Analysis of information sources in references of the Wikipedia article "Hot air balloon" in English language version.
perfect French Fell hot air balloon seam
2 Needle Double Lap Seaming Also called Felled Seam
The double lap seam features two rows of parallel stitching along the folded over fabric seam. A few manufactures use a flat seam.
Cylinders in liquid service are commonly found on forklifts.
Propane tanks used in hot air balloons are mainly constructed of either aluminum or stainless steel. Most aluminum tanks are vertical 10-gallon cylinders (DOT 4E240), built primarily for forklift trucks.
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: CS1 maint: unfit URL (link)all of the seams are the "French fell" type