Tuesday, November 20, 2012

The Magic of Flight: Your Airplane is a Close Relative to the Seagull

By Dan Pimentel
Airplanista Blog Editor

[This blog is enjoying a spike in new readership, so I thought these new Airplanista readers might enjoy this post, it's one of my all-time favorites - dan]

From the first few days when humans watched birds fly, we have been in awe of their beauty and functionality. With effortless ease, they take a few steps, flap their mighty wings, and launch skyward in a full STOL takeoff that would make a Maule seem like a DC-10 cargo ship trying to plunder its way into the sky.

I spent a weekend in 2007 over on the Oregon coast at Lincoln City, which at the time was getting pounded with gusts to 60 mph on its way to a walloping with winds as high as 129 mph at Bay City. But while the wind was blowing, I came across a huge parking lot full of seagulls that were having a ball in those gusts:
One by one, the gulls would just flap their wings, propelling them up gracefully into the wind. At about three feet over my head, they would just hover, not flapping their wings, but letting the wind provide all the lift they needed to stay basically in one place. After that gull was done with his/her kite imitation, another would launch up into the gusts coming off the beach and play the hover game.
I had my newest camera with me, a Canon 40D, with a 200mm prime Canon "L" lens out front. With the drive set to max of about six frames per second, and the autofocus set to continuous (a sports mode), I was able to run all over the lot, chasing hovering seagulls. About 458 images later, I came back to my hotel and discovered some amazing things about birds. These mega-closeups of gulls in hover mode showed me the anatomy of a bird like I had never seen. If you refer to the photo at the top of this post, you will see the following five things:
1. The trailing edge of the gull's wing stretches out substantially to form a very large "flap" which provides additional lift for slow flight. This was confirmed on other shots of the gulls in fast flight, when these "flap" feathers were retracted.

2. Complementing the "flaps" are what appear to be leading edge slats on the wings. When you study the complete design of this gull's wing, it resembles a jetliner's wing in its "dirty" landing configuration. I find the gull's wings to be stunning works of art.

3. In slow flight, the gulls would flare their tail feathers wide, to create a sort of "horizontal stabilizer" to give the southbound end of the northbound bird extra lift. In close with my telephoto lens, I was amazed watching them steer by flexing these aft feathers ever so slightly, just enough to keep their beak aimed directly into the wind.

4. In hovering mode, the gulls would drop their retractable "gear" to help steer and stabilize their fuselage. As the gusts increased, the "gear" would come down to dirty up their airframe...and when the speed of the gusts dropped, the gull would retract their feet to clean up and eliminate any excess drag. Amazing.

5. The gulls kept their aerodynamic beak aimed PRECISELY into the wind. They would hint at their next movement ever so slightly when they would aim that beak left or right just before peeling off in either direction to pull out of the hover.
After a few seconds of hovering, each gull would crank into a hard left or right one-eighty, suck in their flaps and spoilers, yank up those retractable feet, and blast off downwind, picking up speed like they were shot from a cannon. All the time, I imagine they were smiling.

When you really look at birds up close in stop-action, they do have many similarities to the flying machines we fly. They have wings, we have wings. They have a tail, we have a tail. They have natural navigation instincts, we have GPS. They are free as the wind, we must adhere to strict FAA policy and follow ATC's instructions.

Two machines to accomplish the same feat...flight. One is designed by teams of aerospace engineers and costs thousands, even millions of dollars. The other, comes out of an egg.

Good job on that bird idea, God.
Seriously great engineering.