In 2006 the United States
military retired the F-14 Tomcat (of Tom Cruise’s Top Gun fame). The uniqueness of
this plane was that the shape of the wing could change during flight.
The Tomcat was inspired by the studies of the wings of birds, and never
did even approach what swifts (a bird) are able to do. Swifts belong to
a family of birds called Apodidae
which literally means “without feet” in Latin. The swift does have very
small feet, but they are seldom used because feeding, courting, and
sleeping all take place in the air.
The secret to the swift’s abilities lie in the design of its wing. The
swift has forelimb bones that are similar to the bones in a human
forearm. That section of the swift’s wing allows the flapping to get
airborne that we see in virtually all birds. The swift also has
wing-tip bones where we have a hand, and the angle between the hand and
the forearm can be changed. By rotating the wing-tip bones the swift
can vary its wing area by some 30 percent to increase its speed. It can
reduce its wing area and reduce its energy usage by increasing that
In the swept back mode, swifts can travel at some 60 miles per hour.
Scientists at Wageningen University in the Netherlands have determined
that the most efficient flying speeds for the swifts, where least
energy is used and drag and wing lift are in the best balance, is when
the bird is flying at 20 miles per hour. Studies of the swifts have
shown that they actually sleep while flying, and radar has shown that
when they are in the sleep mode their air speed is 20 miles per hour.
Swifts got their name from their ability to travel at high speeds, make
fast turns, and stay in the air for long periods of time. Human
attempts at swept back wings and varying wing angles have not been too
successful as yet. Natural History magazine comments “Human attempts at
variable wing geometry have always been hampered by the complexity and
weight associated with a system engineered from hinges.” The swift has
already had all of this complexity and engineering done for it, and
that makes it another amazing example of God’s design in nature. Truly
we can know there is a God through the things He has made (Romans 1:20).
Source: Natural History,
March 2008, page 42.
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Does God Exist?, SepOct09.