Physical (aircraft) changes during take off
06-22-2010, 06:48 AM
#11
Line Holder
Joined APC: Mar 2010
Posts: 26
Vertical climbs use no lift
Originally Posted by snippercr
When I am really trying to make sure my students fully understand this fact I show a video of an F-16 in a vertical climb. I ask them what is the angel of attack of this jet vs us when we are cruising out to the practice area? If they say "The same" I go onto the next lesson. If they say "MUCH greater" than I know I have a little more work to do.
When you're cruising in our trainer, the lift is not zero, and therefore neither is the angle of attack.
Regards,
Bashibazouk
08-04-2010, 06:04 AM
#12
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Joined APC: Jun 2010
Position: "left seat" engineer
Posts: 26
Originally Posted by Bashibazouk
In a vertical climb, the F-16's wing is producing zero lift. The angle of attack is therefore zero (if measured with respect to the Zero Lift Line. If measured w.r.t. to the chord line, it's negative.)
Regards,
Bashibazouk
Regards,
Bashibazouk
The wing would surely still be producing a force though right??
08-04-2010, 06:51 AM
#13
Flying Farmer
Joined APC: Jul 2006
Position: Turbo-props' and John Deere's
Posts: 3,160
Originally Posted by plane4
The wing would surely still be producing a force though right??
Now in the real world, there would be slight control inputs to keep the plane vertical, so yes there would be small forces applied, but not in the normal sense of a plane flying along the horizontal path.
It's just theory, so it can all be taken for what it's worth.
08-04-2010, 03:26 PM
#16
Gets Weekends Off
Joined APC: Jun 2008
Posts: 193
Originally Posted by tigris72
Not sure if this is the right section but thought I would try as I can't find an answer anywhere else.
I am a teacher, not a pilot but was wondering if anyone had the technical knowledge of aircraft to answer a question I have.
In my lessons we are learning about the property of flight and have covered the science behind how an airline takes off with airflow etc over the wings. However, we have become stuck on what actually changes on the aircraft when a plane reaches a speed where the plane is rotated. We have visited our city's domestic and international ariport which has excellent viewing areas and watched planes land and take off and we were unable to notice anything that changes at rotation. We are specifically talking Boeing / Airbus planes ie A320, 737, 767 etc.
Firstly, does a pilot pull back the yoke or side stick and if so what does this actually do to change the angle of attack on the wings and make the aircraft airborne?
Thank you for any comments that will help my classroom.
I am a teacher, not a pilot but was wondering if anyone had the technical knowledge of aircraft to answer a question I have.
In my lessons we are learning about the property of flight and have covered the science behind how an airline takes off with airflow etc over the wings. However, we have become stuck on what actually changes on the aircraft when a plane reaches a speed where the plane is rotated. We have visited our city's domestic and international ariport which has excellent viewing areas and watched planes land and take off and we were unable to notice anything that changes at rotation. We are specifically talking Boeing / Airbus planes ie A320, 737, 767 etc.
Firstly, does a pilot pull back the yoke or side stick and if so what does this actually do to change the angle of attack on the wings and make the aircraft airborne?
Thank you for any comments that will help my classroom.
This is easier to see on large multi engine aircraft then small ones. A B-52 comes to mind. It looks different and sharper in the air because the wings are not drooping down in flight. The long fuselage even straightens out some, but not enough to see from the ground.
This is in laymen’s terms, cause I am not a rocket scientist.
08-05-2010, 08:28 AM
#17
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Joined APC: Jun 2010
Position: "left seat" engineer
Posts: 26
Originally Posted by Ewfflyer
In this very specific case, no, not until it is deflected against another force. As long as the plane is perfectly vertical, it is the engine doing the work.
Now in the real world, there would be slight control inputs to keep the plane vertical, so yes there would be small forces applied, but not in the normal sense of a plane flying along the horizontal path.
It's just theory, so it can all be taken for what it's worth.
Now in the real world, there would be slight control inputs to keep the plane vertical, so yes there would be small forces applied, but not in the normal sense of a plane flying along the horizontal path.
It's just theory, so it can all be taken for what it's worth.
Originally Posted by jcaplins
even more specific, the wings of an f-16 climbing straight up would not be producing vertical lift, but they would be producing lift in the horizontal direction.
08-05-2010, 08:31 PM
#18
Gets Weekends Off
Joined APC: Jun 2009
Posts: 317
Originally Posted by plane4
The wing is still producing a force just not a "lifting" or vertical force.
Lift, from the definitions I've seen, is the force perpendicular to the relative wind. In the scenario being discussed the oncoming flow of the outside air relative to the airplane (relative wind) is straight down because the flight path is straight up. Lift perpendicular to that flow would be parallel to the ground. In other words, the 'horizontal' force Ewfflyer speaks of is lift.
08-07-2010, 11:02 AM
#20
Gets Weekends Off
Joined APC: Jun 2009
Posts: 317
Originally Posted by EasternATC
If the F-16 wing can be configured symmetrically, and I don't know whether or not it can, then pure vertical flight would produce no aerodynamic force.
I still haven't quite figured out why all the little nit pick over vertical flight and lift. Anyways, if anyone here wants to learn about an airfoils zero lift AOA, then look up Absolute AOA. It is what matters in this demonstration. Flying perfectly vertical can only be achieved if the pilot flies at precisely the absolute (zero lift) AOA. Which can be done at any flight attitude, look at the NASA zero G (zero lift) training aircraft for an example.
Not sure this reply was intended for me, but just in case: I never claimed that perfect vertical flight would or wouldn't produce lift. We already agree, flown perfectly, no lift is produced. However, to claim that the wings will no longer develop a lifting force and instead calling it is a horizontal (or some other pilot made up name) force. That is pure BS.
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