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Unit 24
History of Flight and Bernoulli’s Principal
The pressure exerted by a moving stream of fluid is less than its
surrounding fluid.
Therefore, as the speed of the fluid increases its pressure decreases.
Feather and Flaps
They both act to change the angle of air over the wing to
control lift
There are many forces acting on an aircraft.
The thrust must be sufficient to overcome drag to give enough lift to overcome gravity
How Do Birds Do It?
• They have hollow bones to be very light weight and their strongest muscles are their breast muscles to generate thrust.
Use of Lift by Animals• Riding “thermals” condors and hawks can soar for
hours without flapping their wings.
Use of Lift by Animals• Riding “ocean breezes” albatrosses can literally fly for
days between wing flaps just feet above the water.
Use of Lift by Animals• Flying fish use their fins as wings to fly above the
water. This reduces drag, allowing them to go faster and to avoid predators.
• Penguins use their wings to “fly” underwater at high velocity
Variations on the ThemeOther Examples of Bernoulli’s Principal
• Paper airplanes, frisbees, and boomerangs are all examples of using Bernoulli’s Principal to get lift.
Variations on the ThemeOther Examples of Bernoulli’s Principal
• Hydroplanes use lift to reduce the boat’s drag in the water, allowed them to hit speeds in excess of 150 mph
Variations on the ThemeOther Examples of Bernoulli’s Principal
• Hydroplanes use lift to reduce the boat’s drag in the water, allowed them to hit speeds in excess of 150 mph
• However, if they get too far out of the water, it can be bad news.
Hydrofoils
• Hydrofoils use “wings” underwater to create lift, to reduce drag, for high speed ferries.
Variations on the ThemeOther Examples of Bernoulli’s Principal
• The Stealth Fighter and Stealth Bomber are so unstable to fly, that pilots do not actually control them.
• They are controlled almost completely by computers
Variations on Flight Today
The Harrier can rotate its jets downward to take off or land vertically, or can flight like a normal plane
Helicopters push air downward to rise The osprey is half-helicopter half-airplane
History of Flight
1000 BC to Present
1000 BC
• Chinese Invent Kites
15th Century
• Leonardo Da Vinci, using the basic principals of flight, draws and explains various possible aircraft types.
• He never built or attempted to fly them himself.
1670’s
• Giovanni Borelli, a mathematician calculates human muscles are not strong enough for flight.
• Many attempted before and some still try afterwards.
1783
• Jean François Pilâtre de Rozier and Marquis d'Arlandes make first successful flight in hot air balloon in France.
• They used the concept of bouyancy of gases and density changes with temperature.
1797
• André Jacques Garnerin is first to successfully descend to the ground on a parachute.
1852
• Henri Giffard makes first steam powered airship that can be propelled and controlled.
1891
• Otto Lilienthal starts flying first successful gliders
1902
• Orville and Wilbur Wright begin flying gliders in preparation for their powered flight attempts.
1903• The Wright Brothers make first successful
powered flights at Kittyhawk, NC• First flight only lasted 12 seconds and went
120 feet. The longest was 893 feet.
So Much More Has Occurred Since
• It took many years before flying was common.• In doing your assignment, look up advances in
flight technology that occurred after the Wright Brothers.