The moment has come to step back in time to your school desk, specifically to your Physics classroom. Whether you’ve always been a geek or are relatively new to the experience, today we’re going to brush up on Newton, Bernoulli and Lavoisier in an attempt to understand the laws of physics that allow an aeroplane to fly.
The force that allows an aeroplane to take off from the ground is called lift (L), which is the push perpendicular to the direction of travel, or better still, the push calculated in the direction perpendicular to that of the related wind and generated by the airflow around the wing. Take note! This is a principle that is common to animal flight and mechanical flight. For instance, seagulls and aeroplanes both fly thanks to the same law of physics.
Let’s see how. When air gets ‘cut’ by a body, in our case by the wing, it is divided into two portions: the upper portion is faster than the lower portion. As a consequence, pressure is lower on the top of the wing than underneath it. Put simply, this phenomenon produces enough force to go against gravity, allowing the aeroplane to fly.
Other variables play a fundamental role, such as speed, wing structure and air density. In fact, lift depends both on the speed of the airflow hitting the wing and on the types of wings, which change based on span and curvature.
At a constant speed, the bigger the curvature of the wing, the bigger the lift. This is why we have mechanisms such as flaps, which are activated by the pilot mainly during take-off and landing in order to modify the curvature angle of the wing.
Finally, air density: thin air shows less resistance at cruising altitude, meaning the engines have to work less hard…
When it comes to aeroplanes, lift is not the only force fighting against the force of the aircraft’s weight (the force the Earth’s gravitational field exercises on the aeroplane’s mass), but there’s also the push generated by the engine and the drag in the direction opposite to the direction of travel.
Does that all make sense? Maybe it’s all too easy for you super geeks, but this simple lesson might just reawaken the curiosity of those among you who still don’t yet know that there’s a geek within! 😉