I'm soliciting thoughts on how to tie down the tail wheel. Specifically, it seems like there are two options.

1) Put the wheel near the anchor. This has the advantage of being pretty close to a vertical force on the anchor (which is what most of them are design for), but the liability of being kind of a pain to knot off properly with a rope and other solutions, like ratchets, aren't designed around 6 inch space requirements.

2) Put the wheel substantially in front of the anchor. This is good for ease of use, but puts an almost entirely horizontal force on the anchor (which is not what most of them are designed for) and, in some cases, could even result in the tie down being rubbed to the point of failure. It also is more likely to allow the tail to bounce or swing several inches, which can built up inertia and make it more likely to break the plane or tie down.

Thoughts?

I have always gone with securing the TW right at the tie down for the reason you stated, no lateral force is converted to trying to bend the airplane, or so it seems to me.

flyingzebra wrote:I have always gone with securing the TW right at the tie down for the reason you stated, no lateral force is converted to trying to bend the airplane, or so it seems to me.

That being the case, *how* do you tie it down? Rope? What knots do you use given the small space available? Something else? What else?

Oh boy…
I take the rope from where it attaches to the ground, go vertically up, then loop it around the TW swivel, wrap it around the original vertical bit and then reverse direction to loop it back around the TW swivel one or two times (depending on length) and then tie the remaining end around the original bit coming up from the ground.
I just read this out loud to my dog and he looked at me like I’m nuts. He might be right.
Good luck with it.

So, just like a normal tie down length of rope, right?

what flyingzebra said with shorter rope than mains. More or less....

I like directly below the TW also, for a host of reasons. In general I'm a big fan of rope and knots, but I've used NRS loop straps on the TW for years with good results. It can be girth-hitched to the tail spring and to the ground anchor respectively. I wouldn't rely on toothed cam buckles for the wings, but the tail doesn't have the same lifting forces.

-DP

I've often parked with the tailwheel right on top of those recessed tiedowns some airport ramps have.
I just run a rope through the tiedown and over the top of the tire, and tie it with a square knot.

I tie the tail wheel with the anchor slightly behind the tire. Most of the wind force on the tail is lateral with the Maule due to the large ventral fin. There is normally a washer between the tail wheel assembly and the bolt that attaches to the leaf spring. I replaced the washer with a piece of angle iron with a tie down hole drilled in the vertical portion of the angle. That keeps my tie down rope clear of the grease that always oozes out of the tail wheel pivot bearing.

Thanks for the input everyone. I was shooting a video testing the holding strengths of various tie downs and it got me thinking.

Does your Maule have fuselage handles?

If yes, how about putting the anchor directly under those?

Joe

twflyer wrote:Does your Maule have fuselage handles?

If yes, how about putting the anchor directly under those?

It does! And it's my first plane with them so I never though about that. I think we have a winner!

I think it's more important where the wing tiedown points are in relation to the anchors.
I can't count how many times I've seen airplanes "tied down" with the anchors waay ahead or behind of the wing tiedown points.
IMHO this is the same as tying down with miles of slack in the lines / straps.
Almost might as well not even tie down at all.

hotrod180 wrote:I think it's more important where the wing tiedown points are in relation to the anchors.
I can't count how many times I've seen airplanes "tied down" with the anchors waay ahead or behind of the wing tiedown points.
IMHO this is the same as tying down with miles of slack in the lines / straps.
Almost might as well not even tie down at all.

The only asterisk I would put on that is that there are some tie-downs that are designed to be at an angle. And if you're using one of those straight up and down, you're getting almost no holding power.

And I'll put an exclamation point on slack: If you're tying down with chains and have slack, you're shock loading the hell out of your plane. Slack is bad enough, but slack with chains is a crime against aviation.

hotrod180 wrote:I think it's more important where the wing tiedown points are in relation to the anchors.
I can't count how many times I've seen airplanes "tied down" with the anchors waay ahead or behind of the wing tiedown points.
IMHO this is the same as tying down with miles of slack in the lines / straps.
Almost might as well not even tie down at all.

The ones I'm talking about are on airport ramps, tying down to pre-set anchor points.
Just laziness or carelessness I guess, not parking the plane in the proper position.
I'd think anyone putting in portable anchors (fly-ties, etc) would be doing so after the airplane is parked,
and would be putting them in the optimum spot.

hotrod180 wrote:I'd think anyone putting in portable anchors (fly-ties, etc) would be doing so after the airplane is parked,
and would be putting them in the optimum spot.

Fly-ties is my drug of choice and I notice them because I use them. I wouldn't say it's common, but I've seen some people put them in front of the wing and I've seen people put them at angles to the side of the tie down rings. Again, not common, but I bet I've seen those failure modes a half dozen times.

rw2 wrote:I'm soliciting thoughts on how to tie down the tail wheel. Specifically, it seems like there are two options.

1) Put the wheel near the anchor. This has the advantage of being pretty close to a vertical force on the anchor (which is what most of them are design for), but the liability of being kind of a pain to knot off properly with a rope and other solutions, like ratchets, aren't designed around 6 inch space requirements.

2) Put the wheel substantially in front of the anchor. This is good for ease of use, but puts an almost entirely horizontal force on the anchor (which is not what most of them are designed for) and, in some cases, could even result in the tie down being rubbed to the point of failure. It also is more likely to allow the tail to bounce or swing several inches, which can built up inertia and make it more likely to break the plane or tie down.

Thoughts?

More information required to give the best possible answer.

What kind of anchor point are you using?
Is this for a specific overnighter type of situation with known weather, or a permanent outdoor parking spot?
Similar to above, do you prefer to park tail into wind or nose into wind?

rw2 wrote:

hotrod180 wrote:I think it's more important where the wing tiedown points are in relation to the anchors.
I can't count how many times I've seen airplanes "tied down" with the anchors waay ahead or behind of the wing tiedown points.

The only asterisk I would put on that is that there are some tie-downs that are designed to be at an angle. And if you're using one of those straight up and down, you're getting almost no holding power..

Totally agree RW.
For many conventional tiedown arrangements having an angle is the recommended approach, it is difficult to generalise.

Advice like this (see link) is common and there's a good reason why. But it does depend on the anchor design.
https://www.aircraftsystemstech.com/2018/10/aircraft-tie-down-procedures.html