• Question: How does airplane fly?

    Asked by naresh to David, James, Mike, Suze, Will on 13 Jun 2011.
    • Photo: James Marrow

      James Marrow answered on 12 Jun 2011:

      The curved shape of the wing makes the air flow faster over the upper wing surface (it’s got further to go to meet up with the air travelling the shorter distance on the flat underside). This speed difference creates a pressure difference on either side of the wing. The pressure causes a force (which is proportional to the wing area times the pressure) – and this force lifts the aeroplane. The faster the air, the greater the pressure difference and the greater the lifting force.

    • Photo: David Ingram

      David Ingram answered on 13 Jun 2011:

      There is a really great web page from NASA http://www.grc.nasa.gov/WWW/k-12/airplane/foilsime.html [\embed] which shows how the air flows over a two-dimensional wing section. An interesting thing to note about real wings is the difference in air speed causes a big re-circulationat the wing tip – these cases the condensation trails we see from jets flying at high altitude and can sometimes be seen on wet/foggy days when aircraft land and take off. There were some famous experiments with smoke and a great photo on wikipedia [\embed]

      One odd thing about the wing tip vortex is that the physical law of “conservation of momentum” means the vortex has to be a complete ring (just like a smoke ring). This forms as the plane accelerates down the runway and the wings start to create lift – and stops when the plane comes to rest. So if you flight from Heathrow to JFK in New York yo create a “smoke ring” the width of the atlantic 🙂 (or would if turbulence didn’t exist)

    • Photo: Suze Kundu

      Suze Kundu answered on 13 Jun 2011:

      I’ll let the boys answer this one – I’m a chemistry chick, so my only interest in planes is their ability to get me on holiday! In the meantime, based on what the guys say about aerodynamics, etc, maybe you could try and build your own paper aeroplanes and see whose plane can fly the furthest? Your teachers are going to hate me for suggesting this idea, but it’s a great way to try out new ideas. Experiments are the best way to learn!

    • Photo: Mike Dodd

      Mike Dodd answered on 13 Jun 2011:

      Unfortunately I don’t know enough to answer this question, really sorry. Like Suze, my main interest in planes, is being able to get on holiday 🙂 Sorry

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