Upon tying down my CH750 for the first time on a asphalt apron with typical aircraft tie down points, I noticed that I could push the tail down to the ground even with the wings tied down. This can create a higher angle of attack and could cause major damage (stress on the tiedown points and tail damage) to the airplane if the wind is gusty and strong. I mentioned this in an associated blog of Ron Cola's damage to his airplane from a micro burst type wind. James Depfer experienced this with his airplane. I thought I would bring this up here in this forum to obtain thoughts from other 701 and 750 owners who tie down on a regular basis. It seems to me that the nose gear (and tail?) should be tied down, which is not possible on a typical airport apron, unless one was to turn the airplane around. Would appreciate thoughts, experiences, and ideas.

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Hi Rick, 

I experienced almost the same problem at my local field... My 701 sits in front of my dismounted amphib floats and is tied down the usual way (wings and tail). Since the plane is very light and can really be moved by gusty winds, it got blown sideways over the winter and the bottom fuselage rubbed against one float. Mostly paint scratches but I was wondering what to do about that ... Looks like I'm not the only one having this issue.. My 701 is tied down on grass but the wheels sit on concrete plates ... Maybe I should tie down the front wheel too....

Still pondering.

Regards,

Norm 

Rick,

As indicated on the blog, I wasn't at the airport when this happened to me. I'm only guessing here, but it seems like pushing the tail down when the wings are tied down fairly snug, that the mains will have to move forward. Since the airport personnel put wheel chocks on my mains at the time, I'm thinking this will prevent the tail from going down, at least in a fairly strong wind. I normally carry the light weight plastic chocks in my plane, so I'm hoping they will prevent this problem if I make it a habit to use them whenever I'm tied down in the future.

An option would be to tie the front wheel down as well. Not too tight because that would put stress on the plane.

I think the chocks will help, but unless you use chains that are tight (non stretching), I think there will be enough stretch in a rope to allow the tail to go down in a strong wind. There is a long lever arm from the gear to the tail as compared to gear to the wing hard points (when looking at a side view). The location of the elevator and wind direction will also make a difference.Tying the nose gear and the tail would be the best; Just hard (impossible) to do on typical airport apron tie downs.

Maybe I'm over thinking this, but the last thing anyone of us want is to lose our planes to Mother Nature.

As a new non-builder-owner, I am in no position to advise, but would like to hear more on the subject of tie-downs, especially on this issue, type of line/rope, knots and not-knots, line stretch limits, and anchoring off-airport with a light-weight kit. I know that these subjects have been cussed and discussed in the past, but I'm still unsure about some of them.

It SEEMS to me (be careful!) that there have got to be right ways and wrong ways to do each of them, as well as better ways and worser ways.

From the first, I've been wondering about killing lift on the wings with some kind of lightweight attachable spoilers. I'd be especially interested in any design/test data as well as empirical stuff.

It SEEMS to me (I'm warning you for the last time) (;)> that tying the tail down with the line vertical and the wing lines stretching forward to the anchor points MIGHT help. Maybe I'll try this when I get 750MV rolling again.

A bush pilot posted (elsewhere) a way of tying down on hard surfaces that I liked--in theory--but wiser men than I have trounced, was to carry pieces of strong fishnet that would be lightweight and serve as bags to hold big rocks or sandbags that would add up to enough weight to hold the plane in moderate winds and at least slow the plane's drift down in stronger ones. I am guessing that there's going to be damage or destruction from extremely high winds, tie-downs or no tie-downs. Too bad there're not hangars that transients could rent . . . Rocks and sand would likely be in short supply at most airports, and likely to be frowned upon by airport managers, but a net bag of a few sandbags might help if one wanted to tie the nose down (how have y'all gone about this?). Rather than chock, it seems that some bush pilots bury their tires on soft surfaces. A friend of mine swears by his home-made field tie-down anchors made from a few links of chain and nine spikes. I'm gonna test this out, but I'm thinking I would bury a dead-man in places where I could dig. I'm sure there are a lot of other ideas out there. Anecdotes (the singular of data) would help. Lurkers, ARISE!

WT

I'm looking forward to hearing how these issues have been solved. Does the more than 100 viewers to date mean that almost 100 don't believe it's an issue worth considering, have no clue what to do or not do, or what? Maybe it's ok with them if their plane bobs in the wind?

Wayne,

I have essentially zero experience securing lightweight aircraft to mother earth, but seems to me that a adjustable tail stand (similar to the self collapsing trekking poles that hikers use) could be carried and used in conjunction with conventional tie downs to prevent tail/rudder damage.  Some large transport category aircraft have them to preclude sitting the aircraft on it's tail while loading cargo/fuel  - seems like that might work for us as well?

Dave

Great thoughts. I looked at various airplanes and how they were tied down at Oshkosh this year. I am convinced that where anchors are placed is just as important as how secure the anchors are. I will put together a report of my observations - the good, bad, and ugly. 

Yeah, I had thought of using a piece of PVC pipe, but then my experience is near zero too. Might damage the aircraft in a windstorm?

WT

The tie-down fittings on the 750 seem rather light and subject to wear; also they look like they would abrade a rope or strap, necessitating the use of a hook, which would tend to wear out the fitting (which doesn't look like it would be easy to replace). Anyone have experience with these issues or are they non-issues?

What are the pros and cons on tight vs a little slack, unyielding or slightly stretchable? Rope or chain?

WT

Chain is a bad idea.  There are documented cases of spar failure due to wind causing the airplane to rock against the chains and damage the spar where the tiedown attaches.  It's an interesting problem.  I've seen photos here of a 701 settled onto it's tail due to snow load.  I wonder if one might just tie the tail right down and let the nose wheel rest on pure air?  That might be a good question for the Zenith engineering team. 

could some type of leg be attached to the rear tie down. kinda of like the way we keep our fifth wheel trailer steady when we're camping. Just an Idea.

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