Model Aircraft

One of the biggest living birds is the albatross with a wingspan up to 3.5m, living for up to 60 years, and able to fly 25,000kms in 46 days. The latest edition of Journal of Experimental Biology has an article by G Sachs and J Traugott of Munich with evidence that they fly such vast distances by adopting unusual cycles of flight.
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Instead of flapping their wings the birds  generate lift by turning into the wind and accelerating to a good height. Then they turn so the wind is behind them and they slowly glide downwards. The cycle is then repeated.
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 GPS tracker devices were fitted to 20 birds at the Kerguelen Island in the south Indian Ocean. Results confirmed they fly like a fixed-wing aircraft, lifting because air travels quickest over the top of the wing, away from friction with any surface. 
Samuel Taylor Coleridge’s Rime of the Ancient Mariner said very little about the physics of flight and much about the superstitions and fears of human travel at sea. 
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On their long voyage of the south seas, one of the sailors killed an albatross that brought bad luck, first through becoming becalmed:
Day after day, day after day,
We stuck, nor breath nor motion;
As idle as a painted ship
Upon a painted ocean.
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(Engravings by Gustave Doré)

and then through the torment of thirst.

Water, water, every where,

And all the boards did shrink;

Water, water, every where,

Nor any drop to drink.

In anger, the crew forced the Mariner to wear the dead albatross round his neck, to illustrate the burden he must suffer from killing it, or as a sign of regret:

Ah! Well a-day! What evil looks

Had I from old and young!

Instead of the cross, the albatross

About my neck was hung.

One comment on “Model Aircraft

  1. Jacob Krynauw says:

    We do the same type of flying in paragliding. (gliding using thermals or the updraft from a steep hill or mountain, not killing albatrosses) :). To fly cross country we would gain height from the updraft or rising thermal then fly downwind faster than the wind speed. The glide ratio depends on a number of factors but essentially the paraglider wing is an airfoil, the same shape as a bird or aircraft wing and although the pilot drags down on the paraglider wing the glide is extended. When we hit another thermal or get too low we will repeat the process of gaining height and then gliding. (the paragliding world record is 502 km, set in South Africa).

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