Tarptent design (Lunar Duo clone)

[Ryan Longmire]

Howdy all,

Ive been playing with paper models and Sketchup to brainstorm and visualize different tarptent ideas.

I then have an excel spreadsheet to estimate the weight of the shelter.

Anyway, I'm trying to come up with something that is:
-easy to DIY
-2+ person
-good for TALL people
-decent vestibule space
-lightweight
-relatively easy to pitch

Here is a Lunar Duo clone (without the curved roof, estimate ~35oz):

I was just hoping to get some feedback/discussion on DIY tarptents. If you have a design, I encourage you to model it up in Sketchup (or maybe I can). Its just too easy.

Thoughts?

edit: The floor on that model is 90"x54"..

[Kevin Stephens]

love the graphics….where can i get Sketchup?

[Michael Crosby]

http://sketchup.google.com/download.html

[Kevin Stephens]

thanks for the link…..I too am on the same quest as you, need a lightweight tent that a 6' person can sleep in and that will hold 2+ people.

[Ryan Longmire]

thanks for posting that link Michael. I should have put that in the original post.

Ideally, I would like to get a couple more "open-source" tarptent designs for us DIYers.

I dont know all the pros and cons of different styles and design elements but that is where the collective experience of the forums can be very helpful. With enough discussion and critiquing, hopefully we end up with a well thought-out DIY design.

[John S.]

A similar single wall version was made by Dancing Light Gear.

http://www.backpacker.com/article/1,2646,5171,00.html

[Sam Haraldson]

We had a discussion going last August almost precisely like the current one. Check it out here.

And an even earlier one from March. Check it out here.

[Ryan Longmire]

Thanks for the links!

It looked like the alphamid style was the hot topic. Why is this?

I know they are popular for winter shelters, correct?

Seeing as how im looking at a 2+ person, 3-season, fully enclosed model, does the alphamid/half-pyramid make sense?

[Jason Brinkman]

An Alphamid-style will be my choice when I get around to making or buying a new 3+ or 4 season shelter. I use a bivy and poncho-tarp in 3 season conditions, but want better protection for when snow is likely.

From what I can tell, Alphamid advantages are easy setup, few stakes, few or no guylines, only one pole, good wind shedding, vertical door, etc. I understand that Ryan Jordan has used one quite a bit lately, so hopefully we'll see more articles on this style shelter soon. Some info is available from the recent Arctic Expedition.

Steeper-walled Alphamids supposedly perform better for snow load and condensation (drips run down walls instead of dropping on you). However, if I built one right now, it would be trekking pole height with flatter walls, for which I would compensate by not letting too much snow accumulate and using my bivy inside for drips.

I think we'll hear more about the Alphamid-style shelter in the near future. At least I hope so.

[Franco Darioli]

Hi Ryndel
If you want to have a look a production model of your tent, check out the Mountain Equipment AR Ultralight Helium.
Franco

[Sam Haraldson]

http://www.tensile-structures.de/index.html

I have a friend who works for Google (on the SketchUp project in particular). When I showed him this thread he mentioned SketchUp users would probably be interested in this plugin.

http://www.tensile-structures.de/index.html

It allows for the notion of tensile surfaces which would be useful to fabric designers working with fabric that has the ability to stretch.

[Ryan Longmire]

That plugin is really neat. I am going to play around with it more when I get home.

What are the negatives of this design (the lunar duo style)??

I'm leaning towards making it because it seems like it will be pretty simple to construct.

[Lance M]

Here is another variation of a DIY tarptent. Wide enough for two, but the 84" long floor is probably tight for a six footer.

Weighs 23-1/2 oz with tie outs.
Floor Area is 60" wide front, 48" wide rear, 84" long.
Side walls and end walls tip out 5 degrees. About 8" rainshadow beyond that.

[Sam Haraldson]

Lance,

That's really nicely done. Is it done up in silnylon? I especially like the handiwork along the zippered screen. Very professional.

– Sam

[Joseph Williams]

Lance, that looks like such a nice tent! Can I ask how you worked out the catenary ridgeline?

[Lance M]

Thanks for your comments and questions. Here is some more info.

Re: Is it done up in silnylon?
Fly and floor are silnylon. Netting is standard No-See-Um. Kelty Triptease tie-outs. Optional Easton aluminum poles. #1 grommets. 3/4" grossgrain & webbing. #3 continuous zipper. Mettler polyester thread. #70 needles.

Re: Catenary curve.
I used a spreadsheet to calculate the curve. See
here for previous post of spreadsheet.

Designed with TurboCad Deluxe v12.
Pattern transferred to 36" X continuous craft paper.

[Michael Crosby]

Lance,
Bravo, the tent looks great. I have been looking to replace my old solo tent for some time and looked into DIY and decided I did not have the skills necessary to sew such delicate fabrics.
I ended up buying GoLite’s Lair1 (1.06 lbs) and insert (1.06 lbs). (total cost about $180.00). You saved over .5 lb over the two Lair pieces. How does the cost of your DIY tent compare? How much trouble was it to make?
Thanks

[Lance M]

Materials cost around $65 (silnylon was $2.95/yd from Noah Lamport). I guestimate about 24-28 hours from cutting out the pattern to completion.

Past projects include a flat tarp (still use), down quilt(too short), and cat tarp with bug insert(still use but had too many difficult assembly problems).

The current design and assembly was the simplest and smoothest yet (if you don't count ripping out and redoing yards of stitching). I would build this one again and anticipate it taking much less time.

[dale stuart]

I to have been looking at a Lunar Duo clone. I picked up some 75" 1.3oz silnylon in silver/grey for $2.50/yd. I intended on leaving my roof width 75" and allowing 10" overhang each side with a main body 55" wide. Then moving the trekking pole supports to the 10" overhangs outer edge and having 1/2 the beak fixed like your drawing. Other 1/2 of beak/vestibule would be attached via dual pull zipper. The thought being in bad weather I could close the beak most of the way and still leave top portion open a bit for ventilation, being protected be the 10" overhang.
-Dale

[Ryan Longmire]

I forgot I made this thread and thought I should give an update.

I have almost finished my tent/tarptent. I just have some small things left to do. The current weight, including the floor, netting, and guylines is 31.35 oz. Finished weight should be really close to that.

Here are some pictures before I sewed in the floor and netting:

[Joshua Mitchell]

Nicely done, nicely done.

[Steven Evans]

Nice work on the tent – holds a nice pitch too!

[Jim Colten]

holds a nice pitch too!

that IS a nice pitch …. but backyards are a wimpy test for that. Show me a picture on uneven forest floor the morning after an all night rain and 20*F temperature drop!

But if it does not pitch well in the backyard, the field pitch will be hopeless. The taught pitch in the pictures is indicative of good craftsmanship. Nice job!

[Ryan Longmire]

Thanks for the comments.

My biggest concerns are wind and condensation. It is a big tent, and it catches alot of wind, but I have had it up on some pretty gusty days and everything was fine. There are several extra tie outs if needed.

I spent one night in it (the day I finished enclosing it) and was happy with the performance. I crawled in around 11PM and decided to repitch because the sil was already just soaked in dew. The temp was about 50*F with little to no wind. I decided to leave one vestibule closed and the other half-open. In the morning there was light condensation on the inside, and dew still covering everything outside. I wiped the condensation just to see what it would do. It rolled down the inside of the roof, but didnt drip. Not bad, I thought.

[Paul Tree]

"is an Plugin for Google Sketchup Pro 5.

This Plugin does not work in the free version of Sketchup."

Latest version is 6 and Pro version of sketchup is $450, but there is an 8-hour free trial. Probably learn on the free version first.

[Author]

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