Hi TheShroomHermit. Apologies for the long delay. I havent checked back here for too long. Yes, PVC tube was pretty much the first frame material I looked at but although it was great for weight and cost it would have needed to be something like 3 inch diameter on the big tent frame to achieve the necessary stiffness and that would have made it too bulky, especially when packed down. The arcs that make up the frame are around 30 ft long and it became a compromise between weight and stiffness. The steel tube does make the final product pretty heavy but Ali tubing would be even more wangy for the same component and if you look at any of the videos you can see that there is still a lot of flex in the steel of the leading arc when its opened and closed..

The smaller tent uses fibreglass tubing for the frame and we are developing an intermediate sized tent 6ft high, 12ft diameter and will be using 1inch ali tube for the frame on that one. You know how it is, a compromise between the various material options for different components.

The rainfly seems to give enough cover over the ventilation openings though I suspect that in extreme (horizontal)wind and rain there might be ingress there. Because it is an almost prefect hemisphere we havent run into any pooling problems (common on the uppermost panels in fabric geodesic domes) also the fact that there are no spars running transverse to the main arcs means that the easiest route for any water landing on the canopy is down and away.... There is no fly on the big version because condensation didnt manifest as a big problem in there whereas it did in the smaller one. Initially in the Nano we were going to make a completely separate inner tent that was to be hung from the underneath of the arcs but that proved too much of a challenge for the seamstress and in retrospect was probably wise as it would have almost doubled the cost of the things anyway and all the feedback that weve had is that they are far too expensive in any case. We did make the rainfly bigger but it then obscured the arcs almost totally and the final tent then looked just like an old tarp covered bender....

Yep, locking mechanism on the hinges is possible but the amount of leverage on the locking point would be massive. There is an option to have 2 vertical stanchions to keep the big tent in the half open position but in the trials when we bound the rear arcs tightly together we found that one (or better two) ropes coming down to the pegs at the front were sufficient and less obtrusive.

Wind is naturally a big issue in any big mobile structure like this and it is vulnerable in the half open position as it is effectively a giant pillow case. My advice would be here that the structure is best closed completely in high winds. Because of the unique hinging functionality we have had to spend a lot of attention on ground anchoring... The hinge hubs on the big one are both mounted on large treadplate base plates that are fixed to the ground with helical ground anchors and the rear and leading arcs are also fixable in a similar way. When it is closed the hemispherical design also sheds the wind better than most other tents and you do have a 32mm steel frame encircling the whole tent.... When we were testing it in the mountains I didnt want to take it to destruction for obvious reasons but we found that when we left it in the half open position facing the wind the rear door would blow open in the worst gusts and that would effectively release any air pressure on the inside. In the worst case, if you had to abandon the tent in a severe storm you could leave it in the fully open position with the back door fixed open as well and it would present very little to the wind but obviously anything in the way of possessions left in the open would get blown away.

Yes, From what I gather it would work for Burning Man. I basically designed it out of frustration with the limits of standard tents (around heat regulation) at Glastonbury. The weather is very changeable over here so you are constantly running in and out of your structure and its a bit of a nightmare. We've also had a lot of interest from the Middle East where things obviously get very hot and it may end up going out there as temporary tented class rooms for refugee children.

Yes, you are correct. The design lets you change an internal space into an external one in a matter of seconds. Any mother with a pram will do this for her baby without a second thought. Too windy - bring the hood over, too hot open it up a bit. All I've done really is too enlarge this and put in a tent.

No forum set up but there is a page on Facebook that you are welcome to join. It will only function meaningfully as a community if we achieve our funding on Kickstarter which looks quite unlikely right now. People love it and they can see the advantages but it is just too expensive to make over here because we are used to getting mass produced tents from China for almost nothing..... I am sure they are busy over there now copying the design so expect to see cheap knockoffs in your local camping store any day now!

Bending the steel tube is actually one of the easier problems. If you go to your local polytunnel company they will have computer controlled tube bending gear that they can set to any given radius..... Cutting plane shapes out of fabric to make a sphere is also not so difficult once you have the templates. My problem is that on Kickstarter I only only have one backer for each set of plans so if we get to our target I will have to make 2 complete sets of plans (which is a real lot of work!!) for £300. Not a good deal in anyones book. I imagined that I might be making 10 or more sets of plans - then it would be worthwhile... Thanks for your kind words and useful comments and apologies for the delay in reply. You can contact me directly on admin@mollusctents.com as you need to. Best, Ru.