According to the assembly diagram the base of the dome consists of B-C-C struts (which repeat and they form the circle of the flat base).
I tried to design but it seems that the lengths of these struts , doesnt form a complete circle.
Does anyone have experience with geodesic constructions?
Remember that you are building a 3D shape and so I think the gap you're talking about is what forms the curvature of the dome.
Have a play with a model and you'll see what I mean. You make triangles, which are put together to form hexagons and pentagons. But you'll find that there is a small gap once you glue the necessary triangles together. That gap creates creates sort of cone shaped polygons instead of the typical flat ones. This in turn forms the curvature in the third dimension.
I have seen this webpage and after lot of searching i decided to make a 3v 5/9 geodesic dome. It will be big enough to not let me try to experiment with other constructions.
The connectors will be pieces of metal pipe and the wood struts will be attached around the pipe with metal tape and woodscrews. (same system as this straw dome
We made a model using drinking straws and bent paper clips to hold them together. Try it out with a scale model before trying it for real. IMHO the hardest part is calculating the angles where the pieces come together and getting good joins there. Someone sells kits with metal brackets and you just cut all the wood to 90 degrees and poke it into the bracket, hold it with a few screws. Might be worth the $$.
What put me off about the hub and strut method was the number of hubs you have to fabricate out of metal. This method works really well if you're using metal struts too but I came to the conclusion that because metal struts are thinner, covering the dome would be much more difficult.
I personally came to the conclusion that for me, a wooden frame dome was the way to go using a hub-less design that also doesn't require the complex joints to get the angles right.
Remember, any errors in the angles of a dome compound together so anything less than a perfect joint will result it gaps elsewhere.