October 2, 20214 yr I have read about certain circumstances where aircraft appear to loose speed when flying across clouds. Decided to test, using a scattered sky preset, the default c172 with AP Hdg + Alt modes, and observing any variations in speed. From 95 knot IAS speed drops easily to 90, 88... and RPM drops too while crossing a cloud. The longer the permanence, the wider the drop, although I haven't determined the max drop by setting, for instance, a broken preset, and making sure I stay within the cloud as long as possible. In my tests there was no icing occuring. Flying gliders since 1980 Flightsimming since 1992 AMD Ryzen 5600x, 32GB RAM, GPU Nvidia RTX 3060 Ti 8 GB, 1 TB and 500 GB nvme2 SSD drives, HP 27" 60Hz LED monitor @ 1920x1080, T16000, Hotas from old X52 Pro, Saitek Combat Rudder Pro (2010 model)
October 2, 20214 yr 2 minutes ago, jcomm said: I have read about certain circumstances where aircraft appear to loose speed when flying across clouds. Decided to test, using a scattered sky preset, the default c172 with AP Hdg + Alt modes, and observing any variations in speed. From 95 knot IAS speed drops easily to 90, 88... and RPM drops too while crossing a cloud. The longer the permanence, the wider the drop, although I haven't determined the max drop by setting, for instance, a broken preset, and making sure I stay within the cloud as long as possible. In my tests there was no icing occuring. I have also seen this in several aircraft.
October 2, 20214 yr I know you said there was no icing occurring, but, did you have pitot heat on? Small accumulations of ice that block either the pitot tube or static port would change your indicated airspeed. I have noticed that FS2020 is pretty sensitive to icing...even when you think there isn't any. Also, small amounts of turbulence would change the airplanes momentum, interrupt part of its lift and, thus, cause an actual loss of airspeed. Gregg Seipp "A good landing is when you can walk away from the airplane. A great landing is when you can reuse it." i9 64GB RAM, GTX-5090
October 2, 20214 yr Author Yep Gregg, pitot heat was ON as per std procedures :-) particularly in IMC, and winds were set to calm, no turbulence ( significant ) within the clouds, and, these were quite stratefied and thin... I though about it being due to the modelling that apparently ASOBO does of currents within and around clouds, but the absence of turbulence and also the drop in RPM call my attention to other possible reasons... I would like to know the "justification" isn't based on something like "density", but as per Alexis suggestion, I will enable dev mode and watch the atmosphere data that get's logged... Flying gliders since 1980 Flightsimming since 1992 AMD Ryzen 5600x, 32GB RAM, GPU Nvidia RTX 3060 Ti 8 GB, 1 TB and 500 GB nvme2 SSD drives, HP 27" 60Hz LED monitor @ 1920x1080, T16000, Hotas from old X52 Pro, Saitek Combat Rudder Pro (2010 model)
October 2, 20214 yr It is a known issue. They talked about it in the latest Q&A. As far as I understood they got a parameter wrong by a large factor. It will be fixed in SU6.
October 2, 20214 yr Yes, it’s a known bug..I see it also. Edited October 2, 20214 yr by flyinpilot212121 Intel I7 12700KF / 32 GB Ram-3600mhz / Windows 11 - 64 bit / NVIDIA GeForce RTX 3060TI / 32" Acer Monitor, Honeycomb alpha/bravo, CH rudder pedals, Tobii 5, Buttkicker, Logitech radio panel.
October 2, 20214 yr Author Investigated using Dev Mode, and opening the "Debug Aircraft Sim Tuning" window in order to display "Air Speed IAS", "Ambient Air density" and "Ambient Air temperature", but while sometimes theres a slight drop in ambient air density when entering cloud formations, most of the time it appears not correlated to the siginicative drop we can observe in IAS as the aircraft is crossing the cloud... Flying gliders since 1980 Flightsimming since 1992 AMD Ryzen 5600x, 32GB RAM, GPU Nvidia RTX 3060 Ti 8 GB, 1 TB and 500 GB nvme2 SSD drives, HP 27" 60Hz LED monitor @ 1920x1080, T16000, Hotas from old X52 Pro, Saitek Combat Rudder Pro (2010 model)
October 2, 20214 yr It's mentioned at 1:46:15 in the latest Dev Q&A. It's fixed in SU6, it was basically due to an error in the calculation of the air density inside clouds. My simming system: AMD Ryzen 5800X3D, 32GB RAM, RTX 4070 Ti Super 16GB, LG 38" 3840x1600
October 2, 20214 yr Very old bug! Good thing it will be fixed! Life time flight sim enthusiast, current airplane owner 172P (past C182F). FAA CP/IR ASEL/AMEL, FI ASELMy System: AMD Ryzen 9 9950X3D , MSI X870 GAMING PLUS, 64G RAM, ASUS RTX5090, 4T SSDPut my hands on (pic/dual/given)7GCAA, 8KCAB, BE24, BE76, BE35-C33, BE35, C150, C152, C172B/N/P/R/SP, 182F, M20E,M20C, M20J, AT6(SNJ4), PA28-140,PA28-151, PA28-161,PA28-181,PA28RT-201,PA28R-180/201T, PA24-250, PA32-300R, PA44, AC114, YAK-18T, YAK-52, SR22
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