Pitch instability in 16X

[johnost]

I have a minor, but annoying problem on long x-country or trans-oceanic flights. After reaching cruise altitude, speed, and course with Auto Pilot set, I accelerate FSX to 16X, as I don't have the time to sit through an 8-hour flight.

At altitudes above 18-20,000 feet I then get strong pitch oscillations as much as + - 2,000 feet, depending on the size and weight of the plane. This happens with all default, freeware, and payware planes that can reach those altitudes, but causes no problems other than annoyance.

My memory is cloudy, but it seems to me that this did not happen with the initial FSX installation, but rather appeared after installing SP-1 or SP-2. I am curious to hear if others have the same problem, and - even better - if anyone knows of a solution. It seems to be a universal problem in the auto pilot mode.

John

[fsxmissionguy]

John,

The sim really isn't, unfortunately, designed to be operated that way. Anything above about 4x, and you're on your own. There isn't a solution (saw Phil Taylor address this on AVSIM one day ... so you may wish to do a search there.)

Cheers,

http://fsxploration.blogspot.com
http://www.flightsimulatorxmissions.com

[jwenting]

and no, it's not specific to any particular version.
FS was never designed for that, if you intend to run it at high accelleration you'll have to live with it.
Hardly surprising of course. Everything gets amplified by 16 times, including control input and wind buffetting.

[lnuss]

As mentioned above, you'll likely just have to live with it. I expect you'll find that, if you watch carefully when running at normal speed, you'll see minor excursions of course/altitude, but they're slow enough they don't bother you. Both FS and real life have corrections affecting both course and altitude, even on autopilot. But when you speed things up by 16 times (probably even 4 or 8 times) those minor excursions/corrections become MUCH more obvious. It's just the way things work.

Perhaps you could walk away and have a cup of coffee or two while the accelerated part of the trip is happening, returning only when you expect the trip to be nearly complete, and you're ready to slow things down.

Or, if you're really into it and willing to do some research, you could try changing the autopilot settings in the aircraft.cfg and .air files to smooth things out. Since those settings are not well documented, it'll likely take a LOT of hours (more likely days) of experimentation (for each aircraft) to figure out how to do this (if it's possible at all).

[greggerm]

I've noticed that with any sort of wind, the x16 oscillations are present. I can bump down to x8, and all the oscillations dampen away and the planes fly smooth.

With no wind, I can bring it to 16x with no oscillations.

As always, your mileage may vary, but that is what I've found. It doesn't really disturb me too much because at x8 or x16, you end up with the blurries anyway (going far too fast over the terrain for the engine to keep up), so there isn't much to see anyway.

[kingnorris]

Same here. Mostly with real world weather. As stated above, I just leave for a while, then come back and slow it down. It is annoying, though, to have this high speed "porposing"...

[johnost]

Thanks all for your replies, I think you all are correct, but I was wondering if I had a unique problem. I am quite sure, however, that this was not a problem in FS9.

John