effectiveness = 0.8
aileron_effectiveness = 1.0
rudder_effectiveness = 1.0
pitch_stability = 1.2
roll_stability = 1.0
yaw_stability = 1.0
elevator_trim_effectiveness = 0.8
aileron_trim_effectiveness = 1.0
rudder_trim_effectiveness = 1.0

I can't say anything for sure about this addon aircraft since I don't have it except compare it to the A380 in FSX. When landing the airbus in FSX, as in hand flying it. you must turn the flight control switchs on the overhead panel off. The flight controls should only be activated when using the atuo pilot and "fly by wire" controls. It could be something as simple as that. You might want to scan tha at section in the manual.

Herk

[tasmanet]

Try this

Put your info in [fltsim.0] and change to .cfg

Works fine on 2 of the free a380's

Steve

[wmeimes]

Thanks tasmanet, but I tryed as you said, it bacame far more stable, but vc became a miniture, and the bird took off from Seattle dragging the belly all away the runway. Then I tryed to tweak some data in my config, changing flight tuning and a few other parameters, but then a380 seemed a slain chicken bumping like crazy in the beggining of the runway. It seems clear that the config you sent me belongs to another model and that only a FEW parameters apply to Overland a380, and now I should have to try and try to discover which they may be.
I think I'll keep on searching the patch I saw about somewhere. This model is in many hands and for sure is unstable to everybody, so soon the patch will be available...

Thanks anyway

[wmeimes]

Gentlemen

I'm happy to tell you that with the values underneath i was able to take off, make the circuit and land my United a388 in seattle boeing field. It's still lightly bumpy in level flight, although a big bird like this might just behave this way, I don't know... But approach and landing was absolutely stable and smooth. In the runway axis it was taken by the glideslope whithout bumps , and with a constant pitch angle it landed perfectly.

The values:
[flight_tuning]
cruise_lift_scalar = 1.10
parasite_drag_scalar = 1.000
induced_drag_scalar = 1.000
elevator_effectiveness = 1.1
aileron_effectiveness = 1.0
rudder_effectiveness = 1.0
pitch_stability = 0.4
roll_stability = 0.7
yaw_stability = 0.7
elevator_trim_effectiveness = 1.1
aileron_trim_effectiveness = 1.0
rudder_trim_effectiveness = 1.0

Of course I still don't understand very well the meaning of the values, but I guess the key number seems to be pitch stability=0.4 . It's just a guess.

Thank you all, and I'm happy because a380 is simply spectacular, specially the overland bird and it's very good to have it reliable and working in auto pilot and ILS.

Regads wmeimes

[tasmanet]

pitch_stability I think was your problem

I had something similar in some flight situations where the A380 Autothrottle made the plane pitch swing over 10 degrees in good weather over land. Changed it to 0.500 and all the problems went.

Change elevator_effectiveness and elevator_trim_effectiveness to 0.90 and this might smooth out your A380 a bit more

[wmeimes]

Yes, that's it!! Almost all Overland Airbuses, at least the heavy ones have this nasty tendence. The boeings actually don't. I'll work on your advice for the other aircrafts. The A380 is now far better.
Changing subject, but not that much, what causes an ILS to invert the direction For instance, just now I took off from Milan Linate rnw 36, to land to the right in Bergamo Orio al Serio rnw 11 ILS 108.70 heading 105 . If you try you'll see that ILS sends you left to heading 285 to the Alps, to France, anything but Bergamo as if you were taking off from the airport. Is inverted! How (and if) can this be fixed?

Regards
Walter