Summary

Dummy Clerget 9B engine in 1:5 scale. Originally designed in a smaller scale then enlarged to 1:5 and modified slightly to improve a couple of minor issues. The finished model was printed on a Creality Ender 3 without supports and with only a skirt - no brim or raft. The inlet tubes were printed with the backs up and with supports and raft turned on but with the support overhang angle set to 80 degrees to minimise the amount of support.

Valve rockers have holes to allow the insertion of 16swg piano wire (or 1.5mm carbon fibre) pushrods. Three cylinders have through holes for fixing the motor to stand offs, although there is interference with the inlet tubes to these cylinders. This is why one of the inlet tube stl files has a large cutout in it. Print 6 normal tubes and three with the cutouts.

The joining ring is glued into the front half of the engine prior to assembly and ensures good alignment of the two halves.

The motor is a bit porky. All-up weight with piano wire pushrods is 146 grams (5.2 ounces). However, most WW1 models end up tail heavy so a bit of extra weight up front never goes amiss. Scale detail trumps a lump of lead every time.