The International Cessna 170 Association

Richard, that looks like a great idea. Ever have any trouble pulling them out?

I have the same similar type and just have to pull a little harder. I have rings on top so when they cross the rings are together.

John

sfarringer wrote:Richard, that looks like a great idea. Ever have any trouble pulling them out?

I have a removable landing gear step that I slip over the stakes and rotate the stake and pull at the same time. The stakes usually slip out without much trouble. Damp clay soil and gumbo are the worst.

A simple bar with a hole in one end would work just as well.

So apologies for the dumb question, but a necessary component to tie down anchors are ropes. There is more than a passing chance that I'll be flying 56D to Oshkosh this year because of my friend's Comanche being stuck in the shop. I have a set of the screw-in anchors that my dad used, but I'm strongly favoring the system that Richard uses because of its simplicity and portability in the neat PVC tube.

That said, I'll need ropes, and we're too late to try to order them from Aircraft Spruce. The ropes I'm seeing at Lowe's or similar don't appear to give a tensile strength rating (worded exactly in that manner), rather an absurdly low working strength value. Is it possible to get good quality tie down ropes from a hardware store? I don't want to just put something on the airplane that isn't actually going to hold it in case the wind does pick up.

If you have a Tractor Supply or Ace Hardware nearby, get at least a good quality 1/2" twisted or braided nylon rope. Kern mantle climbing rope is also very good, but expensive. Do not use manilla or cotton as they will both loosen/stretch when wet. Likewise do not use polypropylene, polyethylene, or other cheap synthetic as they will stretch out and break down in sunlight over time. Melt the ends to keep from unravelling. It takes at least 50' to make good tie downs, 20' wings, 10' tail, more is better.

Find someone who can teach you how to tie a slip knot, bowline knot, and a trucker's knot. You always want to use knots that will easily un-tie no matter how hard they are pulled. These three knots will do that if tied properly. The bowline is the best knot for tying a loop in the end of a rope because it can always be untied no matter how tight it is pulled. The trucker's knot has a mechanical advantage of 3, can be tensioned positively, and can be un-tied and re-tied without losing its tension, very handy in a strong gusty wind when the ropes need to be re-tensioned and you don't want to lose tension. A proper trucker's knot will NOT slip. The slip knot is what you use at the bottom "X" where the stakes cross each other, the harder you pull, the tighter it gets. Making a large loop using a bowline, then passing the line thru the loop will make a very strong slip knot that is easy to loosen no matter how tight it has been pulled.

Whatever you do, DO NOT use the common "lazy pilot knot" (similar to tying a horse to a hitching post in the old westerns) where you just loop the loose end around the tension leg two or three times and pull. There is no way to insure proper tension and the loops will slip and loosen the tiedown further. It will slip in a strong gusty wind as there is no positive stop. Always tension tie down ropes fairly tight and let the stretch of the rope cushion any movement of the plane. Leaving them loose or using chains will allow impact loads to be transmitted into your plane when it moves in the wind.

http://www.westmarine.com/buy/west-mari ... ecordNum=1

Been using those for years now.

Here is another very high quality portable tie down system to consider. I have one and am very pleased. It may not be suitible for very rocky soils however. (I have yet to try it in such.)

http://www.abesaviation.com/amelia/sear ... D=1~1&id=1

Of course, if you don't know how to tie the proper knots, any system is useless.

If anyone needs this
Bowline
http://www.animatedknots.com/bowline/in ... crollPoint

Trucker's hitch
http://www.animatedknots.com/truckers/#ScrollPoint

Slip knot
http://www.animatedknots.com/slip/#ScrollPoint

I recognize the bowline but the trucker's hitch and slip knot are not the ones I am talking about. I'll try to make some pictures tomorrow to show them.

hilltop170 wrote:I recognize the bowline but the trucker's hitch and slip knot are not the ones I am talking about. I'll try to make some pictures tomorrow to show them.

I was wondering about that so I put that up. That is a good website for knot tying the boy scouts and other outfits around here use it.

Slip Knot- Use to secure the lower end of the tie down by slipping over the "X" in the rebar tie downs. The harder you pull, the tighter it gets.
Or better yet, tie a loop using a bowline, then make a slip knot to go over the "X" in the rebar tie downs, it tightens evenly around the ground anchor.

Trucker's Knot- Has a 3-to-1 mechanical advantage and can be tensioned and later re-tensioned without losing tension on the tie down as when the tie down loosens in a gusty wind and needs to be re-tensioned. This knot will not slip.

Hi Richard!

Can you explain one more step? On that last pic where you say "tie off the loose end", where are you tying to? The standing part of the rope above the loop? Or back up to the tie down ring?

Hope you are doing well. I sent you an email....

Keith

The first knot Richard shows is called a cow hitch:
http://www.animatedknots.com/cow/index. ... crollPoint

The second is essentially a truckers hitch as previously linked but Richard only showing the first half. Richard also ties this upside down compared to the linked demonstration which assumes the hook to be down.

Maybe this helps...