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What are the similarities between aircraft and birds?

To talk about the similarities between birds and aircraft, we should understand that learning by imitation is one of the most powerful and accessible way to progress whether individual or as a collective. For this reason, it’s no surprise that from early on history the human has dreamt of flying through the skies like a bird.

From the very beginning of aeronautics, the bird’s flight has always been an inspiration for the design of aeroplanes, but how to imitate a skill which the birds have been developing for millions of years?

For obvious reasons, the dream of flying didn’t materialise until around 100 years ago, although, attempts to fly have been documented for over a millennium.

To follow, we will review the similarities and differences between aircraft and birds, which elements have been copied to imitate types of flight and how we reached for the skies without wings.

But, first of all, we show you a new video of 1Minute Aviation that will serve you as an appetiser for everything we are going to tell you… Hit the play!

Is it a bird? Is it a plane?

Machines imitating bird’s flight

In early human attempts to copy the flight of birds, it was believed that flapping wings was essential. For this reason, the first prototypes were focused on raising flight by means of rope mechanisms and pulleys which moved large wings like birds.

However, after many failed attempts and several studies, the conclusion was reached that humans, due to their physiognomy, would never be able to generate the necessary force to lift themselves by flapping their wings and remain in flight.

So, in 1799, Sir George Cayley, a British Engineer and Inventor, devised the first modern concept of an aeroplane based on lift, inspired by the gliding flight of vultures.

By observing these large birds covering huge distances without flapping their wings, just gliding, helped him to realise that to fly all that is needed is speed and fixed levels to influence the air currents generated. This ascending force which balances the weight and counteracts the resistance is known as lift.

You can read more about the Principles of Lift, and watch an interesting explanatory video by clicking on the link.

Similarities between birds and aircraft

As mentioned before, there are certain elements that are clearly shared between aircraft and birds. The first and most visible are the wings, but also the control surface of the tail or flaps. Let’s look at these similarities in more detail.

The wings: An essential element

Gliding like a vulture, reaching the speed of a hawk or suspending like an albatross. Each type of bird has developed its specific wing anatomy adapted to its habitat.

Similarly, what happens with these types of bird wings, the design of aircraft includes different types of wings designed for an activity or to favour a specific type of flight. This way, depending on the aircraft type, it will have a specific wing type.

To show an example, our Diamond DA20 C1 have a very high capacity of gliding thanks to its enormous rectangular wings making it the safest aircraft for learning with.

And the trapezoidal wings of our twin-engine Diamond DA42 provide great stability during flight and at the same time allowing magnificent manoeuvrability at high speeds.

The flaps simulate feathers

Bird feathers play a massive part in flight: without feathers, flight would be simply impossible. By studying types of bird feathers, we understand each group has a specific and unique function.

  • Alulas: Increase the lift index at low speeds and reduce turbulence.
  • Wing feathers: Generate the necessary lift to take off and control the speed on landing.
  • Coverts: Direct air flow under the wings creating an aerodynamic profile.
  • Scapulars: Cover and protect the joint between the wing and the body in scapulars (shoulder blades).

As feathers, flaps are in charge of varying the angle, shape and the surface of the aircraft wings to increase lift at low speeds.

Additionally, the flaps create more resistance so in the design phase of the aircraft, tests are carried out to establish maximum and minimum speeds they can deploy and retract.

The control surface on the tail

As with the wing shapes, aircraft tails are inspired by different types of bird tails.

The main function of the horizontal tail empennage is to stabilise the aircraft creating opposite forces which provide lift. It’s also essential to control the pitch axis of the aeroplane.

All aircraft tail types in charge of these functions and each one of them provides characteristics and benefits adapted to the type of flight they were built for.

Slats and winglets

To finish this series of similarities between aircraft and birds, we’ll discuss slats and winglets.

On one hand, slats are aerodynamic devices situated on the wing leading edge, which once deployed allow a higher attack angle, increasing lift at low speeds. These devices are inspired on the bird’s alula feather and work similarly.

On the other hand, surely you know that birds separate their primary wing feathers to decrease resistance at the wing tips to assist gliding, and in aircraft the winglets have the same function. They also reduce fuel consumption by 10% making them a very important element in today’s aircraft.

Differences between birds and aircraft

It’s clear that although the similarities of aircraft and birds are evident, the human has incorporated new elements such as propellors for propulsion, making some substantial differences. Let’s see them.

Propellers and turbines to generate thrust

The main difference between birds and aircraft is the impossibility of wing beat of the latter. For this reason, while birds generate thrust by wingbeat, aircraft do this with propellers or with turbines in the large commercial aircraft.

Vertical level of the tail

Birds, due to their natural capacity to adapt their body to flight in real time, they don’t need vertical empennage on the tail. Aircraft in contrast, do.

This way, including a vertical level on the empennage of the aircraft tail is imperative to maintain yaw, compensate slippage in asymmetric flights or to cushion oscillations of the aircraft.

How else will aircraft resemble birds in the future?

Maybe in the future, the aircraft fuselage will simulate the movements of birds in flight; or maybe we’ll change turbines for more efficient propulsion systems. We may even be able to make the wings deploy and retract in flight, who can say …

What is clear, is that even though everything about aviation appears to have been invented, we still have much more to learn from the birds to achieve a much more efficient design of our aircraft.