The sparrow is a small 3d printed plane design that is made to hit the sweet spot between what is small enough to be quickly 3d printed, but large enough to use standard electronics, like a brushless motor, ESC, and 9 gram servos. Because of this all of the parts are capable of fitting in an 8in cubed (the common size of many small and cheap 3d printers like the i3clones and ender3), even if you intend to print all the parts at once.

These parts are almost all made to print with one outer layer, and zero top and bottom layers. PLA is the recommended material, as the structure in the body and wing is meant to increase the strength of the design, and rely on an already relatively stiff material like PLA. Print your PLA nice and hot (at 215 C at least) and do not use a fan while you are printing, to help you print achieve great layer adhesion.

If you would like to skip setting up all parts with exactly the right settings, then a S3D factory file will be included in the downloads, as well as a stock G-code file that will work on direct drive extruder printers with a print volume of at least 200 millimeters cubed.

Parts that are meant to be printed with only 1 outer layer, and zero top and bottom layers, and 0% infill are:
-Left Wing
-Main Wing
-Right Wing
-Fuse 1
-Fuse 2
-Fuse 3
-Right Stab
-Left Stab

For the control surfaces I recommend that you print the parts with at least 5 top and bottom layers, so that the control linkage may be strengthened. The other setting should be 1 outer layer and no infill.

The control rod linkages and motor mount should be printed with at least 4 outer, top, and bottom layers and 50% infill.

There are winglets design for the main wing and stabilizer. If you don't wish to use the winglets for the main wing you may add a bottom layer to the left and right wing when you print them to avoid using these parts. For reasons of increased stability you should always use the winglets on the stabilizers.

Do not attempt to print and fly this plane if you are not an experienced RC builder, 3D printer, and are not willing to keep other peoples safety and the flying regulations in mind.