Your opinion on this landing

Paul Tomblin wrote:
In a previous article, Erik said:
Sheista wrote:
http://www.thepollspace.com/polls.php?pollid=1359



I know this already, but it always amazes me to see
the wing holding up the plane. It's propped off of
the ground on the one wing. I know this happens in
the air, it's just neat to see how strong the wings
actually are.

In the air, the load is distributed along the length of the wing, rather
than just on the wing tip. So this wing is taking more torque than a wing
in the air.

Only if you consider an air load of 1G. I'd have to do that calculation
to be sure, but I'm fairly confident that 4G in the air is more moment
at the wing root than is 1G at the tip.

Matt

On May 10, 2:47 pm, Sheista wrote:
http://www.thepollspace.com/polls.php?pollid=1359



It wasn't a good one.

Bertie

d&tm wrote:
"B A R R Y" wrote in message
...
Sheista wrote:
http://www.thepollspace.com/polls.php?pollid=1359


It looks like the place is reusable, so it's fine. G

was that a typo or a new definition of a good landing ?(ie only the place ,
not the plane has to be reusable.. :)
terry



I always heard it like this:

"Any landing you walk away from is good"
"Any landing where they can reuse the plane is great"

Reusing the PLACE puts a whole 'nuther light on the subject! G

On May 10, 6:47 am, Sheista wrote:
http://www.thepollspace.com/polls.php?pollid=1359



Certainly couldn't have happened with the energy of a landing with so
little damage. Looks like the line guy may have been pushing it back
and went just a bit too far back. BTW: When on the Kitty Hawk it was
always amazing to me that none of the A-7's ever got pushed off the
deck. They would push them damn close to the edge, often with the
pilot still in it.

-Robert

On May 10, 3:20 pm, Matt Whiting wrote:
Paul Tomblin wrote:
In a previous article, Erik said:
Sheista wrote:
http://www.thepollspace.com/polls.php?pollid=1359



I know this already, but it always amazes me to see
the wing holding up the plane. It's propped off of
the ground on the one wing. I know this happens in
the air, it's just neat to see how strong the wings
actually are.

In the air, the load is distributed along the length of the wing, rather
than just on the wing tip. So this wing is taking more torque than a wing
in the air.

Only if you consider an air load of 1G. I'd have to do that calculation
to be sure, but I'm fairly confident that 4G in the air is more moment
at the wing root than is 1G at the tip.

Matt- Hide quoted text -

- Show quoted text -

I'm not sure how actual aircraft engineers do it but when I got my
engineering degree that isn't how we would do it. Looking at the
moment at the root seems to imply that the entire length of the wing
is of equal strength and the forces are focused on the root. In fact
the wing is not designed to be equal strength throughout, each section
of the wing is only as strong as it needs to be. Therefore, the chance
of failure (at least ideally) is about equal anywhere along the wing
(root, mid section, tip, etc). There may be practical frabrication
reasons why you would have one section of a wing "over engineered",
but in general, that would not be an engineer's goal.

When I was an engineering student we would look at each spar's forces
as a continous function using calc. That way we could use dx to see
the force on any infinite small section of each spar. Looking at the
max force at any dx we could reduce weight (i.e. strength) if one
section was stronger than necessary. The strength at that section
would be designed to meet the requirement of the force expected. I.e.
we wouldn't make the entire wing the same strength if the forces were
not the same throughout.

-Robert

each section
of the wing is only as strong as it needs to be. Therefore, the chance
of failure (at least ideally) is about equal anywhere along the wing

In fact, there's a video somewhere showing a stress test on a wing; the
entire wing fails pretty much at the same time.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.

Jose wrote:
each section
of the wing is only as strong as it needs to be. Therefore, the chance
of failure (at least ideally) is about equal anywhere along the wing

In fact, there's a video somewhere showing a stress test on a wing; the
entire wing fails pretty much at the same time.

Jose

I'd like to see that video as the odds of this happening are nearly zero.

Matt

On May 12, 11:41 am, Matt Whiting wrote:
Jose wrote:
each section
of the wing is only as strong as it needs to be. Therefore, the chance
of failure (at least ideally) is about equal anywhere along the wing

In fact, there's a video somewhere showing a stress test on a wing; the
entire wing fails pretty much at the same time.

Jose

I'd like to see that video as the odds of this happening are nearly zero.

Matt

Certainly one section would expect to fail first, either by chance or
because one section ends up being weaker for practical reasons. I've
seen the video, when the main spar fails the wing shatters, its a bit
difficult to tell where it failed because of the shattering.

-Robert

Robert M. Gary wrote:
On May 12, 11:41 am, Matt Whiting wrote:
Jose wrote:
each section
of the wing is only as strong as it needs to be. Therefore, the chance
of failure (at least ideally) is about equal anywhere along the wing
In fact, there's a video somewhere showing a stress test on a wing; the
entire wing fails pretty much at the same time.
Jose
I'd like to see that video as the odds of this happening are nearly zero.

Matt

Certainly one section would expect to fail first, either by chance or
because one section ends up being weaker for practical reasons. I've
seen the video, when the main spar fails the wing shatters, its a bit
difficult to tell where it failed because of the shattering.

I've not seen a composite wing fail so maybe they look different than
the metal ones I've seen. The latter always snaps at one point,
typically close to the root. I saw footage some years ago of an
airplane (I want to say an Aero Commander, but I'm not sure anymore)
that pulled up too steeply and shed both wings. They folded up right
near the fuselage on both sides.

I've seen a few videos of airliner wings stressed to failure and when
they fail it looks like a small explosion with debris flying everywhere,
but much of that is the test apparatus flying around. The failure
occurred at a point. It simply isn't possible to design a wing
perfectly enough or, harder yet, assemble it uniformly enough to get a
distributed failure.

Matt

The failure occurred at a point. It simply isn't possible to design a wing perfectly enough or

Well, yes, but at the time of failure, the rest of the wing (in the test
I saw) was stresesed very close to =its= breaking point, so once it let
go wherever it did, the other points also let go.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.