Glider tie down.

There was a commercially available system called Fly Ties that was
essentially a hub or block with 3 holes drilled through it at 45's
through which you pushed or drove straight pointed rods or stakes
through into the ground. This created a pretty good anchor that is
similar in concept to the Claw. I think the Claw might actually be
better but I didn't know about it when I copied Fly Ties. I needed a
super light-weight tie down set as my baggage allowance is pretty
small. I used Delrin cylander stock about 2 inches in diameter by 2
inches long to make the hubs. Eye bolts through the middle of those...
Three aluminum stakes about 3/8ths inch diameter and 10 or 12 inches
long with a right angle handle on one end and points on the other
finish out each unit. The original Fly Tie system has longer steel
rods so is quite a bit larger and heavier. I carry four anchors in a
bag about 6 inches in diameter by 12 inches long which includes rope,
nose hook ring, and a small mallet in case the ground is hard. I can't
remember the weight but it's something like 4 to 7 pounds tops. Those
suckers are really secure and come out easy and clean when ready to go.
Screw-in dog tie downs aren't made for vertical loads as dogs do not
usually fly except perhaps in tornados.