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Acceleration - autopilot problem...

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After installing Acceleration, I noticed a problem with using time acceleration and autopilot. If you have your autopilot enabled, and you go over 4x time acceleration, your aircraft starts gyrating up and down, quite violently. I tried 3 seperate aircraft and the same thing occured with each - has anyone else experienced this problem?? I haven't tested the problem enough to know exactly when the gyrating starts, but it's definitely after 4x time acceleration and it seems that it gets worse, as your altitude increases. I generally have my autopilot set to hold heading, airspeed and altitude. I know many people do not use time acceleration, but since I have very little free time - I must use it when I want to fly longer distances. Hopefully there's a quick fix for this problem - if not, I'm stuck uninstalling FSX and reinstalling without Acceleration. If anyone has any suggestions, please pass them on. Thanks

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Just installed acceleration. Exactly the same problem. Hard to believe after a year the only solution is to uninstall. It only affects big iron. Your Cessnas and Beechcrafts are still fine.I'm going to try a few things over the next few days. It has be the difference between the seperate SP2 and the one included in acceleration. My first attempt will be copy all of fsx to drive D:, uninstall acceleration (which uninstalls everything), re-install fsx and sp2, then copy all the files back discarding any duplicates, that should get the missions and the aircraft without the included service pack - in theory.

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The limit for time compression (ie: sim speed) has always been 4X when the Auto Pilot is being used. Don't know where you guys have been (ever had FS9?) but there is probably not going to be a 'un-install, do xyz, then re-install- but don't install files a, b, or c' type 'fix'. But, of course you will ADVICE simmers as to what to do without having PROOF that anything you say will be 'real', true, or effective, 'repair' (it ain't broke, so that is also erroneously assuming too much). Have a nice 4X AP flight. :( Edit: Of course, you could use SLEW and go 40,000 kts slew rate, as long as you know where you're going. But you can 'turn' when using slew with keypad keys 1 and 3 and 5 to stop. The alternative is to pretend you flew to that airport just 200 miles away (ie: find on 'Map') and key in ICAO to go there after you level off, descend, and do a 'mock' approach. Then take off for 'final' leg of flight picking up ATC and shooting the landing. All pretend, of course.Chuck BNapamule

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--SNIP The limit for time compression (ie: sim speed) has always been 4X when the Auto Pilot is being used. SNIP--
Time compression limit with autopilot has always been 16x. 4x is the limit (AP or not) for AI traffic. Anything over 4x and AI traffic gets disabled. But you can certainly go over 4x with autopilot on.The gyrating problem is a common plague, even if the plane's payload and center of gravity is perfect. I'm sorry, but even I am desperate as to how to fix this so I cannot be of much help here. :(Edited by BoeingGuy, Monday, July 20, 2009

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BoeingGuy,You did not mention anything about whether you were in AP mode concerning the 16x rate (AI or not). How come? You just want to argue? I guess.And you can't blame effects on acelleration. Not even related. Get your facts right before you assume things. Bad science.Chuck BNapamule

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Can everyone calm down. There IS a problem with the acceleration pack, it is nothing to do with how the aircraft is loaded or phugoid oscilation. There IS a fix.Install FSX, install SP1, install acceleration.Copy the whole of the "..\Microsoft Flight Simulator X" to another drive.Un-install acceleration - I know it looks like it un-installs everything but it just drops back to standard FSX installation with SP1.Install SP2.Copy the following subdirectories from your copied installation back to the 'live' installation;CategoriesEffectsGaugesmissionspropdefsrewardsscenery ** Setup - there are changes here but I need to investigate further, hold off on this one **Sound Uires ** I don't know what this is but it does no harmIn simobjects\Airplanes just copy; FA-18 P51_RacerCopy the whole of boats (it's just easier), same for GroundVehicles and Misc.For RotorCraft just copy EH101.You now have the new aircraft and missions. I've tried a couple of the missions and everything looks like it's ok. More importantly, I can now take off from Heathrow, climb to cruising altitude, set the AP, hit x16, go watch TV and come back in an hour ready for the descent into Singapore.Oh, and by the way, where have I been? Had FS9?I've been flight simming since v1.0 by Bruce Artwick back in the seventies on a TRS80.

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Solution far simpler: Ensure aircraft is in trim before engaging autopilot and ensure that barometric pressure is set correctly for FL above 18,000ftThe fomer deals with the oscillations within the FDE as the autopilot (erroneously) uses the elevator trim to control height hold. The latter deals with apparent changes in altitude caused by the Kohlsman changing settings and the a/p adjusting the aircraft altitude to keep altitude `constant`.

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You are obviously not aware of the problem. This is not a gentle wandering of altitude (phugoid oscillation) nor a trim/barometric discrepany. This is the VSI needle banging full scale top then bottom. If memory serves me correctly that's +6,000ft/min to -6,000ft/min (B737/B747/B777) about two or three times a second.

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BoeingGuy,You did not mention anything about whether you were in AP mode concerning the 16x rate (AI or not). How come? You just want to argue? I guess.And you can't blame effects on acelleration. Not even related. Get your facts right before you assume things. Bad science.Chuck BNapamule
Napamule,I do not appreciate your tone of voice. I check my facts before I post, and to prove it to you, here is a screenshot.As you can see, I have the autopilot engaged, yet I'm running at 16x, even though you said that 4x is the limit. You can try it for yourself. Go start a flight, climb to a level cruising altitude with the AP on, and try to raise the simulation rate as much as you can. Going beyond 4x will be easier than you think.

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BoeingGuy,Ok, I'm sorry for being sarcastic and rude. But that is what it sounds like, not what I meant. Simmers will post a 'theory' and then (conviniently) leave out details in order to 'prove' their point. You picture shows 16x and an error message. Nothing I can go by to agree/see/realize/be convinced that you ARE ACTUALLY FLYING AT 16X, while in AP. Only that you are ATTEMPTING 16x, but FSX is ONLY flying (ie: only 'giving you') 4X. (STOP:Think....). But, I might be wrong. It happens. You say for me to go try it (fly with at 16x with AP on) and I ask my self if that is anything I would really 'need' to do. What exactly would I accomplish. Do I get a reward (hehe). So, even if it was true that you can fly 16x while at cruise altitude while in AP (I doubt it-more like 4x), my question is: WHY? And I can fly 16x WITHOUT the AP. Once trimed out it should hold fairly steady (sans the oscillations) where I can go do grocery shoping, ck mail, gas up, grab a drive-thru snack (Fish Burger) and when I come back (unless the cat decided to 'change things' by walking on keyboard-I think he might smell 'Fish Burger') then all should be 'ok' and I can continue on my round the world non-stop trip-TOTALLY HANDS FREE-AUTOMATIC-LIKE A 'CHAMP'. Ridiculous? Of course it is. Simming wasn't meant to be used this way. Bogus flying is not for me, so-No Thanks. Not even curious. I say no more. I post no more. I see no more.Chuck BNapamule

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BoeingGuy,Ok. I went and fired up the B-58 Hustler and took it up to 30000 ft, kicked in the AP and prgressively increased the sim rate to 4x, then 8X, then 16x. Nothing happened. Flew level, smooth as silk. I then pressed 16X again (to go to 32X) but I got the message and it stayed at 16X. Still smooth sailing. I clicked it again and again got the message, but still smooth sailing and holding 30000 exactly. The ground was fuzzy. Did not even get to enjoy any clouds, either.I then changed view to locked spot view and was getting the vapor trails in my eyes, so I used the hat switch to pan around to the nose. Well I got as far as left wing and the engines cut out. I had run out of fuel as I was panning. And I was out of control. Swerved off to the right and dived. Pitch trim went to +19.9. No response. So I used my 'trick' for such an occasion: Hit 'Y' key 2 times (slew on/off quickly) and regained control but was by then at 10000 and dropping (no engines).So I slewed back up to 30000 ft and started the engines ('Stall' screaming at me all the time). So that's it. Got it to go 16X, but not beyond. Did not loose control until I ran out of fuel. (Checked unlimited fuel for the trip back). It was fun. Left California and flew about 6 minutes. Wound up between Skagway and Yukatak Alaska, somewhere out in the boonies. Not my intended 'target'. Nothing to go by in GPS or map. There was nothing there!So there you have my 'pirep'. Hope you don't hold a grudge. I don't mind helping with 'problems' but this qualifies as 'experimental' (ie: screwing with simulator-hehe) in my book. Sorry about that. So as far as I know 16X while on AP works 'ok' and myself I did not get any occillations. I have pitot 'vertical_speed_time_constant=20' in cfg. It's 'live and learn' (daily it seems). Have a nice one (ie: 16X 'trip' while on AP to China or wherever you're going).Chuck BNapamulePS: And yes, I do have Acelleration (FSX 'Gold' Edition) in case you were wondering.

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AS i increase the sim rate from 4x to 16x on my system, even the cpu gets hotter, and i mean much hotter. I have OC'd so i have to check this.Sometimes during summer i can only do 8x and not 16x cause the cpu gets too hot at 16x.What i mean is this, if you dont want to loose control of your plane at 16x give the cpu a chance.1 - Dont use 16x in bad weather2 - reduce your speed to something reasonable like 285 to 300 IAS before engaging time acelleration3- I only use time accel on long flights, so i always climb quite high to FL300 or even 350 where the air is less dense and stableBy following these rules , the FSX is less likely to crash your plane in time accelertation, this is cause the calculations required during time accel are more demanding since everything is moving so fast.My advice, park your plane in a gentle attitude and speed in cruise before engaging time accel.There are so many times time accel starts to wobble my plane , due to bad weather , going too fast or both.The slower and higher you fly , the less likely that time accel will fail.That said i have always used SP2 not Acceleration Pack, however i just installed acceleration due to F18, and i have not had a chance to fly for weeks.Mu moto for smooth long haul flight is, 1 - High altitude2 - Low speed3- High Time accelerationTHAT IS SMOOTH

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Here are a couple of places to look for a cure.1. Firstly, sometimes only a very minor adjustment to the trim authority in the flight model (the .air file) will cure this problem. Slight increases or reductions to this value are likely to produce a good result. Start with a small change of say 10% (both +, and -) and increase the edit progressively until you get a result. Keep the variation from the default value to the absolute minimum you find is necessary to achieve your objective. 2. The autopilot section of the .cfg file (specifically, max_pitch_acceleration=) may provide you with a viable solution. You'll see some of the values change with the different aircraft types. Try dropping that .cfg value, say, 25% (i.e. if it's value is =1.0, then try =0.75) in the situation you describe. If that works, then reduce the change from the default until the problem starts to return. If you assign a hot-key combination from the FS key command menu list to reload the user aircraft you can do that in real time in FS. With an aircraft reload key combination assigned (say, CTRL+SHIFT+R which by default isn't assigned) you can immediately see the results of any edits (both .air & .cfg) but the thing to remember is that if you fix one problem with the AP (like porposing on accellerated alt hold cruise) you may introduce an AP problem in another area. That might be on an AP ILS where you may have wind/weather factors adding to the mix requiring access to the extra trim authority that you might have just removed. These suggestions are easy-access changes anyone can try. It is safe to say that the FS AP is weak, and that it always has been.HTH.Rgds,

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Nice to see a good suggestion. I re-installed FSXA and tried it. I particularly like the reload user aircraft suggestion. This is a new one for me, thanks for pointing it out, one day I'll have to go through the controls.dll to see what other goodies there are.(For others, the command is: <Entry> <Key>CTRL+SHIFT+R</Key> <Down>RELOAD_USER_AIRCRAFT</Down> </Entry>)I had to really bring the max_pitch_velocity_hi_alt down low. It's better at 0.01 but you will get earache from ATC when you start your descent, "Please expedite your descent ...". Below 20000.0, the figures below are good enough for a turbulent ILS approach (these are from the B737_800).max_pitch_acceleration=0.3 // was 1.0max_pitch_velocity_lo_alt=1.0 // was 2.0max_pitch_velocity_hi_alt=0.02 // was 1.5max_pitch_velocity_lo_alt_breakpoint=20000.0max_pitch_velocity_hi_alt_breakpoint=28000.0The following may help for an ILS approach:gs_proportional_control=25.0gs_integrator_control=0.53gs_derivative_control=0.00gs_integrator_boundary=0.70gs_derivative_boundary=0.00but I have yet to investigate the possibilites.Thanks again.Chris.

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You know, I have to say I am missing something here. Take off, set AP, set accel rate, watch TV for an hour and come back in time to land? This is fun?For your computer maybe. Why not just sit and watch TV for an hour and then fire up the sim and set it up so you can land. Less wear and tear on the computer and it certainly has NO EFFECT on your flying enjoyment.Sorry, I realize that everyone uses the sim for their own pleasures but this use, to me, seems really ridiculous.I just can not thinik of ANY reason why I would do anything like that. :(Just MHO,Vic

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max_pitch_acceleration=0.3 // was 1.0max_pitch_velocity_lo_alt=1.0 // was 2.0max_pitch_velocity_hi_alt=0.02 // was 1.5max_pitch_velocity_lo_alt_breakpoint=20000.0max_pitch_velocity_hi_alt_breakpoint=28000.0The following may help for an ILS approach:gs_proportional_control=25.0gs_integrator_control=0.53gs_derivative_control=0.00gs_integrator_boundary=0.70gs_derivative_boundary=0.00but I have yet to investigate the possibilites.Thanks again.Chris.
Chris, your values worked perfectly! Now I can fly at 16x with autopilot on and no oscillations. ILS approaches work fine too :). Thank goodness for people like you that actually find solutions rather than arguing about the problem!It seems that the expansion pack is the cause of the problem though - the Learjet was running fine before I installed Acceleration. It also broke the robinson R22 (the engine stalls when I engage the clutch during the start up checklist for example).

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This is slightly related.I autopilot at 16x sometimes, when you back the time compression down 16x, 8x, 4x, 2x, 1x. The scenery load at 4x kind of annoys me. Ok I realize fsx is a totally awesome product, but I think some how that could be fixed. Just an idea

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HelloWhy do folk use time acceleration, is it just a lack of patience or low boredom thresholdIf all you are interested in is taking off and landing just do shorter flights.For myself I either want to fly the sim or watch TV not both.

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HelloWhy do folk use time acceleration, is it just a lack of patience or low boredom thresholdIf all you are interested in is taking off and landing just do shorter flights.For myself I either want to fly the sim or watch TV not both.
I so agree to this. Either fly shorter routes or don't do anything. Flying at higher speeds defets the purpose of the flight simulator!Btw. just to add: I use 2x or 4x when doing tests of sim crashing at destination, or g3d.dll errors.

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