@ rockpaperscissor - thanks for the comment
. Right, the paper rolls I make are virtually solid, unless I choose to put a wire inside. As you know, it is much easier to get a “solid” short paper roll than a long one. For a short roll (maybe up to an inch, or a bit more) I get a solid center from the start. A longer one tends to have a hole but, by rolling between the thumb and the forefinger, it gradually closes. It is interesting to note that the roll becomes tighter or looser depending on the direction you roll while applying pressure. The paper I use (ordinary 80g/m2) has marked orthotropic properties. If it rolls well on one direction, it will roll badly if you turn 90º…
The airscrew is so big that a quite particular solution had to be devised for the landing gear. I’ll get there. Each blade has a central cylinder, which has to be cut at an angle so that the blades join properly in the hub. I didn’t manage to make acceptable joints and ended up adding parts to cover the joints
