Tent Patterns–Off the Cuff?

[Brad Groves]

Hi, all-

So, one of the projects I'm working on is a UL/SUL double wall tent. A couple of "design parameters" (to make it sound official): 1) sleep two people & two German Shepherds if needed 2) three season use only 3) totally storm/waterproof 4) 2-3#

I have a floor plan, cut out a pattern that I like a lot, will be very multi-functional for me; total area 50.8 square feet. I know what I want to do with walls, pole structure and so forth.

The "problem" I'm having is that this is a complete one-off. I'm horrible with math at any level. I have no fancy computer programs and lack the funds to get one (or CAD, or whatever). My basic "plan" is to just start literally sewing up the tent and cutting panels to fit as I go. It strikes me as a particularly inefficient way to design–particularly since if I get panels cut and sewn in to work, I've then got to cut them out to make patterns off them, but add a bit for seam allowance…

I'm patterning on visqueen; sewing mock-up out of salvation army sheets or muslin. Is there a better way to do this?

Also, I have no idea how technical things such as pole arc, segment length, and so forth are, or need to be. I have some old scrap poles I can bend to something that would basically work; should I just sew up fabric to fit around that?

If you're familiar with the old Dana/Garuda Javelina, this is kind of inspired by that design–basically only in the use of trekking poles with a bridging pole for the central "hoop," (and floor shape) adding one short actual tent pole hoop at the foot end, two single-segment pole sections in the head corners.

Another consideration I have is all the silk yardage I bought for the sleeping bag project that I couldn't use. I'm thinking about using some of that in the tent body panels instead of noseeum mesh. I guess the only way to know how well it'd work is to build up the prototype and try it out. I'm somewhat concerned about tear strength, because one of my pet peeves about tents is achieving a taut pitch… we'll see. One thing that really sticks in my mind about silk is medieval warfare–I just saw a suit of armor from the 1500s that still had intact silk in it. Also remember hearing stories somewhere/time that they'd wear silk shirts because they somehow made pulling out arrows easier. Bizarre, eh?

Sorry if this rambles or sounds a bit neurotic. I've got three projects "in the works," and three of them have hit major glitches. I just want to get one of them done!!!

[Brian Kelly]

Thanks to your friends at Google, you can download a simple 3D modeler for free. A number of people here have used their SketchUp program to mock up some different designs. Might be worth a try.

[Tim Marshall]

i 2nd sketchup. I have used it for my tent, taprs, bug bivys. In fact i am in the planning stages of making a tent fly for another member of the forum. Using sketchup to check our dimensions has saved us a big mistake. It really helps to see what you are doing.

I have in the past used the sew-as-you-go method and for small project and it can have mild success. But for something like a tent which requires taught pitches and proper angles you most likely won't end up with something you love. Maybe, just maybe something that will work. But if you're gonna do all that work you should love it.

I plan to make a UL version of Coleman's Peak 1 cobra, to see if it has some potential. I recommend finding a tent design you like and copying it for you first try.

I made a single wall tent kinda planned kinda sew-as-you-go and though it worked out ok i have dozens of ideas for how to make it better. There are also parts where the tension is way off and this is because i didn't follow a plan

-Tim

[Roger Caffin]

Hi Brad

I am not sure about combining 'SUL' and 'totally storm/waterproof'. Bit of a challenge imho.

Is there a better way to design a tent than either CAD (which I use), maths (which I use), or hacking? YES.

First sketch (pencil and paper) what you want. Work out the poles FIRST!!!
Then make up a light timber frame shaped identical to the poles. Craftwood is perfectly OK for this. Erect this in the lounge. Drape visqueen over this and pin into shape. Now you have your pattern, and within limits it should work.

This link will show you an example of such a frame:
http://www.bushwalking.org.au/FAQ/DIY_RNCSummer.htm#Sven

The silk – I would use it for something else if possible. But if you make the inner tent replaceable for when the silk 'dies', fair enough. Keep the visqueen pattern!

Cheers

[Brad Groves]

Brian & Tim- Thanks for the idea on SketchUp. I played around a couple hours with it today, but think I need to spend more time learning the program before it's useful–there were some things that just didn't work for me that I can see probably would if I were more familiar with it.

Roger- Well, ok, not totally stormproof. Most of my tents are, after all, true four (fourth?) season tents. But dry, at least. If I'm building a timber frame, do I have to use traditional joinery? Have a house-raising party? (Kidding!) Good idea. I could probably even tie in the poles I'd use somehow. Still wouldn't know about panels within panels, ie mesh within the larger wall, but I could just cut that out of the larger whole.

Thanks–and keep it coming!

[Roger Caffin]

> I could probably even tie in the poles I'd use somehow.
You should make the frame and the poles match!
Make up the frame 6 mm too small (such precision!), fit the poles around the outside with duct tape, and drape plastic sheeting.

The mesh inner – maybe this can be slightly less critical? As long as it 'hangs in there'?

Note: this assumes you are going to make the poles fit to the fly. Me, I am a known fanatic about this as it means that the tent is more stable and pitching fly-first keeps the inside dry in a storm.

Photos expected!

Cheers

[David Erekson]

When you are making your poles 6 mm too small, make sure to measure with a micrometer, mark with a crayon, and cut with your chain saw. ;)

[Brad Groves]

Okay, so I'm cutting my aluminum poles to length with that chainsaw… :P

I guess that part of my question is: Do I get some poles, flex them into shape so that they fit to my floor's corners, and use the result to create the frame? Or do I create the frame the way I want it and then make the pole fit? (My feeling is that it ultimately probably won't matter either way, and I suspect it'd be easier to make things fit to existing poles…)

Pics will definitely come. I'm still trying not to gag on materials cost!

[Roger Caffin]

Sketch what you want.
Get the raw pole material.
Make the poles into the exact shape you want.
Make the wood frame to hold the poles in the exact shape you want.
(You can iterate a bit here of course, but the end point is to have the frame PLUS poles in the exact shape you want. Get this before making any patterns.)
Make up the pattern on the frame, etc etc.

Not with my chain saw though…

Cheers

[Christian Wagner]

I have formulas (actually they are spreadsheets) to calculate the fabric patterns of dome- and hoop tents.
the site is in German but here they are anyways:

http://www.flusslinie.de/zeltformel.htm

http://www.flusslinie.de/zeltformeltun.html

the direct links to the (english) spreadsheets are here:

http://www.flusslinie.de/ZELTFORMEL-en.ods

http://www.flusslinie.de/Apsiscat.ods

(use open office suite (free software- do a google search) to open *.ods files)

what you do is, you basically specify the height, width and length of your tent (in case of the hoop tent it is the width, heigth and the depth of the "porch") and the output is a set of coordinates which you draw on your piece of fabric. Cut along the markings with a little seam allowance and there you are.
For the inner tent you simply use different measurements for the height, wdth and length and off you go again.

There is a prototype one man tent on the hoop tent page (actually just a quick cheap fabric mockup) as proof of concept.

An example of a dome tent could be seen here:

http://www.flusslinie.de/winterzelt.htm

@ Roger:
Don't know if you remember but we had an exchange of email a while back, you where very kind to send me your summer tent plans- although I didn't make a hoop tent back then, I still am impressed with your very thought out gear designs. Thanks again.

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