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The "Claw" tie down
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Jabfox(at)hotmail.com
Guest

Posted: Sun Jun 25, 2006 10:19 am Post subject: The "Claw" tie down

On Thursday at the Sentemental Journey Fly-In at  LockHaven, Pennsylvania ( LHV ) we had a severe thunderstorm and at the time  there were around 180 lite aircraft tied down on the airfield. 3 of the 7  airplanes that had damaged were tied down with the " Claw " One of the claw arms  that was holding a J-3 Cub broke, and the other calw tiedowns came out of the  ground. Mabee I was just lucky but my Kitfox was tied down with screw in  type  tie downs.

dan(at)azshowersolutions.
Guest

Posted: Sun Jun 25, 2006 1:00 pm Post subject: The "Claw" tie down

Good information Dave. 3 out of 7 failures is significant...I was just looking into either purchasing or making a "claw" set. Time to re-evaluate. What else is good to look at? I know by experience if the ground isn't damp or somewhat soft, the screw-in type can be a bear to utilize. Here in the Southwest the ground can be extremly hard. 

  Dan

  Kitfox IV / Mesa, AZ



David McCormick <Jabfox(at)hotmail.com> wrote:

   	  Quote: 	
		          On Thursday at the Sentemental Journey Fly-In at LockHaven, Pennsylvania ( LHV ) we had a severe thunderstorm and at the time there were around 180 lite aircraft tied down on the airfield. 3 of the 7 airplanes that had damaged were tied down with the " Claw " One of the claw arms that was holding a J-3 Cub  broke, and the other calw tiedowns came out of the ground. Mabee I was just lucky but my Kitfox was tied down with screw in type  tie downs.

kirkhull(at)sbcglobal.net
Guest

Posted: Sun Jun 25, 2006 1:41 pm Post subject: The "Claw" tie down

when  you say " Claw "  is that the one that the EAA has  plans for one the osh websight?  it is kind of a flat plate with a U bolt  in the middle and 3 holes to drive stakes through.

 [quote]   --

morid(at)northland.lib.mi
Guest

Posted: Sun Jun 25, 2006 1:41 pm Post subject: The "Claw" tie down

I gotta plead ignorant here.  I have no idea  what the claw looks like.  Anybody like to describe it or point me to a  picture?  

 I've always found the screw type to work pretty  well in most ground.  Gotta have some sort of bar to give enough leverage  though.  I wonder if anybody makes them in aluminum?

 Deke

  

 [quote]   ---

dan(at)azshowersolutions.
Guest

Posted: Sun Jun 25, 2006 2:08 pm Post subject: The "Claw" tie down

Kirk, 

  I thought that was the case when I heard "claw" ...I was mistaken. This is the one that Spruce sells. http://www.aircraftspruce.com/catalog/pspages/claw.php

  The EAA one as you mentioned is what I am going to make... http://www.vintageaircraft.org/magazine/aircraft_tiedown.pdf

   

   

  For more info this is what EAA has to say about tie downs: http://www.airventure.org/2006/planning/tying_down.html

  Dan



kirk hull <kirkhull(at)sbcglobal.net> wrote:

  [quote]        when you say " Claw "  is that the one that the EAA has plans for one the osh websight?  it is kind of a flat plate with a U bolt in the middle and 3 holes to drive stakes through.

  [quote]  --

7suds(at)Chartermi.net
Guest

Posted: Sun Jun 25, 2006 2:15 pm Post subject: The "Claw" tie down

Deke,

 I have a set of the screw in type made  from titanium, they came in a set of 3 with a cheater bar for screwing them in  also made from titanium, a friend of mine found a guy who was selling them over  the internet, asked me if I wanted a set (at) $60.00 so we ordered 2. I will ask  him if he still has the contact # if you are interested.

  

 ---

morid(at)northland.lib.mi
Guest

Posted: Sun Jun 25, 2006 2:37 pm Post subject: The "Claw" tie down

Please do.  I'd appreciate that.   

 Thanks,

 Deke

  

 [quote]   ---

runwayrex(at)juno.com
Guest

Posted: Sun Jun 25, 2006 4:01 pm Post subject: The "Claw" tie down

Hi Guys, 

  I have one of the ones that Spruce sells and it's worked well for me in some of Oshkosh's nasty storms. It sure is a heavy package though. Is this the same Claw that three of seven damaged aircraft were using or is it a different one? 

Rex Phelps in Michigan



-- Dan Billingsley <dan(at)azshowersolutions.com> wrote:

 Kirk, 

 I thought that was the case when I heard "claw" ...I was mistaken. This is the one that Spruce sells. http://www.aircraftspruce.com/catalog/pspages/claw.php

 The EAA one as you mentioned is what I am going to make... http://www.vintageaircraft.org/magazine/aircraft_tiedown.pdf

  

  

 For more info this is what EAA has to say about tie downs: http://www.airventure.org/2006/planning/tying_down.html

 Dan



kirk hull <kirkhull(at)sbcglobal.net> wrote:

 [quote]  when you say " Claw "  is that the one that the EAA has plans for one the osh websight?  it is kind of a flat plate with a U bolt in the middle and 3 holes to drive stakes through.

 [quote] --

asq1(at)adelphia.net
Guest

Posted: Sun Jun 25, 2006 4:22 pm Post subject: The "Claw" tie down

The two that I saw looked like these. They were ripped completely out of  the ground.  Larry Huntley

 [quote]   ---

lcfitt(at)sbcglobal.net
Guest

Posted: Sun Jun 25, 2006 6:20 pm Post subject: The "Claw" tie down

Thanks for the post, David.  At the Rans fly-in at West Desert Airpark in 

Utah, I saw my first one being used by one of the local Rans guys.  For 

other reasons I wasn't too impressed, but this is the kicker for sure.



I made up  a set of a similar idea that would apparently not have the 

fragile arm issue



Lowell



---

lcfitt(at)sbcglobal.net
Guest

Posted: Sun Jun 25, 2006 6:38 pm Post subject: The "Claw" tie down

What I didn't like about the claw is that the spikes are driven toward the 

center of the circle.  It seemed to me that heavy enough lifting could 

simply lift a cone of earth out. I would likd the design better if the 

spikes were driven outward, increasing the circumference of the spiked area.



Loewll

---

morid(at)northland.lib.mi
Guest

Posted: Mon Jun 26, 2006 2:55 am Post subject: The "Claw" tie down

Lowell, I agree.   I've thought about this a lot and it just doesn't seem

like it grabs much dirt by angling the spikes inward.  What I've been

thinking about coming up with is something quite different.

First, it's early and I've just started my coffee so I don't know how

coherent this will be, but here goes.



Materials:  I think a simple triangular 5052 aluminum plate about 8X6X1/4

inches with three 9/16" holes in a row on one side about 3" apart and a

large 1" hole in the opposite corner.  The three 9/16" holes would be for

the driving rods and the large hole would be for the rope.  Next I'd need

three 18X7/16" 5052 aluminum rods pointed at one end.



Placement:  Now, the tiedown plate would be placed directly under the

tiedown ring, but about 3 feet laterally outward toward the wing tip and the

stakes driven into the ground at about a 45 degree angle toward the fuselage

with the outward stakes driven at a 20 degree outward angle from the center

stake.  By using these angles and all facing relatively toward the fuselage,

it seems to me that the maximum holding power would be available and all

stakes would have equal holding power.  The angles I'm visualizing here are

only approximate and may need some tweaking for maximum strength.



Some sort of method for removing the stakes and also for capping them so

they won't slip through the holes in the plate would be necessary, but those

are simple details that could easily be solved.  5052 is very strong, but

also very light so the entire package would weigh very little and could be

wrapped in a towel or something while stored in the baggage area.

Obviously these stakes would be good for dirt only, not asphalt or rocks.

I'll try to whip up a drawing or something if this isn't making any sense.

Comments?

Deke

---

Rex Hefferan

Joined: 10 Jan 2006
Posts: 147
Location: Olney Springs, Colorado USA "NOT a Kitpig"

Posted: Mon Jun 26, 2006 3:41 am Post subject: The "Claw" tie down

There can be problems with any temporary anchoring system if improperly 

used. The condition of the soil is going to be a major factor on how 

well it can hold an anchor. I would guess that as it rained the soil 

lost much of it's holding ability. Michel's suggestion of length is wise 

due to the angle of tension for the type of anchor he uses. I don't 

think it would work well for a Claw. I would also expect the soil 

conditions to vary from site to site. So some planes may have been lucky 

that they were over better holding ground. Still, a thunderstorm is 

going to be very tough on any achoring system.

 Reports of real world experiences such as this can be very useful as 

long as you can factor in all the details.

Rex

Florida/Colorado

 



 	  Quote: 	
		  



 The two that I saw looked like these. They were ripped completely out 

 of the ground.  Larry Huntley

_________________
Rex
N740GP - M2/582
Colorado

asq1(at)adelphia.net
Guest

Posted: Mon Jun 26, 2006 5:06 am Post subject: The "Claw" tie down

The ground was soft and wet at Sentimental Journey. I use screw stakes(like 

dog screws ,but longer and larger dia.). They were screwed in ALL the way. 

Dog screws are too light and have a flat spot where the ring is fastened 

that just breaks off if you put too much force on them. The ropes were 

pulled TIGHT and locked w/ 2 half hitches. In the worst of the storm,it was 

not even wiggling. I saw one bird that had torn screws loose,but it had been 

tied w/ a strap w/ only one lpass over the strut,instead of wrapping it 

around so it could not slide down. Of course,it slid down the strut,the wind 

lifted the wing and w/ all the leverage,the screw tore loose. Saw many 

bouncing up and down on ropes that were tied too loosely.

 Screw them down til the ring is at dirt level,lash the ropes tight(my old 

instructor used to say,"two half hitches will hold the devil".),run the rope 

over the strut and then through the ring if there is one,or twice around the 

strut top. Ring does a good job of holding the rope from sliding down the 

strut,but they have been known to break off if the forces get too high.

  There probably is no perfect system,but if there is it probably comes from 

hurricane country. If it has worked there,it will probably work anywhere. In 

40 yrs from Florida to Alaska,I have never had a problem. (Shouldn't aughta 

say that,eh?)     Larry



---

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Jun 26, 2006 11:39 am Post subject: The "Claw" tie down

Deke,



During our Idaho fly-outs we talk of tiedown methods all the time.  Our 

problem is that we are only occasionally in meadow like conditions where the 

screw type would  be ideal.  One of the guys at the Utah fly-in had the 

titanium ones and they are very nice.  The diameter is not great - about 3", 

but they are very light weight and come with a short piece of titanium to 

use as a wrench so the last one is as easy to get into the ground as the 

first two.



Other times - actually very frequently - the ground is rocky and hard and 

the screw type are very difficult to get in.  Of course once in, they will 

hold like a buried anvil.



One of the guys had an interesting idea where two rods - actually the long, 

about 12" construction nails - are driven into the ground at an angle within 

a single link of chain and the tiedown rope looped inder the two heads and 

the chain link  I think this is similar to your idea.  My version uses a 

short piece of 5/8" X 1" aluminum bar with divergent holes drilled through 

so the nails are held at about a 60 or 70 degree angle. I think this is 

something like your idea.  I can drive these in anywhere and the ridgidly 

held angled spikes have to move a lot of dirt to come out.



For removal, I ground the claws on a small hammer to accept the heads of the 

large nails and using the hammer as a large handle they are easily removed. 

The whole thing including hammer and bag weighs just under three pounds.



I think if you angled the holes so the spikes would be held at the angles 

and placed them so the aluminum triagle is parallel with the wing, it would 

have 30% more holding power than mine and if you could find titanium spikes 

it should be a sure winner.



Lowell



---

morid(at)northland.lib.mi
Guest

Posted: Mon Jun 26, 2006 2:37 pm Post subject: The "Claw" tie down

inbedded comments below...



 	  Quote: 	
		   Deke,

 During our Idaho fly-outs we talk of tiedown methods all the time.  Our

 problem is that we are only occasionally in meadow like conditions where

the
	


 	  Quote: 	
		   screw type would  be ideal.  One of the guys at the Utah fly-in had the

 titanium ones and they are very nice.  The diameter is not great - about

3",
	


 	  Quote: 	
		   but they are very light weight and come with a short piece of titanium to

 use as a wrench so the last one is as easy to get into the ground as the

 first two.


	


        I did a little research and those titanium screw-ins are very nice.

They're stronger and lighter than my steel screws, but they're also up to

$80 now.  I think I can come up with a better solution than that.



 	  Quote: 	
		  

 Other times - actually very frequently - the ground is rocky and hard and

 the screw type are very difficult to get in.  Of course once in, they will

 hold like a buried anvil.


	


        Correct.  In rockey ground, or even very dry hard clay, they can be

a bear to work with, but once they're in...  Spikes can handle pretty much

anything other than large rocks.



 	  Quote: 	
		  

 One of the guys had an interesting idea where two rods - actually the

long,
	


 	  Quote: 	
		   about 12" construction nails - are driven into the ground at an angle

within
	


 	  Quote: 	
		   a single link of chain and the tiedown rope looped inder the two heads and

 the chain link  I think this is similar to your idea.  My version uses a

 short piece of 5/8" X 1" aluminum bar with divergent holes drilled through

 so the nails are held at about a 60 or 70 degree angle. I think this is

 something like your idea.  I can drive these in anywhere and the ridgidly

 held angled spikes have to move a lot of dirt to come out.


	


        Hmmmmm.  That link of chain adds a twist to this.  Maybe even two or

three links, each with it's own spike and one link for the rope?  Even more

simple yet.  I think 12" isn't really long enough as they wouldn't do much

in soft ground.  18" will really get down there.  I'm still thinking about

the 5052 aluminum rod rather than nails.



 	  Quote: 	
		  

 For removal, I ground the claws on a small hammer to accept the heads of

the
	


 	  Quote: 	
		   large nails and using the hammer as a large handle they are easily

removed.
	


 	  Quote: 	
		   The whole thing including hammer and bag weighs just under three pounds.



 I think if you angled the holes so the spikes would be held at the angles

 and placed them so the aluminum triagle is parallel with the wing, it

would
	


 	  Quote: 	
		   have 30% more holding power than mine and if you could find titanium

spikes
	


 	  Quote: 	
		   it should be a sure winner.

 Lowell


	


        I really do think the crux of this whole thing isn't so much as

whether it's screw-in or spikes, but the angle of the rope to the wing and

the angle of the spikes.  If the angle of the rope is about 45 degrees from

the wing to the ground and the spikes are at about 60 degrees (inward toward

fuselage) to the rope, I don't think you could get much stronger.

Deke



Deke



[quote]

 ---

bnn(at)nethere.com
Guest

Posted: Mon Jun 26, 2006 4:53 pm Post subject: The "Claw" tie down

At 06:05 AM 6/26/2006, you wrote:

 	  Quote: 	
		  run the rope

over the strut and then through the ring if there is one,or twice around the

strut top.


	


Yikes! Are you side-loading the outboard strut end? VERY SCARY, if so. You 

could easily bend the threaded rod inboard of the rod end.

Guy Buchanan

K-IV 1200 / 582-C / Warp / 99.9% done, thanks mostly to Bob Ducar.

asq1(at)adelphia.net
Guest

Posted: Mon Jun 26, 2006 5:36 pm Post subject: The "Claw" tie down

It doesn't sideload it as much as you might think. If it goes through a 

hurricane,I'll replace the strut ends rather than the whole airplane. This 

probably applies more to other strut systems( like the Avid and others)than 

the Fox. You have a good point,but I will continue as I have. Next time at 

the hangar I will look it over .  Larry



---

rjdaugh(at)rapidnet.com
Guest

Posted: Mon Jun 26, 2006 5:41 pm Post subject: The "Claw" tie down

David,  (Or others),  

The data point that is missing here is how many planes were tied down with the Claw?  If there were three, the failure rate was 100%.  If there were 6 the failure rate drops to 50% - Still not good!  If over half the planes there were using the “Claw”, the failure rate drops to a much more reasonable 3%.  

   

Because the claw is relatively new, I suspect that not very many were using it.  Can anybody provide some insight here?  My first impression of the claw, based on advertisements, was good.   But I think I like Lowell’s design better.  

   

Sorry to be so late coming to this thread.  

   

Randy  

     

.             

  

         

  

From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of David McCormick

 Sent: Sunday, June 25, 2006 12:17 PM

 To: kitfox-list(at)matronics.com

 Subject: The "Claw" tie down  

  

     

On Thursday at the Sentemental Journey Fly-In at LockHaven, Pennsylvania ( LHV ) we had a severe thunderstorm and at the time there were around 180 lite aircraft tied down on the airfield. 3 of the 7 airplanes that had damaged were tied down with the " Claw " One of the claw arms that was holding a J-3 Cub broke, and the other calw tiedowns came out of the ground. Mabee I was just lucky but my Kitfox was tied down with screw in type  tie downs.

runwayrex(at)juno.com
Guest

Posted: Mon Jun 26, 2006 6:35 pm Post subject: The "Claw" tie down

Randy, 

  I'm not sure how new the Claw system is. I bought mine two years ago and had seen it at Oshkosh for at least a couple years before that. I seem to be the Lone Ranger here, but I like mine. Once I have it set up, I can't picture it ever coming out because of winds.  

Rex in Michigan



-- "Randy  Daughenbaugh" <rjdaugh(at)rapidnet.com> wrote:

   

David,  (Or others), 

The data point that is missing here is how many planes were tied down with the Claw?  If there were three, the failure rate was 100%.  If there were 6 the failure rate drops to 50% - Still not good!  If over half the planes there were using the “Claw”, the failure rate drops to a much more reasonable 3%. 

  

Because the claw is relatively new, I suspect that not very many were using it.  Can anybody provide some insight here?  My first impression of the claw, based on advertisements, was good.   But I think I like Lowell’s design better. 

  

Sorry to be so late coming to this thread. 

  

Randy 

   

.           

 

     

 

From: owner-kitfox-list-server(at)matronics.com [mailto:owner-kitfox-list-server(at)matronics.com] On Behalf Of David McCormick

Sent: Sunday, June 25, 2006 12:17 PM

To: kitfox-list(at)matronics.com

Subject: The "Claw" tie down

 

   

On Thursday at the Sentemental Journey Fly-In at LockHaven, Pennsylvania ( LHV ) we had a severe thunderstorm and at the time there were around 180 lite aircraft tied down on the airfield. 3 of the 7 airplanes that had damaged were tied down with the " Claw " One of the claw arms that was holding a J-3 Cub broke, and the other calw tiedowns came out of the ground. Mabee I was just lucky but my Kitfox was tied down with screw in type  tie downs.

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