Is Charley telling us anything about A/C tie-down?

Does anybody know of any wind-tunnel tests for analysis of tie-down
behaviour? I tried a google search without much success.

Having seen the Charley pictures from Orlando Executive and Punta Gorda, I'm
wondering if we are doing the right thing.

The standard for tricycle gear GA planes seems to be wings and tail.

Having been to my own airport, I can see that most of the tail ropes are
usually the rattiest you can find.
Besides, even if the tail tiedown holds, it does nothing to prevent the A/C
rotating on the main gear and bouncing onto the tail and back onto the nose
gear until one or the other gives way.

I am also wondering that even if the tail tiedown stays tight, do the forces
become great enough such that the fuse breaks at its weakest point,
somewhere just in front of the tail feathers?

Thus I wonder if leaving the tail loose, and tieing down at the nose gear
would make more sense. I don't see this as putting more pressure on the
wing-tiedowns because I feel that a tied-down tail would have given way
anyway, long before the wings reach any sort of critical point.

It would be interesting to have wind-tunnel tests (at various directions to
the a/c longitudinal axis) to see the effects on different tie-down methods.

"Icebound" wrote in message
news

The standard for tricycle gear GA planes seems to be wings and tail.

Having been to my own airport, I can see that most of the tail ropes are
usually the rattiest you can find.
Besides, even if the tail tiedown holds, it does nothing to prevent the A/C
rotating on the main gear and bouncing onto the tail and back onto the nose
gear until one or the other gives way.

More than that, if the plane is allowed to rotate, the wing can generate
enough lift to break a rope or, perhaps worse, cause structural damage to the
airframe if the rope holds. Gliders are often tied down with the tail raised
just high enough for the wing to present a zero AOA for just this reason.

Glider owners often also add a front tiedown rope to the tow hook to ensure
that the nose can't raise in a wind. I suppose a tiedown to the nosegear of a
trigear plane could serve that same function, but I might talk to an A&P first.

I have also seen some innovative strap-on spoilers on parked gliders, and
even power planes as large as DC-3s, that are obviously intended to reduce the
lift on the airframe and keep the plane on the ground in high winds.


I am also wondering that even if the tail tiedown stays tight, do the forces
become great enough such that the fuse breaks at its weakest point,
somewhere just in front of the tail feathers?

Never seen it happen.

Thus I wonder if leaving the tail loose, and tieing down at the nose gear
would make more sense.

Only if you can guarantee that the wind will always be coming from the
front of the plane.


Vaughn

Why not the "Belt and Suspenders" approach? Tie both ends down.
Stu Fields (Helicopters have problem with just tying down the rear blade)
"Icebound" wrote in message
news
Does anybody know of any wind-tunnel tests for analysis of tie-down
behaviour? I tried a google search without much success.

Having seen the Charley pictures from Orlando Executive and Punta Gorda,
I'm
wondering if we are doing the right thing.

The standard for tricycle gear GA planes seems to be wings and tail.

Having been to my own airport, I can see that most of the tail ropes are
usually the rattiest you can find.
Besides, even if the tail tiedown holds, it does nothing to prevent the
A/C
rotating on the main gear and bouncing onto the tail and back onto the
nose
gear until one or the other gives way.

I am also wondering that even if the tail tiedown stays tight, do the
forces
become great enough such that the fuse breaks at its weakest point,
somewhere just in front of the tail feathers?

Thus I wonder if leaving the tail loose, and tieing down at the nose gear
would make more sense. I don't see this as putting more pressure on the
wing-tiedowns because I feel that a tied-down tail would have given way
anyway, long before the wings reach any sort of critical point.

It would be interesting to have wind-tunnel tests (at various directions
to
the a/c longitudinal axis) to see the effects on different tie-down
methods.

"Vaughn" wrote in message
...

"Icebound" wrote in message
news

I am also wondering that even if the tail tiedown stays tight, do the
forces
become great enough such that the fuse breaks at its weakest point,
somewhere just in front of the tail feathers?

Never seen it happen.

Neither have I in person, but some of the pictures from Punta Gorda seem to
suggest that it might.



Thus I wonder if leaving the tail loose, and tieing down at the nose
gear
would make more sense.

Only if you can guarantee that the wind will always be coming from
the
front of the plane.



I am not sure I understand why direction is an issue? In the typical
small-GA gust-lock, the tail is set for slight "down elevator".

If the wind is from the front, lifting the tail, that forces the nosewheel
down and its not going anywhere except into the pavement.

If the wind is from the rear, that would force the tail down, and thats why
the suggestion of nose-gear tie-down to prevent the A/C from rotating on the
mains.

I would argue that a *tail* tiedown actually expects wind from the front,
and that it is useless when the wind is from the rear......

Kathryn & Stuart Fields wrote:

Why not the "Belt and Suspenders" approach? Tie both ends down.
Stu Fields (Helicopters have problem with just tying down the rear blade)
"Icebound"


if you expect really bad winds, support the tail, AND tie it down,
--


Mark Smith
Tri-State Kite Sales http://www.trikite.com
1121 N Locust St
Mt Vernon, IN 47620
1-812-838-6351

"Mark Smith" wrote in message
...
Kathryn & Stuart Fields wrote:

Why not the "Belt and Suspenders" approach? Tie both ends down.
Stu Fields (Helicopters have problem with just tying down the rear
blade)
"Icebound"


if you expect really bad winds, support the tail, AND tie it down,
--

I can see the point, but the support-structure-pylon-whatever would also
have to be securely captured to the pavement, or it too may become another
piece of 100-mph-horizontal-debris amongst the field of A/C.

In article , wrote:

Why not the "Belt and Suspenders" approach? Tie both ends down.
Stu Fields (Helicopters have problem with just tying down the rear
blade)
"Icebound"


if you expect really bad winds, support the tail, AND tie it down,

If you expect really bad winds, move the airplane. Even if you
can securely tie it down, it'll just be a target for debris.

--
Bob Noel
Seen on Kerry's campaign airplane: "the real deal"
oh yeah baby.

Like Vaughn said:

" More than that, if the plane is allowed to rotate, the wing can
generate
enough lift to break a rope or, perhaps worse, cause structural damage to
the
airframe if the rope holds."

Back in 1985, when hurricane Gloria hit Long Island MacArthur APT, we found
an Archer that had "flown" into a drainage sump, some 200 feet away from its
tiedown spot. The wing tiedown rings had actually broken! One could have
used the best ropes/chains in the world, and it wouldn't have mattered.

for just this reason.

"Vaughn" wrote in message
...

"Icebound" wrote in message
news

The standard for tricycle gear GA planes seems to be wings and tail.

Having been to my own airport, I can see that most of the tail ropes are
usually the rattiest you can find.
Besides, even if the tail tiedown holds, it does nothing to prevent the
A/C
rotating on the main gear and bouncing onto the tail and back onto the
nose
gear until one or the other gives way.

More than that, if the plane is allowed to rotate, the wing can
generate
enough lift to break a rope or, perhaps worse, cause structural damage to
the
airframe if the rope holds. Gliders are often tied down with the tail
raised
just high enough for the wing to present a zero AOA for just this reason.

Glider owners often also add a front tiedown rope to the tow hook to
ensure
that the nose can't raise in a wind. I suppose a tiedown to the nosegear
of a
trigear plane could serve that same function, but I might talk to an A&P
first.

I have also seen some innovative strap-on spoilers on parked
gliders, and
even power planes as large as DC-3s, that are obviously intended to reduce
the
lift on the airframe and keep the plane on the ground in high winds.


I am also wondering that even if the tail tiedown stays tight, do the
forces
become great enough such that the fuse breaks at its weakest point,
somewhere just in front of the tail feathers?

Never seen it happen.

Thus I wonder if leaving the tail loose, and tieing down at the nose
gear
would make more sense.

Only if you can guarantee that the wind will always be coming from
the
front of the plane.


Vaughn

In article , Mark Smith
wrote:

Kathryn & Stuart Fields wrote:

Why not the "Belt and Suspenders" approach? Tie both ends down.
Stu Fields (Helicopters have problem with just tying down the rear blade)
"Icebound"


if you expect really bad winds, support the tail, AND tie it down,


And, ductape some makeshift spoilers to the wings: some 8 ft pieces of
2x2, taped ahead of the spar line, secured with about 8, 2 ft strips of
2" ductape (top surface) will secure it, provided that there is no dirt
on the wing.

Icebound wrote:

Thus I wonder if leaving the tail loose, and tieing down at the nose gear
would make more sense. I don't see this as putting more pressure on the
wing-tiedowns because I feel that a tied-down tail would have given way
anyway, long before the wings reach any sort of critical point.

Leaving the tail loose will allow a wind from the rear to push the plane over. The
wind will be able to exercise a tremendous amount of leverage on the horizontal
stabilizer.

I normally keep 1/2" nylon tiedowns on my taildragger. When we get hurricane
warnings, I add a set of 3/8" nylon ropes from the tiedown rings to the wing struts.
for the last serious storm, I tied lift spoilers to the tops of the wings.

I've been here over 20 years. So far, our storms haven't been as serious as the worst
of the Florida storms. We rarely see winds higher than 100 mph.

George Patterson
If you want to know God's opinion of money, just look at the people
he gives it to.