Homemade Tie Down Anchors

[jmbrwn]

Does anyone know how to make or have some homemade tie down anchors? I'm trying to work out my schedule to attend OSH, and know that I need to bring tie downs. I'm not impressed with the one's that can be purchased. Have done some research and found some designs and thought maybe someone here had a good idea.

[jrenwick]

EAA has some good advice here: http://www.airventure.org/2005/planning/tying_down.html

Embedded in the text is a link to the August 1993 "Vintage Airplane" magazine. This is a PDF of an article containing detailed measurements, everything you need to make a good set of tiedowns.

Best Regards,

John

[GAHorn]

This subject was discussed fairly well under the topic "Tie Down Pins". I cut and pasted my own recipie below. In response to another member's suggestion of "Fly Ties" I wrote:

The units I've seen consisted of 3 aluminum "pins" about 18" long, driven thru a thick disc which also held an "eye" to receive the ropes. I tested it at Reklaw by pulling up on the tie-down rope attached to it and the owner panicked and said "Stop, you'll pull it out of the ground!" (Sure, enough, it was easy to dislodge with just a hard pull on the rope.) I couldn't help but wonder why anyone would 1- expect that system to hold their airplane in a strong wind or 2- would pay over $110 for it!
I bought some 4' mobile home anchors at the local hardware store, cut the helical disc's off with a saw, and sharpened the ends. Driving one into the ground at an angle, then another immediately alongside it, so they both presented their "eyes" exactly side by side, allows one to tie a single tie-down rope thru both eyes as if they were one. (They are exactly superimposed, with the lower rods driven into the ground at divergent angles like an upside down "V". In other words drive one in like "\" and the other in like "/" so their eyes are exactly lined up with each other.)
The rope prevents one from being pulled up because of the angle against the other. /\
Untying the rope allows each rod to be pulled up easily by wrapping the rope around your waist, and lifting with your knees.
With a pair of these at each tie-down rope, the airplane is very secure and the total cost is about $30. I use a Boy Scout type hatchet as a mallet, and which doubles as a crash axe/survival tool .

Nylon twisted rope makes a good tie down rope. Available at marine stores/hardware stores. Buy at least 3 sections 15' long each, 3/8" or 1/2" dia. I like the ones they have already made up with a loop already spliced/formed in one end. I can slip the loop thru the eye of the tie downs, and then the other end (the standing end) of the rope thru the loop and tie the "standing end" thru the aircraft tie-down ring.

[jmbrwn]

Thanks John and George for your replies. I checked out the EAA info also. I also like your idea George of using mobile home anchors. I'll do some checking around and see what I can find.

[Larry Holtz]

I made a set using the Airventure recipe before going to OSH two years ago. They worked great. We had a major storm and they didnt loosen.
Larry

[GAHorn]

EAA has some good advice here: http://www.airventure.org/2005/planning/tying_down.html

Embedded in the text is a link to the August 1993 "Vintage Airplane" magazine. This is a PDF of an article containing detailed measurements, everything you need to make a good set of tiedowns.

Best Regards,

John

Here's a point of discussion regarding this method: Click on that link and click on and observe that "illustration 1".
Notice that the three "pins" are all driven toward each other from the plate which is at ground level. Notice that in such arrangement...that a triangle is formed by the plate, and the point where the pins all converge. ALL the dirt above that triangle....is useless resistance. In other words....for the same reason as the other types of systems are condemned in the article (namely that the other type systems loosen the soil and thereby do not provide a good anchor for an airplane)... so THIS system has the exact same weakness for about half it's operational depth. The dirt above the point of convergence offers little or no anchoring ability. The best anchoring ability is provided by the portion of the system BELOW the point of convergence. Agreed?
That's why I am fond of my own suggestion of using two long mobile home anchors with the helix's cut off. They are driven DIVERGENTLY such that when completely driven...only their eyes are closely aligned so the rope can pass thru them as if they were only one rod. Tilting them away from the aircraft, a few feet away from the aircraft (such as in the article's "illustration 2") makes them even more effective.
I carry them beneath my rear seat in a long canvas bag stolen from my wife, (it was the carrying case for her collapsible lawn chair) and I stuff the tie down ropes in the bag along with them. Cheap and effective.

[cessna170bdriver]

I still use a set of tiedown stakes made by ron74887 in 1991. Each consists of about a 2-foot long piece (shorter for the tail) of 1/2 inch rebar with an eye (made up of a short piece of the same rebar bent to an angle) welded near the top. I use 5/8 inch braided nylon rope permanently tied to heavy duty (1/2-inch stock) caribiners which clip through the eyes. I drive the two tiedowns several feet outboard and a little forward of the wing tiedowns at an angle such that the stake is perpendicular to the angle of the rope coming from the airplane. I have a tiedown loop welded on the the tailwheel king bolt, so I drive the tail stake just behind the tailwheel so its rope will make a 90-degree angle to the loop. For storage, I leave the caribiners clipped into the eyes and just wrap the ropes around the stakes. Kind of a heavy rig overall, especially with the 2-lb sledge I carry to drive them in, but they are cheap and they work!

Miles