Final answer:
The rule of thumb in aircraft design for lift generation states that wings should produce about 1000 N/m². The calculation of airspeed over the wing to achieve this lift utilizes Bernoulli's principle and varies with flight conditions such as speed and altitude.
Step-by-step explanation:
Frequently Quoted Rule of Thumb in Aircraft Design
A commonly known guideline in aircraft design suggests that wings should produce approximately 1000 N of lift per square meter of wing surface. This standard helps to ensure sufficient lift for various aircraft during different phases of flight, such as takeoff and cruising. However, it's important to note that the actual lift required can differ based on factors like aircraft weight, wing design, and flight conditions.
Calculating Lift and Air Speed Over the Wings
To calculate the ideal lift and the necessary air speed over the upper surface of the wing, we can use Bernoulli's principle, which relates the speed of the fluid and pressure within a flowing fluid. However, this can only provide an approximate answer due to factors like turbulences caused by the airflow over the wing. Additionally, lift is not solely generated by the wings; engine thrust and the body of the plane also contribute.
Let's take the example of an aircraft at takeoff speed (60.0 m/s). If the sea level density of air is 1.29 kg/m³, we can calculate the required air speed over the top of the wing to achieve the desired lift. Similarly, the calculation must be adjusted for cruising speed and varying air densities at higher altitudes.