39

Yes it's called a Deep Stall, and is mostly a problem with T Tail aircraft, especially jets with Supercritical Airfoil wings (like the CRJ Regional Jet line). Such wings stall from the leading edge and the stall's flow separation spreads rapidly and completely across the entire wing all at once, so there is very little residual nose down pitching moment. ...


12

The autopilot pitches to hold the flight level when it captures the level at the top of the climb, so later on as the aircraft gets lighter and wants to climb further, the A/P will lower the nose as required to hold the flight level (the A/P is able to move the elevator through its servo's link to the elevator controls; it can also work the trim if the servo ...


6

What you describe is a tailslide, as another answer has noted -- but there is a condition in which the wing is stalled and the normal recovery method (apply down elevator and wait for the nose to drop and airspeed to build) can't be used. It's called a "deep stall" and is only a problem with certain layouts of flying surfaces. One of the best known is a T-...


4

It depends on general geometry of the aeroplane: The vertical position of the main wing and the horizontal tail. If the aeroplane even has a horizontal tail. The sweep angle. The angle of incidence in the landing flare. When a wing enters ground effect, its lift coefficient rises: the wing creates more lift at a given speed and Angle of Attack. A wing is ...


3

Ground effect makes the airplane more longitudinally stable for two reasons: Ground effect increases the lift curve slope ($\frac{\partial{C_{L_t}}}{\partial{\alpha_t}}$) of the tailplane due to vortex reduction. An increase in tail lift curve slope is equivalent to increasing the effective tail volume. Ground effect decreases the downwash of the wing on ...


3

Yes. Moving CG farther and farther back will eventually cause the plane to be directionally stable falling backwards. Abusing rearward CG limits is contributory to this condition. Secondly, poor design of horizontal stabilizer, particularly, lacking sufficient "weathervaning" area, will cause an aircraft to be more susceptible to the unrecoverable "deep ...


3

As pointed out by HiddenWindshield, the pilot will pitch the nose down slightly as the fuel load is burned off. The pilot does this using the elevator trim control and will from time to time in a long flight add nose-down trim to maintain zero vertical speed. With less load, less lift is required, and trimming away the unnecessary lift will cause the plane's ...


2

There are a lot of things that affect lift beyond just the speed and air density. For instance, the angle of attack. As the weight of the aircraft decreases, the pilot (or autopilot) will pitch the nose down slightly to reduce the AoA, and therefore lift.


1

Strength, ability to withstand the G forces of turning. Secondly, having a stall Angle of Attack as high as possible. A low aspect ratio wing with a very thick airfoil is a good candidate, such as the ones designed by Hugo Junkers and seen on Fokker planes of 100 years ago. These work very well for slow, turning flight. Another candidate would be the ...


1

If a conventionally laid out aircraft is flown into a tail slide, it's unlikely that it could maintain that attitude for long. The tail has low mass relative to the rest of the aircraft and a substantial moment between the tail surfaces and aircraft center of mass. As negative airspeed (falling down tail first) builds, aerodynamic forces on the tail will ...


1

Leading-edge stagnation point moving down with increasing angle of attack is true for inviscid flows, however the same does not always hold for viscous (or more realistic) flows, especially around stall. For a given airfoil, if angle of attack increases, the leading-edge stagnation point could move up or down from the leading-edge depending on the flow state ...


1

Flutter and vortex induced vibrations (VIV) are both dynamic instabilities arising from the interaction of unsteady aerodynamic, inertial and elastic forces. They both extract energy from the air stream to persist. Instead of perceiving the interaction as aerodynamic forces causing structural motion or structural motion generating aerodynamic forces, it is ...


1

Roll is often used as a verb describing rotation around the longitudinal axis of the aircraft (at least with pilots, especially flight instructors). If the aircraft has zero pitch elevation angle, then bank angle could be determined by the amount of roll that occurred from wings level. When at non-zero pitch elevation angle, the rolling movement is used to ...


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