FSUIPC Wind Smoothing suggestion

[steveng]

Hello Pete,

I am currently using FS2004 and Registered FSUIPC.

Question/suggestion for consideration:

Common situation in real life is for the wind at altitude to be fairly smooth with minimal gusts and fairly slow changes in speed and direction. Wind near the surface may be very different with significant gusts and much more rapid changes in speed and direction.

In terms of a single fsuipc set of smoothing settings, these two situations seem to be contradictory. Nice smooth winds at altitude but then virtually no gusts during takeoff/landing/low level flight or realistic surface winds but possibly horrible windshear at altitude.

I am wondering is it a feasible future possibility to divide the fsuipc wind-smoothing function into say 2 separately controlled layers eg - upper and lower. The 2 layers separated by a 'smoothing transition level', probably defined as a level AGL. Then the ability to set the wind smoothing parameters (including no smoothing) separately for each layer.

This would allow for example a highly smoothed setting for the upper layer and a reduced (or no) smoothing setting for the lower layer. This would give nice slow, smooth changing winds at altitude, but still allow more realistic turbulence and gusts below a definable low level close to the ground. Obviously to retain the same results as the current fsuipc, both layers could be simply set to the same smoothing parameters.

Best regards,

Steven.

[Pete Dowson]

In terms of a single fsuipc set of smoothing settings, these two situations seem to be contradictory. Nice smooth winds at altitude but then virtually no gusts during takeoff/landing/low level flight or realistic surface winds but possibly horrible windshear at altitude.

Where are you getting "horrible windshear"? All FSUIPC is doing is preventing the prevailing wind speed and wind direction changing faster than to specified (user controlled) amounts.

There's a separate weather setting each for gusts (wind speed changes) and variance (wind direction changes) which FSUIPC doesn't touch -- they are the prerogative of the weather source, part of the parameters, just like prevailing wind direction and speed.

I am wondering is it a feasible future possibility to divide the fsuipc wind-smoothing function into say 2 separately controlled layers eg - upper and lower. The 2 layers separated by a 'smoothing transition level', probably defined as a level AGL. Then the ability to set the wind smoothing parameters (including no smoothing) separately for each layer.

Well, I think you misunderstand the function of smoothing. The idea of the smoothing is to ease transitions between CHANGES in the weather, eg over time or over distance, which arise incorrectly simply because there are some errors in the way FS blends weather from difference sources.

Simply not having smoothing enabled, or set "less" will not actually generate gusting or variations.

What you want is really part of any weather control program's function. The sort of conditions you want should be easily possible with the correct weather settings, controlled by gust and variance settings for each level.

I think programs like Active Weather and FS Meteo do a pretty good job on these. I don't know how much such detail the FS downloaded weather achieves.

Regards,

Pete

[steveng]

Thanks very much Pete for your reply.

Normally I use Activesky 2004.5 for weather. I understand your explanation that the purpose of smoothing is to limit the effects of changes due to wx processing from different source stations etc.

I have been experimenting with just 'user-defined' weather - manually setting a gusting surface wind eg Speed 20kt Gusts to 40kts (without Activesky running) and then trying different FSUIPC wind smoothing parameters. Then looking at the wind using Shift-Z. (I assume this is the actual wind experienced at the aircraft?)

For example setting the FSUIPC smoothing to limit the wind changes near aircraft to say 1 kt per sec seems to have the effect of limiting the gust onset rate also to 1kt/sec?

Especially when using Activesky winds I really like the ability to smooth the changes in high level winds, possibly using a fairly highly smoothed fsuipc setting (low rate of change/sec). My question is really, how to achieve this without limiting the typically much more rapid onset of gusty winds at low level? Is it possible to achieve that already?

Best regards,

Steven.

[Pete Dowson]

I have been experimenting with just 'user-defined' weather - manually setting a gusting surface wind eg Speed 20kt Gusts to 40kts (without Activesky running) and then trying different FSUIPC wind smoothing parameters. Then looking at the wind using Shift-Z. (I assume this is the actual wind experienced at the aircraft?)

I don't think it does. You should face the aircraft into the wind and read the fluctuations on the airspeed indicator.

Regards,

Pete

[steveng]

Thanks Pete.

The test situation I was using was pretty much as you described, sitting on a north/south runway facing into a northerly wind. The fluctuations of the airspeed indicated seemed to match the fluctuation in the displayed wind.

I guess what I am unsure about here is whether fsuipc wind smoothing is influencing how wind gusts (wind with gusts defined by an external weather program or input via the weather menu) actually effect the aircraft. Is it correct to say that for example a fsuipc smoothing setting of 1kt/sec will also limit the gust rate of onset/decay to 1kt/sec? That is what I seem to be seeing?

No smoothing = rapid changes in wind/fluctuation on ASI with wind gusts;

With smoothing = wind gusts (wind display/ASI movement) with rate of onset/decay proportional to fsuipc smoothing setting.

Regards,

Steven.

[Pete Dowson]

I guess what I am unsure about here is whether fsuipc wind smoothing is influencing how wind gusts (wind with gusts defined by an external weather program or input via the weather menu) actually effect the aircraft. Is it correct to say that for example a fsuipc smoothing setting of 1kt/sec will also limit the gust rate of onset/decay to 1kt/sec? That is what I seem to be seeing?

I didn't think so -- both gusts and variance (fluctuations in wind direction) should be operating normally, I *think*.

The smoothing for FS2004 is different to that provided in previous versions, but it has remained unchanged for the (more than) two years since FS2004 was released. It is a little strange to be thining of changing it now -- I will consider what may need doing for FS200x as and when.

Regards,

Pete