# Tag Info

46

Yes, otherwise airplanes would be unable to go upwards into the sky.

42

Yes, a wing can (given sufficient forward speed and angle of attack) generate lift greater than the weight of the aircraft. As with any "unbalanced" force, this will result in an acceleration of the airplane in the direction of the lift, according to Newton's Second law. $$\mathbf F=m~\mathbf a$$ Please note, the entities in bold face are vector quantities....

18

Furthermore to @Zeiss' answer, whenever an aircraft is steady-state banked, the lift will be greater than its weight. However, its speed will be constant; instead, the acceleration is centripetal and results in a circular turn. Edit, clarification on pull up maneuver: When an aircraft is pitched up via pitch control, and after the short-period mode settles ...

5

Thankfully, aerodynamics in the usual flight range is linear. Therefore, there is a gradient of lift over angle of attack and another one over the flap deflection angle. Both are constant over a range of maybe ±15° and can be combined. The angle of attack is referenced to the fixed part of the flight surface and the deflection angle to the moving part ...

4

It's the component of the aerodynamic force perpendicular to the direction of the air flow, the aerodynamic force being the reaction of the wing to the relative wind.

4

In straight and level flight at an airspeed V, the weight W is balanced by the lift L, and the aerodynamic drag D is balanced by the thrust T. D is much smaller than L. In a passenger liner, D may be 1/12 ... 1/20 of the weight, or so...

3

The suction peak is the point of lowest pressure on an airfoil, in other words the highest point on a typical pressure or Cp graph of an airfoil. On an airfoil it's typically located just after the leading edge on the upper surface, take a look at this image for instance. In that image you can also see that as you increase the angle of attack of the ...

3

This is quite a flabbergasting question... As you're standing on the floor of your home, Lift equals Weight. The lift is supplied by the floorboards to your feet. That's static lift. If you tilt up a floorboard and pull a toy car across it, it will be lifted upwards and even fly up after the floorboard ends. That's dynamic lift. Note that the required ...

2

A trailing-edge control surface, when it deflects, changes the camber of the overall airfoil. More camber means more lift, in whatever direction that airfoil is mounted. In your example, adding up elevator increases the horizontal stabilizer's camber, which increases the downward force it applies. Philosophically, "why" it does this is just, well, that's ...

2

We want to reduce (or simplify) equation 2, to get get dV/dt by itself, so we multiply both sides by g/W. On the right hand side, this reduces to dV/dt. On the left hand side it reduces to what is given in equation 3, but let me show you how: 1. First term is T x g/W 2. Second term is -D x g/W 3. Third term is -u x g/W (W - L). By the distributive ...

2

A kite is a simple aircraft, generating lift. The vertical component of the pull you feel on the string is any resultant lift greater than the weight of the aircraft, the horizontal component being the drag. In a non-tethered aircraft, excess lift causes the aircraft to "rise", or more precisely, causes the flight path to curve upwards.

1

I interpreted the values as follows: The angle of attack at which the specified propeller airfoil generates zero lift The change in lift coefficient per change in $\alpha$ in radians The same as 2, except that it is this value around the stall angle (it is mostly a safety factor for numerical calculations I think, small but non-zero) Maximum $C_l$, which is ...

1

The accompanying text clearly describes an application of the Bernoulli effect. However the resultant backwards airflow shown in the drawing is given no explanation, other than that implied by the fact that the device is drawn forwards. So there is no evidence of the Coanda effect, in which the airstream clings to the device skin, being understood. Would it ...

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