How Wings ACTUALLY Create Lift!

Summary

This video delves into the science behind how planes achieve lift. It explains the common Bernoulli principle and the equal transit theory, then clarifies that lift is actually created by the wing's downward deflection of airflow, not pressure difference. The Coanda effect, angle of attack, and devices like flaps, slats, and spoilers are discussed to show how they influence lift and control the plane's flight dynamics, including stall prevention and safe landing.

Takeaways

• 🛫 Planes fly due to the lift generated by their wings, which is a result of the airflow being turned downwards.
• 📚 The script explains the incorrect common belief that lift is created by a pressure difference, clarifying that lift is actually due to the wing turning the airflow downwards.
• 🔍 The Bernoulli principle is mentioned, highlighting the role of airspeed differences over and under the wing, but also pointing out its limitations in explaining lift fully.
• 🌀 The Coanda effect is introduced, explaining how the airflow 'sticks' to the wing's upper surface and follows its curve, contributing to lift.
• ✈️ Lift can be increased by flying faster or by increasing the angle of attack, which is the angle of the wing relative to the airflow.
• 🚫 Warning about the risk of stalling an aircraft by increasing the angle of attack too much, causing the airflow to separate from the wing and stop producing lift.
• 📐 Flaps are used to increase lift by increasing the wing's surface area, allowing for slower takeoff and landing speeds.
• 💨 Flaps create drag, which is the aerodynamic resistance that opposes the motion of the aircraft through the air.
• 🔄 Slotted flaps are a specific type of flap that allows air to flow between the wing and the flap, helping to maintain airflow attachment at higher angles of attack.
• 🛬 Leading edge slats are devices that extend forward from the front of the wing to increase lift at slower speeds, similar to flaps but at the wing's leading edge.
• 🛑 Spoilers are used to reduce lift during landing and to create drag for slowing down the aircraft, but their use can cause turbulence and discomfort for passengers.

Q & A

What is the primary reason planes are able to fly according to the video?

Planes fly primarily because of the lift generated by their wings, which is caused by the turning of airflow downwards, not just a pressure difference as commonly misunderstood.

What is the Bernoulli principle mentioned in the video?

The Bernoulli principle, as mentioned, is a part of the explanation for lift, stating that as air flows over the top of the wing, it speeds up, creating an area of low air pressure above the wing.

What is the 'longer path or equal transit theory'?

The 'longer path or equal transit theory' is a common explanation for how wings generate lift, suggesting that the air flowing over the top of the wing has a further distance to cover and thus speeds up, creating lower pressure above the wing compared to the higher pressure below it.

What is the Coanda effect and how does it relate to lift?

The Coanda effect is the tendency of a fluid to follow the contour of a surface. In the context of wings, the airflow 'sticks' to the top of the wing and follows its curve, which contributes to the downward deflection of the airflow and the generation of lift.

How can you increase lift on an aircraft?

Lift can be increased by flying faster to increase the speed of airflow around the wing or by increasing the angle of attack, which is the angle of the wing relative to the airflow.

What is the danger of increasing the angle of attack too much?

Increasing the angle of attack too much can lead to a stall, where the airflow cannot follow the top of the wing and separates, causing the wing to stop producing lift and the plane to fall.

What are flaps and how do they help in generating lift?

Flaps are movable sections on the trailing edge of a wing designed to increase the wing's surface area, allowing the plane to produce more lift at slower speeds, which is useful for takeoff and landing.

What is a slotted flap and how does it function?

A slotted flap is a type of flap that, when extended, has a small gap between the wing and the flap itself, allowing air to pass from underneath the main wing over the flap, helping the airflow to stay attached at higher angles of attack.

What are leading edge slats and their purpose?

Leading edge slats are devices that sit over the front of the wing and can extend forward to increase the wing's surface area, producing more lift at slower speeds, which is beneficial for takeoff and landing.

What are spoilers and what is their function on an aircraft?

Spoilers are flat panels that extend from the top of a wing to disrupt the airflow and reduce lift. They are used during landing to ensure the aircraft touches down safely and to prevent it from taking off again.

What are the secondary effects of using spoilers?

The secondary effects of using spoilers include creating a lot of drag or wind resistance, which helps the plane slow down to a safe taxi speed, and causing turbulence and noise, which can be uncomfortable for passengers.