# Tag Info

38

In theory they can stop moving relative to someone standing on the ground. In practice this does not occur. Aircraft fly through the air and, yes, below a certain airspeed, an aircraft will stall. Let's take a super-simple example to explain the situation: You are standing on the ground on a very breezy day. It's quite windy on the ground, and blowing ...

24

Unequivocally: no. Big airliners (or passenger planes of any size for that matter) do not hover in air. From a moving car, train or such it is possible to have an illusion that an airplane hovers midair, but someone who was claiming that they were standing still and witnessing an airliner hover in the air, was most probably deceived by one's senses. It ...

6

A plane requires air moving over the wings to generate lift. If there is no air movement, there is no lift, and the plane will fall. Note that this requires that the plane is moving relative to the air, but not necessarily relative to the ground. In theory, you could have a plane pointed into a very strong wind that would have an airspeed sufficient to ...

6

Before I get into the question about the turning fighter jet, a few words about airplanes' being extremely sensitive to gusts during final stages of landing. If this was actually true, I'd be dead by now. Seriously. Airplanes are sensitive to gusts during landing, I'll give you that, but I think it's exaggerating beyond reason to say it is extreme. Now, ...

3

It's a change in wind direction but it's not considered windshear. The change in "wind direction" will be imperceptible to the pilot and passengers other than a change in the plane's groundspeed and even that is only detectable with a groundspeed readout.

2

If a jet airliner "suddenly just paused in mid air for 30 seconds before starting to move again," a hundred passengers would be furiously tweeting about it. We'd also likely have video of coffee sloshing over everything in the cabin and similar unpleasantries, resulting in an FAA Incident Report. The lack of such on-board complaints of sudden braking and ...

2

At cruising altitude and airspeed, a change in wind is almost a non-issue. Wind velocity (direction and speed) changing will not noticeably affect airspeed. It will, however, affect groundspeed. Windshear (a sudden and/or drastic change of wind velocity) will affect airspeed momentarily until the plane’s momentum is overcome by the aerodynamic forces acting ...

2

First we can use the definitions of w, u, alpha, and beta to define $$\frac{w}{u} = \tan\alpha$$ $$u = Vcos(\alpha)cos(\beta)$$ Now lets look closer at the first equation you provided using the definitions above: \frac{d\alpha}{dt} = \frac{1}{1+\frac{w^2}{u^2}} \left(\frac{w'}{u}-\frac{u'w}{u^2}\right) = \frac{1}{1+\tan^2\alpha} \left(\frac{w'}{...

2

The plane takes off vertically, with the prop wash blowing over conventional control surfaces. To tilt forwards the pilot pushes the stick forward in the usual way to "lower" the elevators and tip the nose "down". As the plane tips progressively over, it progressively gains flying speed and lift transfers to the delta wings. At the same time, the elevators ...

1

The control surfaces are in the prop-wash, and so are effective even when the aircraft is standing still. To manoeuvre the aircraft all you do is tilt the fuselage, which tilts the prop and thus tilts the lift/thrust just like a helicopter does.

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