On Sep 19, 6:05*pm, wrote:
On Sep 19, 5:38*pm, sisu1a wrote:

On Sep 19, 2:47*pm, "Bill Daniels" bildan@comcast-dot-net wrote: I one of them was Paul Hansen's Sisu 1A in California the other was a
Schweizer in Texas - Houston I think. *Anyway there are dozens more stories
of stakes pulling out leading to the distruction of gliders in the history
of gliding.

I don't think it's a matter of mechanical engineering, it's soil
engineering. *Stakes will hold in turf or damp soil held together by strong
roots. *The dry sand and gravel of western deserts just won't hold a stake
no matter how cleverly it's designed. *Even half axle shafts driven in with
a sledge hammer have pulled out. *The act of driving in the stake loosens
the soil enough to prevent the stake(s) from holding making the whole

I agree with Bill. *I did a test with the claw attached to my trailer
jack and the wheel on a scale. *The claw pulled out of compacted
decomposed granite in my driveway at about 250 lbs, came completetly
out at 300, but this was aided by weed stop fabric under the DG. *The
soil was damp to a great depth due the the Socal rains in January this
year, but not soggy. *I doubt that dry, uncompacted sand would do
better.

I have the claw in my Cirrus as an emegency tie down only, I think it
is a good product for that application.

For permanent tie downs nothing like a tire buried with a chain around
it. *One the sand is watered down, it is not goining anywhere.

Mike Malis.

Ditto. I think the claw is a good option as an landout or similar
situation. I've tried a few screw in types and you just cant get them
into either the hard compacted dirt or rocky soils in many locations.
The best place for the glider to be is inside it's box or a hangar.
Otherwise get a real tie down installed, the claw and screw-ins are
all completely inappropriate for permanent tie downs. It is not that
hard to dig a hole, sink some anchors and fill with concrete.

Darryl