How do planes fly?

An Airbus 380 on a 13 hour flight carrying up to 500 passengers plus cargo with 150,000 KG of fuel weighs over 500 tons when it takes off. So how does something that weighs that amount get off the ground in the first place?

post-howfly-cartoonWe came across this great diagram by lefthandedcartoons.com which shows what some people might think happens but unfortunately, for this writer, it’s a little more complicated and harder to explain. That said, we’re not going to delve into the intricacies of fluid dynamics today – which I’m sure most of you won’t be too disappointed about (we sure aren’t). 

So, in basic terms, what gets the plane into the air is forward motion creating airflow over the wings which in turn creates lift. Ok, that probably needs a little further explanation so bear with us. 

The forward motion is created by the engines. On an A380, four large turbofan engines each create 80,000 lbs of thrust which push the plane forward causing the air to flow over the wings. Now here comes the slightly tricky part. 

post-howfly-aerofoilFor this, a (magic free) diagram is necessary. This shows the cross-section of the wing of a plane, otherwise known as an aerofoil. It is shaped so that the curve on the top is longer than the curve on the bottom. When air arrives at the front of the wing it splits and some air particles go along the top and some along the bottom.  The same air particles then meet back up at the back of the wing. Now because the air particles that take the journey along the top of the wing have a further distance to travel (in order to meet back up with their counterpart who took the lower route), they have to travel faster. This spreads them out further along the top of the wing (think cars on a motorway having more distance between them the faster they go) than on the bottom which in turn causes lower air pressure on top than below.

This difference in pressure (more underneath and less on top) is what creates the lift. The faster the airflow the greater the lift which is why planes have to get up to speed to create enough lift to overcome the opposite force of gravity.

So that’s it in a nutshell. There are other factors such as drag and angle of attack which we will cover again in probably a much more boring article but for now, if you have any questions give us a shout on hello@askthepilots.com

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