I had seen planes appear to be standing in air (Esp near airports probabaly waiting for the clearence to land) , but as per its working principle it shudnt. unable to crack it.....!!!!!
2006-08-29 06:11:27 · 14 answers · asked by pradeep` n 1 in Science & Mathematics ➔ Engineering
It's called perspective. No, they are not stopping.
2006-08-29 06:15:09 · answer #1 · answered by poorcocoboiboi 6 · 0⤊ 0⤋
Sir:
Commercial airplanes need to fly at a speed of about 130 miles per hour (the exact number is specific to the particular plane) to maintain sufficient left over the airfoil surfaces of the wing and wing roots to keep the aircraft aloft.
If you have seen commercial aircraft apparently hovering in mid air, I suspect that the sight was an illusion based upon your angle of viewing the aircraft. When an aircraft is flying very slowly and coming right at you, or going directly away from you, it is hard to detect motion in a brief glance. This inability to etect motion is increased by zero changes in altitude, and increased distance from the viewing point.
The only commercial aircraft I am aware of that can actually "hover" in place are certain commuter helicopters that shuttle passengers from one place to another on short hops. A helicopter can hover in one spot for long periods of time if need be due to the fact that the lift required is generated by air flow over the rotor blades not over actual aircraft wings. The wings need movement through the air to develop lift.
2006-08-29 14:00:34 · answer #2 · answered by zahbudar 6 · 0⤊ 0⤋
I agree with the idea of perspective... but...
A commercial aircraft flies at around 400kn (Knots per hour) or 400 Nautical Miles per hour.
When landing, it reduces speed to about 220 kn.
If it were to face a head wind of 220kn, it would be stand still in relation to you, on the ground!
We call that "ground speed". That is the real speed of the aircraft in relation to the ground. It is the combination of the air speed of the aircraft and the wind direction.
Flying a light aircraft, with a landing speed of 60 Knots, it happen quite often that we move only a few Knots in relation to the ground:
Say I am approaching at 60Knots, and I have a head wind of 40Knots: I am moving, for you, at 20 Knots only! (I should not be flying, mind you: wind is too strong!).
It has been reported that fighter aircrafts entering jetstreams at high altitude were flying... backward!
There were flying at 600Knots in a head wind of 7 or 800Knots!
2006-08-29 13:24:06 · answer #3 · answered by just "JR" 7 · 0⤊ 0⤋
For the plane to be in air, flowing air is required to create the low pressure area above the plane. Normally this air flow is obtained by the movement of plane in the front direction and adjusting the ailerons. However if there is a natural wind flow which can create enough low pressure to keep the plane in air, then it is possible stall.
but i feel that this must be difficult for a commercial planes as they are heavy. (the low pressure must compensate for the weight of the plane).
Hence in practise this is not possible.
2006-08-30 11:26:14 · answer #4 · answered by natanan_56 2 · 0⤊ 0⤋
No, A commercial Plane Cannot stand in mid-air, Even if the plane slows down considerably, it would stall(where no air passes above the wings, to create lift), Thus would crash.
The reason why you see them as standing still in mid-air is because of perception.
2006-08-29 14:16:04 · answer #5 · answered by Nithin R 3 · 0⤊ 0⤋
Theoretically, yes, a jet could stand still. However, it's unlikely in practice.
A jet flying at near stall speed into the strongest part of the jet stream could have a groundspeed near 0. It certainly can't happen near the ground unless the jet is flying while there's a hurricane in the area.
2006-08-29 13:20:57 · answer #6 · answered by Flyboy 6 · 0⤊ 0⤋
No they can't stand in air (with the exception of the Harrier jet used by the Marine Corps). What you were seeing was either a still shot, or a video where the background didn't have relative motion so you couldn't tell how fast it was going.
2006-08-29 13:17:55 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Standard airplanes cannot hover, because they must have speed for their wings to keep them up. If they don't appear to be moving, they're probably moving directly towards or away from you. Certain military airplanes and VTOLs can hover, but they usually aren't commercially available.
2006-08-29 13:19:39 · answer #8 · answered by Anonymous · 0⤊ 0⤋
As in flying vertical - probably for a short period of time before the airframe rips away due to the horizontal shear stresses.
2006-08-29 13:17:32 · answer #9 · answered by Anonymous · 0⤊ 0⤋
its a perspective thing... also if your so used to plans slowly moving above us in the air (they are usually gogin 200mph) so if the slow down to less than half that on entry..and your kind of lined up (so it looks liek tis coming directly at you... or directly away from you) it would probly apear to hover... but its not
2006-08-29 16:03:17 · answer #10 · answered by Anonymous · 0⤊ 0⤋
IT DOES NOT.
AN APPROACHING AEROPLANES TOWARDS YOU FROM A LOND DISTANCE APPEARS AS IF IT IS STANDING. THIS IS BECAUSE THE RATE OF CHANGE OF ANGLE (AS SEEN FROM EYE) IS NEGLIGIBLE FOR CONSIDERABLE DISTANCE OF MOVEMENT OF AEROPLANE.
2006-08-30 03:59:08 · answer #11 · answered by sures 3 · 0⤊ 0⤋