|Search||Hot Links||What's New!|
Please let me remind all of you--this
material is copyrighted. Though partially funded by NASA, it is still a private
site. Therefore, before using our materials in any form, electronic or otherwise, you need
to ask permission.
There are two ways to browse the site: (1) use the search button above to find specific materials using keywords; or,
(2) go to specific headings like history, principles or careers at specific levels above and click on the button.
Teachers may go directly to the Teachers' Guide from the For Teachers button above or site browse as in (1) and (2).
There are four forces acting on an airplane in flight. These are thrust, drag, lift and weight(gravity).
1. THRUST. The force exerted by the engine and its propeller(s), which pushes air backward with the object of causing a reaction, or thrust, of the airplane in the forward direction.
2. DRAG. The resistance of the airplane to forward motion directly opposed to thrust.
3. LIFT. The upward force created by the wings moving through the air, which sustains the airplane in flight.
4. WEIGHT. The downward force due to the weight(gravity) of the airplane and its load, directly opposed to lift.
When thrust and drag are equal and opposite, the airplane is said to be in a state of equilibrium. That is to say, it will continue to move forward at the same uniform speed. (Equilibrium refers to steady motion and not to a state of rest, in this context)
If either of these forces becomes greater than the force opposing it, the state of equilibrium will be lost. If thrust is greater than drag, the airplane will accelerate or gain speed. If drag is greater than thrust, the airplane will decelerate or lose speed and consequently, the airplane will descend.
Similarly, when lift and weight are equal and opposite, the airplane will be in equilibrium. If lift, however, is greater than weight, the airplane will climb. If weight is greater than lift, the airplane will sink.
The material for this section is reproduced from the publication, FROM THE GROUND UP, with the permission of its copyright owner, Aviation Publishers Co. Ltd. No further reproduction is authorized, in any print, electronic or other form of media, without the prior consent of the publisher athttp://www.aviationpublishers.com . Any questions regarding this portion of the website should be directed to Dr. Claudius Carnegie. Questions regarding the publication, FROM THE GROUND UP, should be directed to the publisher at firstname.lastname@example.org.
The format in which the material has been presented for the entire section is copyrighted by the ALLSTAR network.
Send all comments to email@example.com
© 1995-2017 ALLSTAR Network. All rights reserved worldwide.
|Funded in part by||Used with permission from Aviation Publishers|
Updated: May 03, 2008