Foldable / Portable Quadcopter

This instructable mainly focuses on making a compact or foldable quadcopter frame which should fulfill following requirements.

• It should be easily folded or de-fold within a minute.
• Complete system includes quad-copter, battery,camera and transmitter must be fitted easily in a typical laptop bag.

Required material for frame:

• Balsa wood of 6mm and 8mm thickness is used for the quad-copter body.
• Balsa cutter
• CA glue and super glue
• Carbon rod (or equivalent steel rod) 20 cm long and 6 mm diameter.
• Hot glue and solder iron

This instructable is more focused on making the foldable frame instead of quadcopter electronic setup.

Above video shows, a quadcopter and transmitter is put inside a typical laptop bag and still lots of space available for extra equipment.

• As shown in the first image take a balsa wood piece of 11 cm *11 cm having a thickness around 8mm. Even 10mm would also work.
• As per the second image make a groove of width 2cm and up to half of depth of balsa wood thickness. Just leave the center of 3.5 cm square.
• Now as shown in the 4th image make grooves that have width same as carbon fiber rod.

• Make four pieces of carbon rod having the length of 3.5 cm of each.
• Make four arms and Note that all these arms have a different length. Two of them has length of two of them has length of 19cm and rest two has length of 21 cm.
• Now make slots to the one end of arms and stick carbon rod over there.
• Now secure all arms in that slot of base-plate with staple pins.and use CA glue to fix it permanently. Keep the same length of arms in opposite direction.(this would make folding of the arm with motor easy)

• Make a cross arrangement to lock that movement of the arm. make center part of it thicker for higher strength. This part of quadcopter would undergo maximum stress so batter to use thicker balsa wood for that.
• Take an M6 or M8 bolt and make a tight in the base plate of the same diameter and fix bolt to the base plate using super glue. Make the same hole in locking plate too.
• Now you can check locking mechanism is working properly and not interfering with anything.

Now you can fit motor but it is better to have some offset as shown in an image.

As it is not in a single line it won't block each other and fold in smallest space. (without propellers)

• Attach ESC with a little bit of care such that wire does not stretch while folding or de-folding.above image shows some extra fold of wire needed so that it can be easily folded.
• Use thin balsa strips (3*6mm) to make battery and control board mount as shown in a figure.

Connect ESCs to frame and attach ESC to your preferable control board. I am not going to detail for electronic setup as this is my first quadcopter and do not have more idea about a variety of stabilizer board. There are many instructable you can found with detailed description about electronic connection and setting everything up.

1. This quadcopter consists of lots of moving parts so higher chances of failure. So use good amount and good quality of adhesive and balsa.
2. It is batter to not try any aerobatic on this quadcopter (if you are not sure about strength) as it most probably to fails during Higher G stunts.
3. Most probable part that can fail:
   • Joint between carbon fiber to balsa arm,
   • Brushless DC motor base attachment (if propeller is unbalanced),