Question about air turbulence?

[QuantumHED]

How fast does air around the fuselage of a plane move compared to its
velocity. for example, if a plane is flying very close to the ground at
300mph per hour over my head, will I get blasted by 300mph gust? somebody
let me know. thanks.

[Orval Fairbairn]

In article <fg9Sf.91233$bF.7206@dukeread07>,
"QuantumHED" > wrote:

> How fast does air around the fuselage of a plane move compared to its
> velocity. for example, if a plane is flying very close to the ground at
> 300mph per hour over my head, will I get blasted by 300mph gust? somebody
> let me know. thanks.

No -- you might feel some wind as it goes by, due to air
displacement/replacement, but nothing like 300 mph. Remember, the air is
standing still, with the plane flying through it. What you will feel is
the turbulence due to air friction and lift -- sort of like what you
feel when a car speeds by.

[Brian Whatcott]

On Thu, 16 Mar 2006 02:23:35 -0600, "QuantumHED"
> wrote:

>How fast does air around the fuselage of a plane move compared to its
>velocity. for example, if a plane is flying very close to the ground at
>300mph per hour over my head, will I get blasted by 300mph gust? somebody
>let me know. thanks.
>
Here's my guess ..er.. I mean estimate: a downdraft of 30 MPH, which
proceeds as fast as the wings. It takes downwards air to lift planes
up.

Brian Whatcott Altus OK

[QuantumHED]

So would it be safe to say that a large commercial aircraft flying overhead
at a stupidly low altitude like 20 feet wouldn't be nearly strong enough to
overturn vehicles?

"Orval Fairbairn" > wrote in message
...
> In article <fg9Sf.91233$bF.7206@dukeread07>,
> "QuantumHED" > wrote:
>
> > How fast does air around the fuselage of a plane move compared to its
> > velocity. for example, if a plane is flying very close to the ground at
> > 300mph per hour over my head, will I get blasted by 300mph gust?
somebody
> > let me know. thanks.
>
> No -- you might feel some wind as it goes by, due to air
> displacement/replacement, but nothing like 300 mph. Remember, the air is
> standing still, with the plane flying through it. What you will feel is
> the turbulence due to air friction and lift -- sort of like what you
> feel when a car speeds by.

[Mark Robinson]

QuantumHED wrote:
> So would it be safe to say that a large commercial aircraft flying overhead
> at a stupidly low altitude like 20 feet wouldn't be nearly strong enough to
> overturn vehicles?

At the local international aiport a road goes past each end of the runway well
below the flightpath. I've never heard of was tipping anything over on these
roads. However there is an embankment at one end which is close to the level of
the runway which when I was young was fun to stand on when the planes came in
or took off overhead. The wash here was significant but fear made people fall
down more then the wind. These days there are signs there warning of the
dangers of jet blast and men come and yell at you if you stand there. I guess
people were injured after being knocked over by the wash or falling down in
fear. The wake of the body of the plane going over was inconsequential compared
to the wash from the engines. I reckon it would be possible to knock over a
high sided vehicle with the engine wash, but it'd need to be sideways under a
large jet taking off.

[Peter R.]

QuantumHED > wrote:

> So would it be safe to say that a large commercial aircraft flying overhead
> at a stupidly low altitude like 20 feet wouldn't be nearly strong enough to
> overturn vehicles?

Take a look for yourself <G>:

http://www.strangevehicles.com/content/item/111667.html

--
Peter

[Brian Whatcott]

On Thu, 16 Mar 2006 21:28:45 -0600, "QuantumHED"
> wrote:

>So would it be safe to say that a large commercial aircraft flying overhead
>at a stupidly low altitude like 20 feet wouldn't be nearly strong enough to
>overturn vehicles?

Ahem... I was held for takeoff behind a good size passenger jet at
Exeter (I think it was) long ago in a powered g;lider (a Fornier RF4)
When cleared I hit it, and at about 50 feet did a smart involuntary 90
degree roll, and headed straight for the tower. I corrected when I
could, and put it down to vortex interception.

Controllers weren't so careful of it at the time


Brian Whatcott Altus OK