# Tag Info

## Hot answers tagged roll

23

It's so easy to sit in our comfy lounge chairs and wonder how on Earth pilots get things wrong. The error didn't happen without context. It was dark. There was little to no external visual reference due to cloud. The pilots were manually flying in a busy phase of flight. And the captain was probably adversely influenced by a medication/opioid. Even ...

21

In the aerobatic community we would call that the beginning of an Aileron Roll. It's harder than it looks.

19

This answer is specifically for a fixed-wing airplane, not a helicopter or multicopter, although some aspects of it will apply to them too. What is a turn? A turn is a curvature in the flight path. This means a turn is a form of acceleration. Specifically, a centripetal acceleration-- the flight path is being continually "bent" toward the center of the ...

19

What you want is the roll constant $\text{T}_R$. This is basically one of the characteristics wich determines the equations of motion of an aircraft. It gives the slope of the roll speed increase over time with full aileron deflection and an ideally stiff wing, and equally the rate of decrease once the ailerons are set to neutral during a rolling maneuver. ...

18

The key thing missing in your interpretation is that the order is important. Applying the same roll, pitch and yaw angles in a different order will result in a different orientation (mathematically this is because rotation matrices do not commute). The correct order is: Yaw (for an airplane this is typically called the heading) Pitch Roll For any given ...

16

You do a roll change maneuver. In German it is a "Rollwechsel", and the time it takes to do this from -45° bank to 45° bank is an important measure for the agility of a glider. The maneuver is meant to teach you how to quickly change the direction of circling, and for most gliders it limits the minimum size of their vertical tail surface. The European ...

14

For a proper discussion, we should first define what a pendulum is. Only then can be established if such an effect can exist in airplanes. Let's base the definition on Wikipedia. It says that A pendulum is a weight suspended from a pivot so that it can swing freely. Maybe it is also worth to look closer what a pivot is: A thing on which something turns. ...

13

Roll, pitch and yaw are referred to in one word as the attitude.

13

What you're talking about is called "knife edge" flight, where all of the lift is coming from the sideways fuselage, making it a lifting body aircraft with big fins (the wings) sticking up and down that aren't doing anything (rolling sideways during a ballistic arc doesn't count). The rudder is doing the job of the elevator, and the elevator is doing the ...

11

Your question is an essence a question about aerodynamic damping in the roll axis. As the aircraft rolls, the rolling motion increases the angle-of-attack of the descending wing and decreases the angle-of-attack of the rising wing, eventually causing the lift created by each wing to be equal despite the deflected ailerons. At this point roll torque is zero ...

10

Just adding few more points to already existing answers. I agree with previous commenters - some understanding of pilot perception and context is needed. @Claudix, the image used in your original question can be misleading for 2 reasons: 1) Both instruments are tilted to the right side on your original image. This is, however, not how pilots would see the ...

10

Yes, that will work. If the entire wing tip pivots, it simply acts as an aileron that takes up the entire chord of the wing. Other alternatives to ailerons include: Weight shifting. If you can shift the aircraft's center of mass left and right a significant amount, thus will cause the aircraft to roll in the same direction. This is how hang gliders turn. ...

9

What are the exact meanings of roll, pitch and yaw? It depends somewhat on whether you are speaking from a pilot's point of view or from an engineer's point of view. Your reference to yaw, pitch, and roll ANGLES is indicates you are looking at the situation from an engineering point of view. A pilot would tend to think more in terms of yaw, pitch, and ...

9

Think about the airplane as a body you want to control. That object has 6 degrees of freedom, including rolling. If you remove rolling you will not be able to control airplane's roll. Imagine a situation, when an small mass is over the wing and the airplane starts to roll and you are not able to compensate it. Saying that, the way to control yaw is to use ...

9

In addition to the use in turning, you need to realize that the atmosphere is not static. It's in constant motion, both horizontally and vertically. The vertical currents can be strong enough, and localized enough, to tilt one wing or the other*, thus causing an involuntary roll. If you don't have some means to counteract this induced roll, you now have a ...

9

The ailerons should be connected so that they move opposite each other. When one aileron moves up, the other one must move down, and vice versa. In fact, in full-size aircraft, the ailerons are connected so that it's actually impossible to move them in the same direction*. So, to answer your question, to roll to the right, the right aileron must move up and ...

8

The basic premise has been mentioned by everyone above: the basic instinct is to 'right the wrong', and if we see some indication tilted left, we instinctively want to move it right. It's possible to train for everything, but in stressful or confusing situations instincts will take over, it's just a question when. The reverse ('Russian') indication didn't ...

8

Roll, pitch, and yaw have two different meanings. They can refer to either Euler angles, which describe the attitude (orientation) of an aircraft, or ways that an aircraft can rotate. Euler angles The attitude of an aircraft can be described by three angles: heading, pitch, and bank angle (sometimes called roll angle). The heading $\psi$ (psi, sometimes ...

8

When you turn by yawing you are skidding the airplane to point the nose to the side, to offset the trust vector to move the plane sideways as it's going forward. The rate of turn you can achieve this way is very low and there is a massive drag of being in a skid as you slither around like a car on ice with the fuselage side presented to the airstream. To ...

7

That depends on the coordinate system, and the Wikipedia answer uses the most common convention. Flight mechanics uses a coordinate system with X in flight direction, Y sideways to the right and Z downwards positive. If you now apply the right-hand-rule for the positive direction of rotation around each axis, you will get a positive roll angle around X when ...

7

The pendulum effect is there in high wing a/c in theory but the effect is negligible because the moment arm of the center of mass is so short relative to lateral aerodynamic center. As with dihedral, for the effect to work you have to have sideslip, and the center of mass has to be below the lateral aerodynamic center of the sideslipping fuselage so that a ...

7

(Images from flickr.com and pilotsofamerica.com) Adding to @Ben's answer, another source of confusion when it comes to human factors is even present within Western attitude indicators. Boeing and Airbus aircraft use the style on the left, whereas Garmin (and mechanical gyros in light aircraft) the style on the right. Note the roll angle and its indicator in ...

6

Increasing thrust on the right engine only will make the aircraft yaw and then roll to the left. The thrust does generate a yawing moment to the left, but the secondary effect of yaw is roll. In simplistic terms, a yaw to the left means that the right wing not only momentarily moves through the air faster than the left, but more of the wing is exposed to ...

6

The attitude angles are explained in this wikipedia page, but it seems your confusion stems from the fact that they can present a singularity. Each set of unique Euler angles, outside of the gimbal lock state, represent a unique attitude. In the singularity state, however: The angles α, β and γ are uniquely determined except for the singular case that ...

6

Yes it has differential stabilators. Below is a description from the F/A-18's (A/B/C/D) NATOPS flight manual. Almost every surface including the flaps and leading edge devices are used in rolling the aircraft (fly-by-wire magic): 2.8.2.8 Control Augmentation System (CAS). The lateral control system uses ailerons, differential trailing edge flaps, ...

5

Typical airplane is not stable in roll. The outside wing flies a bit faster, which does indeed make it produce a bit more lift and that in turn will make it bank into the turn, tightening it and if left uncorrected, ending in a spiral dive. In a coordinated turn, an aircraft even can't be made stable in roll. There is no way to create a restoring force ...

5

A constant turn requires a constant centripetal force, i.e. perpendicular to the direction of motion. This force has to be generated aerodynamically (unless rocket engines are used). An aerodynamically generated force is always accompanied by induced drag - even if the force is generated by the fuselage (due to sideslip) instead of a traditional airfoil. ...

4

Pitch, roll and yaw are rotation angles relative to the earth gravitational field. In order to fully describe the state of an unrestrained rigid body in space, there are six Degrees of Freedom required. This site states it as follows: 4.1.2 Degrees of Freedom of a Rigid Body in Space An unrestrained rigid body in space has six degrees of freedom: three ...

4

To answer what you wrote: $c_{n_q}$ is the yawing moment induced by a pitching motion. In a conventional, symmetric configuration this is zero for the airframe and has a small value for propeller aircraft, depending on the rotation direction of the propeller. If the tractor propeller is spinning clockwise (when seen by the pilot), a positive pitch motion $q$ ...

4

Boeing considers 90 degree bank to be an out of control event, and this paper discusses methods to recover. https://www.boeing.com/commercial/aeromagazine/aero_03/textonly/fo01txt.html HIGH BANK ANGLES. A high bank angle is one beyond that necessary for normal flight. Though the bank angle for an upset has been defined as unintentionally more than 45 ...

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