MAJOR wind problem with FSUIPC version of today's date

[jbinner]

Using LDS767, ActiveSky, and online with SB3, with weather coming from ASV....

Instead of winds changing very slowly on entering a new zone, full-force wind change hit me and foced an overspeed condition and caused the flight to overstress the airframe.

WHY was this change, and how can I adjust?

Thanks,

John Binner

[Pete Dowson]

Instead of winds changing very slowly on entering a new zone, full-force wind change hit me and foced an overspeed condition and caused the flight to overstress the airframe.

WHY was this change, and how can I adjust?

No change I know of. Can you repeat with Weather logging on please? Save a copy of the log as soon as you get such an effect, and ZIP up the Log as it will be rather large. Send it to me at petedowson@btconnect.com.

The version 3.51 that was released generally yesterday has been available as 3.507 for many weeks here, in the "new versions" announcements, and has been extensively tested by many folks over a number of weeks, with ASV as well. I use ASV myself and have had no similar problems over many hours of flight.

Regards

Pete

[Pete Dowson]

Hi again,

I've just done some more scientific tests on wind smoothing, and it seems to work perfectly. I set winds 270/30 at EGCC and 90/30 at EGGP, about 30 miles away, enabled weather logging and the Shift+Z display and flew from EGCC to EGGP. The smoothing did exactly wehat I asked of it in the FSUIPC Winds page.

Without FSUIPC's smoothing the changes were more jerky -- not exactly a 180 degree sudden change, but in jumps (according to the Shift+Z display) of more like 30 degrees. I think this is FS's own idea of "smoothing".

It sounds to me as if you haven't got FSUIPC's wind smoothing enabled. You didn't delete your FSUIPC.INI file when you updated to FSUIPC.DLL 3.51, did you? If so you'll need to re-establish all your options the way you like them.

Also check the options in ASV. I think it overrides some of FSUIPC's settings.

Regards,

Pete

[tstewart]

I had the same problem last nite. The LDS 767 and ASV. I flew same flight yesterday with 3.50 and all was fine. Just updated the .dll to 3.51 and left .ini in place and wind shifts, overspeeds,autopilot disconnects. There is a problem here. Put 3.50 back in and all is fine again. Will log flight with 3.51 and will send to you Pete.

[Pete Dowson]

Will log flight with 3.51 and will send to you Pete.

Can you include your FSUIPC.INI file, and the FLT + WX files too please (the last AutoSaved ones if you use that, otherwise could you refly and save the flight for me)?

There's really been no change which should do this, quite the reverse in fact -- there was a particular case when in versions earlier than 3.507 it could generate windshifts at the aircraft even though they were not apparent in the weather reports.

There have been at least 20 folks flying with programs like ASV and FSMeteo with 3.51's release candidate for several weeks, and I've had no other reports until these two today. It is most odd. I have flown with Radar Contact and ASV many flights over the past few weeks (first time I've managed so much flying for ages!) without any wind shifting problems. I can't understand it. :-(

All I can do is promise to look at the logs and any other data when I receive it. I may have to ask for more tests with different logging options or even with special test versions of FSUIPC.

Regards,

Pete

[tstewart]

Will do Pete. It is 8:40 am here in the eastern USA and I have to work today but I will gather all info for you as soon as I get home. I do have wind smoothing enabled and did not change any setting on ASV or FSUIPC. I was getting wind shifts of 30 plus degrees and wind speed changes of 100 plus knots. I had this problem before but I can't remember what It was. When I encountered this last nite I was at 35000 and I thought maybe it was the JS but winds were reported and 53 knots and there were no gusts. There were no other aircraft around either. Kind of an odd one.

[Pete Dowson]

I was getting wind shifts of 30 plus degrees and wind speed changes of 100 plus knots.

Did you check to see if there was any "wind variance", gusts or turbulence being added by ASV? These are all possible and are not normally affected by FSUIPC smoothing or other options, except outright suppression in the latter two cases.

... I thought maybe it was the JS but winds were reported and 53 knots and there were no gusts.

Ah .. no gusts. But what about turbulence and, especially, wind variance? (You might need to run WeatherSet2 to see variance values).

Regards,

Pete

[jbinner]

I did check FSUIPC settings after the flight and wind-smoothing was turned off. I will try it again this morning with smoothing on and see what I get. I'll fly the same route from KLGA to KFLL (I only got past the SID) since the winds on the east coast are still fairly rough with large gradient shifts.

Thanks,

[Pete Dowson]

Just a question on this:

I had the same problem last nite. The LDS 767 and ASV. I flew same flight yesterday with 3.50 and all was fine. Just updated the .dll to 3.51 and left .ini in place and wind shifts, overspeeds,autopilot disconnects. There is a problem here. Put 3.50 back in and all is fine again.

With a flight one day then the next, as well as FSUIPC changing from 3.50 to 3.51, the weather set by ASV would have changed too. In the last part of your statement above you imply that you had virtually the same weather both times on the second day. Is this so? Can you actually be sure to use the same weather, so there is a direct comparison? That is possible with ASV, isn't it?

I've checked and double-checked and the differences between 3.50 and 3.51 in the area of winds are really very very small and cannot account for what you are reporting. I need to be absolutely sure it isn't more due to a specific set of data. The other reporter ("jbinner") reported "... the winds on the east coast are still fairly rough with large gradient shifts". I notice you are on the East coast too. Was that where you were flying? I'm concerned now that all this fuss is really more due to unusual real weather conditions or rather unusual or erroneous data in ASV's weather server -- ASV and the East coast seem to be the common factor between the only two reports.

Oh, I've just noticed -- "jbinner" was actually flying with FSUIPC's wind smoothing switched off. That makes your experiences unique at present.

Regards,

Pete

[jbinner]

I went into modules and removed the ini file, rebuilt it. I then set settings to wind smoothing ON, along with some other minor tweaks as well. All seems to have helped, as my climb out of KLGA was fine this morning. I let it cruise for 35 mins to make sure and it seemed much better.

My fault on this one it seems. :) I forget sometimes that when I update I need to reconfigure as well. :)

Thanks,

John Binner

[Pete Dowson]

I forget sometimes that when I update I need to reconfigure as well. :)

Phewthat's a relief. thanks for letting me know. One down one to go! ;-)

BTW you should not need to reconfigure when merely replacing the FSUIPC.DLL file. I take great care to retain all the options in your existing INI file. But some folks automatically delete FSUIPC files when updating -- it isn't necessary. Only delete your old INI file if it is years ago when you last updated FSUIPC -- some of the defaults may have been changed or old parameters made obsolete.

When updating simply copy the new DLL into the FS Modules folder. It will replace your previous one with no other changes needed.

Regards,

Pete

[Pete Dowson]

I was getting wind shifts of 30 plus degrees and wind speed changes of 100 plus knots.

One further note. I just checked, and when I said "Did you check to see if there was any "wind variance", gusts or turbulence being added by ASV? These are all possible and are not normally affected by FSUIPC smoothing or other options, except outright suppression in the latter two cases." in fact I was wrong -- the FSUIPC gust suppression does suppress wind variance as well. So all three influences can be suppressed in externally supplied weather, if you wish.

Your report is most definitely sounding as if it is due to one of two things: either you have wind smoothing turned off, after all (as in the other reported case), or the downloaded ASV weather had some really weird values in it. More likely a combination of both. If you think neither to be the case still, send the files and I'll see what I can find -- but if it is a problem in FSUIPC I'm pretty sure it isn't new to 3.51.

Regards,

Pete

[tstewart]

Hi Pete,

Back to report there was definitely a problem but it is not with FSUIPC. It had to be with ASV and the reporting weather. I just flew the same route and all was well. I apoligize jumping to conclusions. I must have updated to 3.51 at the worst of time and usually when I have a problem I backtrack to find out the what I did last and investigate.

Thank you for your great SUPPORT and PROGRAM.

Ted :D

[Pete Dowson]

Back to report there was definitely a problem but it is not with FSUIPC. It had to be with ASV and the reporting weather. I just flew the same route and all was well. I apoligize jumping to conclusions. I must have updated to 3.51 at the worst of time and usually when I have a problem I backtrack to find out the what I did last and investigate.

Not a problem, thenthanks for letting me know so quickly. I was getting all prepared with some extra logging and diagnostics, just in case.

I think, sometimes, ASV or FSMeteo may be generating too much "wind variance". This is abrupt changes in direction, usually reported as "VRBL" or similar. FSUIPC doesn't smooth these (though they can be suppressed using the option to suppress all gusts -- that suppresses gusts and variance.

I may add another option in the next version to limit the wind variance, possibly with the limit being inversely proportional to the wind speed. For example, something to give roughly these limits (only probably derived by a formula, to give a smoother scale):

0-5 knots, no limit (360 degrees allowed: i.e +/-180)

5-10, allow -90 to +90

10-20, allow -45 to +45

20-50, allow -22.5 to +22.5

over 50, allow only -10 to +10

Any comments?

Regards,

Pete

[Pete Dowson]

Hi,

I've posted two updates to FSUIPC in the top announcement here as part of an attempt to get the wind smoothing system working correctly (again). Please try them out and let me know what you think. I've reproduced the notes about them here, below, so you can see what is going on.

Best regards

Pete

===============================================

FSUIPC.DLL Versions 3.511 and 3.512

I've posted two test versions at the same time in an attempt to find out if they both behave the same, wind-wise, or if one is better than the other. I am testing here, but wider usage is needed, please.

The 3.51 fix in the wind smoothing algorithm which additionally makes the wind direction written to offset 2DE0 have the correct effect at the aircraft, now appears to be in error. The direct wind control facilities at offsets 2DE0 and 2DE8 are used by ASV (optionally, but defaulted). The fix applied to get the apparently correct effect at the aircraft via these offsets has the unfortunate side effect of making FS set incorrect crosswind and head/tail wind components.

Worse, even weithout anything using direct wind control, with Wind Smoothing is enabled, the same, "corrected" algorithm is used and again applies the incorrect wind components -- although then these don't appear to be read as such by navigational instruments.

I cannot make a lot of sense of all this at present, though after a couple of days of investigation it does appear to me that FS's wind simulation is rather different when the aircraft is on the ground than when it is in the air. I can 'fix' things on the ground, and in the air, but with different algorithms. Although I can detect the difference ("aircraft on ground") I cannot actually implement both fixes because the wind changes have a delayed effect on the aircraft. I've tried, but no matter what I do, things get screwed up for a while just after take-off, i.e. at the worst possible time.

So I'm abandoning the attempts to get the wind control working on the ground. Hopefully I'll be able to do better with the next version of FS, as and when.

Just by way of explanation of what the original change in 3.51 was all about: the problem in 3.50 and before with the wind direction written to 2DE0 was that the effect actually implemented in FS at the aircraft was a wind 180 degrees opposite, as could be found by turning a static ground aircraft into wind as measured on its ASI. The fix in 3.51 certainly fixed that, and quite a bit of exposure here (as 3.507) failed to detect the airborne inconsistencies which arose.

The differences between 3.511 and 3.512 are in how much "fiddling" FSUIPC does with the winds inside FS when smoothing or providing direct control. Over the last two days I think I've proven to myself that some of the things I was changing don't matter, and may make things worse, so 3.512 eliminates that part of the code.

Please try both 3.511 (without "AircraftWindRev=Yes") and 3.512 (it doesn't have that parameter), and let me know which you find better, if you notice any difference at all. Thanks!

Regards

Pete