7 Cylinder Radial Engine Model

by plusalphaDesigns May 26, 2019
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What type of machine can someone use to make the engine work?

Printed this in four colors and it came out perfect! Thanks, everyone who sees it loves it and I'll be printing a few more. I sprayed it with silicone after putting it together and it all moves very nicely.
Printed on a Maker Gear M2, Head set to 210c, Bed set to 60c (plus Aquanet), .2 layer height and a 1 layer raft on everything, . Used Slic3r and Pronterface and Solutech filament.

Great model! For anyone having difficulties, I had to make two tiny alterations:
1) I expanded the holes in the piston rods with a 1/8" drill bit. The posts on the hub snap off very easily so it's better for them to go on easy.
2) I printed the pin at 104% scale since the default size did not have enough friction to hold everything together.

After printing this and showing it to people I've been informed that it's actually a rotary engine and that radial engines have a rotating crank case. I'd always referred to both of those as radial engines and thought of rotary engines as the pistonless designs like the Wankel engines used in the Mazda RX-7 and RX-8 but apparently this is actually a rotary engine as well.

Either way I love this design and my print turned out great, thanks for sharing this!


Only if you're holding the lever and spinning the crankcase. If you are holding the motor and spinning the lever, then it is a radial according to the link you provided.

The counter-balance to the hub gives it away as a rotary and not a radial.

I still think most people call either design a radial and I enjoy it either way. Just thought I'd share what I learned.

Thanks for posting this and some of the details. Can you provide more details? I just printed all of the parts over the weekend and the largest (longest print time of 14hrs) was the cylinder block. I did print with infill of 100% on my Ender 3 with the stock bed. I used Shiny Silver PLA at 205 Celsius with my bed at 60 Celsius. Some of the heads warped pretty bad for some reason. I usually get pretty good adhesion on most things. The pistons will not go through 3 of the cylinder block heads.
Can you describe the details of your print of the cylinder block? Thanks.

I had a lot of issues printing the cylinder head as well. Your print time sounds high though, mine took a lot less time than that on an Ender 3 Pro with .2 layer height and the Creawesome mod which is significantly slower than the default Cura settings, what else have you changed?

I'm convinced now that my bed being a little dusty was my main issue. I tried everything and finally tried printing with a brim instead of a skirt and it worked great, but then I couldn't separate the brim from the model. I tried printing it with a skirt again about 5 degrees cooler than I usually print and it finally worked.

I used SunLu PLA+ at 210 with the bed at 55. Normally I print at 215. Try printing with a skirt, adjust temps until you get the first several layers going down right but cancelling before you get too far into it. After that those spots on your bed will be much cleaner and it should print better with a skirt.

14 hour print time sounds very long to me.. Maybe you can drop down the infill so the part cools more evenly? I print with 15% infill and layer height 0.2mm. If that doesnt’t help maybe you can consider using rafts or brims. With that setting and raft, my print time was about 4 hours.