BatRay Experimental Airplane

My latest airplane fixation is on Barnaby Wainfan's underdevelopment FMX-7 BatRay. It is a two seat, tube-and-fabric construction, low aspect ratio aircraft and a progression on the ideas pioneered in his one seat facetmobile that first flew in 1993.

BatRay is designed to be quicker and cheaper to construct than a conventional aircraft without sacrificing performance, demonstrating that a low-aspect-ratio lifting body can match conventional aircraft in real world transport-efficiency. Barnaby's design advantages are: lower parts count, higher structural efficiency, and near-elliptical span loading. The result is a deeply stall-resistant flight character that virtually eliminates the stall/spin accidents too common amongst inexperienced pilots.

Print Settings

This is a challenging print, at least in PETG, because the tips of the nose and tail of the main body halves like to loose build plate adhesion and peel up a bit. This leads to gaps the nose and tail center seam when the two halves are snapped together. The Smooth PEI sheet can help to minimize this, but I haven't found a combination of settings that completely eliminates it.

• The main body of this plane prints prints in two halves at 0.15mm layer height with lightening infill and no supports.

• The propeller prints best with full supports and the finest layer height you're comfortable with.

• Print the windscreen on a textured plate and in a contrasting color

• The rest of the pieces print with default infill settings and no supports. I find the smooth build plate works best for these small parts and is fine for the other parts too.

Post Printing

• The brim around the tail needs carefully removed with a razor

• Weights in nose (at least 0.75oz, but ideally 1oz). I used square 1/4 oz steel pinewood derby weights, but anything with heave and that fits will do.

• Place each wheel in the gear side of their assembly, lightly wet the fairing side with thin superglue and press the fairing onto the landing hear to complete the fairings. The wheels sit freely within the fairings and will not fall out.

• Glue the main gear assembly and nose gear assembly into their respective locations with a small amount of superglue.

• Crease the windscreen along the score lines and glue it into the windscreen recess. 

This is an independently created model meant to represent Barnaby's experimental airplane created using publicly available pictures from Barnaby's substack page and Robert Hains' CNC build log. 

Additional thanks to Levi Sitts for his H-Snap Connector: 
https://www.printables.com/model/322309-h-snap-connector