How fast can a 737-800 fly?

Question

Hello,

How fast can a real 737-800 fly? In Flight Simulator X, you're only aloud to go 340 knots then the overspeed alarm comes on. And I know that when I fly on a 737 we're easily going 450 knots.

Thanks!

-Matt

Answer 1

The previous answer is exactly correct.  I'll just try to give you a little more explanation.  Especially at high altitudes, INDICATED airspeed is much lower than TRUE airspeed.  The indicated speed at which the overspeed warning sounds varies because of your maximum Mach limit of 0.82.

At altitudes in the upper 30,000s, cruising at Mach .78 will give you a true airspeed of about 440 knots, but your indicated airspeed will be somewhere around 260 knots.  The air is so thin up there that the pressure on your pitot tube (the sensor that measures dynamic pressure and translates it to an indicated airspeed) is much less than at lower altitudes, even with the plane going faster.

Answer 2

Mach .785 of the speed of sound or .785 of 761mph at sea level and 0785 of 660mph at cruising altitudes of most commercial jets....(597 mph at sea level and 518 at altitude)this are general figures as weight,weather,and many other things can affect speed.http://en.wikipedia.org/wiki/Speed_of_so...

Answer 3

The top speed depends on wieght, altitude and air temp/press, etc. I think it can't go beyond:

Mach 0.78 even at 50,000ft without threatening to break up.

On MS-FlightSim I normally fly my 734 (737-400) at 40,000ft at between Mach 0.75 - 0.76

Answer 4

Cruise speed is Mach 0.78.    You are getting the warning at 340 kts indicated, which is less than true airspeed- because it is the equivalent to sea level airspeed.

Answer 5

A 737-800 could achieve its maximum speed (TAS) when at at a altitude of 26,000 feet. This is the cross over altitude where Vmo = Mmo (i.e 340 kts IAS = M0.82).

At ISA temperature this equates to 491.8 kts TAS. If the temperature were higher it could go faster.

Take your FSX B737 to 26000 ft then accelerate to the red line speed (340 Kts IAS). Then check the TAS.