What does gravity have to do with aeroplanes?
Abby Wolfe
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The Big Question 
Hi Abbey
What has gravity to do with aeroplanes, (or anything else for that matter!).
If we start with an aeroplane that is parked on the runway, then the fact that is stays on the ground is directly due to gravity, which is the force that keeps all objects on the ground!
So, now you’ve boarded the aircraft, and all is well to take off, (I’m assuming you’ve flown before?) then the pilot will “taxi” – that is “slowly move the aricraft” under its own “power”to the start of the runway.
As soon as the pilot has permission, he/she will then start “take off” – which means the engines (usually jet engines) are raised to maximum thrust, and YOU feel the aeroplane accelerating quickly to a fairly high (in car terms) speed.
NOW – as the earoplane goes faster and faster, the air flowing over and under its wings (the “airspeed”) starts to create “lift “**
That is, there is a force being generated which is trying to “overcome” the force of gravity keeping the plane “on the ground”
NOW….. once this “lift” is equal to or greater than the force of gravity, then the pilot can start to “fly” the aeroplane off the ground , that is ….. where the pilot “rotates” the aircraft so the “nose” end goes up, and it the then “flies” along an “upward” incline.
All the pilot needs to do now is ensure that the lift always exceeds gravity ….. so you dont crash !
If the lift doesn’t exced gravity …. and this can happen if
the airspeed drops below a minimum limit due to insufficient engine thrust say, the the aircraft will “drop” due to gravity, until sufficent airspeed is regained ( that is “get the nose down”, or inrease engine power or both ……. so
You can see that “take off” is always a stressful time becuase you haven’t got much height to play with if something goes wrong. – so pilots like to get up high, with optimum airspeed as soon as possible!
So there you are, an aircraft flies becuase in a delicate balancing act betweeen gravity trying to pull it down, and air flowing over the wings creating an “opposite” force (lift) to keep it up !
Hope that helps !
(**you can feel this “lift” by putting your hand out of a car window travelling at speed, and by “angling” your hand “upwards”, you will feel it being forced upwards by the flow of air over your hand)
Gravity wants to pull things towards the greater mass, in our case, “down.”
A plane works by going forward fast enough that there is “lift” under the wings (the air particles push hard enough against the underside of the wings) to “push” it up and overcome gravity.
The late Douglas Adams said:
“The trick to flying is to fall and miss the ground. This happens only when someone falls and becomes so preoccupied with something else that they forget that they are falling, and therefore are no longer doing it. Flying is just a permanent state of falling, minus the hitting the ground part.”