Hey there, fellow pilots. Does any one know why my Cessna 182 Skylane will have a left banking tendency? What confuses me is all of the realism settings that add to the left-turning tendency are all disabled. It is also funny that some days it'll do it and some days it won't. Does anyone else have this problem?
is your realism settings all set to easy? they have left turning tendency because its one propeller, and the propeller is turning in one direction, which causes the "left turning tendency"
Yeah, they are all on easy. But what really bugs me is this problem comes and goes. I think it might be my control setup....
Ofcourse, the tendency to bank is mostly noticable on single engine propellor driver airplanes, and does not exsist on jet aircraft, so that might be the reason why you got the feeling it comes and goes.
The cause of the banking tendency is, apart from the peopellor torque, three other things:
Spiral Stream:the prop generates and it "wraps" itself around the fuselage of the airplane and "hits" the vertical stabilizer from the left side, causing it to move towards the right, and the actual airplane to yaw to the left, making the left wing "heavier"
The "P" Effect: is the effect of the propellor itself, and it is a result of one of the prop blades "grabbing" less air during one half ov the rotation cycle, meaning that side of the prop generates less thrust, and of course, yawing the airplane a little and making the wings drop.
The gyroscopic precession (spelling ): Is the tendency of the prop's gyroscopic behavior to move the force applied to it by 90 degrees into the rotation, meaning that if you pull the nose up with the elevators, you are putting force onto the lower part of the prop, but if it is turning clockwise, the force will be moved in the direction of the rotation, and it will, again, yaw the airplane a little.
A very good fix to this is the yaw damper, which most of the modern airplanes have fitted. It compensates for all theese forces and also keeps all turns well coordinated, regardles of whether you make them or the AP does. That's for real airplanes, in the sim..apart from the payware airplanes I doubt the others have a working yaw-damper, and therefore, I doubt that will help you much. But if you turn on "autorudder" in the realism settings, that should do the trick. If course, with autorudder, you won't be able to do cool side-slips and decrab's on the 747.
Reminder: this is a pilot's lounge, and therefore, don't be surprised when a pilot/instructor decides to explain the whole phenomena/problem/dispute in detail!
I appreciate all of the advice. I have a very good understanding of aerodynamics and am very familiar with the Skylane. My controller is calibrated right.....maybe I should check the weather and wind setting. I do find it kinda tricky that some of you experience this and some of you don't.
The "P" Effect: is the effect of the propellor itself, and it is a result of one of the prop blades "grabbing" less air during one half ov the rotation cycle, meaning that side of the prop generates less thrust, and of course, yawing the airplane a little and making the wings drop.
How does that one happen Max? In a Cessna 172 for example, unless the a/c is in a sideslip or something, when does a blade grab more and less air in one cycle?
I know this happens in a chopper, since the movement of the blade is in the plane of rotation, but here it is perpendicular to the rotation plane. So...?
P Factor (From the FAA)
When an airplane is flying with a high angle of
attack, the “bite” of the downward moving blade is
greater than the “bite” of the upward moving
blade; thus moving the center of thrust to the
right of the prop disc area—causing a yawing
moment toward the left around the vertical axis.
That explanation is correct; however, to prove
this phenomenon, it would be necessary to work
wind vector problems on each blade, which gets
quite involved when considering both the angle
of attack of the airplane and the angle of attack of
each blade.
This asymmetric loading is caused by the resultant
velocity, which is generated by the combination of
the velocity of the propeller blade in its plane of
rotation and the velocity of the air passing horizontally
through the propeller “disc.” With the airplane
being flown at positive angles of attack, the right
(viewed from the rear) or downswinging blade, is
passing through an area of resultant velocity which
is greater than that affecting the left or upswinging
blade. Since the propeller blade is an airfoil,
increased velocity means increased lift. Therefore,
the downswinging blade having more “lift” tends
to pull (yaw) the airplane’s nose to the left.
Simply stated, when the airplane is flying at a high
angle of attack, the downward moving blade has a
higher resultant velocity; therefore creating more lift
than the upward moving blade. [Figure 3-34] This
might be easier to visualize if the propeller shaft was
mounted perpendicular to the ground (like a
helicopter). If there were no air movement at
all, except that generated by the propeller
itself, identical sections of each blade would
have the same airspeed. However, with air moving
horizontally across this vertically mounted
propeller, the blade proceeding forward into the
flow of air will have a higher airspeed than the
blade retreating with the airflow. Thus, the blade
proceeding into the horizontal airflow is creating
more lift, or thrust, moving the center of thrust
toward that blade.
I would think that if all settings were on easy, then the torque, slipstream, and precession forces were eliminated. My PC's down right now, or I would join everyone in a test to see what's up.
Oops! It is exactly like the chopper! I didnt think of that!
Only the angle of the propeller disk is far steeper here than in the case of the helicopter and hence the effect is far less pronounced (smaller transverse component)! You see, I did not think about it in connection with the aircraft's AOA.
When I fly the C172, the ''P'' factor happens when at high angle of attack, and at low airspeed. It feels more like a yaw then a bank. The procedure is to put in right rudder. When you practice chandelles for the commercial pilots licence, at the turn out of a chandelle, the P factor is most very strong.
Ofcourse, the tendency to bank is mostly noticable on single engine propellor driver airplanes, and does not exsist on jet aircraft, so that might be the reason why you got the feeling it comes and goes.
The cause of the banking tendency is, apart from the peopellor torque, three other things:
Spiral Stream:the prop generates and it "wraps" itself around the fuselage of the airplane and "hits" the vertical stabilizer from the left side, causing it to move towards the right, and the actual airplane to yaw to the left, making the left wing "heavier"
The "P" Effect: is the effect of the propellor itself, and it is a result of one of the prop blades "grabbing" less air during one half ov the rotation cycle, meaning that side of the prop generates less thrust, and of course, yawing the airplane a little and making the wings drop.
The gyroscopic precession (spelling ): Is the tendency of the prop's gyroscopic behavior to move the force applied to it by 90 degrees into the rotation, meaning that if you pull the nose up with the elevators, you are putting force onto the lower part of the prop, but if it is turning clockwise, the force will be moved in the direction of the rotation, and it will, again, yaw the airplane a little.
A very good fix to this is the yaw damper, which most of the modern airplanes have fitted. It compensates for all theese forces and also keeps all turns well coordinated, regardles of whether you make them or the AP does. That's for real airplanes, in the sim..apart from the payware airplanes I doubt the others have a working yaw-damper, and therefore, I doubt that will help you much. But if you turn on "autorudder" in the realism settings, that should do the trick. If course, with autorudder, you won't be able to do cool side-slips and decrab's on the 747.
Reminder: this is a pilot's lounge, and therefore, don't be surprised when a pilot/instructor decides to explain the whole phenomena/problem/dispute in detail!
That's what happens when people who don't know what they're saying simply can't stop saying. Why do you have to post something you think you know and of course, then someone else has to write twice as much, two more times because of it.
The answer that I had written earlier, the one I quoted, is 100% correct and reflects what the FAA and JAA textbooks say about this particular topic. I guarantee that the info given here is true and is the way it's done in real aviation.
When I fly the C172, the ''P'' factor happens when at high angle of attack, and at low airspeed. It feels more like a yaw then a bank.
Naturally it is more at high angles of attack. My understanding (primarily from Max's and Tenspace's posts above) is like this.
When the a/c is at zero AOA, the propeller disk is exactly vertical and hence the forward velocity of the upswinging and downswinging blades are the same as that of the a/c. Hence they both "grab" the same amount of air.
However at a high AOA the propeller disk is not vertical but tilted with its top angled towards the tail of the aircraft. Now it is easy to visualize that downswinging blade is moving forward with respect to the upswinging blade and hence it "grabs" more air that the upswinging blade. Naturally the downswinging (right hand side) blade generates more thrust and hence tends to yaw the a/c towards the left. And naturally this effect increases with increasing AOA! In other words the forward velocity of the RHS blade is a/c velocity plus horizontal component of blade's rotational velocity while on the LHS it is a/c velocity minus the horizontal component of its rotational velocity. And this horizontal component increases with increasing AOA.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
):
