We made the EAA ones last year and they worked great but as for total
holding power, the further apart the stakes are, the larger the funnel shape
would be and the heavier right? I think either would be stronger than the
screw type and you could always use longer rods for softer soil. 500 lbs
straight up times three seems like quite a bit of hold down to me. Also I'd
think that if there were a storm so large at an event like Oshkosh, the
planes that weren't tied down at all and the ones that weren't tied well
would be tossed into the ones that stayed put anyway causing plenty of
damage. A friend of mine sold his 172 and where it was after the sale had a
big storm hit. The planes were all tied down to a tensioned cable going
across the apron. The planes all clumped together and flopped over still
connected to the cable. These are temporary tie downs we are talking about.

I'd like to see that test as well. Like a chain only as strong as the
weakest link. If one failed, the other would be sure to follow. Last year I
was on the lake on my boat, tied off to several other boats watching a
floating concert. There were about 20 boats tied side by side, several of
them were little ones, then out on the end was two 30 foot pontoon boats. A
storm came up quickly and twisted that line into a J shape, ropes started
breaking, cleats started flying around like mad. Many boats were damaged and
most of their owners had done nothing wrong except allowing one other boat
to be added to the line. My buddies now know why I carry a knife with me
almost all the time, so I can cut free before I get stuck in the middle of a
mess like that.

Wayne


"Maule Driver" wrote in message
. com...
The 'Claw' and the EAA design are different. They both use 3 stakes per
tiedown. The 'Claw' uses a collapsible tripod claw that lies flat on the
ground with stake holes that guide the stakes inward towards the center.
The EAA design appears to consist of a plate with stake holes that allow
you
to drive the stakes outward.

Notably, the 'Claw' specifies that tiedowns should be placed directly
underneath the tiedown point (which won't work very well on the tail of a
taildragger). The EAA design specifies that the tiedown should be placed
so
that the tiedown rope will apply pressure at an angle.

Aviation Consumer tests resulted in the Claw failing in one case by
pulling
out a large plug of dirt (presumably funnel shaped). When pulled at an
angle, it failed by breaking one of the arms. Failure occurred at 500lbs
(straight up) and 475lbs (at unspecified angle). They stressed that
tiedown
strength varies significantly by soil type.

It would be interesting to compare the 2 systems in identical soils. I
would guess that the claw would be stronger in a straight up pull but have
no opinion on an angle pull.

Hope I never have to care.

"Mike Z." wrote in message
...
I just built some close to the EAA plans with a little scrap and the rod
and u-bolts from Home Depot for about $20. Plus rope and
the hammer of course.
http://www.vintageaircraft.org/magaz...ft_tiedown.pdf

It helps to have access to a vise and a die set of course.

Mike

"Justin Case" wrote in message
...
I only asked because the number didn't work for me. Well, I didn't
want to wait any longer so I constructed my own patterned after ones I
found on the net. Given the construction time involved, it was not a
money saver. $125.00 isn't a bad price to pay for a nice set of
tiedowns.