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

[Icebound]

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]

"Icebound" > wrote in message
.rogers.com...
>
> 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

[Kathryn & Stuart Fields]

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
.rogers.com...
> 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]

"Vaughn" > wrote in message
...
>
> "Icebound" > wrote in message
> .rogers.com...
> >
> > 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......

[Mark Smith]

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

[Icebound]

"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.

[Bob Noel]

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.

[tom418]

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
> .rogers.com...
> >
> > 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
>
>
>

[Orval Fairbairn]

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.

[G.R. Patterson III]

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.

[CFLav8r]

"Icebound" wrote in message ...
> 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.
>
I can tell you from recent experience that the only way to safe guard your
plane
in winds exceeding 50knots, is to move it to some place safe.
There are pictures on three websites that will show you planes that were
tied down
and still damaged, some still tied down and damaged in place.
http://www.flyinggators.com/news/hurricane/exec.htm
http://www.floridascubadiver.com/hurricane_charley.htm
http://www.avweb.com/news/features/187931-1.html

David (KORL)

[Del Rawlins]

On Sat, 21 Aug 2004 19:56:55 GMT, Orval Fairbairn
> wrote:

>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.

A couple years ago when we had high winds in Anchorage and a bunch of
airplanes were lost, the weak point on tube and fabric types seemed to
be the rear wing strut. In addition to extra tiedowns, lots of guys
would lash and/or duct tape a 2x4 to the strut to brace it and prevent
buckling.


================================================== ==
Del Rawlins--
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
Remove _kills_spammers_ to reply

[guynoir]

An old bush pilot told me they used really long wing tie downs to a
single point and left the tail untied in high winds in Alaska. This
allowed the aircraft to lift off and weathervane in high winds. The
aircraft were staked out far enough apart that they wouldn't collide
with each other. I'd be interested to know if anyone's actually
witnessed that method. A Cozy owner told me that by retracting the
nosegear of a Cozy or Long EZ, it could withstand 60 knot winds without
being tied down. I don't know how much truth there is to that one,
either, but there obviously aren't very many airplanes that CAN'T
withstand 100mph+ winds.

Icebound wrote:
> 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, ev
--
John Kimmel


I think it will be quiet around here now. So long.

[C J Campbell]

The hurricane hitch should be able to withstand winds of 150 knots, given
rope of adequate strength. This is the only knot that should be used for
tieing down aircraft, yet my personal observation is that fewer than one
pilot in 50 knows how to tie it. The knot is described in E.F. Potts' book
on bush piloting.

Chains are worse than inadequate as tiedowns. They cannot be attached
without some slack remaining, and sudden stretching of the chain will cause
it break when it snaps taught. Loose and broken chains are also dangerous in
and of themselves. A rope can be made tight, so that all stretching is
continous and there is no sudden stop.

Aircraft owners should carry their own lines and ensure that they are in
good condition. They should also make sure that their tiedown rings are in
good condition and, if strong winds are expected, should consider
reinforcing the tiedown by giving the line a couple turns around the strut
as well as running it through the tiedown ring.

Even tieing an airplane down is not a guarantee against damage. Winds may
still generate enough lift that the airplane could be damaged anyway. There
is one picture of a severely damaged Bonanza that pulled the concrete
tiedown blocks completely out of the ramp, collapsing the nose, wrinkling
the wings, and probably damaging the wing spars in the process! Tied down
airplanes can still be damaged by flying debris (such as improperly tied
down airplanes) as well as by severe hail and other things caused by the
weather.

Cessna recommends tieing aircraft down at both nose and tail, though this is
rarely done and few tiedowns have provision for doing this. A gust striking
an airplane that is tied only at the tail and wings can still send the tail
slamming down hard on the concrete, breaking it off. Gusty winds can make
the airplane bounce on its nose gear, too, possibly damaging the nose gear,
firewall, engine mount, propeller and engine. The airplane can also be set
on its tail by heavy snow or ice.

[Del Rawlins]

On Sun, 22 Aug 2004 04:35:24 GMT, guynoir >
wrote:

>An old bush pilot told me they used really long wing tie downs to a
>single point and left the tail untied in high winds in Alaska. This
>allowed the aircraft to lift off and weathervane in high winds. The
>aircraft were staked out far enough apart that they wouldn't collide
>with each other. I'd be interested to know if anyone's actually
>witnessed that method.

Did the old bush pilot start out by saying "now this ain't no
bull****"?

================================================== ==
Del Rawlins--
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
Remove _kills_spammers_ to reply

[Jeremy Lew]

All the Cherokees of the world seem to use the seatbelt as a gust lock,
which ties the yoke back in full up-elevator and about half aileron
deflection. Seems like this would be terrible in high winds.

"Icebound" > wrote in message
ble.rogers.com...
>
> "Vaughn" > wrote in message
> ...
> >
> > "Icebound" > wrote in message
> > .rogers.com...
> > >
> > > 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......
>
>
>

[Ryan Young]

"C J Campbell" > wrote in message >...
> The hurricane hitch should be able to withstand winds of 150 knots, given
> rope of adequate strength. This is the only knot that should be used for
> tieing down aircraft, yet my personal observation is that fewer than one
> pilot in 50 knows how to tie it. The knot is described in E.F. Potts' book
> on bush piloting.

It's actually FE Potts, and everything you ever need to know about tie
downs can be found here:
http://www.fepco.com/BF.images.gentle.breeze.html

[Del Rawlins]

On 22 Aug 2004 09:17:31 -0700, (Ryan Young) wrote:

>"C J Campbell" > wrote in message >...
>> The hurricane hitch should be able to withstand winds of 150 knots, given
>> rope of adequate strength. This is the only knot that should be used for
>> tieing down aircraft, yet my personal observation is that fewer than one
>> pilot in 50 knows how to tie it. The knot is described in E.F. Potts' book
>> on bush piloting.
>
>It's actually FE Potts, and everything you ever need to know about tie
>downs can be found here:
>http://www.fepco.com/BF.images.gentle.breeze.html

The primary advantage of that knot is that it can be tightened in the
middle of high winds without first untying anything. A trucker's
hitch works just fine, but you have to loosen the half hitches holding
it in order to add more tension.


================================================== ==
Del Rawlins--
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
Remove _kills_spammers_ to reply

[geo]

"Icebound" > wrote in message
.rogers.com...
> Does anybody know of any wind-tunnel tests for analysis of tie-down
> behaviour? I tried a google search without much success.
>

It's amazing that people who spends 10s or 100s of thousands of dollars on a
plane won't spend ~$10.k for a tornado proof, hurricane proof, fire proof
hangar.
http://www.monolithic.com/gallery/commercial/hangar_door/index.html
http://www.monolithic.com/gallery/commercial/hangars03/

[Ben Jackson]

In article >,
Kathryn & Stuart Fields > wrote:
>Why not the "Belt and Suspenders" approach? Tie both ends down.

Yeah, you want to make a stationary target for all of the other planes
on the ramp that break loose.

--
Ben Jackson
>
http://www.ben.com/

[Thomas Borchert]

Geo,

> It's amazing that people who spends 10s or 100s of thousands of dollars on a
> plane won't spend ~$10.k for a tornado proof, hurricane proof, fire proof
> hangar.
> http://www.monolithic.com/gallery/commercial/hangar_door/index.html
> http://www.monolithic.com/gallery/commercial/hangars03/
>

It is amazing that there is not one single photograph I could find on the
website that shows a real hangar in use with an aircraft. All I could find is
concept drawings - and your word that it's tornado proof. And you're really
surprised people don't spend 10k on it?

--
Thomas Borchert (EDDH)

[roo]

You can get much more tension from a Versatackle:

http://www.geocities.com/roo_two/Versatackle.html

Once you get the loops placed correctly for your setup, you can leave
the loops in place unless you need to use the rope for something else.