I need tie downs for OSH

unsafervguy said:
In my English classdoes not recommend was not the same as does not allow........
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Fair enough, but they drive the point home well enough to not use them. Id be pretty ****ed if some cheap skate next to me had his plane ding mine because the triangle top straightened out. But 9 times out of 10 they will work fine but I still wouldn't trust them. Both times Ive been to OSH Ive seen some nasty storms and seen planes levitate on the tie downs.

I bet insurance companies are nervous wrecks when OSH goes on. 1 tornado I would suspect would put a hurting on the industry.
 
If I remember correctly the outcome at sun n fun during the tornado was all different kinds of tie downs failed and all different kinds held. You can't beat Mother Nature. It all comes down to how well the dirt holds. My thought is the deeper and more abundant number of stakes the better off you are.
 
I'm surprised no one has mentioned these yet: http://www.flyties.com/

I'm convinced that they should hold a little better than the claw, but mostly I just like the design. Any weather that will break one free will break the other.
 
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SixPapaCharlie said:
Just had that thought. Angle Iron and a couple accessories.
Might be a winner.
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I did this but used thick aluminum angle iron for weight. Eye bolt in the middle and 18 inch spikes off of Amazon. Four spikes in opposing directions over 20”.
 
172andyou said:
I'm surprised no one has mentioned these yet: http://www.flyties.com/

I'm convinced that they should hold a little better than the claw, but mostly I just like the design. Any weather that will break one free will break the other.
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I've got a set that I used last year at Osh. They're great! Less bulky than the Claw, and with the smaller footprint you're less likely to trip over them when you're clambering around the plane in HBC. The way the holes are drilled in the aluminum pieces, it splays the stakes in three different directions for a very secure hold.
 
simtech said:
But was the claw one of them? :)
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Yes, unfortunately many people reported the Claw failing at Sun-N-Fun. I'm pretty sure it was a tornado though, so who knows what would stand up to that.

FWIW, I use Stormforce. Looked like a better, simpler design, and as some have shown here, you can make your own if you're so inclined!
 
I had craws BREAK at Cody, Wyoming. They didn't give completely, but they were rendered non-fucntional. To their credit, the Craw guy gave me new components just on my sayso at Oshkosh.
 
THE cheapest (I excel at that) and hardiest (best holding power) is...
Buy a 6’ heavy gauge T-post.
Using a metal cutting blade on your skilsaw, cut it into 3 pieces, making rhe cuts at a 60* angle. (One end of the middle piece will need cutting at 90* when that is done)
Drill, or blowtorch holes into sides of the 3 flat ends, place a single link of chain in each hole. (they come threaded or crimp style).
Add ropes.
Take small mallet with you.
Install into ground at correct location and angle.
<$15.
 
When you arrive you’ll be offered a set of inexpensive but functional tie downs. I think they “sell” for $25 but you can “sell” them back for $10, if memory serves. I’ve had my aircraft tied down with them in truly hellacious storms and never had a problem. I’ll probably be screwed if a tornado comes through, but I think I’ll be screwed no matter what. Nothing is going to stand up to a tornado.
 
Ugly, but effective: 28" rebar,. Heat the end, bend it around to form a loop. Heat, quench. Cut a point on the other end.
Strong enough to pound with a hammer, and it will hold a big plane in a big wind.
 
I had a set of tie downs made several years ago using the 1993 EAA plans quoted above. I use a single hole with the rope knotted under the plate. The tie down hold very well and never had the airplane shift position during any of the wind storm / thunder storm / tornado which come through the North 40, one or two each year. Took me a few years to learn how to pull the pins when it is time to leave. 1. Step down on plate. 2. Use vise grips on the lock nut and pull straight out.
On a side note, here is what not to use: Gust spun the airplane 90 degrees and parked it on his tent.


WindStorm4.JPG WindStorm3.JPG WindStorm2.JPG WindStorm1.JPG
 
SixPapaCharlie said:
I was looking at that claw system on sporty's which i think is what @tecprotb used for his RV the year we went.

I don't have any tie downs and am torn between getting something formal like this or just grabbing some spikes and rope from home depot for a bit less money.

What sayeth the peanut gallery?
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Abe’s Anchors were strongest in the Aviation Consumer pull testing a few years back... broke their pull tester rather than failing!

It’s instructive to stand near the Claw booth at OSH and watch the parade of folks bringing in broken claws...

Paul
 
I can’t help but think there is more to the anchor strength than the anchor itself. The angle of the loads also has to be considered. The 747 that had a load shift and went down in the Middle East was using inadequate tie downs because of the angles the loads were pulling.

Now I’m just a bean counter by day, so I welcome any of you actual engineers to chime in. Am I wrong thinking the design of the anchor needs to be matched with the angle of the load to determine the true strength of the tie down system?
 
aggie06 said:
I can’t help but think there is more to the anchor strength than the anchor itself. The angle of the loads also has to be considered. The 747 that had a load shift and went down in the Middle East was using inadequate tie downs because of the angles the loads were pulling.

Now I’m just a bean counter by day, so I welcome any of you actual engineers to chime in. Am I wrong thinking the design of the anchor needs to be matched with the angle of the load to determine the true strength of the tie down system?
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Yes.
The angle of the load changes the forces on the anchor, plus it changes how hard it is to pull out of the ground - pulling in line with a stake is the easy way to get it out. Pulling at an angle makes it harder. Making the lines less vertical also helps a lot to reduce the tension in the lines from the wind blowing an aircraft along the ground, but increases the load if there is enough lift that the airplane tends to lift off.
 
aggie06 said:
Now I’m just a bean counter by day, so I welcome any of you actual engineers to chime in. Am I wrong thinking the design of the anchor needs to be matched with the angle of the load to determine the true strength of the tie down system?
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For sure. Fly-Ties, for example, recommends that the line come straight down from the wing in order to have the pull be as close to vertical as possible, thus spreading the load equally across all three stakes.
 
Mine start as 2, 48 inch long, 1" diameter oak dowels cut at their midpoints to a 60 degree angle to yield 4, ca. 26 inch long dowels with chisel points on one end of each. I drilled 1, 9/64 inch diameter through-hole 2 inches down from the flat end of each dowel, and another through-hole 3 inches from the end. I fit a U bolt (1/8 inch diameter with a 1 inch width) through the holes with a nut on each side of the dowel.

Pound the dowels into the ground at a the proper distance so that the dowels are at about a 45 degree angle to the ground with the U bolt oriented away from the plane at a distance so that the rope will be roughly perpendicular to the dowel. About 8 inches of dowel extends above the ground. Thread the rope around the dowel through the U bolt (the rope is tied to the dowel, not the U bolt, the U bolt simply keeps the rope from slipping up or down on the dowel).

I mount one to each wing tiedown, and two to the tail tiedown (each at about a 45 degree angle to the fuselage long axis). They don't move. To get them out I have to insert a 14 inch long screwdriver from my tool kit through the U bolt to provide leverage to rotate the dowels. Then hammer them side to side until they loosen. Keep pulling and wiggling until they come loose.

Dowels are simple and light. The 2 lb hand sledge does add weight. Total cost of about $10 for materials and $8 for the Harbor Freight sledge.

I actually purchased a 6 ft length of 1" diameter aluminum rod to make what I expected to be stronger, lighter versions, but the oak dowels are working so well I haven't bothered to make new ones.
 
Having the rope pulling at an angle to the tie down is important. I use the the homemade EAA Design. With any of the multiple spike designs you will get maximum grip if none of the spikes are driven into the ground parallel to the angled rope.
 
Nobody’s mentioned that it doesn’t really matter what tie downs you have at OSH.

The guy next to you has some jackass setup that won’t hold if you go pull on it.

So when the real storm hits, their airplane will be on top of yours anyway.
 
Two pix I took from the Sun n Fun Tornado. If you look closely, you can see one of the auger-type tie downs hanging from the yellow float plane and one of the Claws being dragged by the blue plane. The Flyties did the best job but it may have been luck or the kind of soil (sandy) at Lakeland. Tornado.jpgTornado 2.jpg
 
swingwing said:
Having the rope pulling at an angle to the tie down is important. I use the the homemade EAA Design. With any of the multiple spike designs you will get maximum grip if none of the spikes are driven into the ground parallel to the angled rope.
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The Claw directions say to put it right under the tie down ring so the rope goes straight up.
 
Greg Bockelman said:
The Claw directions say to put it right under the tie down ring so the rope goes straight up.
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Another interesting point. Seems that the direction of force relative to the angle of the rope and also rope angle vs tie down anchor angle are both important. I think that also means the AvWeb method of testing might not be the most telling.

Really this means that we need two things. First, an overbuilt test rig to determine the best combination of anchor point and rope angles. Second (maybe more important), is a satirical YouTube spot about tie downs. @SixPapaCharlie ?
 
Am I the only one who gets the shivers (and a mental image of Jim Carey) every time I hear "the claw"?
 
New ad in one of the aviation magazines for a new kind of tiedown you can put in with either a ratchet handle or a cordless drill.
 
Ravioli said:
EAA does not recommend the "doggie ring" style that can quickly fail. The triangle-shaped top portion straightens under heavy loads...
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Apparently not. (But it did pull out of the ground)
Cogito said:
Two pix I took from the Sun n Fun Tornado. If you look closely, you can see one of the auger-type tie downs hanging from the yellow float plane and one of the Claws being dragged by the blue plane. The Flyties did the best job but it may have been luck or the kind of soil (sandy) at Lakeland. View attachment 64402
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The soil will make a big difference both in how much force can be developed by any particular anchor, and which kind of anchor will work best.
 
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