2) I am using the excel spreadsheet "Hemisphere Parachute Calculator Spreedsheet" on the site: http://www.cit.gu.edu.au/~anthony/kites/parafauna/chute_design/ to work out the sewing pattern for my canvass.
Could people check this out and see it it is useful and accurate.
I am going to use it for the 5/8 3v dome that I am building.
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You could use the 2 triangle template patterns (BCC and BAA) from your dome and use them to create the cover panels. Overall you`d need 5 panels like this: click here Each section could be further divided to make best use of the available canvas width. Don`t forget to add a good margin for the hems.
I've had a go at doing a pattern for a 5/8 3v cover, the grey shaded bits are one fifth of the cover required. All you need to do is mark five of each, using the patterns and sizes in the dome calculation page. (I've fixed the colour coding on this page now)I've also included hems (marked in black)
It may be an idea to stitch the hems inside the above panels to keep the weather out.
I am assuming that neither of these patterns would leave a flat base? Would I need to modify the bottom row with colins green and grey measurements.
Yes you would need to make ajustments for a flat base, having said that you would also have to alter the patterns to allow for doors or some other form of access.
don`t forget to add the hubs into the lengths otherwise you`ll be around 3" short.
If the cover material is stretchy you might need to modify the sizes to get a nice snug fit.
Having said that, almost every kind of material including the actual frame timbers will expand and contract to some degree. Canvas may stretch or shrink after it settles in.. or after it gets wet.
Plastic or poly tends to be the worst..saggy as a sock in summer and tight as a drum in winter :)
How is the dome coming along? Any chance of some pics?
Hi Colin, do I add 76 mm to all strut dimensions on your sewing pattern to solve this?
The dome is up and I will send pictures soon and description.
That`s marvellous, look forward to seeing them.
If it`s already up, you might as well measure the actual lengths directly from the dome.
If you modify the drawing of the cover pattern from the "click me" link above to include the green and grey flat base struts, you can use it as a reference while you measure. You`ll only need to measure one of each strut type from the centre point of one hub to the centre of the next (V to V).
Transfer the "actual" measurements to the cover layout pattern and make the cover from that. If you use a fabric tape measure (rather than a rigid one) it will conform perfectly to the shape of the hubs (flat topped) very much like the actual covering fabric will when it`s fitted.
Your patterns look very complicated. I have simplified the sewing pattern for domes so as to only use two shapes and as few seams as possible creating Threadform's signature detachable roof panel.