Anatomy Of A Pack Saddle

Making your own tack for your horses has a big upside. It's custom fit for the horse and the quality is as good as you can make it. I made the saddle for my pack horse and it's lasted for 12 years now and has seen all sorts of rough duty. Nothing has ever failed, and I don't ever expect it to. My saddle for my trail horse was made for me by a saddle maker I know since I don't have some of the equipment needed for the job. It too is custom fit and when you ride for days on end having a saddle that fits the horse and your backside well can be a blessing. This post is about how I made a pack saddle.

The first thing you need is a sewing machine that can accept heavy duty needles and thread and go through at least 4 layers of heavy weight duck canvas. I use duck canvas because it's relatively inexpensive, comes in a variety of neutral colors, and can be made water resistant or nearly water proof. A mixture of beeswax, and linseed oil makes for a good water resisting agent or you can use a silicone based commercial product.

Planetary Orbital Eccentricity Updated

In my previous post on the subject I mentioned how I didn't have the eccentricity of the Earth's orbit quite right yet. I have pretty much corrected that. The old data set and the new are shown below the break.

No not that Climatology

Well, back to writing some posts. A fellow I know needed me to help him move some cattle. That meant quite a bit of time in the saddle, and then hauling winter feed to the new location. Oh great I get to ride drag, and no that doesn't mean riding in women's clothes. It's where you get to smell the cow flatulence all day and eat dust for hours on end at the back of the drive.

I have worked with a lot of people over the years in what I call planetary sciences. This also includes atmospheric research. Over the years I have built a number of instruments and conducted experimental studies in support of this type of work so I naturally developed an interest in the subject. One aspect of this field is obviously the climate of earth both in the past and the present. The present day arguments over modern climate change don't hold much interest for me but the past or paleoclimate studies do. 

What Do You Believe?

Given our last election and some of the rather unusual events I thought I would create a mathematical model to explore this strange space. So the first thing to do is to express the thing in some form and see if it makes sense. An exponential model first comes to mind such as:

Explosives Applications: The Shaped Charge

One major use for explosives is in the oil and gas industry to complete a well. For a simple well the process is straightforward. The well is drilled, cased and then perforated. This involves inserting a length of tubing with a series of shaped charges along it's length into the cased well and setting off the charges that perforate the casing and the oil and gas bearing strata.

A shaped charge in its simplest form is nothing more than a metal cone surrounded by explosives. The charge is end initiated and the explosive collapses the conical liner into a jet of material that penetrates at very high velocity. The jet penetrates in the same manner as I previously posted about hypervelocity penetration. A model of a simple 65 degree angled shaped charge is shown in the first video. As the detonation proceeds up the charge the cone collapses inward in a symmetrical manner with an upwards momentum. At the collision point the cone coalesces into a jet of material that has a high velocity and has a final form of a long slender rod.

Over the Hills and Through The Woods...

It's getting close to that time of the year when the snow flies. I like to hit the mountains once there is a fair amount of snow. These pictures are from last winter after the first storm. There was 3 feet of snow in that storm. That's me snowshoeing in (uphill, both ways) with a sleigh full of supplies.

Mush, Mush I say.

Sweet Seclusion.

It's always enjoyable to be up there when the snow is coming down. I'm at about 7000' and just below the ridgeline so the clouds pile up there during a snowstorm. The snow crystals form right in front of your eyes and then fall just a few feet to the ground. It's odd, but quite mesmerizing.

How About a Nice Curve Fit?

I've been meaning to do this for some time. That is developing a Windows based system for fitting equation of state terms to experimental data, rather then relying on other people's fitting routines. One of the more common equations of state (P-v relationship) people like to use in the explosives world is the Jones-Wilkins-Lee (JWL) equation of state. There are others but I won't go into them for now. One form of the JWL equation of state for the products of detonation is given by:

The data to fit to has to be in an Excel file and can be imported directly into the application. The data file needs to be in the form displayed. The pressure units are in GPa.