Silly Question, but here goes

[Utah-Jay]

How long are your wing tie down ropes? Headed to West Marine this week.

[Battson]

4 meters (13 ft), better too long than too short

[jaredyates]

I really like this stuff: https://rwrope.com/products/sterling...29560646533173
At the moment they don't have the shorter 60-69' option, but with one of those I made a home set and a travel set and still had a little left. If I had to replace one now I'd go for the same stuff. The first batch is holding up well. I used 12' for each wing and a shorter piece for the tail, 4-8' or so.

[kestrel]

The funny thing is that with some common tie-downs, our RV-4 that sits close to the ground needs longer ropes than our Bearhawk. The tie-down rings aren't out wide enough because of the short wingspan!

[Utah-Jay]

The vast majority of my tie scenarios will be in the dirt using my claw tie downs

[rrbeck11]

I hope the claw works for you, Jay. A buddy and I had to divert from Oshkosh to Appleton a few years ago after a cell blew through and drenched OSH. Parking at ATW was on the grass. When we arrived two Carbon Cubs were upside down on the grass. Each of them had two Claws still tied on and resting nearby with small clumps of uprooted grass. I use the EAA design https://www.eaa.org/~/media/files/ea...20tiedowns.pdf with 3/8” x 18”rebar stakes.

[Nev]

I use the EAA design https://www.eaa.org/~/media/files/ea...20tiedowns.pdf with 3/8” x 18”rebar stakes.

This is great - thanks Randy.

[Utah-Jay]

rrbeck11

seems the EAA diagram is a very similar system to the claw with the 3 long stakes angling in, the claw seems to have a wider diameter. But in that midwestern saturated clay I am not sure much short of a duckbill would hold in gale force stop storm winds

[rodsmith]

I hope the claw works for you, Jay. A buddy and I had to divert from Oshkosh to Appleton a few years ago after a cell blew through and drenched OSH. Parking at ATW was on the grass. When we arrived two Carbon Cubs were upside down on the grass. Each of them had two Claws still tied on and resting nearby with small clumps of uprooted grass. I use the EAA design https://www.eaa.org/~/media/files/ea...20tiedowns.pdf with 3/8” x 18”rebar stakes.

Lots of back country strips in the west where those wouldn't work, just too much rock. I'm not sure what a good solution would be. I had homemade similar tiedowns I used in Alaska, sometimes worked. Other times I rolled the largest rocks I could find into place and tied off to them.

[Battson]

rrbeck11

seems the EAA diagram is a very similar system to the claw with the 3 long stakes angling in, the claw seems to have a wider diameter. But in that midwestern saturated clay I am not sure much short of a duckbill would hold in gale force stop storm winds

'Long stakes' being the key words. If we are talking about the same "claw" tie downs, the stakes are so short. At least the ones I have seen.

Getting off topic slightly, I have little faith in so many common tie down anchor solutions - sure most of them "feel" great if one pulls hard on the rope by hand. But we can apply a paltry 50 or 60 kg, or something like that - the Bearhawk will pull 1,500 kg in a 50 knot gust on the nose.... And the gusts might be repeated or sustained. There is absolutely no comparison. Most of the little screw anchors and folding anchors would probably bend or break at that point.

Dirt / earth transfers force at something like a 45 degree angle, in the most general terms, so every inch deeper means a considerable increase in holding weight. For that reason, I try and pitch the pegs as deep as possible, if I am expecting to leave the plane alone for any length of time. I don't think my "two giant pegs" anchor would hold sustained lifting force from extreme gusts, not for long anyway, but I personally think it would be stronger than most of the "commercial off the shelf" solutions sold on Aircraft Spruce or similar...

https://www.eaa.org/~/media/files/ea...20tiedowns.pdf I like the 18" rebar stakes, I don't know if that's a great idea having them all angled inward though. With the pegs all angled in like that, you are only relying on a small area of dirt to spread the force. If they angled out, it seems like it should be far superior, based on my very limited knowledge of this stuff. I am sure someone here is a Civil Engineer and can provide a better explanation!

[rrbeck11]

Good discussion guys. A simple Google search will result in lots of different tests/opinions on the matter (including a test where the Claw wins!) https://www.aviationconsumer.com/acc...is-a-top-pick/

Some good discussion here: https://backcountrypilot.org/forum/t...s-anchors-5455

A clever tie-down that any homebuilder can replicate cheaply: https://abesaviation.com/pages/test-results

A couple of notes:

Jay, I think the primary difference is that the Claw spreads the stakes out at the surface, angled in so that the tips are close together underground. EAA contraption is the opposite. Not saying it's good or bad...I note that Claw recommends anchoring directly below the tie-down ring (due to its design). Most other systems recommend a 45 degree angle between the tiedown and ground.

Battson hit the stake on the head: length matters! RE: angle - with a 45 degree offset a,d the stakes angled in, the pull would be close to 90 degrees against the farthest stake. Angled outward would tend more towards a direct pull. With longer stakes the crossing point is higher (relatively speaking) and the spread much wider than depicted in the EAA pdf above.

Rod - I can see where on some strips you'd be SOL. Tying to the heaviest thing you can find seems like the right idea.

My takeaways:

!) There is no best solution - YMMV depending on soil type, moisture and consistency.
2) None of these solutions are going to hold up against severe gusts. I am thinking that good local knowledge and weather information are the best risk mitigation.

[kestrel]

We seem to have taken an off-ramp from the original question. I'm not sure I've ever seen that happen before and I'm certain that I've never been the cause of it.

I am not impressed with the EAA design. I like the long pins, but I can make long pins for a claw or any other system.

Any of these systems is generally dependent on the geology it is being installed in. Some are pins. Some are spades. I carry Claw and/or Storm Force. Claw generally tests best for typical soil while being able to get it in to typical soil. The spade types (Abe's) will be hard to install in soil with stones. Pins will have better luck. The Storm Force tie isn't heavy and they pull differently than the Claw. I can use them to double up or if the ground is soft, I can bury them to perform more like the Abe's system. If I put them below ground level with slot "cut" for the rope to go direct to the wing, the cross bar will be pulling through mostly undisturbed soil/sand.

...but I think my main point/thought is that no single system is best and you'd better consider the context when securing your airplane.

Sometimes digging holes to roll the wheels into and burying logs as anchors is the way to go. Oh, I also sometimes carry a set of duck bills. Those things tend to stay put, if you can get them in.

[kestrel]

I should note that I get to very little very cool flying like Battson does, and so I do sometimes carry this stuff but have not made extensive use of it.

[Utah-Jay]

Great discussion, and certainly true especially in Utah with so many different soil/rock types.