JEbus! Sounds like the calcs I was doing trying to figure out how much tape to use for the quad dome... edges, sealing halvsies, hinging, pre-taping, playa taping, sealing gaps... ugh!
Actually, they were a lot simpler than this... Congratulations Richard, for having the capacity to figure this out. On Jul 15, 9:47 am, Richard Ginn <[email protected]> wrote: > Elfie this is a great idea! Let's play with some calculations: > > Conclusions at the top for convenience: > > 1. The 1.2 x 2.4 meter panels don't appear to work for the Octayurt as they > are too short to span the distance from the wall to the center. > > 2. Longer panels do work but may not be available in Australia. If you > construct your own structural panels this won't be an issue. > > 3. Octayurt encloses 53% more space than Hexayurt while using 33% more > materials. > > 4. IMPORTANT: MY CALCULATIONS COULD BE WRONG, SO DOUBLE-CHECK THEM! > > Showing my work: > > Using the The Regular Polygons Calculator that you used > athttp://www.cleavebooks.co.uk/scol/calpolyg.htmand assuming an 8-foot wall > length we see that the hexayurt has a floor area of 166 square feet and the > octayurt has a floor area of 309 sf. That's a gain of 143 sf for the > addition of 2 wall panels and 2 roof panels. Adding 33% more wall panel > increases the floor area by 53% (166/309=.53). > > Using the The Right-angled Triangles Calculator on the same > websitehttp://www.cleavebooks.co.uk/scol/calrtri.htmand The Regular Polygons > Calculator athttp://www.cleavebooks.co.uk/scol/calpolyg.htmwe can see what > the roof angle will be: > > Regular Polygons Calculator: > Hexayurt in-radius 6.93 and Octayurt in-radius 9.66 > > Right-angled Triangles Calculator: > Given edge b as 6.93 feet and edge c as 8 feet it shows edge a as 4 feet, > and the standard hexayurt roof height is 4 feet, as shown > here:https://secure.wikimedia.org/wikipedia/en/wiki/File:All_hexayurts_web... > so that calculator works for determining roof height for a hexayurt. I'm > going to guess that it will also give a correct number for the roof height > of the octayurt: > > Given edge c as 8 feet again (same roof triangle as the hexayurt) and the > octayurt in-radius of 9.66 feet, it gives a roof height of .... oh! > that's not going to work, is it? The radius is larger than the length of > the roof panel. So now let's see what 10-foot and 12-foot panels do? Also, > I see > onhttp://www.gunnersens.com.au/products/building-products/plywood/exter... > that you can get 3050 x 1220 mm panels in Australia, so I will run those > numbers too. > > Using 4x10 foot sheets: > Panel length (edge c) 10 feet, in-radius (edge b) 9.66 feet = roof height > 2.59 feet (edge a) > Ratio of radius to roof height: 9.66/2.59 = 3.7 (a measure of outward force > on the roof-wall edge, this is also the Tangent function of a triangle) > > Using 4x12 foot sheets: > Panel length (edge c) 12 feet, in-radius (edge b) 9.66 feet = roof height > 7.12 feet (edge a) > Ratio of radius to roof height: 9.66/7.12 = 1.4 > > Standard Hexayurt using 4x8 sheets: > Panel length (edge c) 8 feet, in-radius (edge b) 6.93 feet = roof height 4 > feet (edge a) > Ratio of radius to roof height: 6.93/4 = 1.7 > > We know how the Standard Hexayurt holds up, so a 1.7 ratio works well > enough. > So the 4x12 sheets (probably) work even better at a 1.4 ratio (less force on > the roof-wall edge), and the 4x10 sheets at a 3.7 ratio might be putting too > much force on the roof-wall edge. > > Australian plywood dimensions (I'm guessing that the insulating panels come > in this size too?): 3050 x 1220 mm panels > Regular Polygons Calculator: Length of edge = 2440mm > in-radius = 2950mm > Panel length (edge c) 3050 mm, in-radius (edge b) 2950 mm = roof height 775 > mm (edge a) > Ratio of radius to roof height: 2950/775 = 3.8 > 3.8 might be putting too much force on the roof-wall edge, just as the 4x10 > foot sheets do, but as you said, you have no snow or storm issues, so maybe > this will work? > > My non-engineering guesstimate is that if 3.8/1.7 = 2.2 then maybe that's > also about 2 times the force on the roof-wall edge comparing the standard > hexayurt and the octayurt with 10-foot or 3050mm panels. > > Also, searching for Australian plywood dimensions I am not finding anything > larger than this 3050mm panel so your quest for a longer panel, if you want > one, may be lengthy (no pun intended :) > > My conclusions, also posted at the top so you don't have to read to the > bottom to see that: > > 1. Since the in-radius of the Octayurt is 2950 mm and the panel you want to > use is 2400 mm long, it's not going to work at all because the roof triangle > is not long enough to span the distance from the roof-wall edge to the > center. > > 2. In English measurement the 12-foot panels will probably work very well > for the roof panels, and the 10-foot panels will work but they might put too > much force on the roof-wall edge. The Metric equivalent of the 10-foot > panel is the 3050 mm panel and that will have the same force issues as the > 10-foot panel. > > 3. I'm not finding anything longer than 3050 mm sold in Australia. Maybe if > you make your own structural panels with plywood and foam core you can get > the shape exactly as you want it. > > 4. IMPORTANT: MY CALCULATIONS COULD BE WRONG, SO DOUBLE-CHECK THEM! > > The roof panels of the standard hexayurt are 8 feet long from tip to base, > being made from 8 ft panels cut diagonally. > > On Mon, Jul 11, 2011 at 9:57 PM, Elfie Sullivan > <[email protected]>wrote: > > > > > ** ** > > > ** ** > > > I am thinking if 15 sheets of 2.4meter x 1.2meter sheets to make a > > 1.80meter high hexayurt gives me about 15 square meter area.**** > > > Is it possible to make an octagon Yurt using 20 sheets of 2.4meter x 1.2 > > meter to make a 1.80meter high octayurt that gives me a much bigger area > > around 27 Square meter. I would really like some feedback if it would work, > > be strong enough and has anybody done one. I am aware the roof would be at a > > different angle but think it is Ok as I have the 1.80 meter high wall. I > > used the polygon calculator here > >http://www.cleavebooks.co.uk/scol/calpolyg.htm**** > > > And just put 8 for number of sides to get my calculations.**** > > > ** ** > > > P.S I live in ****Australia**** so I don’t have to worry about Snow, > > hurricanes or sand storms. I would like to make it a permanent structure > > with adding a skylight/ clear umbrella at the tip of the roof. **** > > > My email is [email protected] any advice is appreciated. **** > > > Cheers > > Elfie > > >www.reikitoyou.com.au**** > > > Share <http://www.facebook.com/sharer.php?u=www.reikitoyou.com.au&src=sp> > > with > > your Facebook friends. > > **** > > > ** ** > > > -- > > You received this message because you are subscribed to the Google Groups > > "hexayurt" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > > [email protected]. > > For more options, visit this group at > >http://groups.google.com/group/hexayurt?hl=en.- Hide quoted text - > > - Show quoted text - -- You received this message because you are subscribed to the Google Groups "hexayurt" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. 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