half pyramid - any math whizzes out there
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Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
tent name on 09/04/2006 15:12:02 MDT Print View

B.P.L.amids?

Regarding a consensus on a design, seems there's too many folks, too many different levels of experience, too many needs, too many different desires for comfort, or lack of, etc.

Dwight

Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
half pyramid with overhand on 09/04/2006 21:01:40 MDT Print View

like this? Or probably something that would pull lower if needed.


half pyramid with canopy

Mark Larson
(mlarson) - MLife

Locale: Southeast USA
Re: half pyramid with overhand on 09/04/2006 22:12:46 MDT Print View

Maybe I'm missing something here, but it seems like we just re-invented the Dancing Light Gear Ultralight Brawny Tarptent (see a BGT review), or maybe the DLG Tacoma Solo. Of course, DLG isn't manufacturing anymore... but it looks like this problem already has at least 2 solutions. I'm confused on how these proposed designs are different/ better.

Oh, and I do appreciate the software and modeling tools that have been mentioned. That's good stuff.

-Mark

Edited by mlarson on 09/04/2006 22:20:08 MDT.

Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
reinventing on 09/04/2006 23:04:38 MDT Print View

Because reinventing is the cousin of MYOG.

I did find the Brawny online after I fooled around with the tet idea, though. Of course, I was pretty sure it wasn't original when I thought of it.

Seems like the cat tarps are a more efficient use of material though.

Dwight

Mark Larson
(mlarson) - MLife

Locale: Southeast USA
Re: reinventing on 09/04/2006 23:36:18 MDT Print View

"Because reinventing is the cousin of MYOG."

Great point! I figured it was either:
1-A problem-solving exercise from scratch to learn the tools and products, sort of hacking and reproducing.
or
2-Improving the design or features of something already available. I didn't think I was seeing anything 'new', so I just wanted to make sure I wasn't being a blockhead and missing something cool.

Like in this case, I know sometimes I just have to start with a clean sheet of paper and think it through, even if I'm retracing someone else's steps. For me, that critical thinking is one of the best parts of UL hiking.

Anyway, I appreciate seeing everyone think out loud on this one.
-Mark

Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
And that too on 09/05/2006 03:48:16 MDT Print View

For me it was also item 1, going through the steps myself so I know the why's and why nots for if I ever do do something original.

Its also encouraging that I come up with ideas that have been implemented commercially by more accomplished tent builders.

Edited by zydeholic on 09/05/2006 03:50:32 MDT.

Joshua Mitchell
(jdmitch) - F

Locale: Kansas
Recently did a similar excercise... on 09/05/2006 10:10:54 MDT Print View

To determine the dimensions of a seamless conical tent made from a roll of tyvek could be (aka limited to 9ft in one dimension)

If I could remember what in the world I did and where in the world I put my notes... I stumbled upon an equation that would have helped with this discussion and with determining dimenstions in general... but, I can't find it...

Anyhow, very interesting work everyone...

Edited by jdmitch on 09/05/2006 10:12:05 MDT.

Joshua Mitchell
(jdmitch) - F

Locale: Kansas
90 Degree Angles on 09/05/2006 10:15:40 MDT Print View

Oh, and Dwight, you are correct on the 90 degree angle thing. Well, at leas you are correct if you want there to be a straight line (when viewed downward from the top) between the two leading corners going through the tip of the pole.

Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
90 degrees on 09/05/2006 19:20:09 MDT Print View

Thanks for the validation on that Josh. And you're right, I'm assuming a right angle for the face of the tent to the ground.

Yukio Yamakawa
(JSBJSB) - F

Locale: Tokyo,JAPAN
狭そうに思います on 09/06/2006 11:45:24 MDT Print View

http://www.snowpeak.co.jp/catalog/spo/html/2006/pentaease/pentaease.html

やはり、スノーピークのサイズぐらいは
必要と、JSBは考えています。

Joshua Mitchell
(jdmitch) - F

Locale: Kansas
Penta Tent (US Version of Yukio's Link) on 09/06/2006 14:40:27 MDT Print View

Penta Tent

Very cool find. Looks very similar.

Bill Fornshell
(bfornshell) - MLife

Locale: Southern Texas
Half Pyramid/Alphamid on 09/06/2006 15:00:11 MDT Print View

It looks a little like mine.

R Alsborg
(FastWalker) - MLife

Locale: Southwest
Re: Penta Tent (US Version of Yukio's Link) on 09/06/2006 15:23:33 MDT Print View

Josh

You’re right the Penta Tent it is a cool design!

I especially like the bug shelter base and the way they incorporated a canopy on to the tarp. Nice options for keeping the mosquitoes out and even more protection then the typical 1/2 Pyramid / Alpha-mid from wind blown rain.

Penta Tarp

Edited by FastWalker on 09/07/2006 11:06:56 MDT.

Joshua Mitchell
(jdmitch) - F

Locale: Kansas
Either great minds think alike or... on 09/06/2006 15:56:01 MDT Print View

Someone @ snowpeak hacked Bill's brain!

Miguel Arboleda
(butuki) - MLife

Locale: Kanto Plain, Japan
Re: Either great minds think alike or... on 09/06/2006 20:45:58 MDT Print View

"Someone @ snowpeak hacked Bill's brain!"

No, the Penta Tarp has been around quite a while now. I've had mine since 2001. The inner tent and removeable awning are new, however, only coming out a year ago.

The Penta was originally designed for kayakers camping on beaches (it even comes with a separate sleeve to accommodate a paddle for use as a pole). It is HUGE! However, the shape allows for all sorts of configurations, from a two meter tall pyramid with one side missing, to a low, wide wing that can sleep four, to a tent awning like Bill's, to a bat-like A-frame. My only gripes with the design are that it has no provision for a front door and the catenary cut sides are a little too deep. The material is a 75D polyester (doesn't stretch) impregnated with silicon on one side and the other side covered with polyurethane. It's very strong (much stronger than the usual silnylon), but also quite heavy.

I liked the design so much that I used the pattern to design my own Lunar-Solo-like tent about a year before the Lunar Solo came out, cutting down the dimensions for one person, making the catenary sides shallower, and adding doors to the open side of the pyramid. Alas, it is still too big, so one day when I have the time I want to cut it down still further.

The original Penta itself I have few occasions to actually use. It is just too big and heavy for backpacking, and I don't go camping with enough people usually to justiify bringing it on my trips when I am not alone. If Snow Peak would make a smaller version they would have a wonderfully versatile and strong tarp on their hands.

Edited by butuki on 09/06/2006 20:54:52 MDT.

Joshua Mitchell
(jdmitch) - F

Locale: Kansas
Yeah, the tarp's been around a while on 09/07/2006 10:39:51 MDT Print View

The tent combo thing is what is new to me.

Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
9 ft Tyvek cone on 09/10/2006 22:00:34 MDT Print View

here's my off the top of my head calcs.

Finished diameter will be:

D = Length of curved floor edge / Pi
L = ( Length of curved floor = 9 x PI if using full width of sheet and 18 ft length)

Height will be:

H = ((9^2 - (D/2)^2)^.5

Ok, simplified formula, or rather, not so many steps:

R = Radius (9' in this case)

A = Angle of arc of flattened cone (180 degrees in this case)

Height = (R^2 - (2R * A/360)^2)^.5

Diameter of raised cone will be:
D = 2R*A/360

H = 7.79'
D = 9'


You could make a pyramid tent too, with corner to corner length being 9', and wall to wall length being a little over 6'.

Well, both of these instances give no slop for attaching the wall edges. So you've have to figure an inch in there I guess.




Dwight

Edited by zydeholic on 09/10/2006 23:55:38 MDT.

Dwight Shackelford
(zydeholic) - F

Locale: San Francisco Bay Area
New Spreadsheet for Half Pyramid tent on 09/28/2006 12:57:09 MDT Print View

Ok, through the cumulative efforts of several people on here, I've pulled together a new version of the spreadsheet and charts.

This one calcs the layout points for the half-pyramid shell itself, and also shows the layout points for the doors, given a specified width of a vestibule.

If anyone is interested in getting a copy, and checking my math certainly, email me at zydeholic@yahoo.com.

This is adapted from my original version where the fabric width, tent width, and tent height are specified. I've added the specification of the vestibule width.

Rich had a spreadsheet that allowed you to approach it from a few different directions regarding specified dimensions. Feel free to take what I've done and add it to Rich's spreadsheet if you so desire.

Dwight

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Either great minds think alike or... on 10/05/2006 23:54:10 MDT Print View

Hi Miguel

> The material is a 75D polyester (doesn't stretch) impregnated with silicon on one side and the other side covered with polyurethane. It's very strong (much stronger than the usual silnylon), but also quite heavy.

Source of this material?

Cheers
roger@backpackinglight.com

Miguel Arboleda
(butuki) - MLife

Locale: Kanto Plain, Japan
Re: Either great minds think alike or... on 10/06/2006 02:20:55 MDT Print View

Source of this material?

Hi Roger,

Er, when you say "source" do you mean where was material manufactured, or where did I get this information?

The information was written right on the package that came with the tarp when I bought it. I still have the package because the diagram on the front helped me when I design the pattern for a silnylon copy I made. You can also find the information here (Snow Peak's official site... though it's in Japanese, if you scroll down you can see "75D" and next to it, in Japanese, "polyester taffeta") and here (the unofficial, but recognized site of people devoted to the Penta here in Japan. Again you can see the "75D" and next to it "polyester taffeta").

If you're asking where the fabric was manufactured, I haven't the foggiest. Contact the people on the Snow Peak or Penta e-Club sites. Someone is bound to speak English.

Edited by butuki on 10/06/2006 02:23:37 MDT.