Small Whirly copter with a spiral spinner stick

thingiverse

The STL's are scaled to a height of 150mm as that is the max for our printer. The copter is ~80mm diameter. It's small but we were making small toys to give away at a fund raiser carnival. Two sets with supports under the blades requires ~7m of 1.75mm filament. Also attached is OpenScad file adapted from seedwire's 'The Whirly One' http://www.thingiverse.com/thing:36217. It should be possible to change the turns per cm of the spin stick and the blade pitch/thickness/width. You can generate STL's from the scad file for many configurations. You can see a quick demo of it here: https://www.youtube.com/watch?v=lJM2tqc2pL4 Instructions We had a number of failed spin sticks when a single stick is printed. Because each layer of the spin stick is so small, my assumption was that the underlying layer did not sufficiently cool before the next layer was applied and eventually gravity caused a melted mass of goo. I was able to get a good print by slowing the print way down, or by printing 2 sticks-- the head moving to the other stick each layer seems to have been sufficient to avoid the mess. But beware, if the head knocks it over (big lever arm 6" in the air with a small base), then it will fail as well. Possibly printing only 2 spin sticks with a sufficient brim around each would provide highest yield. I'm still playing with it. If you want to print everything at once, you can use the full plate STL, but again, it must be done very slow, or arrange 2 plates such that the sticks are reasonably close to get the fastest print without melting messes. I had to use support structures for successful blades-- ours could not bridge the ~30mm. I'm still very new to 3D printing (1.5 weeks experience!) so I struggled to get enough support but not too much out of slic3r which is the only slicing tool I've learned to use thus far. I had good results by setting the angle to 60, and forcing for the first 10 layers and unclicking the 'Don't Support Bridges' checkbutton. I believe the blades could be greatly optimized. My first attempt was to take the defaults in seedwire's scad file and halve the dimensions while keeping some items like blade_thickness big enough. That first attempt had only 2 full revolutions along the stick and while it flew, it had very little lift. I increased the pitch and widened the blades and upped it to 3 full revolutions on the stick and it is 'ok' for a 25 cent carnival toy and I really have too many other things to spend my time on at this point as it is good enough for our purposes. But feel free to play with it and adapt the blade structure/dimensions, etc. I was really quite happy with how well it spun on the spiral, but I imagine there will be some limit to the number of twists that will still allow you to push the propeller up.