The reasonable way would be to do the prototype with a 3D printer, create a mold and cast the metal. This wouldn’t work here either, but if you already have the CAD/CAM file you could just get it milled by a professional CNC outfit. If you’re not too cheap with the steel, it might not even kill you and still cost less than $1600. OTOH, if you can afford a helicopter that shouldn’t be an argument for you. Half an hour in the air will cost you more than that.