Wing it!

Reach for the skies with Tom Jackson as he reveals the secrets of flight.

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Take a moment to gaze up at the blue sky T and those fluffy clouds, and no doubt you'll soon see something flying by. That could be a flock of swooping birds, a thundering passenger jet drawing a white trail across the sky, or perhaps a bee buzzing busily by. Or maybe that buzz is actually a drone hovering overhead? Creatures have been winging it through the sky for millions of years, but humans have only figured out how to fly relatively recently. People use flying machines to get airborne, and have been inventing different types for nearly 250 years. Many flying machines are based on animals, but how close is human tech to animal flight? And is there more to learn from flying critters to create better aircraft?

The secret of flight

First off, let's understand why some things can take off and stay in the air, while other things stay firmly on the ground. All flight, whether animal or human-made, involves balancing four forces thrust and drag; lift and gravity. These four forces are two sets of opposite pairs.

Lift pushes objects upwards, while the force of gravity pulls everything back down to the ground.

Thrust pushes an object forward, while drag is the force of friction that tugs on anything that travels through the air.

The reason you can't just fly to school is because your body cannot generate the right forces to get you off the ground and keep you up there. You just keep falling back down. To rise, you really need some wings. When viewed side-on, most wings have a special curved shape, called an aerofoil.

Once air moves over an aerofoil, the stream of air generates a lift force that pushes upwards on the wing. To get moving, you also need a thrust force to push you forward (and make your wings slice through the air to keep generating lift). The thrust must be stronger than drag. If your wings generate enough upward lift to beat the pull of gravity and enough thrust then up, up and away you go!