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What lightweight tie-downs do you pack for travel?
Rope or strap and cinch?
Screw, claw or ??? anchor style?
Got an inexpensive homemade design to share?
tnx
[edit] I should add I'm leaning towards the design from August 1993 issue of EAA’s Vintage Airplane magazine, plate only without the u bolts.
A couple of thoughts in this. I was involved in a group that flew a yearly back country trip and this was a fairly frequent point of discussion and we tried a lot of different approaches.
The augers or spring shaped devices that screw in are fine if the soil is sandy or soft. They won't work if the soil is hard or if it is rocky. The spider shaped device is pretty well thought out, but I think there was one incident where the centrally pointed spikes, pulled out a cone shaped divot in a high wind situation. In this particular instance, I wonder how the others would have fared as the winds were very high.
What I always took was a three lengths of 3/8" climber style rope and three home made devices that consisted of a 5/8"X1"X3" aluminum bar that was drilled so that one foot spikes could be passed through them and hammered into the ground. The drilled holes diverted so that the spikes were in about a 30 degree angle to each other pointing outward. The tiedown rope was then wrapped around the center portion of the bar. The individual spikes could be removed from the ground fairly easily, but together they resisted quite a veritaical force. They worked on hard ground and rocky ground, however I don't think thay would have worked as well in sandy soil but in our destination area that was never an issue .
Lowell
I got a "Claw" set for my plane. I've been impressed with the quality and ease of use and would think that it would hold to all but the most extreme conditions as Lowell mentioned. In that instance, I would wonder if there would be mechanical failure of the tie-down points or wing spar attachments...
My only (-) to this set was the rope comes as one piece that you must cut to three lengths. (2-wing lines and 1-tail line) It is difficult to cut and cauterize to make it not fray and loose the strength of the inner core.
Thanks guys. I can't use the corkscrews with my soil but never trusted them anyways. I was favoring the design linked because it's lightweight and the pins don't just drive in toward center like the 'Claw', but also cross below grade. To my thinking, this seems to make the potential for pulling out a cone shaped divot as Lowell mentioned a bit more difficult. Should work better in more sandy soils as well I would think? Now I'm wondering whether this holds as good or better than the 30* opposing pins in similar soils? Both would be super simple to D.I.Y.
Regarding the rope ends, I melted mine as the rope was Poly. If you prefer, you can whip the ends like we did in my sailing days. check the link - I used a neede for the frapping turns as the lines were braided.
http://www.animatedknots.com/sailmakers/index.php
I built a set of the tie downs that you referenced from the vintage magazine article. Easy to make and have worked great for the 6 years I have been flying my Kitfox. Tremendous hold down ability when you drive the stakes in at an angle. I have a special hammer to pull them out of the ground . I ground the hammer claw to fit around the stake. My tie down kit weighs in at 8 lbs. Bruce Lina N199CL
The EAA tie downs are what they recommend at Airventure. They are effective and light weight. The pins are only 1/4 inch diameter steel and the whole set up with three tie downs and a hammer weighs about 5 lbs. Note the revised version does not use the "U" bolt. The weight could be less if you make the plates from aluminum.
The only negative is the pins can flex and bend when pounding them into rocky soil or hard clay.
One additional thing that is very important is the angle the tie downs are located from the aircraft attach point.
Note in the Burnside video the test using an engine hoist was pulling straight up. None of the portable tie downs do well pulling straight up. But if you pull at an angle to the stakes you get much higher resistance.
The net result is this: Do not put the tie downs directly under your aircraft attach points. Again, refer to the Airventure site under "flying in to Oshkosh"/ tiedowns. The've been doing it for years and they know what works and what doesn't.
JP
a few years back at LockHavens Semential-Journey we had a strong T-storm and several small airplanes were damaged. a Cub that was damaged had the "Claw" brake and another damaged airplane Aronica Defender had a "Claw" arm bent, there was also a Stearmen using the "Claw" damaged. the ropes did not fail just the Claw. I may have just been lucky but I had my Kitfox tied down with screw in type tiedowns I bought at a hardware store like you would tie a dog to and it held. My tent that was under my wing with 6 drive in stakes and all my gear inside blew away showing how much wind was at my Kitfox.
There is no such thing as a guaranteed fool proof, portable tie down. I would ask how many other planes were tied down (properly?) with a "claw" set and were not blown away at that event. These sets are very convenient, well designed and IMO worth the money.
After seeing a 100# labrador pull out a "dog screw" from the ground, I would never trust my plane to one (or even three). I don't even trust the canopy on my camper to them. (I have a claw set for that, too. ;))
I've decided to make a set of the EAA recommended tie-downs, in part because I haven't heard anything negative about them and have some 1/8" plate, but mostly because the other anchors eliciting good testimonials are pretty spendy