What are the forces on a tied down glider?

"Andy" wrote in message
...

Others would say why worry - put it in the box!


"Glider trailers parked on the field were crushed from being tossed about
like dice."

(to be fair "The hangar right across the alleyway had it's roof and walls
blown off.")

http://iac78.org/newsletter/NL%20Fal...05%20Color.pdf Page 8.



Now, can someone explain why I can remember (and find) something I read
nearly 3 years ago, but I can't remember what I was doing on Friday when I
get back to work on Monday?


--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

How interested you were in Friday?

Capt. Geoffrey Thorpe wrote:
"Andy" wrote in message
...

Others would say why worry - put it in the box!


"Glider trailers parked on the field were crushed from being tossed
about like dice."

(to be fair "The hangar right across the alleyway had it's roof and
walls blown off.")

http://iac78.org/newsletter/NL%20Fal...05%20Color.pdf Page 8.



Now, can someone explain why I can remember (and find) something I read
nearly 3 years ago, but I can't remember what I was doing on Friday when
I get back to work on Monday?

On Aug 13, 8:13*pm, "Capt. Geoffrey Thorpe" The Sea Hawk @See My
Sig.com wrote:

Now, can someone explain why I can remember (and find) something I read
nearly 3 years ago, but I can't remember what I was doing on Friday when I
get back to work on Monday?

That's the way human brains work and why it never helps to cram the
night before a test. Your brain needs time to create links to new
information, making it easier to retrieve later. This all happens in
the background without your being aware of it.

-Doug

"Doug Hoffman" wrote in message
...

... it never helps to cram the night before a test.

That might be true for you, but certainly not for me. I have taken thousands
of tests over my lifetime (military, college, FAA). I consider myself very
good at taking tests and I can't think of once that I have failed to profit from
last-night and even last-minute preparation.

Vaughn

Vaughn Simon!
wrote:



"Doug Hoffman" wrote in message

...

... it never helps to cram the night before a test.

That might be true for you, but certainly not for me. I
have taken thousands
of tests over my lifetime (military, college, FAA). I
consider myself very
good at taking tests and I can't think of once that I have
failed to profit from
last-night and even last-minute preparation.


I envy your abilities. :-)

--
Regards,
Doug

** Posted from http://www.teranews.com **

Andy wrote:


On Aug 13, 11:01=A0am, Eric Greenwell
wrote:
I see gliders tied down in a bewildering variety of ways,
all apparently
"adequate" in the owner's mind.

Perhaps the real question is how well does it have to be tied
down to
satisfy the insurance company that you were not negligent.

Another significant factor is what is it tied too. We seem to
take
for granted that tie down wires etc that we find at the
airport are
secure, but I've seen a whole line of cable and the anchors
pulled out
of the ground. I used to trust the rings on the ramp at Hobbs
until
one year I cleared all the dirt out of the hole and found the
rings
corroded almost all the way through. Last time I flew there I
dug
around until I found a good one and tied the CG hook to it.

Seems like wing and tailfeather covers should help some. Maybe
a lot. The full covers I've seen (Jaxida) hang down a lot of
covering beneath the wings and horizontal stabs/elevators. To my
eye the covers might be far more effective than even open
spoilers in destroying lift.

--
Doug

** Posted from http://www.teranews.com **

Doug Hoffman wrote:

Seems like wing and tailfeather covers should help some. Maybe
a lot. The full covers I've seen (Jaxida) hang down a lot of
covering beneath the wings and horizontal stabs/elevators. To my
eye the covers might be far more effective than even open
spoilers in destroying lift.

My observation is the the wind puffs up the covers so they stand
completely off the top and bottom of the wing. In a strong wind, the
covers look like they are inflated to a high pressure, making the wing
look more like a sausage than anything else. My guess is this is a high
drag, low lift "airfoil", but I have no documentation for it.

It also provides protection from hail, which just bounces off the taut
wing covers and never gets near the wing skin.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

"Eric Greenwell" wrote in message
news:x7Mok.925$xv.899@trnddc02...
My observation is the the wind puffs up the covers so they stand
completely off the top and bottom of the wing. In a strong wind, the
covers look like they are inflated to a high pressure, making the wing
look more like a sausage than anything else. My guess is this is a high
drag, low lift "airfoil", but I have no documentation for it.

--
Eric Greenwell - Washington State, USA

My observation is similar . . . except to me, the puffed up covers look like
the thick, high lift wing on a trainer.

I'd feel a lot better about covers in high winds if there were spanwise
fabric tubes sewn in to allow pipe foam insulation to be inserted for full
length spoilers.

bumper
zz
Minden
USA

On Aug 13, 7:55*pm, "bumper" wrote:
"Eric Greenwell" wrote in message

news:x7Mok.925$xv.899@trnddc02...

My observation is the the wind puffs up the covers so they stand
completely off the top and bottom of the wing. In a strong wind, the
covers look like they are inflated to a high pressure, making the wing
look more like a sausage than anything else. My guess is this is a high
drag, low lift "airfoil", but I have no documentation for it.

--
Eric Greenwell - Washington State, USA

My observation is similar . . . except to me, the puffed up covers look like
the thick, high lift wing on a trainer.

I'd feel a lot better about covers in high winds if there were spanwise
fabric tubes sewn in to allow pipe foam insulation *to be inserted for full
length spoilers.

bumper
zz
Minden
USA

The standard Jaxida covers look like this in the wind...

http://www.flickr.com/photos/darrylramm/517165653/
http://www.flickr.com/photos/darrylramm/517140648/

(maybe it was really faster than 20 knots in these photos).

Does Jaxida offer a sewn in place to insert a foam tube?

Darryl

I have heard of a case where a Blanik was wrecked by a violent gust of wind
during a storm, even though it was very well tied down. The lift on the
wings was sufficient to lift the glider. The wingtips were both tied down
and the mainspar was damaged beyond economic repair by the resulting
downwards bending loads!

Del Copeland


At 20:49 13 August 2008, Andy wrote:
On Aug 13, 11:01=A0am, Eric Greenwell wrote:
I see gliders tied down in a bewildering variety of ways, all
apparently
"adequate" in the owner's mind.

Perhaps the real question is how well does it have to be tied down to
satisfy the insurance company that you were not negligent.

Another significant factor is what is it tied too. We seem to take
for granted that tie down wires etc that we find at the airport are
secure, but I've seen a whole line of cable and the anchors pulled out
of the ground. I used to trust the rings on the ramp at Hobbs until
one year I cleared all the dirt out of the hole and found the rings
corroded almost all the way through. Last time I flew there I dug
around until I found a good one and tied the CG hook to it.

Others would say why worry - put it in the box!

Andy