Hello, I bought FS9 about 8 months ago (if that)I'm trying to get the overspeed indications correct for a specific aircraft, but I don't know what is going on with the configuration files. I've messed with planes since FS98, and the plane that I am flying now was setup for FS2002. My question is no matter what I do with the overspeed indications in the "Air" file (Primary Aerodynamics) nothing seems to work. Here's the indications that I am getting, and if this makes any sense. Flight level 350 MSL, IAS: 313/314 kts, Mach: .885 (Gulfstream specs), TAS: 513 kts, this is where/when the overspeed indication light comes on. In my "Config" file under reference speeds I have the following: Max Mach: .885, Max Indicated Speed: 309 (is this number cas?). If I increase/decrease the max indicated speed it changes the overspeed indications, but if I change the max mach nothing happens. My next question is would this be correct for an aircraft to have a max speed of say 313/314 kias flying at an altitude of 15000 ft MSL, TAS: 379 kts? Thanks J.R. Duda

Vmo (expressed as CAS/IAS) is constant as CAS/IAS is the speed the aircraft thinks it is flying at and is not related to altitude.Mmo is variable and dependent on temperature not altitude. Local Speed of Sound = 38.94 * SQRT(Temp in Kelvin). On a ISA day, 15,000' would be about -15 deg C. LSS = 38.94 * SQRT(273-15) = 626 kts. Mach 0.885 = a Vmo of about 554kts TAS. On such an ISA say, using the rule of squares, 554 KTAS would be about 443kts IAS/CAS.

Hello, Thank you for the info...much appreciated. Take Care J.R. Duda