Thanks
UAL T38 Phlyer. It took me a bit, but I think I finally understand the relationship between IAS, TAS and Mach.
As for FL500 in a BE1900, if it did make it up that high, the flight envelope would be rather small between overspeed and stall.
Hypotheticallly, if I where to make it up that high the 110 inch diameter prop setting would have to be at the max 1700 RPM.
Circumference equals Diameter Multiplied by Pi = 110 X 3.141 592= 345.575 in
345.575 in divided by 12 inches = 28.7979 feet in Circumference
28.7979 ft X 1700RPM = = 48,956.457 fpm
48,956.457 fpm divided by 6,076 feet = 8.0573497 knots per minute
8.0573497 kts per minute X 60 minutes = 483.44 knots (speed of propeller blade tips)
Assuming standard temperature lapse rate at 50,000 feet the outside air temperature would be -85 C which results in a mach 1 speed of 534 knots.
This means my propeller blade tips would be mach .904... Localized airflow around the prop blade most likely above Mach 1....
That can't be good either.
(For comparision at SL the prop blade tips would be at Mach .73 and at FL250 Mach .81)
I think I would rather be in your F4 Phatom.
Again thanks to all that replied. Have a nice day.