Hi Mak,
Faustformeln gibt's auch im IVAO Instruction Pack (
http://www.ivao.org/training/tutoria...Start_Here.htm )unter "L5-Speeds".
Da steht:
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2 - TRUE AIRSPEED (TAS) :
The TAS is the speed of an aircraft into the air mass it is in, whatever the density of this air mass is. It is often shown on FMS or GPS or can be calculated from IAS (see below).
The TAS is a flight planning and navigation speed which enables calculations of deviation or ETA (see GS).
When expressed in knots (general case), the TAS is often written KTAS.
Relation between TAS and IAS :
- for IAS between 240 and 400 kt and FL between 50 and 250, a good approximation is given by
TAS = IAS + FL/2
Imagine an aircraft steady at FL 120 and 320 KIAS, KTAS = 320 + 120/2 = 380
- for IAS lower than 240 kt,
TAS = IAS + (1.5% IAS x altitude) (alt expressed in thousands of feet).
Imagine an aircraft steady at FL 150 and 220 KIAS, KTAS = 220 + ((1.5% x 220) x 15) = 220 + (3.3x15) = 270
However, remember the lower and slower the aircraft is, the closer to the IAS is the TAS.
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Gruß in meine 40km entfehrnte Kreis-Stadt,
Dancer out.