The Little Aircraft

                        Albatross

Albatross are Pacific Ocean seabirds of biological family Diomedeidae and they weigh up to 10kgs. They are highly efficient in flying because of their aerodynamic techniques such as dynamic soaring and slope soaring. They travel from one country to another country during climate change. They travel from southern to northern hemisphere in clockwise direction and in reverse as in anti clockwise direction. They belong to Carnivores clan of species.

They are the largest among the flying birds and the procellaniformes. When discovering the structure of this bird it resembles an aircraft with high aspect ratio wings. These high aspect ratio wings are suitable for long flight distances. Albatross lives in North and South Pacific Ocean.

Discovery of albatross

Albatross has a long, strong and sharp edged bill. The bill is composed of several horny plates and two long tubes called nostrils that give order for its name. Its nostrils allow them to measure the exact air speed in flight which is similar to the Pitot tube in modern aircraft. The Pitot tube senses the atmospheric pressure and calculates the temperature and airspeed in the atmosphere during flight. Modern aircrafts and the albatross need the exact air speed to perform dynamic soaring.

 Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary of air masses of significant different velocities. Such zones of high wind gradient are found near any obstacles and close to the surface. It is mainly used by birds and radio controlled gliders at higher altitudes to gain speed. Albatrosses are particularly adept at exploiting the technique and they use it to travel many thousands of miles using very little energy from flapping.

When the bird pulls up into the wind out of the still air in the lee of a wave, it suddenly becomes exposed to a head wind, so the speed of the air over its wings increases. It then turns in the other direction and, with the wind behind it, dives back into the shelter of a wave. This also results in an increase in its air-speed. So by repeating this "wheeling" pattern, the bird can continue flying almost indefinitely without having to put in much effort besides steering. In effect it is harvesting energy from the wind gradient.

Dynamic soaring involves the birds gaining height by angling their wings while flying into wind. This involves flying from the relatively windless layer close to ocean waves into the region of much wind above it. This gives the birds a boost in airspeed that allows them to soar 30 to 50 feet in the air. Then they turn gliding with the wind to get an additional speed boost while swooping downward close to the sea waves. By repeatedly using this method the wandering albatross can travel thousands of miles without flapping its winds.

The wing structure of albatrosses resembles of high aspect ratio wings of an aircraft. They are stiff, cambered with thickened streamlined leading edges. With this capabilities they can travel up to 6000 kms in an average speed of 67km/hr. The maximum distance covered by the albatross is about 10000 kms. The maneuver allows the bird to cover 1000km/per day without flapping its wings once. Northern pacific albatross uses a flight style known as flap gliding, where the bird progresses by bursts of flapping followed by gliding. When taking off albatross need to take a run up to allow enough air to move under the wing to provide lift.

Slope soaring is another technique used by albatross in the rising air on the wind ward direction of the large waves. This technique is mainly employed in hilly regions.

The strong wind which blows facing the hill or cliff creates a lift for the birds and gliders. By using this method albatrosses remain in flight for a long period of time. These birds have high glide ratios around 22:1 to 23:1. This means for every meter they drop they can travel 22 meters.

They do not get tired easily because they have the ability to sleep at flight and their heart rate is same while flying and resting. They are aided in soaring by a shoulder lock, a sheet of tendon that locks the wings when fully extended, allowing the wing to be kept outstretched without any muscle expenditure.

They are been researched by scientists in the areas of unmanned aerial vehicles and they might be an inspiration for long range aircraft's with high aspect ratio wings, which will discussed in future in my blog.