Up and Down

[the_zonk]

Can anyone help? Some of my aircraft oscillate wildly up and down in flight when i let go of the stick or when i engage the autopilot. not all my aircraft are affected.

[ozzy72]

Zonk you need to trim the aircraft perfectly before hitting the AP, or else she'll start oscillating worse and worse, and normally you'll end up with a dirt sandwich. Its just a question of getting the trim bang on, and not touching anything

Ozzy

[N4733D]

Yep. Trim is mucho importante in most planes. In reality, pilots trim, or at least get the airplane in the right position, before invoking the autopilot. Make sure you are trimmed before takeoff. Some planes do this more than others. My G-V I downloaded is FAR to sensitive in pitch, period. I just barely touch the stick and it will bob around like there is no tommorow.

[microlight]

It can still happen even if you trim before turning on the autopilot. Another cause of this kind of oscillation is insufficient lift and/or thrust, especially noticeable in big jets, for which the flight dynamics are not tuned right. This can be fixed but it means editing the aircraft.cfg, which may include editing the airplane geomentry, or the flight tuning sections.

[N4733D]

Yep but for some editing challenged people, the only solution is download another airplane. Any respectable aircraft maker will take the time to adjust it properly.

[YSBKpilot]

My 777 and 747 planes all seem to oscillate with autopilot and rate set to 16X, the oscillations slow down at 8x, the same thing is now happening with my 737 even at 328kts.

[N4733D]

Well in indicated airspeed a 737 shouldn't be going that fast, but that's another story. Ok, at 16x that is common buddy. At 1X, which most people cruise at, you notice the plane oscilate slowly up to 100 feet sometimes. It isn't really noticable, unless you are going 16 times that and then those little oscillations look much bigger and more obvious. This is somewhat true to life, many autopilots will veer from altitude up to a hundred feet either way to maintain speed without moving the throttles.

[microlight]

One way past this is to nudge the 'pitch stability' setting in the 'flight tuning' section of the aircraft.cfg file up from 1.0 until the oscillation stops.