Home-made Tiedowns
Posted: Mon Aug 06, 2012 11:36 pm
by N111YX
I made these from 1.5 in extrusion and some 10 inch bolts for about $35. There is a company making something similar and I’m not trying to take away any business but if one can build a Sonex, these should be no problem. I’m sure that plenty of Mooney pilots will cough up $100.00 so as to not get their hands dirty… :lol:
Re: Home-made Tiedowns
Posted: Tue Aug 07, 2012 1:39 am
by 142YX
nice. how much does the whole setup weigh?
Re: Home-made Tiedowns
Posted: Tue Aug 07, 2012 9:26 am
by N111YX
It’s about 4.5 lbs. The stakes are the bulk of it!
Re: Home-made Tiedowns
Posted: Tue Aug 07, 2012 2:07 pm
by structurespilot
Nice job on the tie downs Kip. We used to use spiral screwing style dog tie downs with our C182. They worked great in grass, but not so good in gravel.
Re: Home-made Tiedowns
Posted: Tue Aug 07, 2012 6:46 pm
by N111YX
I have found that the dog tie downs are frowned upon ever since the Lakeland tornado. I was a bit embarassed to be using them at OSH and was even more embarassed when one broke while I was tightening it into the hard ground at OSH. I “rented” a set from EAA during the stay but now I have a real set… 
structurespilot wrote:Nice job on the tie downs Kip. We used to use spiral screwing style dog tie downs with our C182. They worked great in grass, but not so good in gravel.
Re: Home-made Tiedowns
Posted: Tue Aug 07, 2012 7:07 pm
by structurespilot
What happen at the lakeland tornado? Did planes flip over due to the dog ties?
Norm
Re: Home-made Tiedowns
Posted: Tue Aug 07, 2012 7:38 pm
by N111YX
Many airplanes were flipped and/or destroyed. It seems that nearly all tie-down sysytem types failed but the dog tie downs were the first to go. It makes sense. Would the desingers really engineer a multi-thousand pound pull force capability for dog security…?
structurespilot wrote:What happen at the lakeland tornado? Did planes flip over due to the dog ties?
Norm
Re: Home-made Tiedowns
Posted: Thu Aug 09, 2012 12:29 am
by fastj22
I talked to the vendor at Airventure selling the design you used. He had a really good design but wanted $70 for his kit.
I guess he didn’t realize that us home builders could do the same thing for $10 with spare material from our kits and a trip to Home Depot. Or like you said, was marketing to the Mooney guys who don’t want to get their hands dirty.
However, it did get me thinking. I thought the steel spikes were excessively heavy. I have a source of titanium rod that will machine it to the size of the steel spikes. But I would need some commitment from enough builders to make them economical. Maybe around a $1 per spike if I order 1000 of them. Or just use aluminum rod as the shear force per rod would be minimal. I get enough folk, I’ll make it happen.
Re: Home-made Tiedowns
Posted: Thu Aug 09, 2012 10:41 pm
by N111YX
I think I paid $1.32 per “spike” (10 inch bolt) so that price would be attractive…
Re: Home-made Tiedowns
Posted: Sun Aug 12, 2012 11:23 am
by 142YX
fastj22 wrote:I have a source of titanium rod that will machine it to the size of the steel spikes. But I would need some commitment from enough builders to make them economical. Maybe around a $1 per spike if I order 1000 of them. Or just use aluminum rod as the shear force per rod would be minimal. I get enough folk, I’ll make it happen.
I would love to believe that price, but unfortunately i must assume you have some figures incorrect given the price for titanium rod, even 3/16" diameter is about $10 per foot:
http://www.mcmaster.com/#standard-titanium-rods/=itf7qp
what’s your source?
Re: Home-made Tiedowns
Posted: Mon Aug 13, 2012 3:12 pm
by radfordc
Bob Mika tested several different types of tie downs to see which held the best. The best was a spiral dog stake. They are difficult to get into really hard ground without breaking. Years ago I bought a set of spiral stakes made from titanium…you can screw then into asphalt if you want to.
N111YX wrote:Many airplanes were flipped and/or destroyed. It seems that nearly all tie-down sysytem types failed but the dog tie downs were the first to go. It makes sense. Would the desingers really engineer a multi-thousand pound pull force capability for dog security…?
structurespilot wrote:What happen at the lakeland tornado? Did planes flip over due to the dog ties?
Norm
Re: Home-made Tiedowns
Posted: Mon Aug 13, 2012 3:28 pm
by radfordc
Here is Bob’s test info:
Today I tested my heavy duty dog anchors. I got a big surprise.
Here are photos and results:
http://www.flickr.com/photos/53052604@N03/page5/
http://www.flickr.com/photos/53052604@N03/page6/
The first test was the Sport Aviation tie down. The SA anchor pulled out at 120 lbs when pulled at 90 degrees and 90
lbs when pulled at 45 degrees.
The the dog anchors were tested. The bottom line was using my 50 lb luggage scale I could not move or pull
out a single anchor. At a 90 degree pull I applied at least 277 lbs to the
anchor. The only thing it did was to rotate slightly to align the rope and
anchor to the force vector.
I then did a 45 degree pull and applied at least 275 lbs. Same result. No
movement, except a little rotation to align to the force vector.
With these results I am going to use two heavy duty dog anchors on each
wing placed about 6" apart. I will use a single anchor on the tail.
Remember, these numbers will be affected by soil type and moisture but the
relative
Bob (number crunchier) Mika
Re: Home-made Tiedowns
Posted: Mon Aug 13, 2012 9:20 pm
by structurespilot
Thanks for the run of tests you performed Bob. Your tests substantiate my thoughts on the dog ties. I was wondering why the tog ties had broken during the storm. I’m thinking that the people were using dollar store quality dog ties. The dog ties would have way more tension strength provided the metal quality wasn’t in question. The strait pins would only have the tension strength provided by the friction of the soil. They both should have similar results in shear strength, provided the metal was of equal diameter.
Not to discount the efforts of people who made the strait rod style tie down, I think they will work just fine. But for me the dog tie style makes sense.
Thanks again for sharing your results,
Norm
Re: Home-made Tiedowns
Posted: Mon Aug 13, 2012 11:28 pm
by N111YX
I guess mine were made from Chinese steel…!
Re: Home-made Tiedowns
Posted: Tue Aug 14, 2012 10:46 pm
by fastj22
My source for titanium stakes is Chinese. Hence the 1000 minimum order and relatively cheap unit price.
However, I was at the local hardware store and they sold 6061 3/8 aluminum rod for $1.5 a foot. I would think 3 stakes (9 total) made from this would well exceed our needs per Kips design and weigh a lot less than steel ones. Sure they couldn’t be driven into pavement, but could work in grass and sand.
Re: Home-made Tiedowns
Posted: Fri Jul 08, 2016 9:59 pm
by Bryan Cotton
Cheap Ti rod:
http://www.titaniumjoe.com/index.cfm/products/bar/