Gliding flight: speed and acceleration of ideal falcons during diving and pull out

Some falcons, such as peregrines (Falco peregrinus), attack their prey in the air at the end of high-speed dives and are thought to be the fastest of animals. Estimates of their top speed in a dive range up to 157 m s-1, although speeds this high have never been accurately measured. This study investigates the aerodynamic and gravitational forces on 'ideal falcons' and uses a mathematical model to calculate speed and acceleration during diving. Ideal falcons have body masses of 0.5-2.0 kg and morphological and aerodynamic properties based on those measured for real falcons. The top speeds reached during a dive depend on the mass of the bird and the angle and duration of the dive. Given enough time, ideal falcons can reach top speeds of 89-112 m s-1 in a vertical dive, the higher speed for the heaviest bird, when the parasite drag coefficient has a value of 0.18. This value was measured for low-speed flight, and it could plausibly decline to 0.07 at high speeds. Top speeds then would be 138-174 m s-1. An ideal falcon diving at angles between 15 and 90 degrees with a mass of 1 kg reaches 95 % of top speed after travelling approximately 1200 m. The time and altitude loss to reach 95 % of top speed range from 38 s and 322 m at 15 degrees to 16 s and 1140 m at 90 degrees, respectively. During pull out at top speed from a vertical dive, the 1 kg ideal falcon can generate a lift force 18 times its own weight by reducing its wing span, compared with a lift force of 1.7 times its weight at full wing span. The falcon loses 60 m of altitude while pulling out of the dive, and lift and loss of altitude both decrease as the angle of the dive decreases. The 1 kg falcon can slow down in a dive by increasing its parasite drag and the angle of attack of its wings. Both lift and drag increase with angle of attack, but the falcon can cancel the increased lift by holding its wings in a cupped position so that part of the lift is directed laterally. The increased drag of wings producing maximum lift is great enough to decelerate the falcon at -1.5 times the acceleration of gravity at a dive angle of 45 degrees and a speed of 41 m s-1 (0.5 times top speed). Real falcons can control their speeds in a dive by changing their drag and by choosing the length of the dive. They would encounter both advantages and disadvantages by diving at the top speeds of ideal falcons, and whether they achieve those speeds remains to be investigated.

Species

The sequence follows the taxonomic order of White et al. (1996), except for adjustments in the kestrel sequence.

1. 
   

• Madagascar Kestrel, Falco newtoni
• Seychelles Kestrel, Falco araea
• Mauritius Kestrel, Falco punctatus
• Réunion Kestrel, Falco duboisi - extinct (c.1700)
• Spotted Kestrel, Falco moluccensis
• Nankeen Kestrel or Australian Kestrel, Falco cenchroides
• Common Kestrel, Falco tinnunculus
  • Rock Kestrel, Falco (tinnunculus) rupicolus
• Greater Kestrel, Falco rupicoloides
• Fox Kestrel, Falco alopex
• Lesser Kestrel, Falco naumanni
• Grey Kestrel, Falco ardosiaceus
• Dickinson's Kestrel, Falco dickinsoni
• Banded Kestrel, Falco zoniventris
• Red-necked Falcon, Falco chicquera

Speed And Types !!

Ferocious Speed



Peregrine Falcons have been recorded diving at speeds of 200 miles per hour (320 km/h), making them the fastest-moving creatures on Earth. Other falcons include the Gyrfalcon, Lanner Falcon, and the Merlin. Some small falcons with long narrow wings are called hobbies, and some which hover while hunting are called kestrels. The falcons are part of the family Falconidae, which also includes the caracaras, Laughing Falcon, forest falcons, and falconets.
The traditional term for a male falcon is tercel (British spelling) or tiercel (American spelling), from Latin tertius = third because of the belief that only one in three eggs hatched a male bird Some sources give the etymology as deriving from the fact that a male falcon is approximately one third smaller than the female^[4] (Old French tiercelet).
A falcon chick, especially one reared for falconry, that is still in its downy stage is known as an eyas ^[5][6] (sometimes spelt eyass). The word arose by mistaken division of Old French un niais, from Latin presumed nidiscus ("nestling", from nidus = nest). The technique of hunting with trained captive birds of prey is known as falconry.

A Falcon !

A Falcon is any species of raptor in the genus Falco. The genus contains 37 species, widely distributed throughout Europe, Asia, and North America.

Adult falcons have thin tapered wings, which enable them to fly at high speed and to change direction rapidly. Fledgling falcons, in their first year of flying, have longer flight feathers which makes their configuration more like that of a general-purpose bird such as a broadwing. This makes it easier to fly while learning the exceptional skills required to be effective hunters as adults.