Axial Compressor (not very effective)

thingiverse

Who hasn't wanted to build their own jet engine? It turns out to be harder than it first looks ;-) This attempt at an axial compressor requires a lego axle, and a motor to drive it. A lego power functions motor is sufficient to create a slight breeze from this. I've tried driving it with a power drill at 2600rpm. This created sufficient output pressure to inflate a balloon to the point that the rubber started to resist, IE hardly any pressure, much less than you can blow. Unfortunately 2600rpm creates enough internal friction to partly melt and fuse the components when they stop, so I don't recommend it. So why am I publishing this? Well, it works a little bit. Maybe someone can suggest improvements. And I think it's still quite cool. The scad source is available on github, if anyone wants to have a go. The compressor has 6 rotor and 6 stator elements, each of which attempts a 10% compression (way too optimistic!). The stator elements snap tightly into the case, the rotor elements rotate freely between them. A lego axle runs down the central axis. If you intend printing this, I've attached axlex.stl and axle_hole.stl as test components for testing the axle fit. Print Settings Supports: No Notes: I printed this in PLA filament. Most components can be printed straight to the bed, but I recommend a raft for the case. Post-Printing Preparation The lego axle has to be able to rotate freely through the stators. I wrapped sandpaper round a thin screwdriver to free them up. After a test assembly I also found that tiny differences between the stators caused friction on the axle, so a rolled up tube of sandpaper was used to even them out. The rotors have to be able to grip the axle, but slide along it when pushed. Smooth off any rough or catching edges. Assembly Start by inserting stator11 (the smallest one). Make sure it is fully and evenly cliped in. Place the axle through this. Now place rotor10 on the axle, and push it down to meet the stator. It should spin easily. Insert the next stator using the axle to guide it. This makes it easier than the first stator. Continue inserting rotors and stators alternately until complete.