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Hi Geoff


I use the "Screw It" tie down kit which is pretty good and light enough to keep in the aircraft all the time. I haven't come across it yet but I believe that in REALLY hard ground they may struggle a bit. I did have a more heavier duty kit that would almost go into concrete but was about 5kg.



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  • 2 weeks later...

(smiley6.gifI know I'll regret saying this, but perhaps I represent a few others and you never know we might learn something from this)


What calculation?? I chose my tie down rope for its colour matching the a/c. Oh, and yeah, it looked strong enough as well as lending itself to splicing.





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Hi Crew


It would be helpful for these type of questions to be answered by constructive information then we might all learn something.


The colour scheme is a start - have we got any more suggestions?





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Well, the reason I ask is that I was thinking along the lines of: If the wind is strong enough to get lift the aircraft off the ground, then Lift is probably greater than weight - if weight is a maximum of say 400kg (no persons on board), and you want the rope to hold the plane in the even of 1 of the 3 tie down points coming loose / failing, then the breaking strain of the rope should be at least 200kg - but I am not sure of this reasoning is correct.


Colour? Hmmm, my rope is Orange and the plane is Blue! (I chose it so people dont walk in to the rope)



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Hi Crew


Is yellow rope suitable for the cases below?


What happens to the lift force when the wind speed changes to way above the clean stall speed?


What about the difference between the lift on a tail dragger versus a tricycle UC with three wheels tied down on the ground?


Is the taildragger already stalled when tied down for head winds & tail winds?


What happens in both cases when the tail is into the wind?


If we have negative flaps should they be applied for the tail dragger or for the tricycle when tied down?





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I can't talk from years of experience or any great insights, I can only offer my thoughts that went into my choices.


To go with my recently purchased plane I bought a set of Screw-Its at Narromine based on a recommendation at the time and various favourable conversations I had had over the prevoius 12 months.


I chose 6mm nylon rope to go with the Screw-Its for a couple of reasons.


1. 6mm is big enough to undo tight knots with frozen hands at dawn.


2. Nylon has some give so if the plane gets lifted the attach points are not subjected to massive shock loads as the rope takes up.


3. Nylon anchor rope is generally UV stabilised.


4. Easy to splice (if you want to)


Choosing the rope size based on handling negated the strength issue as the breaking strain is 735kg so each rope is capable of holding more than double the 340kg MTOW of my plane.


I haven't used them yet, but then I bought them on the basis that the first time I needed them it would be too late to be thinking about buying them.







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I'm not sure about genuinely positive suggestions, but I can tell you some of the negatives I've learnt the hard way! :;)1:


I once bought a set of those cheap 'ratchet' type strap kits, (they didn't actually ratchet, just had a sprung loaded jaw that gripped the webbing) which had black webbing with an Orange trace.


These worked really well for about six months in the sun, then just fell to bits.


I wasn't there when the big gust came through, snapped one side, and stood my plane up on it's wingtip!, fortunately another club member grabbed a strut before it could go over. Thanks JÃÂN


The other lesson came at Holbrook many years ago when at a fly-in it was suggested we all tie down 'cause a storm was due that night.


I had some left over tent pegs, the little 6" rod ones which I had to hammer into the hard clay ground, couldn't imagine them coming loose but..


When the storm came, there was a sudden torrential downpour followed by an equally sudden strong wind.


With most of the attendees inside a large marquee, holding it down, word came through that someone's plane had blown across a taxiway from one parking area to another and collided with another plane, neither plane was now flyable. 068_angry.gif.cc43c1d4bb0cee77bfbafb87fd434239.gif


My initial thought was "There's always someone that can't be bothered to think ahead"


Then the whole news got through, IT WAS MY PLANE!!


When I got out to look, sure enough, there was my plane wedged onto a friend's plane, still with the tie downs attached with the pegs still stuck into six inches of sod!


The ground had simply turned to mud and lifted away in two big lumps. :ah_oh:


I now carry a 'Screw-It' kit and just hope rain wicking down the rod will not soften the ground as before.





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Hi Crew


One point that worries me on the Jabiru is that the strut connect point on the wings is shielded by "flocked on" and screwed on fibreglass shielding. This makes the point of connection to the wing unavailable for tiedown ropes.


The onlytype of load the struts should experience should be axial tension or very low compression but in the axial plane in line with the the centre line of the holes in the ends of the struts. That is load in line with the long length only. This would avoid bending the long small diameterstruts (ie very unsuitable for side loading by tying ropes on them any distance from their ends).


Some GA aircraft actually have an eye bolt screwed into the underside of the wing to facilitate the tiedown.


Others with struts have enough room around the connection for a rope to be threaded through the connection avoiding the problem altogether.


Any suggestions





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