Graduated visibility question...

[karm]

Hi Pete,

I just got FSUIPC a few days ago and had a question regarding graduated visibility..I've read the docs and have done a search here but my question seems a bit more specific. :>)

I've set General Limits as follows...

Clear 3000

Cloudy 2000

Overcast 2000

Rainy 1000

Question 1. Surface visibility means just that; these are the max values on the runway, correct?

My graduated visibility is set as follows...

From 0

Up to 25000

Upper visibility 4000

Question 2. Let's say it's a clear day, I take off and climb to 25000 ft. Does FSUIPC increase visibility to 4000 gradually given no weather changes? If I'm downloading Real Weather every 15 minutes (I don't have ActiveSky or FSMeteo installed) how does this change things, if at all?

Now that things are clear as mud... :>)

Thanks,

Mark

[Pete Dowson]

Question 1. Surface visibility means just that; these are the max values on the runway, correct?

"Surface visibility" is actually short for "surface layer visibility", which simply means the layer from zero to whatever is set for the upper altitude of that layer.

I think originally FS was meant to support multiple visibility layers, but it has never worked with more than one, so "surface" means "the extent of the FS visibility layer".

Question 2. Let's say it's a clear day, I take off and climb to 25000 ft. Does FSUIPC increase visibility to 4000 gradually given no weather changes? If I'm downloading Real Weather every 15 minutes (I don't have ActiveSky or FSMeteo installed) how does this change things, if at all?

It keeps the surface visibility, whatever value that may have (30 miles or less, because it is a clear day and your limit for that is 3000) up to the top of the visibility layer, whatever that may be (FS dialogues or downloads set it, FSMeteo and other external programs set it -- though FSUIPC offers an optional override for that), and THEN it gradually and smoothly changes the value from that altitude to 25000 feet, by which time it will be 40 miles, your upper limit.

The reason the changeover from a fixed (surface) visibility to the graduated one is at the top of the visibility layer is that you specified 0 as the lower altitude -- this is a special facility to operate in this way, and it is recommended as you then get the best results.

Regards,

Pete

[Pete Dowson]

Sorry, I just noticed a "Question 3" hidden in there:

If I'm downloading Real Weather every 15 minutes (I don't have ActiveSky or FSMeteo installed) how does this change things, if at all?

If the visibility soecified for the FS visibility layer is changed, or the upper altitude of the visibility layer changes, then your limits are re-imposed if neceassary and then everything is ra-calculated to give a new target visibility for your current altitude. If you haven't got the FSUIPC smoothing enabled, it will change as quickly as FS tries to change it. With smoothing enabled it changes at the rate you have specified.

Regards,

Pete