To learn more about tomorrow's flying machines, scientists are studying a safe, successful and proven aeronautical design that's been around for a long time -- the dragonfly. Engineers at Boeing Company in Seattle, researchers at the University of Colorado and others have investigated the dragonfly's graceful flying maneuvers.
For its small size the dragonfly can fly an incredible 60 miles per hour. It can dart quickly from side to side, fly backwards and stop instantly in midair. It can lift 15 times its own weight. Such feats are not yet possible with human aircraft. How is it possible with the dragonfly?
Curious researchers visited swamps and captured dragonflies to find out.
One reason they chose to study the dragonfly is because it's a comparatively simple flying creature. It doesn't change the shape of its body or wings when flying, taking off or gliding like a bird does. For example, a hummingbird's wings change shape continually during each stroke. In addition, its feathers pop up or stay down at various periods throughout each cycle. Scientists would like to know more about the hummingbird's flight, but it's just too difficult to reproduce.
The dragonfly's life
Dragonflies, looking neither like dragons nor flies, resemble little airplanes. This insect has been mystically nicknamed "snake doctor," "snake feeder," "devil's darning needle" and "horse stinger." The only accurate nickname is the "mosquito hawk." With its claws it captures mosquitoes in the air and devours them in flight. In half an hour it can eat the equivalent of its own weight.
Life starts under water when they hatch from eggs. These greedy, ugly, newly-hatched dragonfly nymphs then live in the water from one to five years, snagging victims with their long bottom lip which has snapping hooks.
Then, one day, they stop eating, climb out of the water and hang motionless from a reed or twig. In a short time their skin splits open and out comes the adult dragonfly. Two pairs of transparent, fairly rigid, shining gauze-like wings emerge. Each pair operates independently of the other. The dragonfly is now ready to take off and put on its aerial show. In temperate climates this period lasts only two weeks before it dies. In tropical climates the dragonfly's flying phase may extend to a few months.
While flying dragonflies spend most of their time cruising up and down streams and along the shores of lakes and ponds in search of prey. With their extra-large spherical eyes that cover half their head they can see everything around them at once. They can spot a motionless mosquito six meters away, a flying one at an even greater distance.
It was at this stage of the dragonfly's maturation that researchers brought the netted insects back to the laboratory for a look. Since the flying season of the dragonfly is short, they had to act quickly.
First, they anesthetized them to slow down their wing action to about 30 flutters per second. Then they glued their hard bodies to small wires. With non-poisonous smoke and stroboscopic photography freezing the action, they could see exactly what the air flow around the wings looked like during each part of the stroke. What did they learn?
How it flies
The dragonfly's method of flying is completely different from the smooth flight of airplanes and soaring or gliding of birds. It's a mode called "unsteady aerodynamics" which means there is constant turbulence around the wing.
The front pair of wings churns up a small vortex of rapidly whirling air. Meanwhile, the back pair of wings, which may be down when the front wings are up (or vice versa), captures the extra energy from this turbulence. This produces extraordinary lift as the air flows much faster over the top of the dragonfly's rear wing than along the wing's lower surface. By changing the tilt and speed of its wings and varying the timing between them, the dragonfly performs its graceful acrobatics.
What's intriguing about air turbulence is that in man's flying machines, both fixed-wing and helicopters, these gyrating air currents are usually harmful and can be deadly. Helicopter blades weaken because each whirling blade runs into the turbulent path of the preceding blade. Resultant vibrations eventually weaken the metal. Many planes have crashed due to turbulence. But, the dragonfly actually produces precise, predictable turbulence and uses it to its advantage.
Applications for man
Aeronautical engineers would like to know more about the secret of harnessing turbulence. Applying this principle to aerodynamic design is still a bit complicated with today's technology because execution must be simple and predictable.
More immediate applications of what's been learned from the dragonfly's flight could be to modify existing airplane wings to give extra lift when needed. For example, if an aircraft were stalling, a wing could sense the dangerous turbulence. Then, a flap would turn up near the leading edge of a wing and stabilize the aircraft.
Learning about controlled disturbances in air and fluids could lead to more efficient designs for turbines. Also, race cars could improve their track performance.
Studying unsteady air currents never got much attention in the past because of their complexity. Today, scientists make use of supercomputers, wind tunnels and water tanks that help them understand the subtleties of airflow. And by learning from working designs in nature, aeronautical engineers are drawing closer to developing a new generation of supermaneuverable aircraft.
There's still much more scientists would like to know about the dragonfly. How does it control its flight? How does the nervous system activate its flying mechanism?
By inspecting the perfect construction of the dragonfly, which is much more advanced than anything man has yet developed, our attention should be directed to the greatest Aeronautical Engineer of all -- the Creator God. If you came across a sleek Boeing 777 jet and stepped inside its sophisticated cockpit, you would never reason that the aircraft just developed on its own; that there was no designer and builder.
The closer we look at creation, the more evident God's reality should become. In Romans 1:20 Romans 1:20For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:
American King James Version×we read, "...His invisible attributes are clearly seen, being understood by the things that are made." (So how could anyone believe that the dragonfly achieved its design by evolution? Good question. For thorough answers, please request our free booklet titled Creation or Evolution: Does it Matter What You Believe?)
The dragonfly's design is perfect. Every flaw has been engineered out. If it weren't, the little creature simply could not fly. Incidentally, dragonflies have to fly to reproduce. They mate only in midair!
What God has created is mysterious and sometimes baffles human understanding. "It is the glory of God to conceal a matter, but the glory of kings is to search out a matter" (Proverbs 25:2 Proverbs 25:2It is the glory of God to conceal a thing: but the honor of kings is to search out a matter.
American King James Version×). It is for man to uncover and learn from these mysteries.
When scientists began studying dragonflies, they discovered designs even more complex and advanced than what they expected. Dragonflies are amazing, but greater than dragonflies is the Designer and Creator of dragonflies. Our God is an awesome God. He deserves our worship.