Aircraft 'porpoising' under AP - anyone else experienced this?

[Thunderbird8 1]

On a fairly steep VNAV descent with about a 20kt tailwind I experienced a lot of rocking of the nose back and forth a few degrees, known as porpoising. Speed was about 270kts however the rate of descent was about -4000 (not my choice, stupid ATC instruction). I found the same happening as I was experimenting with the flight controls and flying the aircraft for my own amusement at 210kts and 1000ft AMSL over the ocean. Nose up, nose down, nose up, nose down.... All under AP. Anyone else had this?

[JokersWild 34]

On a fairly steep VNAV descent with about a 20kt tailwind I experienced a lot of rocking of the nose back and forth a few degrees, known as porpoising. Speed was about 270kts however the rate of descent was about -4000 (not my choice, stupid ATC instruction). I found the same happening as I was experimenting with the flight controls and flying the aircraft for my own amusement at 210kts and 1000ft AMSL over the ocean. Nose up, nose down, nose up, nose down.... All under AP. Anyone else had this?

I've seen that on real world maintenance reports a lot. Could it be a failure?

[Thunderbird8 1]

I've got no failures programmed...

[Thunderbird8 1]

Just re-read your reply Jokerswild and seen the significance of 'RW' reports. Guess it's modelled then!

[martin-w 3,234]

I see slight porpoising too, in a VNAV decent. Not an extreme decent, a normal VNAV decent. It isn't an exaggerated porpoising, but it is there. Martin Wilby

[David Vega 348]

Would weight and balance be a factor?

[Qatsimo 7]

Ive seen this also. What helped was setting FSUIPC's wind and pressure update to very low values. For wind a 1 knot/degree change every 8 sec's and smooth pressure change of 5/100. Supressing all turbulence could also help.

[clum 2]

i think this is weather related as I can be guaranteed to see it in a climb, every time I'm using ASE. Without ASE running, I've never seen it happen. I've yet to configure FSUIPC for wind smoothing so will give that a bash as per above.

[falcon999 24]

Weather smoothing for winds, pressure and temp is s must. Turning off turbulence options doesn't hurt either.

[clum 2]

Yep, been using ASE with direct weather control though so that should have taken care of it.

[Thunderbird8 1]

Is that weather smoothing possible in the full registered version of FSIUPC?

[Qatsimo 7]

Is that weather smoothing possible in the full registered version of FSIUPC?

Unfortunately yes.

[Jen 0]

I thought it wasn't necessary to have FSUIPC installed to operate the 737NGX...Has this scenerio changed?jen noulet

[GHarrall 494]

I thought it wasn't necessary to have FSUIPC installed to operate the 737NGX...Has this scenerio changed?jen noulet

FSUIPC is NOT required to operate NGX.It IS needed if you want to access the weather (wind, temp, pressure) smoothing options that FSUIPC provides to nullify the 'wild winds' that FSX often provides.I think DWC on Active Sky also has the same kind of feature.

[quadraspleen 7]

Been experiencing this in CRZ - same thing as in here: http://forum.avsim.net/topic/360095-unruly-behaviour-in-wind/is it really RW behaviour? I have no failures..thx