Lear 45 overspeed error

[Scotch]

Hello all,

I was not sure where to post this so I'll put it here. Plz feel free to let me know if it needs to be somewhere else.

I usually fly the default Lear 45 at a cruise speed of 300 kts IAS. Anything faster than 330 kts I get the

[Skittles]

330kts is the fastest the air can flow by the aircraft. This is known as Knots Indicated Air Speed (KIAS). If you're flying at FL350, you could be going 450KTS over ground before you get to 330 KIAS

[Scotch]

330kts is the fastest the air can flow by the aircraft. This is known as Knots Indicated Air Speed (KIAS). If you're flying at FL350, you could be going 450KTS over ground before you get to 330 KIAS

So the KIAS is diffrent than ground speed and the rating Bombader gives for the Lear 45 is ground speed at sea level.

[Nexus]

KIAS and groundspeed is only the same at seal level in no wind conditions
Then as the air density decreases, it will induce an error in the airspeed incidator, since less air particles will travel though the pitot tube. At just 18000ft the pressure is about half of what it is at sea level so basicly you have to travel twice as fast at 18000ft to have the same KIAS read-out  compared to when flying at sea level.

Bombardier might be using TAS, which is true airspeed.

[Scotch]

Ok, I understand now.

Thank you!
Scotch

[OTTOL]

Bombardier might be using TAS, which is true airspeed.  If you have a groundspeed of 440kts and have a 20kt headwind, your TAS would obviously be 460kts. TAS increases roughly 2% for each 1000ft of density altitude.

You know that I have the highest respect for your technical knowledge but that's not correct.

If you have a TAS of 460kts and a tailwind of 100kts, your TAS is still 460kts. Your GROUNDSPEED, however, will now be 560kts.  
TAS: the actual speed your airplane moves through undisturbed air
CAS(Calibrated Airspeed): indicated airspeed(IAS)corrected for installation and instrument errors
"Manufacturers use IAS primarily as a basis for determining aircraft performance"
(takeoff, landing, climb, fuel burn etc.)
At altitudes above fl290 mach is used, not IAS. The reason the manufacturers generally list performance in KTS and not Mach, is because the people that BUY the airplanes, generally drive cars, not airplanes.
Just like the man says: For an approximate conversion, add 2% of IAS for every 1,000feet.
Lear 45 at 35,000ft at an Indicated airspeed of 270kts(m.79).......35,000/1,000=35  .02*270=5.4    5.4*35=189    189+270=459

and "have a nice day"  8)

[Nexus]

Whoops, that's of course right OTTOL.
Groundspeed is TAS corrected for wind, I kinda mixed it up earlier, my apologies!

Well that goes to show how much I learn from "Flying for dummies" books....cripes  ::)

[Fox_Molder]

Regarding that learjet. what is the crusing altitude. 35 or more. And at crusing alt can you go from NY to France?

thanks for input

[OTTOL]

Regarding that learjet. what is the crusing altitude. 35 or more. And at crusing alt can you go from NY to France?

thanks for input

I believe the Lear45 is certified to FL470. In the real world you would have to stop in Iceland or the Azores. If you want to fly it, the most common route is KTEB/KJFK/KLGA:CYYR/CYQX:BIKF:Destination.....