There'll be an exam on this!

The albatross was immortalized in Samual Taylor Coleridge's famous poem, The Rime of the Ancient Mariner but these birds have always been watched by sailors. They don't so much as fly as soar across the waves in a swoopping flight pattern upwind in wind speeds of 10 to 20 knots.

Albatrosses spend the majority of their long lives above the ocean. By the age of 50, an albatross has typically flown at least 1.5 million miles. The adults routinely fly hundreds of miles to gether food before returning to feed their chicks. The lucky ones make it, the unlucky die trying to grab the bait on the miles of long hooked fishing lines. Their wingspans can reach up to 12 feet but they rarely flap their wings

Phil Richardson, a retired oceanographer but still at Woods Hole Oceanographic Institution, has studied the aerodynamics of the birds which can fly in any direction including into the wind without losing speed or steadiness in flight and with no wing flapping.

With his knowledge of sailing, gliding and his work with the movement of ocean currents, he began to look closely at the albatross.

Richardson came up with a theory involving the interaction between wind and ocean. In the trough of waves, there is little wind, because the waves block it. But above the waves and their troughs, winds blow briskly across the ocean in thin layers. Lower layers are slowed by air-sea friction near the ocean surface, but winds speeds increase as you go farther from the surface and higher up.

He concluded that albatrosses needed a minimum wind speed of 7 knots to soar and calculated that they could soar upwind at a speed of 12 knots. An albatross ascending from a wave trough at an angle would encounter progressively faster winds increasing its speed in the air as a burst of kinetic energy that enables it to climb to heights of 10 to 15 metres. (Hello, are you still with me) It then makes a tight turn downwind and swoops into another wave trough, adding airspeed as it descends through the wind sheer into progressively slower winds. Each addition of airspeed balances the loss of energy caused by drag on the bird. The albatross keeps up this cycle and each swoop cycle takes about 10 seconds. (a heck of a lot shorter than it took me to understand this).

This phenomenon is called dynamic soaring and glider pilots know it well. Richardson still didn't know how they flew upwind but being a sailor it came to him that the birds were tacking as ship's sails do. He went back to his model and calculated that the fastest course upwind for an albatross is to tack about 30 degrees to the right and left of the wind. He observed that the birds climb upwind but often dive perpendicular to the wind to maximize their average velocity in an upwind direction. (WAKE UP, this is interesting)

Of course the military are interested in all forms of flight dynamics at a small scale, using bird, bat and insect flight as models for the development of autonomous drones for use in war zones. They already have them but want better ones, don't they always?

"Great albatross! The meanest birds

Spring up and flit away,

While thou must toil to gain a flight,

And spread those pinions gray;

But when they once are fairly poised,

Far o'er each chirping thing

Thour sailest wide to other lands,

E'en sleeping on the wing."

Perserverando by Charles Godfrey Leland