Monday, May 14, 2012

Do Aircraft Plane - Yes

Newton's Laws; Bernoulli Effect or Both? Air is a gas made up of atoms linked together to form molecules of the different components of air. Atoms have mass, even though we can't see them with the naked eye.

For comparison think of a pair of skis planing over the surface of packed snow; a water board planing over the surface of a lake. Now you get the idea for a airplane!

Yes, airplanes do plane through the air and both Newton's Third Law and the  Bernoulli's  Effect are operating to produce the concept of Lift together. In special cases only Newton;s Law is responsible for the force that pushes a aircraft upward into the sky.

Wow. It isn't that difficult.  First, Newton's Laws are all about Force. Bernoulli's Principle is about creating a Negative Pressure area that allows nature to do its thing - namely to reduce that Negative Pressure. Remember, nature hates a vacuum. It has nothing to do with Force.

Lets talk Newton: His 3rd Law states that for every action there is a equal and opposite reaction. Think of "action" as a "force", like a pressure of air molecules measured in pounds per square inch. As the airplane skims across the air it pushes the mass of air molecules downward with a force that reacts upward on the bottom surface of the airplanes wings. If the sum total of all the reacting forces on the wings reaches or exceeds the weight of the airplane, in pounds, the airplane is flying.

Lets talk Bernoulli: His effect states that air flows, in this instance, faster on the upper surface of the wing than it does on the bottom surface of the wing and it creates a "negative pressure" region on the upper surface of the wings. It would seem the airplane is "sucked up" into the air. One additional example is a chimney  from a home. air passing over the top of the chimney creates a low pressure (or negative pressure) area above the opening of the chimney. The air pressure of the atmosphere is higher than the pressure just above the chimney. Net result pushes air(which is smoke)  up the chimney. We make use of pressure differentials when breathing. Beware, this is a very simplistic example and the mathematics is too complicated for this Blog.

Lets talk Newton and Bernoulli together: What Bernoulli accomplishes is making it possible for a airplane to move slower at a slightly increased "angle of attack" to create a reaction force to push the airplane into the air. Example, a small private airplane will takeoff and land at slower velocities that a similar more aerodynamically designed airplane. Another example is a interceptor jet airplane that performs best by reducing the overall drag on the airplane by using symmetrical wings. There isn't a "camber" that produces the Bernoulli Effect. Without that help the jet airplane must move much faster to achieve the upward force that equals its weight in pounds before becoming airborne. Lift, thrust, weight and drag are all involved in the design of a airplane and its ultimate purpose.

Lift is not just Bernoulli Effect alone or, except as noted, just as Newton's 3rd Law can't operate in lowered power airplanes without the Bernoulli Effect.