OK, you were asking about turns. The way you turn a plane is by putting it into a bank. With the ailerons, by monentarily turning the yoke left, and then re-centering it. Suppose you bank it 30 degrees to the left. That tilts your lift vector, so that half of it is accelerating you to the left, and. To keep gravity from winning, you apply back pressure on the yoke, creating more lift. A turn has much in common with a climb, unless you want to descend at the same time.
You also need to give it some more power, to maintain speed through the turn. Here's a degree bank: where you have to pull 2Gs of lift in order to maintain constant altitude, and add quite a bit of power. That's a pretty stressful maneuver, and you can't do it at slow speed because if you pull that hard it will stall.
That shows you the similarity between a turn and a climb. You were asking why doesn't the plane just accelerate sideways rather than turn? If it did, then pretty soon it would be feeling this sideways wind on it. Every airplane is a weather-vane.
It turns into the wind it feels. So, roundabout, that's the answer to your question. This creates a spanwise difference in the lift distribution.
In order to maintain level flight, the pitch angle must be increased; this also changes the thrust vector. In order to maintain unaccelerated flight specifically to not lose speed , thrust must be increased as drag increases with increasing pitch angle.
The differential lift distribution on the wing tips also creates a differential drag distribution; for most conventional airplane configurations, this comes in the form of adverse yaw i.
This is countered by application of balanced rudder force. Summary: in an unaccelerated level turn, the side force on the vertical tail due to rudder deflection keeps the nose tangential to the circle, while the horizontal component of lift due to bank angle provides the centripetal force. Emilio is correct that engine torque gyroscopic coupling can be an issue; it is typically negligible at low rotation rates.
EDIT not enough rep yet to comment on other's answers : yes, the lift vector 'naturally' stays normal to the velocity vector by definition ; it's the component of the aerodynamic force that is normal to velocity, while the component parallel to velocity is labeled 'drag'.
For the block-on-ice portion: you describe: any thruster that applies force along a line that passes through the center of mass will not cause the object to rotate.
You can add a horizontal component of acceleration, as you suggested, but the block won't spin and you won't be able to get it to move in a circle with just that thruster.
I like this question, and I find the link to be of great utility, but I'll still go over several issues I have with its explanation. First, we need to establish the completely plausible situation of a balanced plane operating normally, then being slanted to the left or right, and the fact that it will shimmy in that respective direction and downward.
This requires only a first-level force diagram. The gravity vector is the same magnitude but rotated relative to the plane and the aerodynamic forces are unchanged relative to the plane.
There are several mentions of force moments in the link, but I Consider that normally the wings exert a lift force upward relative to the aircraft and the horizontal tail exerts a lift force downward.
If we assume that we do not change the air velocity relative to the aircraft then changing the gravity vector at CM has no ability to create a net force moment in any direction. Both lift and gravity act at the CM, and one has to move for us to obtain a moment like they do in buoyancy problems.
In the simplistic view of a point force balance, steering the plane is not possible at all. The link presents an attempt to resolve this conflict.
I disagree with this. Consider the fundamental perception of movement - velocity with no acceleration or reference frame is not perceptible. The pilot would have to literally look at the altimeter and pull the yoke in order to compensate. It is much more perceptible that you start pointing toward the ground as opposed to moving toward the ground.
Again, if you're losing altitude, you might notice eventually, but seeing the horizon move creates For instance, when an airplane is banked and moves sideways through the air as in the parallel move discussed above , the relative wind will hit the airplane from the side it is banked towards.
The pilot will then pull the yoke back possibly imperceptibly to compensate for the horizon's movement. This is my preferred explanation, and I should disclaim that I have very little experience directly with flying planes and my writing is strictly academic physics oriented.
With my current hypothesis, we have one major prediction to note:. It is interesting to consider applying this to experience. How fast does does the turn start once the aircraft is oriented in the banked position?
Does turning inherently result in a loss of altitude? My explanation predicts "slow" and "yes". Unless you had counter-rotating dual or more, even number engines, this adds an asymmetrical component. It becomes easier to turn left or right, depending on the direction of spin. I know WWII era dogfighters were acutely aware of this fact in many situations.
When a plane banks the wing up-and-back lift force becomes partly sideways. When level average force of the 2 wings goes through the centre of gravity. When it banks the force is in front of the centre of gravity and induces a moment of force which turns the aircraft. The more the bank the more the force moves forward and more the torque. It's a 3D problem that is diff to imagine. To further complicate matters the outer wing has to move faster and experiences more drag which can prevent the turn and the plane will turn and dive the other way!
I think there is another flap to correct for that if required. If the aircraft has a non-zero moment of inertia about the yaw and pitch axes, then a yaw torque and a pitch torque will be required to intiate the turn. Even once a steady-state turn is established, the tail surfaces will typically need to be positioned differently, and will need to create different forces, than they did in wings-level flight at the same angle-of-attack. An effect called "aerodynamic damping" exists which causes the rotation rates about all axes to tend to trend toward zero.
This effect is related to the fact in a turn, different molecules of the aircraft are moving in different directions through the airmass at any instant in time, since the yaw and pitch rotation rates are not zero. The other component is an unopposed side force which is in the direction of the roll, and perpendicular to the flight path. As long as the aircraft is banked, the side force is a constant, unopposed force on the aircraft. The resulting motion of the center of gravity of the aircraft is a circular arc.
When the wings are brought level by an opposing motion of the ailerons, the side force is eliminated and the aircraft continues to fly in a straight line along a new heading. Notice that the rudder is not used to turn the aircraft. With the rudder pointing in the right direction, airplanes can turn on runways, even if they are being taxied. When researching some of the different types of washers used in the aerospace industry, you may We use cookies to improve your experience. By your continued use of this site you accept such use.
For more information, please see our privacy policy. Monroe is committed to customer satisfaction, we strive for Continuous Improvement in our products and our people. Read More. Call Us: Skip to content. The Basics of Turning There are many different types of turns pilots can make. How Airplanes Turn on Runways Airplanes turn on runways using a similar method that allows them to turn in the air. More Popular Posts. November 14, Products.
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