We are a team of 12 individuals, interested in the field of aeronautics, applying that for the SAE Aero competition, taking place every year in USA.
For this instructable you need basic knowledge of:
Ansys: The anlaysis sofware, used to find out the tension a material can withstand before collapsing
NX: The software used to model the aircraft
Arduino: The Data Acquistion System is based on the arduino
Step 1: Modelling: Selection of Airfoil & Modelling the Plane in the Nx9 Software
To start with the plane i needed to:
1. Have a proper model of the plane on which analysis can be run and which can act as a refernce to the fabricating team.
2. Procure some materials that were essential to the building process so that no time is wasted after the airfoil is chosen.
I have used for the actual fabrication:
1) Balsa wood
2) Ply wood
3) Carbon Fibre Cloth
4) Carbon Fibre Rods
5) Monokote (To cover the ribs)
In the Electronics Department:
1) Arduino UNO
2) MS6507: Altimeter module
3) MPU6050: IMU module
4) Zigbee For Communication to ground station
5) A PCB for ease of connections and debugging
In the actual RC of the plane, controlling the plane movements:
1) Standard Servos (i used: Futaba s3003)
2) Transmitter Futaba (Futaba T7CA 2.4Ghz 7-Channel Radio)
3) Reciever (OrangeRx Futaba FASST Compatible 8Ch 2.4Ghz Receiver)
Step 2: Data Aqcuistion System
Now, for a normal RC plane you wouldnt require this, but i needed my plane to be able to tell me the heiht it was at as well as the orientation of it.
Simply connecting the Sensors to the Arduino would give you the values of Altimeter(Ms6507) and Orientation(MPU-6050).
The connections are given in the images.
The example codes are:
https://www.parallax.com/product/29124 (For the Altimeter)
http://www.i2cdevlib.com/devices/mpu6050 (For the IMU)
With the help of a ZigBee module, the telemetry from the sensors in the plane to the ground station was achieved.
Step 3: Fabrication
1) Procure Balsa Wood in the dimension you require: we used 20mm width balsa sticks.
Anything above the 10 mm mark is very difficult to be laser cut, which might cause it to burn the material, therefore only the Balsa sheets of 3mm, Ply wood of 4mm and the Jigs of 6mm (Acrylic) were laser cutted(This Jig went no where in the plane hence i didnt mention this before). Jigs are used to set the laser cut ribs into place and are specifically designed to hold the wing (i.e. the carbon rods and ribs) while the are being glued together, before the monokoting process.
Since balsa of that size cant be laser cut, we used the Dremil Sander in the video to sand/shave off the excess region. But since we had only one dremil the speed was slow and the rest of us resorted to hand shaving(using sanding paper)
After rounds of running the dremil over the wood, we made trailing edges and leading edges for both of our wings(size=1.69 meters/per wing)
2) Insert the Carbon rods into the holes of the laser cut ribs
3) Stick this with adhesive to ensure stability(We used standard resin and hardner)
Step 4: The Fuselage
The plan for the fuselage was to use rapid prototyping to make the body and then wrap a layer of carbon cloth over it to ensure its strength.
This will not only allow us to complete the process of making a fuselage without a mould, which would mean we can make any design as per ones requirement, but still ensure that the fabrication of the fuselage will only last a few more days than with the mould.
Step 5: Fly
After the rapid prototyping, the wings are attached onto the fuselage with the help of the indentations on the 3D Printed Fuselage and the protruding Carbon rods from the wing end.
The servos are tested and attached onto the wing between two ribs either using a stent made of ply or another laser cut piece of ply then stuck onto the ribs. Using control horns, clevices and cycle spokes, the ailerons are lifts and downs. using Y-Connectors in the fuselage and then attaching the Y connectors to the recievers channel for ailerons, the aielons are connected such that the movement of the left aileron is complimentry to the one of the right.
Like this the stabs and the throttle is connected onto the reciever.
Over this the ribs of the wing are mokoted (Plastic sheeting is ironed onto it) to generate te lift required to fly the plane.
Once all of this is tried and tested, you finally get to the good part that is flying the plane!!!