Hi there,Am I the only one still experiencing the annoying porpoising when on autopilot? (both with -600/700 and -800/900)I've tried unregistering FSUIPC as suggested in a another post, but the problem persists.what am I doing wrong? - someone please help!thanksPaul

I tend to blame the pilot! lol no just kidding ;-) Well Paul can you tell me EXACTLY what you are doing to set up the A/P? Are you experienced on 737s? Do you have any add-on weather programs running? WHat's the speed set to when you engage the A/P? Anything that you think could help and a screenshot works too![h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

Hi Randy,It occurs if I use the autopilot with or with the FMC programmed, even with a simple ALT HOLD and Autothrottle. I will usually engage A/P with the speed at 250 knots, the aircraft climbs perfectly (it reduces the V/S every now and then to maintain airspeed). The autopilot then overshoots the set altitude slightly (300-400 feet), where the porpoising then starts.I have noticed that even when the aircraft is just 300 feet under the set altitude (in the pitch down cycle of the porpoising), the A/P commands a 1500fpm climb resulting in the autothrottle bringing the engines up to full power (to maintain airspeed). Not suprisingly, the aircraft then overshoots the set altitude, and the cycle repeats. The autopilot seems to level-out too slowly resulting in the overshoot.I have also noticed that the aircraft reacts very violently to any heading changes (via FMC or manually).I also, only experience this problem with the PMDG 737. I don't have problems with any other aircraft, payware or freeware.I don't have any add-on weather. I hope that you can make sense of the above!regardsPaul

Well I am not sure there Paul. I am wondering what "very violently" means in regards to a heading change? What is very violent about it? You did not answer my question to wether you are at all familiar with how a real 737 NG operates? I do not see any serious overshoot in a climb to level atitudes so I gather that yu are light and full thrust? Did you choose any reduction in takeoff thrust? I still would LOVE to see a screenshot the moment you are bouncing up and down from the 2D cockpit if you can manage one here it would be great.[h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

I've never posted screenshots - I hope I've done it right!This one shows the "violent behaviour", look at the tracking line-it swing left and right before settling on the heading (the aircraft rolls accordingly)http://forums.avsim.net/user_files/76376.jpgThis is at the top of the overshoothttp://forums.avsim.net/user_files/76377.jpgThis is a few seconds later, as the A/P tries to recoverhttp://forums.avsim.net/user_files/76378.jpgI don't have real-life experience, but I have covered all the PMDG manuals so I think I quite familiar with the aircraft-perhaps I'm completely wrong!I hope that this make the problem a bit clearer for you.regardsPaul

Paul,I had that problem and discussed it in another, earlier post. Subsequently I discovered that for me the problem was caused by using FSUIPC to calibrate my CH yoke and RCS rudder pedals. I use the CH pc joystick drivers for Win XP and connect the yoke and pedals to a sound card game port. When I use FSUIPC calibration I have the problem. When I take the calibration out of the FSUIPC.ini file, it goes away. Buttons are OK in the .ini file. Don't know what the real cause is, but when I am using the PMDG NG I do not use FSUIPC calibration. And altitude hold and VNAV are spot-on.Jim Harnes

I still have this problem, even if I don't use FSUIPC calibration.Paul

Paul,From your screen shots you don't appeare to have a vertical mode selected (VNAV, LVL CHG,ALT HOLD or VS). How are you controling the airplane?

hi,I've selected ALT HOLD and LVL CHG. have a look at the FMA.Paul

Hi Randy,Any suggestions?regardsPaul

Seems to me you have some crazy winds perhaps going on up there? You have Active Sky going?[h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

I don't have ActiveSky. There was no wind at all.Other ideas?Paul

In these cases I suggest a full re-install. 1] Use the remover tool, get it herehttp://www.precisionmanuals.com/downloads/inc_downloading.asp?iFile=2092] Go into the C:Program FilesMicrosoft GamesFlight Simulator 9Aircraft and remove any [/b] PMDG 800 - 900 folders left after you run the remover tool.3] Install 600-700 and make sure it is updated to 1.3.4] Install the 800-900. 5] Come back and tell us if all is well for you.6] Tell me what you are runing pleasea: operating systemb: windows version[h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

Just wondering what the specs of your computer are like, Paul? When I was running only 250Mb of RAM, I was getting a similar affect. I now have 3 times as much.Cheers.Ian.

Hello PaulI have noticed violent behaviour at altitude and it could be MSFS. The wind modeling is pretty brutal, do you still get it with no weather set, ie clear all weather? Also if you change your flight display type to PFD/ND using the menu bar PMDG/Styles then just under the ground speed is a vector that displays wind speed and direction, does the violent behaviour correspond with a wind change?Also I am not sure if this would be a factor but is there any reason you have 250 KIAS dialled into the MCP. Normally the FMC would have you at 315 KIAS after passing FL100. Could your angle of attack be very low and the strange behaviour is because you are at the edge of the flight envelope (long shot I know)? Again in the styles menu you can switch on the Angle of Attack (AoA) indicator, is your AoA approaching (past?) the red mark? You could try setting your speed to 315 KIAS and see if the porpoising goes away.hope it helps, Nick