Aircraft are designed to fly in the air and to do this, they must maintain lift at a certain angle in the atmosphere. If they fly above the limit at which they should, their lift will decrease and cause what is known as a stall. This article will discuss what the stall speed of aircraft is.
What is Stall Speed in Aviation?
The Stall Speed of an aircraft is the slowest speed an aircraft can fly to maintain level height. To maintain the same lift, the aircraft has to “tilt” its wings to an angle. The angle of attack is the angle at which oncoming airflow meets the wings. But if the aircraft finds itself in a position where the wings have been tilted too far, the air that flushes against the top part of the wings is pulled away and the aircraft will lose its lift. This is what is known as the stall speed.
When the aircraft has increased speed, the fast air moving against the wings will prevent the aircraft from falling to the ground.
If the speed is low, airflow to its wing may become lacking, and the aircraft will be unable to lift. Hence what is known as an aircraft stall. Usually, speed is presented as KIAS in aviation.
You should know that different aircraft have varying stall speeds. So what factors influence stall speed? Let us get to find out below.
Factors Affecting Stall Speed
Several factors affect the stall speed of an aircraft, but for brevity, we shall highlight just a few.
- Weight:
Weight will change the speed when a stall occurs, but it does not have anything to do with the angle of attack at which the wing will stall.
- Turbulence:
Flying at a higher speed in turbulent conditions may affect the rate at which the wing will stall.
- Wing Contamination
The contamination of the wings with ice, snow, frost, and rime is also a factor that can affect the stall speed of an aircraft.
Other factors include:
- Altitude
- Power and climb
- Load factors, etc.
Whatever the factor that affects a stall, aircraft must fly at a higher speed than their stall speed to maintain lift.
What is the Stall Speed of an F35?
The F-35 stall speed depends on the configuration of the jet, but normally can vary between 100knots and 200knots.
What is the stall speed of a B737?
The stall speed for a B737 is around 110 knots. But this stall speed depends on several factors, which include aircraft weight and flap configuration.
The B737 has a Flap 30 configuration but can do a Flap 40. However, to prolong service life, a B737 does a Flap 30 to reduce flap load.
When the B737 is about to land, the touchdown speed (Vref) can vary based on wings, selected flap settings, and landing weight. The Approach speed (Vapp) can be varied by air control.
In general, the touchdown speed can be 1.3x multiple of the B737 stall speed, which is enough provision for safety. In addition, 5-10 knots may be added for wind conditions.
All these taken into account may increase the stall speed of a B737 in the range of 130 to 150 knots.
What is the stall speed of 747?
The stall speed of a 747 is 138 knots.
The stall speed of a 747 depends on a lot of factors:
What is the minimum weight of the 747 in question:
Is the weight of the 747 empty or loaded? Is it loaded to half capacity? It is noted that any aircraft can fly so long as its lift speed generated by the wings is equal to or exceeds the 747 weight.
What is the flight configuration?
Under this factor, we try to ask whether the flap is extended and how far out it is.
What is the angle of attack?
If there is a far pitch from the aircraft, the air will be unable to get over the upper surface of the wing and affect the lift.
Thus, all of these are put into account to determine the lifting force of the 747.
Based on engineering opinions. if the 747 goes twice as fast, the speed will increase by four times.
It all comes back to the lifting force generated by the 747’s wings. The lift equation used by engineers says that when you go twice as fast, the lift increases by four times and four times your airspeed means sixteen times your lift, and so on.
In conclusion, we have discussed the stall speed in aviation. Then the article took the light of some aircraft to determine their stall speeds. It is noteworthy that different factors affect the numbers discussed here, as well as how the stall speeds are gauged. Thus, all these factors only helped us to provide the average stall speeds of these aircraft.