Hello, Im an architecture student at pontificia Universidad Catolica de Chile. This is a project i did for a class using a cnc machine.

The great thing about this airplane is that you can switch the wing to a different one, even to a low wing by placing the battery on the top part of the fuselage. The plane is very small so its very easy to take it everywhere and by having the model on rhino you can replace the pieces if you brake them.

Step 1: Tools and Materials:

Electronics:

3 micro servos (Hitec HS-55)
speed controler (Thunder bird 9, 1.5 amp)
reciver (Spektrum AR6000)
motor ( Hacker, 2200 rpm/V)
Battery (Thunder Power, Li-Polymer 730 mAh/ 7.4V)
radio (Spektrum DX5e)

Materials:

3mm balsa wood (ailerons)
5mm cell foam (elevator and rudder)
3mm mdf (motor support)
25 mm high density styrofoam (fuselage and wings)
3mm carbon strip (wing structure)
1 mm wire (servo connection to the aile, rud, ele)
micro control horns
small nylon hinges
plastic propeller

Tools:

cutter
20 cm ruler
pencil
cutting board
Tape
epoxy glue
foam CA
sand paper (size 120)
masking tape
small milling machine (dremel, robust or similar)

Step 2: 3d Model

I made the model from a cessna 172 using plans i found on google.
Once the model was complete i separated it into segment so it would fit the cnc machine.
i made the pieces that fit a 20.3 x 15.2 x 3 cm box.
Save every piece in a different .stl file.

cessna 172 nuevo.3dm
Download

Step 3: Cnc Machine:

I imported the .stl files to modela player 4 to make the cnc traces for every piece.
Measure and cut every piece of styrofoam so the pieces fit inside.
Place the styrofam in the cnc base making sure that it is parallel.
Mark the center of the styrofoam box.
import the traces to the cnc and make sure that the center is aligned.
Repeat for every piece.

Note: this can take a lot of time so be pacient, in my case every piece was cut in aprox 1 hour.

Step 4: Wing:

Sand every piece so they are perfectly flat.
Add glue and join the pieces (I added some tape for extra strength)
Cut a strip along the wing to place the 3mm carbon strip, then glue.
Mark and cut the ailerons.
Make new ailerons with the balsa wood and with the small hinges attach them to the wing (you can also attach them with tape)
Glue the control horns in the ailerons and attach the pushrod system.
Glue the servo the servo and attach the pushrod system
Glue the 2 pieces together.

Note: The pushrod system can be a great help later in the process by helping to calibrate the aile, ele, rudd.

Step 5: Fuselage

Sand every piece so they are perfectly flat.
Mark with a pen the place where all the electronics are going to fit.
Cut with the milling machine and test if all the pieces fit inside.
I cut the lower piece in 3 segments to fit the battery and glue magnets so i can access it.

Note: The cut doesn´t have to be perfect, it will be corrected later in the process.

Step 6: Rudder and Elevator:

Print the elevator template from the model.
Cut the template in the 5mm foam.
Glue the carbon strips to the front to add strength.
Make a 45 degree cut in the back part (this will help them move easier).
Join the front and back part of the elevator using a hinge or tape.
glue the horn to the back part.
make a cut un the fuselage to fit the elevator and glue it parallel to the wing.
Reapeat the same process with the rudder.

Note: make sure the elevator and rudder are 90 degrees, if it's not it will not fly correctly.

Step 7: Electronics:

Glue de motor with the mdf and glue everything to the fuselage
Connect the speed controller to the motor
Place the servos according to the picture and attach them to the control rods.
Glue the receiver to the fuselage and connect servos, speed controller and battery.
Manage the cables so they fit in the fuselage.