6 blade Fan Prop 30cm

thingiverse

This is 2Watt 800RPM push blower for my beer can Stirling engine. It´s pushing fair amount of air with silent operation. It would work with 3 or 4 blades, but with 6 its looking more respectable. Also spinner is more for looks than aerodynamics here. It is out from CH10SM airfoil data (slightly modified and high angle of attack for lower power and speeds). Time to share if someone finds a use for this - under 1000 RPM, low power and accelerations only. You can just imagine to fly with this - unfortunately design is no good for that and will be dissapointment with whatever material and engine. For general home use this fan is quite "directional" with efficient narrow air flow several meters away... Now I revealed you that this is really not optimized for doing anything useful. Take care. Instructions This is put into upwright position and shorted to fit all in one Huxley bed. I had problems with one part and I added some support holding it upright. It came out with 1 perimeter infill 20% with slow speed very light and quite easily blade will break. This more like a safety feature for my fingers. I increased for 2 perimeters in order to have material for some sanding and its much easier to solder parts togeather. Print the parts. -clean support -use temperature controlled soldering tip around 240°C for blade assembly. Just short touches from here and there - avoid heating too much. Good way is to put up temperature to 260-300°C to make things happen faster. If you think about painting a smooth surface on blades this is right moment to do sanding on blades before there is no other things attached on them. I find out that VERY coarse sanding paper actually works to PLA and after that you can go for a smoother one also water seems to work with sanding - plastic comes out of small particles like dust and no melting. My sanding tests are just with hand. Before attaching blades to their bases put them standing side by side on the table. This way you can easilly adjust the blade angles same level. Now its time to stop and think a second or two in what direction your are rotating and direction of air flow. Mine is pushing air. While making you mind its time to search M4 nut and even better a really a long one - I used 16mm long from some electronics parts. This is for attach axle and spinner from other end. On spinner I used piece of plastic M4 thread. I used epoxy AND some superglue AND soldering tip heat to attach all blades to hexagonal part in one go. (I just hate to make glueing jigs...). I have M4 threads in engine axle so I just turned propeller in place and attached spinner to finalize the look. Final checks for free rotation and ready to start engines. In the picture the prop is idling with prototype engine and help of tiny blue flame approx 600rpm already moving fair amount of air... I do not know the quality of STL´s, but these I used. Sorry no scad... original model is not totally perfect eighther... I´m not going to develop this prop any further - if I got new engine running I propably need to design a new prop for it. If someone really really need it better I might take a look for another formats. I have not stop wondering what this little machine can produce with some consentration and efforts.