Also, when thinking about how to tie down, think more about the ropes and tiedowns you use. Use a good quality adequate diameter rope. You can look up load rating on the Web and you should get a material that is resistant to sunlight. For the tiedowns, it's more about how big a chunk of dirt has to be pulled out. A deep small diameter screw is probably worse than a large diameter mid depth tiedown. I like the idea of Fly Ties and made a home made version of them that I carry.

Wayne

c180pilot wrote: Think maneuvering speed. You want the airfoil to stall to unload the wing which means high angle of attack. Tie the trail to the ground and with a TW aircraft, you'll be about right.

Wayne

That's an interesting theory, but every tail dragger I've ever flown would start flying from the 3-point attitude at very low airspeeds. I don't see that as a stalled airfoil. I guess the best of both worlds would be a flat angle of attack and air disruptors installed on the wings.

I couldn't agree more about selecting quality tie down lines.

Hammer,

Yes they tested duckbills. We were some of the first to use them as permanent (and emergency) tiedowns. They are hell for stout, but leaving them in the ground, or digging them out at OSH would be "unwelcome". Cutting the cables as you described might work, but you'd still have to dig a heck of a hole and those cables don't cut all that easy....

As the man said....do the best you can do in the circumstanes. I once flooded the floats on a seaplane to try to save it in a big blow. The next day, as I'm pumping those floats out, I had to carefully consider if next time I'd just let the plane blow away..... .

MTV

Hammer wrote:

A number of years ago, the Alaskan Aviation Safety Foundation sponsored a test of tiedowns. The tests were run with a strain gauge and cable. In every case I recall, the tiedowns held best with a straight vertical pull.

MTV

Do you recall if they tested duckbills? Since they have to pull through more undisturbed soil (at an angle) I believe they should hold more in that configuration. Picketed wooden stakes will definitely hold better at an angle...I've done the tests with a load cell, and while I didn't pull straight up, the mechanics are pretty obvious. There's a post somewhere here on "field tie downs" with photos and numbers. All good information.

I think you already said it Mike, but for me it's the pulling / rocking action that will usually defeat makeshift tie-downs. The steady pull test is very useful information. I think in a gusty situation, they might fail sooner or at lower load.

One question which I have always had, without drifting too far off-topic, is how to tie down on a gravel riverbed?
Stakes are clearly a waste of time.
Logs aren't always available to tie onto.
Sandbags heavy enough would be untold labour to fill and crazy-bulky.
Is there a technique I am missing?

Wayne
I have to disagree. You will have a lot more lift with the tail down (increase AOA). Think about it do you take off with the tail high or lower it to lift off? Digging the tires in or putting the tail on a 50 gal barrel is common for high wing protection. Another thing would be wing covers with lift spoilers. Common for the cold weather boys/girls. You can make some with them pool noodles and rope in a pinch. As far as tiedown on gravel bar, Duckbills work great!! Depending on rock size gill nets work but it will take a bit of work to fill the nets.
DENNY

This just a question, I fly a tricycle gear plane so can't offer "suggestions" to secure a tail dragger:

Wouldn't lashing spoilers to the wings and tail help mitigate issues generated by high winds?

From my perspective for my tricycle external gust locks on all control surfaces (with streamers!) pose less risk of damage than depending entirely on the internal control locks. With either spoilers or control locks the pre-flight would be the first line of defense in removing them. The stop to stop control checks during taxi and prior to takeoff are two additional error traps for control locks.

One question which I have always had, without drifting too far off-topic, is how to tie down on a gravel riverbed?
Stakes are clearly a waste of time.
Logs aren't always available to tie onto.
Sandbags heavy enough would be untold labour to fill and crazy-bulky.
Is there a technique I am missing

The sandbag idea isn't as bad as you might think with a slight modification. Instead of a bag, think of a one square meter piece of cordura tarp with webbing handle loops coming off all four corners...not directly at the corners, but 10~15 cm on each side of the corner.

The webbing handles are complete loops that go through to the other end of the tarp, making the opposite handle as well. The tarp is sewn to the webbing, but when you pull on a webbing handle you're only pulling on webbing, not on the webbing-tarp interface.

Lay this under your wing and start loading it up with gravel. If you're using a real shovel you should be able to get 300~500 kg on the tarp in a few minutes. (I just moved 3,000 kg of gravel with a shovel and wheel barrow, and it really didn't take that much time.) Pull all four corners together and tie off to your plane. If a storm is coming spend a few more minutes putting a hundred more kilograms of gravel on the tarp. When it's time to leave, getting the gravel off the tarp is relatively easy...grab one corner and pull it up and over, rolling the gravel off as it goes.

These rigs would be light and compact and last a reasonable amount of time. The materials are fairly inexpensive, though there's a bit of money in the sewing.

Some folks poo-poo above ground anchors, but in many soils in-ground anchors don't hold for crap. I'd much rather know I had 500 kg of anchor because I just shoveled it than drive some stakes into poor ground and not really have any idea what the holding power is.

Deadman anchor or pickets. Bury them well and they can be very strong. Can be improvised with cord and found objects like tree branches.

http://dmmclimbing.com/products/deadman/

https://www.rei.com/product/881081/msr-snow-picket

You might also consider some sort of cargo net or wire mesh that could be filled with rocks. Durability is the big issue I would imagine:

https://www.cargogear.com/OneItemInfo.aspx?partnum=MGMINI

https://www.cargogear.com/OneItemInfo.aspx?partnum=BNCCNET

I've seen people make small wire bags out of thin wire cable or rope that is woven and swaged with a gathering opening at the top. Very lightweight and strong portable anchor. Fill it with rocks, cinch and bury under other rocks.

Hammer wrote:[quote
The sandbag idea isn't as bad as you might think with a slight modification. Instead of a bag, think of a one square meter piece of cordura tarp with webbing handle loops coming off all four corners...not directly at the corners, but 10~15 cm on each side of the corner.

The webbing handles are complete loops that go through to the other end of the tarp, making the opposite handle as well. The tarp is sewn to the webbing, but when you pull on a webbing handle you're only pulling on webbing, not on the webbing-tarp interface.

Lay this under your wing and start loading it up with gravel. If you're using a real shovel you should be able to get 300~500 kg on the tarp in a few minutes.

Some folks poo-poo above ground anchors, but in many soils in-ground anchors don't hold for crap. I'd much rather know I had 500 kg of anchor because I just shoveled it than drive some stakes into poor ground and not really have any idea what the holding power is.

You must be a LOT better than me at stacking sand. Start out with a 1 yard square piece of material, and you're going to KEEP a thousand pounds of sand/gravel on that as you cinch up those straps? Good luck.

With that size tarp, you'll be lucky to get it to hold a couple hundred pounds, and most planes will lift that just fine.

I'll take tiedowns any time over a little sand in a bag, but if that's all you've got.....

MTV

You must be a LOT better than me at stacking sand.

What can I say...I've got skills.

Hammer wrote:

One question which I have always had, without drifting too far off-topic, is how to tie down on a gravel riverbed?
Stakes are clearly a waste of time.
Logs aren't always available to tie onto.
Sandbags heavy enough would be untold labour to fill and crazy-bulky.
Is there a technique I am missing

The sandbag idea isn't as bad as you might think with a slight modification. Instead of a bag, think of a one square meter piece of cordura tarp with webbing handle loops coming off all four corners...not directly at the corners, but 10~15 cm on each side of the corner.

The webbing handles are complete loops that go through to the other end of the tarp, making the opposite handle as well. The tarp is sewn to the webbing, but when you pull on a webbing handle you're only pulling on webbing, not on the webbing-tarp interface.

Lay this under your wing and start loading it up with gravel. If you're using a real shovel you should be able to get 300~500 kg on the tarp in a few minutes. (I just moved 3,000 kg of gravel with a shovel and wheel barrow, and it really didn't take that much time.) Pull all four corners together and tie off to your plane. If a storm is coming spend a few more minutes putting a hundred more kilograms of gravel on the tarp. When it's time to leave, getting the gravel off the tarp is relatively easy...grab one corner and pull it up and over, rolling the gravel off as it goes.

These rigs would be light and compact and last a reasonable amount of time. The materials are fairly inexpensive, though there's a bit of money in the sewing.

Some folks poo-poo above ground anchors, but in many soils in-ground anchors don't hold for crap. I'd much rather know I had 500 kg of anchor because I just shoveled it than drive some stakes into poor ground and not really have any idea what the holding power is.

That's 661.4 to 1102.3 lbs and 6613.9 lbs, respectively. In case anyone else doesn't have a working knowledge of kilograms.

Hammer wrote:

MTV wrote:You must be a LOT better than me at stacking sand.

What can I say...I've got skills.

Sorry, but Mike's point is pretty good. In a pinch, ya I guess t's better than nothing, but for day in day out... not so much.

Using gravel you would have to cover every square inch of that 39.3701" square for 12" in height (really good stacking) to equal 1047 pounds... We could take a stab at calculating what kind of pyramid (pile) you could reasonably expect to get out of gravel, to get a more accurate measurement, but since substrate will vary from location to location, It'd be a pretty pointless exercise. Using less weight would be pointless in a high wind event, as at that point all you'd be doing is adding a set of click-clacks to the mix to make sure your airplane is thoroughly beat to heck when the wind is done I guess if you are going to carry bags, and a set of spoilers, you might have something tho...

Never the less, I too would be interested in how to make the plane stay, on gravel. I can't imagine trying to drive a duckbill in gravel, but have honestly never tried. I will make a point of it as soon as I get home to satisfy my curiosity.

Wayne? blonde moment? even a trike rotates to lift off sooner Not only is the typical T/W aircraft not in an excessive attitude at 3pt., but most people that go to larger tires find their ground roll shortening when they do so from the added AOA... It was an interesting thought, but probably less than accurate

Take care, Rob

Using gravel you would have to cover every square inch of that 39.3701" square for 12" in height (really good stacking) to equal 1047 pounds... We could take a stab at calculating what kind of pyramid (pile) you could reasonably expect to get out of gravel, to get a more accurate measurement, but since substrate will vary from location to location, It'd be a pretty pointless exercise. Using less weight would be pointless in a high wind event, as at that point all you'd be doing is adding a set of click-clacks to the mix to make sure your airplane is thoroughly beat to heck when the wind is done I guess if you are going to carry bags, and a set of spoilers, you might have something tho...

OK…I think even I can figure this one out…make the tarp bigger?

The bottom line is that if you’re parked on loose gravel, sand, or cobbles, driving something into the ground, at least something you can cary in the airplane and drive with a hammer, isn’t going to hold. Steel duckbills might work assuming you could drive them deep enough without a jackhammer, but even if you mange it, that gets expensive fast.

The inverted Cub at the Chicken Strip prominently displays a Claw tie down dangling from the tail spring…it didn't even hold the tail of a J-3 in gravel. Even in dirt, Fly Ties and similar devices pull out at between 200 to 600 pounds, depending on the soil. The makers claim much higher loading and I believe they can probably get it under ideal conditions, but it doesn’t prove out in day to day testing. Used in loose gravel or sand they are nothing but decoration. Believing something has good holding power just because it was driven into the ground is not logical.

Any system employed on a gravel/cobble/sand bar is 100% dependent on the amount of material you can physically move. Burying a dead man or filling up a container…both require shovel work and will give back exactly what you put into them. If you want 1,000 pound tie downs, get ready to move 2,000 pounds of gravel and rocks.

If you’re happy using Fly Ties or the Claw or similar devices in dirt, you should be equally happy with a few hundred pounds of gravel in a sack. The only difference is that with in-ground anchors you’re flat-out guessing what the pull strength really is, and once they start pulling out, they're done. A 300 pound weight is more secure than a ground stake that pulls out at 300 pounds, because a 310 pound tug from a gust will render the stake useless, while the weight will just bob up a bit and then keep on providing 300 pounds of anchor. Don't buy into the dogma that there's only one right way to do things.

We all want bombproof tie down anchors, but field solutions RARELY meet that definition. Every solution has to be customized to the location and conditions, and not every solution is going to withstand very high winds. I love the click-clack visualization, but hanging 200 pounds off each tie down point, while hardly ideal, is not pointless. That plane will withstand more wind than it would without those loads attached. If you're parked in an area prone to high winds then you'd better come up with something better of course, or don't park there...

I agree with Hammer:

Better to think on your feet than rely on a monolithic idea (of being perfect or ideal). When sailing we use ropes and lines in unorthodox ways to advert disaster. Rather than employing the standards which we were "taught" by the grand knowing of the crowd.

Two page discussion on suggestions on how to tie an aircraft down.. Lol cmon, it's not that hard to figure out.

Bdiazair wrote:Two page discussion on suggestions on how to tie an aircraft down.. Lol cmon, it's not that hard to figure out.

At face value? yes... but I think what the OP was getting at was how to try and avoid being one of these;

http://www.airport-data.com/aircraft/ph ... 88489.html

And I would bet that at least 99% of these folks thought there was no rocket science to tie downs either...;

http://www.flyingmag.com/photo-gallery/ ... d?image=17

http://newyork.cbslocal.com/2010/11/17/ ... nes-in-nj/

http://www.stwnewspress.com/news/five-o ... cbc79.html

I don't think I read every post on this one, and probably am equally as guilty regarding thinking I've got tie downs pretty much figured out as well... But thanks to Hammer I've already revised one part of my typical tie down regime... If it takes a two pager to find out another gem? I'm ok with that...

Hammer, Ya, I get it... and ya, probably a shit ton better than nothing. In fact probably better than anything I've come up with for gravel / sand yet, but I *think* Battson was perhaps hoping for a better mousetrap here? Perhaps something overlooked? I know I sure was. As it is, I do use a webbing 'headache rack' similar to the illusive Mountain Wave one. I think it might do for at least the tail in a pinch

Take care, Rob

edit; So the funny thing is I was gonna ask if anyone knew of someone that actually carried this webbing / cordura mess around with them... and then it dawned on me that I use a smaller (24"x24") cargo net to secure the extended baggage station (like the one Rob56? uses), and then I have the one that splits the seating area.... Guess I've already got the tail and one main covered

Just got back from a 'family medical emergency' trip to Florida and drove into my property noticing trees down, branches all over the place and an overall mess. House smelled funny (food in the fridge had spoiled) and found out the power was out for two days due to a storm.
I found out this bad storm had winds over 80 mph, with some saying up to 100 mph.

Three planes flipped at Bemidji Airport and a lot of old Norway pine trees destroy in Itasca State Park. The force of nature is nothing to mess with! The trees look like twisted toothpicks!

Ok, making a short story long, as soon as I read and heard about this storm and the damage down to the planes, my thoughts were exactly the topic of this thread. I was wondering how these damaged planes were tied down and if anything could be done to help alleviate the chance of it happening again. Thanks all for the great info!

To revive an old post...

Will be flying a tiny (580 lb empty) Corben Baby Ace cross-country in a few weeks. Cargo space is extremely limited. Will be trying to stick it in a hangar each night, but I don't think that will always be possible.

Any techniques specific to very light aircraft? I can't exactly carry sledgehammers and bags of rocks!

Hambone wrote:To revive an old post...

Will be flying a tiny (580 lb empty) Corben Baby Ace cross-country in a few weeks. Cargo space is extremely limited. Will be trying to stick it in a hangar each night, but I don't think that will always be possible.

Any techniques specific to very light aircraft? I can't exactly carry sledgehammers and bags of rocks!

Most airports have tiedown anchors. Buy some 6mm climbing cordage and learn a couple good knots. Tie down all three points and chalk the tires. Good to go!

Contact Flying taught me a great way to chock a taildragger. I use it when I am going to be close to the airplane but not in the immediate vicinity... say when I'm at lunch. Here's the tip: Turn the tailwheel 90 degrees to the airplane and chock THAT. The airplane can't pivot with the tailwheel chocked, and it can't move forward or backward with the tailwheel at 90 degrees.