A new twist on a mid?

[Gunnar H]

Regarding change of wind direction overnight. A 90 degree change of wind direction is common in places where you have low pressure systems passing with the centre reasonable close. But that does not change that your best bet is mostly to pitch along the valley if you are in a not too shallow valley – if wrong it will not get bad anyway. As long as there are no reason to expect strong Föhn winds where you are.

[R]

Black Diamond Beta Light vs TarpTent StratoSpire 2.

Top:

Side:

End:

Perspective:

The corner stays are of course distinctive, but otherwise, pretty much the same thing.

I had to get some of the dimensions by holding a ruler to a screen, enlarged on a 27″ monitor, measured to the nearest 1mm.

[Stumphges]

Rene, I also noticed recently how the Stratospire is a stretched out, then lopped off, Betamid. Knot/Aricxi, a tentmaker (and tent-copier) in western China, saw the possibility of rotating the inner 90 degrees, leaving massive vestibules on either end, but did not see the possibility of altering the geometry to increase the living space/vestibule ratio, with their 1p inner for their Betamid clone.

[Franco Darioli]

Rene,

I have already mentioned that if you had seen both shelters and were somewhat familiar with them you would know that in practice they are nothing at all alike.

[Franco Darioli]

[R]

Stumphges, thanks for the links.  Interesting lot of designs they have.  They didn’t even bother to rename their trailstar clone!

[Stumphges]

Rene, ha no, they did not, and Ron B. from MLD did a video some years back wherein he savaged their inferior silnylon in apparent retribution.

But apart from their cloning, they actually have some nice pyramids. The cat-cut hems on their octagonal pyramids, I think, allow for easier pitching, as one does not have to worry as much about balancing tension on the ridges and the hems; it may also be a matter of compensating for silnylon with too-high bias stretch. In any case, the hems don’t seem to flap as badly as some mids. And the octagonal pyramids pitch very tight and pull into nearly a cone shape, which seems to be very good in wind. In general, though, their cat cuts are a bit much.

[R]

One more observation on the StratoSpire 2.

A few posts back I mentioned I was keeping an eye out for patterns that are easy to make.  Here’s the SS2 superimposed with an icosahedron.

Solid faces of the icosahedron (blue lines), with the skeleton of the SS2 passing through it (black lines):

Solid faces of the SS2 (black lines) with the skeleton of the icosahedron passing through it (blue lines):

End view with the left side showing the solid faces of the SS2 (black lines), and the right side showing the faces of the icosahedron (blue lines).

The two in perspective:

As the icosahedron is a regular polyhedron, all of its sides are identical equilateral triangles.  Tent patterns don’t get much simpler than that!  Only one curve template to make for the side cuts.  The right triangles are just one equilateral cut in half.  As all the angles are the same, all the bias cuts will match.  The warp fibers can be arranged across the ridge line and the bottom of the end panels.

The edges as shown are 62″, making the tent 50″ tall, just fitting a 52″x84″ ground cloth.  The height of a 62″ equilateral triangle is about 54″ which fits across a fabric roll width with room for seam allowances – you could even do it in DCF if you don’t mind going a few inches smaller.  This lays out on a roll very easily with almost no fabric waste.

The icosahedron ends up about a foot shorter in length than the SS2, and a few inches narrow.  The end panels are three degrees steeper.  The big, obvious difference is the height of the pitch lock corner – 30″ on the icosa vs 15″ on the SS2.  As the lower panels are triangles, only 1/4 of their area is above 15″, and the two walls are at an angle to each other, which will help spill wind.  The slope of those low walls can be set to that of the sides of a tunnel tent by adding 2″ – 5″ to the short sides of the right triangles.  This will move the corner of the foot print out 10″, and still fit nicely on the roll layout.  The roof panels on the icosa have a slope similar to the Saddle 2.

[Sam Farrington]

NM

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