23 votes
Accepted

Why do flying wires hum louder in a sideslip?

Here is one reason. It once was common for suspension wires to be flattened rather than circular in cross-section, to reduce drag. those wires were then aligned with the airflow past the wing and ...
18 votes
Accepted

Is it dangerous to do a skidding turn to lose altitude without increasing airspeed?

As Ron Beyer pointed out in a comment, your instructor was showing you a forward slip - a pretty standard maneuver for light aircraft. A spin would involve full rudder and a stalled wing, which ...
15 votes
Accepted

Does slipping in turns allow higher climb rates?

Source: Wikipedia. Origin of the theory Klaus Holighaus, one of the famous glider pilots of the 70s, and himself a glider designer at Schempp-Hirth, is at the origin of a controversy when he ...
  • 68.3k
11 votes
Accepted

Why does a T-tail produce a pitch-down moment in sideslip?

I've found some useful research here: E.C. Polhamus. Some factors affecting the variation of pitching moment with sideslip of aircraft configurations. Technical report, NACA T.N. 4016, 1958. The ...
  • 6,221
9 votes

Why does elevator input move the turn coordinator ball in steep turns?

In a steep turn you are making power changes, pitch changes and also making constant corrections with aileron to hold the bank angle, without even realizing it. Once established in the turn some ...
  • 112k
9 votes
Accepted

Why does a turn and slip indicator matter?

The turn and slip instruments are combined for convenience and by convention more than anything else, slip is important whether you are in a turn or not. When you slip it means one wing is more ...
  • 50.9k
8 votes
Accepted

How is a sideslip maintained (aerodynamically)?

(Source) Here's a representative image of the variation in lift coefficient with respect to angle of attack. The same airfoil is considered in a "clean" configuration, with a deflected flap, and ...
  • 3,631
8 votes

Why should one not slip a Cessna 172 with flaps extended?

The basic problem is that sideslip induces a cross flow over the fuselage that can increase the local negative AOA and flow disruptions beyond that already caused by the turbulence and downwash being ...
  • 112k
7 votes

What causes the ball to not be centered in a slip/skid?

It is the same thing that makes you slide sideways in your seat going around a corner in your car. Or the same thing that would cause you to slide sideways the other way if you were driving straight ...
  • 19.7k
7 votes

Do aircraft pitch down even at very low angles of attack (below 0°) in a strong sideslip?

As John K was alluding, AoA of -10 or -15 are not really practical and do not correspond to a powered dive like you think. Even in a descent or a dive, most aircraft will have positive AoA. You are ...
6 votes
Accepted

How can using split throttles help when landing twins in crosswinds?

The use of asymmetric thrust when landing a twin in a crosswind effectively accomplishes the same thing that rudder input does. It induces a yawing moment about the aircraft’s vertical axis, the same ...
6 votes

Is it dangerous to do a skidding turn to lose altitude without increasing airspeed?

I just want to go back to the OP's concern that rudder one way and aileron the other way is related to a spin - it's my understanding that this is a cross-controlled situation, and that is something ...
5 votes

How does sideslip indicator react during crosswind?

1. Answer to original OP In a stable airmass, the amount of sideslip/skid indication is irrespective of the wind strength and orientation; it is a function of the relative velocity of the airplane ...
  • 10.8k
5 votes
Accepted

What does the balance ball actually indicate?

1. Preamble The ball reacts to the body force (or acceleration), with the exact same working principle as a bubble level. In airplane frame, the force is expressed as: $$Y+mg\cos{\theta}\sin{\phi}=m(...
  • 10.8k
5 votes

Is drift and sideslip angle the same in the accompanied figure?

The answer to the title question is no, sideslip angle and drift angle are not the same thing. (in this figure, or any other...) What the diagram shows is drift angle, and drift angle only. If you ...
  • 19.7k
4 votes

What is the relationship between the UH60 Blackhawk stabilator function lateral sideslip and pitch coupling?

The sideslip to pitch coupling is a result of the canted tail rotor and the asymmetry of the main rotor downwash. The tail rotor thrust pushes the tail to the right and upward (pitch down). The main ...
  • 18.2k
4 votes

What is the direction of the sideslip induced by roll on a conventional aircraft?

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 ...
4 votes

Is it dangerous to do a skidding turn to lose altitude without increasing airspeed?

Slipping an aircraft is mostly perfectly safe. I say mostly because there are exceptions: Some aircraft operator's manuals explicitly forbid slipping. This might be because of the general handling or ...
  • 2,154
4 votes

In which direction will an aircraft drift after taking off in a crosswind?

The DPE is correct, the airplane will drift in the direction of the wind. If you are piloting a boat across a river, and point the bow at the opposite side of the river with the rudder amidships then ...
  • 50.9k
4 votes

Which way (if at all) do the ailerons need to be deflected in a full-rudder sideslip in a Cessna 152 or 172?

Yes. If you apply full rudder with no aileron, you initially just get a flat skid, but then differential lift starts to have an effect and the inside wing drops because that wing has slowed down, the ...
  • 112k
4 votes
Accepted

Finding Angle of Attack/Angle of Sideslip using East/North/Up Coordinates

What you've proposed is a reference frame translation of the aircraft velocity, so instead of the velocity referenced to East, North, and Up (ENU), it's referenced to the direction the aircraft is ...
  • 6,423
4 votes

Why should one not slip a Cessna 172 with flaps extended?

There could be several reasons for such recommendation, but specifically for C172, its POH explains it as follows (section 'Normal Landing'): Steep slips with flap settings greater than 20° can ...
  • 8,755
4 votes

Viable to slip onto the center line?

I’m not totally sure how you’re orienting that, are you talking about aligning the aircraft up on final approach from a base leg, then doing a slip to final alignment on the runway CL for final ...
3 votes

Why does a turn and slip indicator matter?

The "slip" part of the Turn and Slip Indicator (T/S) measures the lateral (transverse) acceleration of the airplane. When the slip indicator is centered, the pilot and passengers will feel gravity ...
  • 10.8k
3 votes

Why does elevator input move the turn coordinator ball in steep turns?

It is important to realize the "ball" is simply rolling back and forth in a curved glass tube to indicate the direction of net G forces. It is also known as an inclinometer. What is ...
3 votes

Is a high alpha sideslip possible and safe?

You would be risking your life. Cross controlled approaches should only be done well above stall speed and only after testing at a higher altitude. Increasing AOA will slow your plane down. If you ...
3 votes

Is a high alpha sideslip possible and safe?

Let's assume that to first approximation, a given rudder deflection (say, full deflection) creates a given slip angle of the fuselage. So for a given rudder deflection, don't you generate a lot more ...
  • 18.4k
3 votes

In which direction will an aircraft drift after taking off in a crosswind?

You drift downwind unless you turn into it. In a normal crosswind takeoff, say with the wind from the left, at rotation, you have left aileron to keep the left wing from lifting and right rudder to ...
  • 112k
3 votes

How can using split throttles help when landing twins in crosswinds?

In General Aviation light twins, when landing in heavy crosswinds, what are some considerations to using asymmetric (or Split) throttles to induce a sideslip, to align the fuselage with the ground ...
  • 18.4k
3 votes
Accepted

In a non-symmetric turn, how do the side slip angle and thrust side slip angle affect the equations of motion?

Relying on physics, causing a mass to execute a circular path requires a suitable centripetal force. In an airplane in a banked balanced turn, this comes from the inward component of lift due to the ...

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