2 questions

[holtvg]

What is this alphasim name at the beginning of a lot of aircraft and what is the difference between true airspeed and indicated airspeed. :-?

[macca22au]

Air becomes 'thinner' with altitude and temperature, therefore Indicated Airspeed may remain constant, but effectively you plane is flying faster as you climb into higher and thinner air.   True Airspeed (TAS) is the speed after the Indicated airspeed (IAS) has been corrected for temperature and altitude.   In absolutely still air, TAS and groundspeed are the same.  So why do we persist with IAS  -  simply no matter the altitude - your aircraft will stall, will have turbulence limits, maximum speeds, bank limits and the like all based on IAS.  That the plane is going faster through the air is irrelevant - IAS is the measure.  The tutorials associated with FSX should help you there.

[Hagar]

What is this alphasim name at the beginning of a lot of aircraft

Alphasim is a payware company that releases its older FS aircraft as freeware.