Monthly Archives: January 2013

A light and strong structure

Strong but not heavy

Sky Yurt – model #3

To hold the Sky Yurt up in the air, and to attach the awning for the workspace I was going to need a strong core structure. But the Sky Yurt itself could be made of much lighter structural materials. It only had to hold itself together, like a pop-up camping tent. I was driving into Willsboro one afternoon and saw a backyard trampoline with a kids low play tent stretched over tramp. I knew about trampolines from my trimaran sailing. A few people jumping on a trampoline generate a strong downward force that needs to be resisted by the frame. So trampoline frames are built to be very strong. .But they are also portable and are pretty light for the stresses they have to deal with.

Using the trampoline frame to hold up the Sky Yurt

For the next model I went hunting for circular rings. Found what I was looking for in a craft shop – those hardwood rings that are used for needlepoint work. I made a new balsa wood and plastic straw model, and I really liked the look and feel of it. I was ready to build my first prototype. Now I was getting into the real building project. My scare-level increased to the point where I thought I might need to start wearing a metaphorical diaper. I asked my friend Andy Wekin – he was an artist who had gone back to school to be an engineer and he came with his partners Otis and Ezra (more on this team later) – to be the consulting engineer.

Beginning to build the first prototype

Sky Yurt – PVC prototype

I found a trampoline frame on Craig’s List and hauled it home. They are really available, sort of like old hot tubs and spas. They are in those class of things that at the time seem like a good idea, but they stop being used (you don’t want your kid to break her neck) and they take up space a lot of space in the outdoors. My friend Robin runs a preschool at a farm. They had a lot of PVC pipe that had been used in an irrigation project, and for a small donation I had my beams. I made hubs out of plywood and scrounged for PVC connectors that I could cut up and experiment with. I had SS wire from some of my old sailing rigs. Mostly I wanted to learn from this first structure -see if the basic engineering would work, where I would need extra support and how the Sky Yurt structure would interface with the trampoline frame. And it started out looking pretty promising.

Working on the Ground – Living in the Sky

First concepts

Sky Yurt drawing #1

I started making very rough sketches years ago. I wanted an open, circular, covered workspace on ground-level. The living space needed to be elevated, so you could almost walk underneath it, or at least see through it. I flattened out the tall tipi shape to make it more like a diamond, like in my early dowel and wire model. I decided the yurt would set on vertical uprights, doubled under each set of beams. The workspace tent structure would then radiate out from the eight-sided elevated yurt-like living space. The fabric cover on the workspace would need to be adjustable, so one side could be tucked down to block the wind, while the opposite side might want to be open wide and high to let in the warm early morning sun..

First models

Sky Yurt Concept #2

I made a painstaking model out of dimensional balsa wood -held together with pins and light wire. That got lost in the shuffle over the years. The next model used clear straws for beams and joists, pipe cleaners at the outer ends of the beams, and cardboard and hot glue for the center hubs. I really liked the look of the design but some real concerns began to emerge.

I was still stuck on using vertical posts to hold the yurt off the ground. The whole structure was looking less like a tension structure. Those posts were going to need to be heavy and I was thinking that the whole structure was going to need to be pretty beefy to match it. And hell, this needed to be nomadic – meaning light and strong.

I ain’t no designer

You need to know as I walk you through this process, if you haven’t figured it out already, that my skills as a designer are severely limited. I can’t draw worth a hill of beans. I am dyslexic and have trouble with sequencing. I can get an idea, walk around thinking about it almost all the time – but I have to build the damn thing so I can begin to figure out if my “design” idea will really work. My neighbor Bruce, who has watch my “follies” emerge in the backyard laughed the other day, “I have heard of design/build, but I think what you do is build/design”. And he hit the nail on the head. That my process – build/design. It ain’t pretty, won’t work for a brick and mortar house, but with my Sky Yurt, I can take it apart, fix what doesn’t work and give it another shot.

The Sky Yurt concept

How could I put a tipi-like structure up in the air?

Sky Yurt structure

I began to make some models and do some rough drawings. I was influenced by Bucky Fuller who said that structures should have an integrity that didn’t depend on gravity. I think he called that “tensegrity”. If the house I live in now, a Greek Revival built in the 1860’s, were pushed off into space, the components would begin to come apart. A tensegrity structure would hold together, like a bicycle wheel. It wouldn’t depend on the forces of gravity.

Long ago I built an eight-sided model out of dowels, eye screws and wire. I was impressed with how stiff the structure was and how strong it it felt. I carried that model through all my life changes and moves. I hung it up in a prominent place in my office or living space so I wouldn’t forget the concept.

An amazingly strong structure

Strength testing the basic structure

The strength in the structure comes from the compression ring around the outside diameter – much like a yurt. I added the tension wire in the middle, but was sure that I wanted a design that would be completely open inside. I would need to create another way of tensioning the yurt.

Today, I went ahead and strength-tested the structure to see if it was really as strong as i imagined. Amazingly, it held my weight (200 lbs.). In the current prototype of the Sky Yurt the downward tension comes from fabric cover.

The vision – a shapeshifting village of nomadic artists and crafters

The vision

Sioux village

An open field, surrounded by trees. A small river just over the bank on one side of the field. Woods and mountains in the distance. Just after noon the first nomad arrives in a van with trailer in tow and begins to set up. Through the afternoon and into the early evening, nomads arrive. Each arriving nomad chats with his neighbors, sizes up the available space, and chooses a spot that feels right.

The village takes shape

Each shelter is unique and yet each is a variation on a common theme – a round, open, fabric structure with an awning like a sun umbrella – the workspace. And in the center, perched above the open tent, a round and private living space – yurt-like, dome-like or maybe free-form. The village grows organically as the nomads arrive. Some folks chose to cluster together, some prefer more distance and privacy and set up on the fringes of the village. The kids roam freely, checking out the new arrivals, and reporting back on what the river is like and the play spaces they have found in the bushes.

Where did this vision come from

In Vermont, I built my tipi from a pattern in the bible that John and I used – the Laubin’s book, The Indian Tipi – Its Structure and Use. As I hand stitched the canvas together – some of the seams were 50 feet long and I ended up with a knot in my back as big as my fist – I imagined the Sioux swinging into the meadows along the Little Big Horn, and setting up their tipis in an open circle with the hubbub and organic chaos of dogs, kids, horses and dust.

Nomads all

The Sioux tipis were private shelters. They were hunters and gatherers and were often out of village. They were horse powered, and couldn’t haul a lot of stuff. My nomads are makers, might be veggie-diesel powered. They need to bring their workspaces and materials with them. But like the Sioux, they will be on the move to where the grass is sweet and the “hunting” is good.

Why a shelter sky high?

First time getting the tipi cover up with help from J C and Pew

The idea for Sky High Shelters has been brewing since I lived in a tipi on the top of a hill studded with small pines in Cavendish, Vermont in the 1970’s. My brother John had a tipi one field over. I had an open-sided kitchen lean-to with an old wood stove for baking bread and a cable spool from the power company as a table. We would sit in directors chairs around the table, drinking perked coffee, smelling the bread in the oven, watching the day unfold. Then I would turn to my bro and ask, “So what are we going to do today?”

Outside all day

I loved being outside all day. I had a kick wheel for making pots with local clay tucked under the lean-to. Even in the tipi with a fire going I was “outside”. I could feel any change in the sky or weather through the white canvas. And the inside air never heated up – all the warmth came from the radiant heat of the fire on my body – just like the warm sun on a cold day.

When I stood on this spot on the top of the hill where the snow had melted away, and I looked at the view of the valley and mountains to the east and the deep woods to the west, I realized that as soon as I put my tipi on this beautiful spot, I was going to lose this 360 degree view. The structure would be in the way.

What if…

What if I could put the tipi up in the air and have an tent structure under it that could be open on all sides when the weather was fair. The smoke flaps on the tipi could be adjusted like a jacket collar to block the wind so the fire would draw well. Maybe the open tent structure’s fabric could adjust to block the wind or be wide- open to light breezes on a beautiful day. And that open tent space would become my kitchen and workshop. And at the end of the day my sweetheart and I could retreat into our tipi nest, sit around the small fire, talk, plan, make love and fall asleep breathing the cool evening air.

The dream deferred

But life changed. I married a woman with small boys. Lived in houses. Got a real job. Had a daughter. Got a graduate degree. Divorced. Fell in love. Got married again. Lived in an old school house. Made babies, boys this time. Got a bigger house in town. And a summer house. And a series of sailboats. And all the time I kept making drawings and models of my “Sky Tipi”. Two summers ago I asked my new friend Andy, an artist who had gone back to school to be an engineer, to work with me and we started to build the first prototype in the backyard. I started to call it my “Sky Yurt”.