Centrifugal Force

 Web www.tpub.com

Home

Information Categories
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion

CHAPTER TWO
T-34C CONTACT
If the airplane's speed is too slow, the angle of attack required will be so large that the air can no
longer follow the upper curvature of the wing. This results in a swirling, turbulent flow of air
over the wing and "spoils" the lift. Consequently, the wing stalls. On most types of airplanes,
this critical angle of attack is about 15 to 20 degrees.
When the propeller rotates, it provides the force to pull the airplane forward. This forward
motion causes the airplane to act on the air to produce lift. The propeller blades, just like a wing,
are curved on one side and straight on the other side. Hence, as the engine rotates the
forces similar to those of the wing create "lift" in a forward direction. This is called thrust.
Up to this point, the discussion has related only to the "lifting" force. Before an understanding of
how an airplane flies is complete, other forces must be discussed.
2.
GRAVITY. While the airplane is propelled through the air and sufficient lift is developed
to sustain it in flight, there are certain other forces acting at the same time. Every particle of
matter, including airplanes, is attracted downward towards the center of the earth by gravitational
force. The amount of this force on the airplane is measured in terms of weight. If the airplane is
to keep flying, lift must overcome its weight or gravitational force.
3.
DRAG. Another force that constantly acts on the airplane is drag. Drag is the resistance
created by air particles striking and flowing around the airplane when it is moving through the
air. Aircraft designers constantly try to streamline wings, fuselages and other components to
reduce the rearward force of drag as much as possible. The portion of drag caused by form
resistance and skin friction is termed parasite drag, since it is not the result of the production of
lift.
A second part of the total drag force is caused by the wing's lift. As the wing deflects air to
produce lift, the total lift force is not exactly vertical, but is tilted slightly rearward. This means
that it causes some rearward drag force. This drag is called induced drag, and is the price paid to
produce lift. The larger the angle of attack, the more the lift force on the wing tilts towards the
rear and the larger the induced drag becomes. To give the airplane forward motion, thrust must
overcome drag.
In a steady flight condition (no change in speed or flight path), forces that oppose each other are
also equal to each other and are always present. That is, lift equals weight, and thrust equals
drag.
202.
CENTRIFUGAL FORCE
Still yet another force that frequently acts on the airplane is centrifugal force. However, this
force occurs only when the airplane is turning or changing the direction (horizontally or
vertically) of the flight path. Another of Newton's laws of energy states that "a body at rest
tends to remain at rest, and a body in motion tends to remain moving at the same speed and in
the same direction . . . " Thus, to make an airplane turn from straight flight, a sideward inward
force must act upon it. The tendency of the airplane to keep moving in a straight line and
outward from a turn is the result of inertia and it produces centrifugal force. Therefore, some
2-2 INTRODUCTION TO T-34C AERODYNAMICS

 Integrated Publishing, Inc.