Without getting real technical. Grade 2 is cp-2 and around 55 ksi tensile strength. Grade 5 is 6al4v or aerospace type 128 ksi. Think 6061 vs hardened steel. As far as pounding never pounded an cp but sheet bends easily. Grade 5 fasteners don't mark easily with a rivet gun. Weight of Ti is 67% of steel aluminum is 1/3.

Hammer wrote:

As someone who recently realized how little he knows about ropes and knots, let me thank you for the steady stream of porn you've been putting out lately.

A while ago we were heading north and ran into a series of low pressure systems moving across our path. It was going to be five days of storms, so we diverted to a strip with good hiking, good fishing, and lots of fire wood to wait it out.

We picked a protected area to park and I did my usual OCD field tie downs. I didn't know how much wind was going to accompany the storms and I knew we were going to be away from the plane most days, so I prepped it for wind.

The weaker an anchor, the more important the geometry of the tie down lines. Movement of the airplane across the ground can put tremendous strain on the lines and all they're attached to. If you only tied down the wings and then went to the tail and started pushing it sideways, the leverage you would bring to bear on the tie down lines would be fantastic. Field anchors would quickly get pulled out of the ground.

Tying down the tail is the obvious solution here, but unless you use a two part tail line and guy it out to the sides, the tail can still get pushed sideways. One way to keep the airplane where you parked it is to use wheel chocks.


When using logs for chocks they have a tendency to "walk" out from under the tire. Pounding a stake next to them snugs them up and eliminates any movement. These chocks are a bit undersized for the tires, but taut tie down lines keep the tires firmly on the ground.


Driving stakes alongside the tailwheel keeps it from twisting and increases the rigidity of the tail tie.


This simple rig secures both the rudder and the horizontal stab. Stretchy line and a couple prusik knots make it easy to tension and remove. I've really never had a problem with the aileron's moving in wind, but the rudder takes a tremendous beating if not secured.


So is all this tying and chalking a staking overkill? Obviously. A 206 at the same strip survived the storms just fine with nothing holding it down but gravity and a parking brake. As it turns out there wasn't very much wind.

But on the other hand, at no time in the history of aviation has a pilot come back to their upside-down plane and said "I thought that might happen when I left..."

I like it.... very nice post.

Although, if you REALLY get stuck and have to leave the plane, nothing compares to digging holes and sinking the wheels / MLG up to the fuselage / prop, and THEN tying it down to boot

Battson wrote:I like it.... very nice post.

Although, if you REALLY get stuck and have to leave the plane, nothing compares to digging holes and sinking the wheels / MLG up to the fuselage / prop, and THEN tying it down to boot

I was thinking the same. Borrowing the idea from Vadu Marina in Fiji which buries large sail boats up to the keel in the invent of a storm or typhoon.

Battson wrote:I like it.... very nice post.

Although, if you REALLY get stuck and have to leave the plane, nothing compares to digging holes and sinking the wheels / MLG up to the fuselage / prop, and THEN tying it down to boot

I've dug holes for the tires before. We were in Utah and a real big blow was forecast: 50 mph +. The soil there is terrible for a ground anchor, so I dug a couple axle-deep holes for the main gear and pushed her in.

It's a great technique...it acts like super-chocks and lowers the angle of attack. Very secure. VERY secure...

You know that expression "dig yourself out of a hole"? I never gave it much though till it was time to leave. As it turns out, you cannot actually dig yourself out of a hole.

It took a couple hours and some real creative rope systems and anchor construction to get the airplane free. The same crappy soil that wouldn't hold a ground anchor for the wings wouldn't hold a ground anchor to lever the airplane out, either. Bushes that might have held were out of reach. I cary a lot more rope with me now.

Couldn't you modify a duckbill type anchor by putting a "retrieve line" on the near end of the pivot? When you are ready to leave, pull up on the retrieve line and it folds the duckbill pivot back "inline" and it comes out of the hole. While the airplane is tied down you would have the retrieve line just coiled up on the ground not being used.

Last week I parked my airplane at a backcountry strip, cut and drove wooden stakes for the wings and tied them down, then went to tie the tail. Turns out my tailwheel was over a bunch of rocks buried a couple inches below the surface. Try as I might I simply couldn't get a wooden stake into the ground for the tail.

A rapidly approaching thunderstorm made untying the wings and repositioning the airplane less than desirable. I moved up to the Bass pull handles and found the ground there would hold a stake, so that's what I used.

The connection to the handle is one of my amsteel softlinks with a triple-wrapped Prusik, which turned out to be completely secure, even when wet. I wasn't super thrilled about the set up at first, but the more I examined it the better it looked. It doesn't work great for keeping the airplane from moving forwards, but it's much better than a tail tie off for keeping the airplane from moving side to side.

I'm not sure I recommend it in place of tying the tail wheel, but when I'm going to leave my airplane unattended for a few days while I go backpacking or packrafting, I plan on adding this tie down to the matrix. Just one more tool...



At a different location I was able to drive stakes well enough, but because of gusty afternoon winds coming from the side I decided to double-tie the tail. I was going to be gone all day every day and didn't want to worry about what was happening to my airplane. Also, I like screwing around.

It definitely held fast...not sure if it was necessary, but what the hell. Better safe than sorry and all that.



another angle

The layout of the stakes in the first post is much the same as a technique that I learned from an old army mechanic, for recovering stuck trucks.

Drive three 3-6' stakes ( I think they carried steel rods) in a row, weave a chain from the front to the back and back to the front, then hook your winch to the chain.

In winching your load is mostly horizontal, where as the tiedowns are angled up. Still it seem to hold pretty good in Hammer's test.
Guess if you wanted more holding capacity you could try using longer rods.