Something strange with SP2 Beta 3: clouds are supposed to be few at 1600 ft and scattered at 3000 ft, but in the sim (see screenshot) the clouds touch the ground! Never happened before...

 

 

 

 

I did reload the weather, it seems that this did not occur again. Anyway it seems that the clouds are heavier in frame rate with respect to before SP2, is it only my impression?

I did reload the weather, it seems that this did not occur again. Anyway it seems that the clouds are heavier in frame rate with respect to before SP2, is it only my impression?

 

No I've had a massive performance hit with SP2.

SP2 includes the new "Overcast Enhancement" feature, which is on by default right now, which carries a performance penalty. To provide solid overcast, many cloud sprites must be drawn and this can indeed cause a significant hit. We are working to improve performance further on this.

 

You may wish to disable the overcast enhancement feature if you would prefer better frame rates instead of more solid overcast.

I see there's a new version out. Refer to the first page of this thread for details and link.

 

Hook

SP2 includes the new "Overcast Enhancement" feature, which is on by default right now, which carries a performance penalty. To provide solid overcast, many cloud sprites must be drawn and this can indeed cause a significant hit. We are working to improve performance further on this.

 

You may wish to disable the overcast enhancement feature if you would prefer better frame rates instead of more solid overcast.

 

Ah that makes sense thanks. Had uninstalled SP2 due to the hit. Will reinstall and check it out again without overcast enhancement. Thanks!

Did a test to reproduce the strange climb out temperatures all seems a lot better now.

 

But!

 

I did a flight today EHAM-EGLL and see the follow altitudes vs temperatures.

 

EHAM 071825Z 21011KT 2500 -DZ FEW003 BKN004 OVC005 06/06 Q1025 TEMPO SCT004

 

EHAM TAT 6c

FL070 TAT +16!! SAT +3 (wx-report gives +6.3 at FL060)

FL100 TAT +11 SAT -1 (wx-report gives +4.8 at FL090)

FL150 TAT +9 SAT-11 (wx-report gives -4.0 at FL120)

FL200 TAT -2 SAT -22

FL200 TAT -7 SAT -31

 

During the decent to EGLL

 

EGLL 071950Z 20009G19KT 170V240 9000 BKN027 09/07 Q1025 TEMPO BKN012

 

FL070 +15c (wx-report gives +8.6 at FL060)

5000ft +15

1200 still +13 degrees.

 

And always after take off and temperature is 4 or like that it peaks to +15c around FL070. Not only this flight but i see it everytime around FL070. Looks like FSX goes back to standard temperature. Refresh or restarts doesn't make sense.

 

Flight LEMD-EHAM

 

LEMD was +4c

 

on FL080 it was +12 and on FL180 it was still +4 degrees. closed station was LECV.

A quick (and possibly a dumb question).

 

What "temperature" is injected by the weather engine?

 

Lets say that weather engine injects the following weather:

 

FL100: ISA +3

 

If ISA is -4.8 @ FL100, then ISA +3 would be -1.8 degrees celcius.

 

What should the aircraft report in this situation (x being a value that can be calculated from the -1.8 temperature)?

 

a) TAT = x and SAT = -1.8

 

b) TAT = -1.8 and SAT = x

 

c) something else?

 

I thought that weather engines send a value that can be seen as SAT and it's up to the aircraft to calculate the TAT. How wrong am I?

Mmm, I never had these temperature issues with ASE, all what I know for sure.

Did a test to reproduce the strange climb out temperatures all seems a lot better now.

 

But!

 

I did a flight today EHAM-EGLL and see the follow altitudes vs temperatures.

 

EHAM 071825Z 21011KT 2500 -DZ FEW003 BKN004 OVC005 06/06 Q1025 TEMPO SCT004

 

EHAM TAT 6c

FL070 TAT +16!! SAT +3 (wx-report gives +6.3 at FL060)

FL100 TAT +11 SAT -1 (wx-report gives +4.8 at FL090)

FL150 TAT +9 SAT-11 (wx-report gives -4.0 at FL120)

FL200 TAT -2 SAT -22

FL200 TAT -7 SAT -31

 

During the decent to EGLL

 

EGLL 071950Z 20009G19KT 170V240 9000 BKN027 09/07 Q1025 TEMPO BKN012

 

FL070 +15c (wx-report gives +8.6 at FL060)

5000ft +15

1200 still +13 degrees.

 

And always after take off and temperature is 4 or like that it peaks to +15c around FL070. Not only this flight but i see it everytime around FL070. Looks like FSX goes back to standard temperature. Refresh or restarts doesn't make sense.

 

Flight LEMD-EHAM

 

LEMD was +4c

 

on FL080 it was +12 and on FL180 it was still +4 degrees. closed station was LECV.

 

These aren't actually wrong - as you're probably aware the TAT increases with mach. There's a relatively simple ratio for working out the TAT.

 

t/s = 1 + [(x-1)/2]m*m

 

Where t is the TAT, s is the static air temperature, x is the ratio of specific heats and m the mach number.

 

I'm going to use your FL070 TAT of +16C as an example. I'm guessing you were doing 250 knts at FL070, which translates to a mach of approximately 0.43

 

For simplicity the ratio of specific heats for dry air is approximately 1.4 and so the t/s ratio is going to be

 

t/s ~ 1 + 0.2(0.43*0.43) = 1.037

 

That is to say, the TAT is 1.037*SAT

 

So for an SAT of +3C (276.15K) the TAT should be ~1.037*276.15 = 286K which is +13C.

 

When you consider the conditions were damn, the ratio of specific heats would have been slightly higher (not sure if simulated in FSX) and in reality the TAT would've been slightly higher - which could explain why you were actually getting 16C.

Thanks for your explanation!

 

That means that the SAT is more precise at low speeds.

 

Read some wiki pages..

 

SAT= outside airtemperature

TAT= temperature between airplane and air. More speed more friction=higer temperature.

Thanks for your explanation!

 

That means that the SAT is more precise at low speeds.

 

Read some wiki pages..

 

SAT= outside airtemperature

TAT= temperature between airplane and air. More speed more friction=higer temperature.

 

Exactly. When under Mach 0.2 the difference between TAT and SAT is pretty negligible. The reason the TAT > SAT after Mach 0.2 is down to the kinetic heating (the friction between the air and the aircraft), although this is pretty insignificant in comparison to something called adiabatic compression, which is the result of the kinetic energy of the air molecules travelling in the probe becoming stationary extremely quickly, which converts the kinetic energy into heat essentially.

Damian, if I keep the enhanced overcast coverage coming with SP2, do you also advice to maintain the FSX.cfg setting "CLOUD_COVERAGE_DENSITY=12" or can I restore the value 8 as maximum coverage? I mean, will I get even better overcast depiction with 12 instead of 8 when the overcast enhancement is enabled?

 

 

Exactly. When under Mach 0.2 the difference between TAT and SAT is pretty negligible. The reason the TAT > SAT after Mach 0.2 is down to the kinetic heating (the friction between the air and the aircraft), although this is pretty insignificant in comparison to something called adiabatic compression, which is the result of the kinetic energy of the air molecules travelling in the probe becoming stationary extremely quickly, which converts the kinetic energy into heat essentially.

 

Thank you @Luke !

Again, this is what I found upon arrival at LIRA (Beta 4 installed)

 

 

 

Is this normal?