This engine mount is for making your Hobbyking Bixler 2 into a twin engined one. It has the bolt pattern for a normal 28mm outrunner motor.
The motor is 3 degrees downward, which will result in the motor being 0.5 degrees down due to the positive angle of incidence of the wing. I recommend printing it with 100% infill as it will make it stronger and will only add 2 grams compared to 40% infill. Rotate the part 3 degrees on the X axis in Repetier for it to sit flat on the printer bed. Mount the motor and glue it to the wing with CA.